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Tourette syndrome (TS), or simply Tourette's, is a common
neurodevelopmental disorder Neurodevelopmental disorders are a group of mental conditions negatively affecting the development of the nervous system, which includes the brain and spinal cord. According to the American Psychiatric Association Diagnostic and Statistical Manu ...
that begins in childhood or adolescence. It is characterized by multiple movement (motor) tics and at least one vocal (phonic) tic. Common tics are blinking, coughing, throat clearing, sniffing, and facial movements. These are typically preceded by an unwanted urge or sensation in the affected muscles known as a premonitory urge, can sometimes be suppressed temporarily, and characteristically change in location, strength, and frequency. Tourette's is at the more severe end of a
spectrum A spectrum (: spectra or spectrums) is a set of related ideas, objects, or properties whose features overlap such that they blend to form a continuum. The word ''spectrum'' was first used scientifically in optics to describe the rainbow of co ...
of tic disorders. The tics often go unnoticed by casual observers. Tourette's was once regarded as a rare and bizarre
syndrome A syndrome is a set of medical signs and symptoms which are correlated with each other and often associated with a particular disease or disorder. The word derives from the Greek language, Greek σύνδρομον, meaning "concurrence". When a sy ...
and has popularly been associated with
coprolalia Coprolalia ( ) is involuntary swearing or the involuntary utterance of obscene words or socially inappropriate and derogatory remarks. The word comes from the Ancient Greek language, Greek (), meaning "dung, feces", and () "speech", from () "to ...
(the utterance of obscene words or socially inappropriate and derogatory remarks). It is no longer considered rare; about 1% of school-age children and adolescents are estimated to have Tourette's, though coprolalia occurs only in a minority. There are no specific tests for diagnosing Tourette's; it is not always correctly identified, because most cases are mild, and the severity of tics decreases for most children as they pass through adolescence. Therefore, many go undiagnosed or may never seek medical attention. Extreme Tourette's in adulthood, though sensationalized in the media, is rare, but for a small minority, severely debilitating tics can persist into adulthood. Tourette's does not affect intelligence or
life expectancy Human life expectancy is a statistical measure of the estimate of the average remaining years of life at a given age. The most commonly used measure is ''life expectancy at birth'' (LEB, or in demographic notation ''e''0, where '' ...
. There is no cure for Tourette's and no single most effective medication. In most cases, medication for tics is not necessary, and behavioral therapies are the first-line treatment. Education is an important part of any treatment plan, and explanation alone often provides sufficient reassurance that no other treatment is necessary. Other conditions, such as
attention deficit hyperactivity disorder Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterised by symptoms of inattention, hyperactivity, impulsivity, and emotional dysregulation that are excessive and pervasive, impairing in multiple con ...
(ADHD) and
obsessive–compulsive disorder Obsessive–compulsive disorder (OCD) is a mental disorder in which an individual has intrusive thoughts (an ''obsession'') and feels the need to perform certain routines (''Compulsive behavior, compulsions'') repeatedly to relieve the dis ...
(OCD), are more likely to be present among those who are referred to specialty clinics than they are among the broader population of persons with Tourette's. These co-occurring conditions often cause more impairment to the individual than the tics; hence it is important to correctly distinguish co-occurring conditions and treat them. Tourette syndrome was named by French
neurologist Neurology (from , "string, nerve" and the suffix -logia, "study of") is the branch of medicine dealing with the diagnosis and treatment of all categories of conditions and disease involving the nervous system, which comprises the brain, the ...
Jean-Martin Charcot for his intern, Georges Gilles de la Tourette, who published in 1885 an account of nine patients with a "convulsive tic disorder". While the exact cause is unknown, it is believed to involve a combination of genetic and environmental factors. The mechanism appears to involve dysfunction in neural circuits between the
basal ganglia The basal ganglia (BG) or basal nuclei are a group of subcortical Nucleus (neuroanatomy), nuclei found in the brains of vertebrates. In humans and other primates, differences exist, primarily in the division of the globus pallidus into externa ...
and related structures in the brain.


Classification

Most published research on Tourette syndrome originates in the United States; in international TS research and clinical practice, the ''
Diagnostic and Statistical Manual of Mental Disorders The ''Diagnostic and Statistical Manual of Mental Disorders'' (''DSM''; latest edition: ''DSM-5-TR'', published in March 2022) is a publication by the American Psychiatric Association (APA) for the classification of mental disorders using a com ...
'' (DSM) is preferred over the
World Health Organization The World Health Organization (WHO) is a list of specialized agencies of the United Nations, specialized agency of the United Nations which coordinates responses to international public health issues and emergencies. It is headquartered in Gen ...
(WHO) classification, which is criticized in the 2021 ''European Clinical Guidelines. In the fifth version of the DSM (
DSM-5 The ''Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition'' (DSM-5), is the 2013 update to the '' Diagnostic and Statistical Manual of Mental Disorders'', the taxonomic and diagnostic tool published by the American Psychiat ...
), published in 2013, Tourette syndrome is classified as a motor disorder (a disorder of the
nervous system In biology, the nervous system is the complex system, highly complex part of an animal that coordinates its behavior, actions and sense, sensory information by transmitting action potential, signals to and from different parts of its body. Th ...
that causes abnormal and involuntary movements). It is listed in the
neurodevelopmental disorder Neurodevelopmental disorders are a group of mental conditions negatively affecting the development of the nervous system, which includes the brain and spinal cord. According to the American Psychiatric Association Diagnostic and Statistical Manu ...
category. Tourette's is at the more severe end of the
spectrum A spectrum (: spectra or spectrums) is a set of related ideas, objects, or properties whose features overlap such that they blend to form a continuum. The word ''spectrum'' was first used scientifically in optics to describe the rainbow of co ...
of tic disorders; its diagnosis requires multiple motor tics and at least one vocal tic to be present for more than a year. Tics are sudden, repetitive, nonrhythmic movements that involve discrete muscle groups, while vocal (phonic) tics involve laryngeal, pharyngeal, oral, nasal or respiratory muscles to produce sounds. The tics must not be explained by other medical conditions or substance use. Other tic disorders include persistent (chronic) motor or vocal tics, in which one type of tic (motor or vocal, but not both) has been present for more than a year; and provisional tic disorder, in which motor or vocal tics have been present for less than one year. The fifth edition of the DSM replaced what had been called ''transient tic disorder'' with ''provisional tic disorder'', recognizing that "transient" can only be defined in retrospect. Some experts believe that TS and persistent (chronic) motor or vocal tic disorder should be considered the same condition, because vocal tics are also motor tics in the sense that they are muscular contractions of nasal or respiratory muscles. Tourette syndrome is defined only slightly differently by the WHO; in its
ICD-11 The ICD-11 is the eleventh revision of the International Classification of Diseases (ICD). It replaces the ICD-10 as the global standard for recording health information and causes of death. The ICD is developed and annually updated by the World H ...
, the International Statistical Classification of Diseases and Related Health Problems, Tourette syndrome is classified as a disease of the nervous system and a neurodevelopmental disorder, and only one motor tic and one or more vocal tics are required for diagnosis. Older versions of the ICD called it "combined vocal and multiple motor tic disorder e la Tourette. Genetic studies indicate that tic disorders cover a spectrum that is not recognized by the clear-cut distinctions in the current diagnostic framework. Since 2008, studies have suggested that Tourette's is not a unitary condition with a distinct mechanism, as described in the existing classification systems. Instead, the studies suggest that subtypes should be recognized to distinguish "pure TS" from TS that is accompanied by
attention deficit hyperactivity disorder Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterised by symptoms of inattention, hyperactivity, impulsivity, and emotional dysregulation that are excessive and pervasive, impairing in multiple con ...
(ADHD),
obsessive–compulsive disorder Obsessive–compulsive disorder (OCD) is a mental disorder in which an individual has intrusive thoughts (an ''obsession'') and feels the need to perform certain routines (''Compulsive behavior, compulsions'') repeatedly to relieve the dis ...
(OCD) or other disorders, similar to the way that subtypes have been established for other conditions, such as type 1 and
type 2 diabetes Type 2 diabetes (T2D), formerly known as adult-onset diabetes, is a form of diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent ...
. Elucidation of these subtypes awaits fuller understanding of the genetic and other causes of tic disorders.


Characteristics


Tics

Tics are movements or sounds that take place "intermittently and unpredictably out of a background of normal motor activity", having the appearance of "normal behaviors gone wrong". The tics associated with Tourette's wax and wane; they change in number, frequency, severity, anatomical location, and complexity; each person experiences a unique pattern of fluctuation in their severity and frequency. Tics may also occur in "bouts of bouts", which also vary among people. The variation in tic severity may occur over hours, days, or weeks. Tics may increase when someone is experiencing stress, fatigue, anxiety, or illness, or when engaged in relaxing activities like watching TV. They sometimes decrease when an individual is engrossed in or focused on an activity like playing a musical instrument. In contrast to the abnormal movements associated with other
movement disorder Movement disorders are clinical syndromes with either an excess of movement or a paucity of voluntary and involuntary movements, unrelated to weakness or spasticity. Movement disorders present with extrapyramidal symptoms and are caused by basa ...
s, the tics of Tourette's are nonrhythmic, often preceded by an unwanted urge, and temporarily suppressible. Over time, about 90% of individuals with Tourette's feel an urge preceding the tic, similar to the urge to sneeze or scratch an itch. The urges and sensations that precede the expression of a tic are referred to as premonitory sensory phenomena or premonitory urges. People describe the urge to express the tic as a buildup of tension, pressure, or energy which they ultimately choose consciously to release, as if they "had to do it" to relieve the sensation or until it feels "just right". The urge may cause a distressing sensation in the part of the body associated with the resulting tic; the tic is a response that relieves the urge in the anatomical location of the tic. Examples of this urge are the feeling of having something in one's throat, leading to a tic to clear one's throat, or a localized discomfort in the shoulders leading to shrugging the shoulders. The actual tic may be felt as relieving this tension or sensation, similar to scratching an itch or blinking to relieve an uncomfortable feeling in the eye. Some people with Tourette's may not be aware of the premonitory urge associated with tics. Children may be less aware of it than are adults, but their awareness tends to increase with maturity; by the age of ten, most children recognize the premonitory urge. Premonitory urges which precede the tic make suppression of the impending tic possible. Because of the urges that precede them, tics are described as semi-voluntary or "''unvoluntary''", rather than specifically ''involuntary''; they may be experienced as a ''voluntary'', suppressible response to the unwanted premonitory urge. The ability to suppress tics varies among individuals, and may be more developed in adults than children. People with tics are sometimes able to suppress them for limited periods of time, but doing so often results in tension or mental exhaustion. People with Tourette's may seek a secluded spot to release the suppressed urge, or there may be a marked increase in tics after a period of suppression at school or work. Children may suppress tics while in the doctor's office, so they may need to be observed when not aware of being watched. Complex tics related to speech include
coprolalia Coprolalia ( ) is involuntary swearing or the involuntary utterance of obscene words or socially inappropriate and derogatory remarks. The word comes from the Ancient Greek language, Greek (), meaning "dung, feces", and () "speech", from () "to ...
, echolalia and palilalia. Coprolalia is the spontaneous utterance of socially objectionable or taboo words or phrases. Although it is the most publicized symptom of Tourette's, only about 10% of people with Tourette's exhibit it, and it is not required for a diagnosis. Also see Echolalia (repeating the words of others) and palilalia (repeating one's own words) occur in a minority of cases. Complex motor tics include copropraxia ( obscene or forbidden gestures, or inappropriate touching), echopraxia (repetition or imitation of another person's actions) and palipraxia (repeating one's own movements).


Onset and progression

There is no typical case of Tourette syndrome, but the age of onset and the severity of symptoms follow a fairly reliable course. Although onset may occur anytime before eighteen years, the typical age of onset of tics is from five to seven, and is usually before adolescence. A 1998 study from the Yale Child Study Center showed that tic severity increased with age until it reached its highest point between ages eight and twelve. Severity declines steadily for most children as they pass through adolescence, when half to two-thirds of children see a dramatic decrease in tics. Citing In people with TS, the first tics to appear usually affect the head, face, and shoulders, and include blinking, facial movements, sniffing and throat clearing. Vocal tics often appear months or years after motor tics but can appear first. Among people who experience more severe tics, complex tics may develop, including "arm straightening, touching, tapping, jumping, hopping and twirling". There are different movements in contrasting disorders (for example, the
autism spectrum disorder Autism, also known as autism spectrum disorder (ASD), is a neurodevelopmental disorder characterized by differences or difficulties in social communication and interaction, a preference for predictability and routine, sensory processing di ...
s), such as self-stimulation and stereotypies. The severity of symptoms varies widely among people with Tourette's, and many cases may be undetected.Hollis C, Pennant M, Cuenca J, et al. (January 2016).
Clinical effectiveness and patient perspectives of different treatment strategies for tics in children and adolescents with Tourette syndrome: a systematic review and qualitative analysis
". ''Health Technology Assessment''. Southampton (UK): NIHR Journals Library. 20 (4): 1–450. . .
Most cases are mild and almost unnoticeable; many people with TS may not realize they have tics. Because tics are more commonly expressed in private, Tourette syndrome may go unrecognized, and casual observers might not notice tics. Most studies of TS involve males, who have a higher
prevalence In epidemiology, prevalence is the proportion of a particular population found to be affected by a medical condition (typically a disease or a risk factor such as smoking or seatbelt use) at a specific time. It is derived by comparing the number o ...
of TS than females, and gender-based differences are not well studied; a 2021 review suggested that the characteristics and progression for females, particularly in adulthood, may differ and better studies are needed. Most adults with TS have mild symptoms and do not seek medical attention. While tics subside for the majority after adolescence, some of the "most severe and debilitating forms of tic disorder are encountered" in adults. In some cases, what appear to be adult-onset tics can be childhood tics re-surfacing.


Co-occurring conditions

Because people with milder symptoms are unlikely to be referred to specialty clinics, studies of Tourette's have an inherent
bias Bias is a disproportionate weight ''in favor of'' or ''against'' an idea or thing, usually in a way that is inaccurate, closed-minded, prejudicial, or unfair. Biases can be innate or learned. People may develop biases for or against an individ ...
towards more severe cases. When symptoms are severe enough to warrant referral to clinics, ADHD and OCD are often also found. In specialty clinics, 30% of those with TS also have mood or
anxiety disorder Anxiety disorders are a group of mental disorders characterized by significant and uncontrollable feelings of anxiety and fear such that a person's social, occupational, and personal functions are significantly impaired. Anxiety may cause phys ...
s or disruptive behaviors. In the absence of ADHD, tic disorders do not appear to be associated with disruptive behavior or functional impairment, while impairment in school, family, or peer relations is greater in those who have more comorbid conditions. When ADHD is present along with tics, the occurrence of conduct disorder and oppositional defiant disorder increases. Aggressive behaviors and angry outbursts in people with TS are not well understood; they are not associated with severe tics, but are connected with the presence of ADHD. ADHD may also contribute to higher rates of anxiety, and aggression and anger control problems are more likely when both OCD and ADHD co-occur with Tourette's. Compulsions that resemble tics are present in some individuals with OCD; "tic-related OCD" is hypothesized to be a subgroup of OCD, distinguished from non-tic related OCD by the type and nature of obsessions and compulsions. Compared to the more typical compulsions of OCD without tics that relate to contamination, tic-related OCD presents with more "counting, aggressive thoughts, symmetry and touching" compulsions. Compulsions associated with OCD without tics are usually related to obsessions and anxiety, while those in tic-related OCD are more likely to be a response to a premonitory urge. There are increased rates of anxiety and depression in those adults with TS who also have OCD. Among individuals with TS studied in clinics, between 2.9% and 20% had autism spectrum disorders, but one study indicates that a high association of
autism Autism, also known as autism spectrum disorder (ASD), is a neurodevelopmental disorder characterized by differences or difficulties in social communication and interaction, a preference for predictability and routine, sensory processing d ...
and TS may be partly due to difficulties distinguishing between tics and tic-like behaviors or OCD symptoms seen in autistic people. Not all people with Tourette's have ADHD or OCD or other comorbid conditions, and estimates of the rate of pure TS or TS-only vary from 15% to 57%; in clinical populations, a high percentage of those under care do have ADHD. Children and adolescents with pure TS are not significantly different from their peers without TS on ratings of aggressive behaviors or conduct disorders, or on measures of social adaptation. Similarly, adults with pure TS do not appear to have the social difficulties present in those with TS plus ADHD. Among those with an older age of onset, more
substance abuse Substance misuse, also known as drug misuse or, in older vernacular, substance abuse, is the use of a drug in amounts or by methods that are harmful to the individual or others. It is a form of substance-related disorder, differing definition ...
and
mood disorder A mood disorder, also known as an affective disorder, is any of a group of conditions of mental and behavioral disorder where the main underlying characteristic is a disturbance in the person's mood. The classification is in the ''Diagnostic ...
s are found, and there may be self-injurious tics. Adults who have severe, often treatment-resistant tics are more likely to also have mood disorders and OCD. Coprolalia is more likely in people with severe tics plus multiple comorbid conditions.


Neuropsychological function

There are no major impairments in
neuropsychological Neuropsychology is a branch of psychology concerned with how a person's cognition and behavior are related to the brain and the rest of the nervous system. Professionals in this branch of psychology focus on how injuries or illnesses of the brai ...
function among people with Tourette's, but conditions that occur along with tics can cause variation in neurocognitive function. A better understanding of comorbid conditions is needed to untangle any neuropsychological differences between TS-only individuals and those with comorbid conditions. Only slight impairments are found in intellectual ability, attentional ability, and nonverbal memory—but ADHD, other comorbid disorders, or tic severity could account for these differences. In contrast with earlier findings, visual motor integration and visuoconstructive skills are not found to be impaired, while comorbid conditions may have a small effect on
motor skill A motor skill is a function that involves specific movements of the motor system, body's muscles to perform a certain task. These tasks could include walking, running, or riding a bike. In order to perform this skill, the body's nervous system, m ...
s. Comorbid conditions and severity of tics may account for variable results in verbal fluency, which can be slightly impaired. There might be slight impairment in social cognition, but not in the ability to plan or make decisions. Children with TS-only do not show cognitive deficits. They are faster than average for their age on timed tests of
motor coordination In physiology, motor coordination is the orchestrated movement of multiple body parts as required to accomplish intended actions, like walking. This coordination is achieved by adjusting kinematic and kinetic parameters associated with each bo ...
, and constant tic suppression may lead to an advantage in switching between tasks because of increased inhibitory control.
Learning disabilities Learning disability, learning disorder, or learning difficulty (British English) is a condition in the brain that causes difficulties comprehending or processing information and can be caused by several different factors. Given the "difficulty ...
may be present, but whether they are due to tics or comorbid conditions is controversial; older studies that reported higher rates of learning disability did not control well for the presence of comorbid conditions. There are often difficulties with handwriting, and disabilities in written expression and math are reported in those with TS plus other conditions.


Causes

The exact cause of Tourette's is unknown, but it is well established that both genetic and environmental factors are involved. Genetic epidemiology studies have shown that Tourette's is highly heritable, and 10 to 100 times more likely to be found among close family members than in the general population. The exact mode of inheritance is not known; no single gene has been identified, and hundreds of genes are likely involved. Genome-wide association studies were published in 2013 and 2015 in which no finding reached a threshold for significance; a 2019
meta-analysis Meta-analysis is a method of synthesis of quantitative data from multiple independent studies addressing a common research question. An important part of this method involves computing a combined effect size across all of the studies. As such, th ...
found only a single genome-wide significant locus on chromosome 13, but that result was not found in broader samples.
Twin studies Twin studies are studies conducted on Identical twin, identical or Fraternal twin, fraternal twins. They aim to reveal the importance of environmental and genetics, genetic influences for traits, phenotypes, and disorders. Twin research is consid ...
show that 50 to 77% of identical twins share a TS diagnosis, while only 10 to 23% of
fraternal twins Twins are two offspring produced by the same pregnancy.MedicineNet > Definition of Twin Last Editorial Review: 19 June 2000 Twins can be either ''monozygotic'' ('identical'), meaning that they develop from one zygote, which splits and forms two e ...
do. But not everyone who inherits the genetic vulnerability will show symptoms. A few rare highly penetrant genetic
mutations In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mitosi ...
have been found that explain only a small number of cases in single families (the '' SLITRK1, HDC'', and '' CNTNAP2'' genes). Psychosocial or other non-genetic factors—while not causing Tourette's—can affect the severity of TS in vulnerable individuals and influence the expression of the inherited genes. Pre-natal and peri-natal events increase the risk that a tic disorder or comorbid OCD will be expressed in those with the genetic vulnerability. These include paternal age; forceps delivery; stress or severe nausea during pregnancy; and use of
tobacco Tobacco is the common name of several plants in the genus '' Nicotiana'' of the family Solanaceae, and the general term for any product prepared from the cured leaves of these plants. More than 70 species of tobacco are known, but the ...
, caffeine,
alcohol Alcohol may refer to: Common uses * Alcohol (chemistry), a class of compounds * Ethanol, one of several alcohols, commonly known as alcohol in everyday life ** Alcohol (drug), intoxicant found in alcoholic beverages ** Alcoholic beverage, an alco ...
, and
cannabis ''Cannabis'' () is a genus of flowering plants in the family Cannabaceae that is widely accepted as being indigenous to and originating from the continent of Asia. However, the number of species is disputed, with as many as three species be ...
during pregnancy. Babies who are born premature with low birthweight, or who have low Apgar scores, are also at increased risk; in premature twins, the lower birthweight twin is more likely to develop TS. Autoimmune processes may affect the onset of tics or exacerbate them. Both OCD and tic disorders are hypothesized to arise in a subset of children as a result of a post- streptococcal autoimmune process. Its potential effect is described by the controversial hypothesis called PANDAS (pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections), which proposes five criteria for diagnosis in children. PANDAS and the newer pediatric acute-onset neuropsychiatric syndrome (PANS) hypotheses are the focus of clinical and laboratory research, but remain unproven. There is also a broader hypothesis that links immune-system abnormalities and immune dysregulation with TS. Some forms of OCD may be genetically linked to Tourette's, although the genetic factors in OCD with and without tics may differ. The genetic relationship of ADHD to Tourette syndrome, however, has not been fully established. A genetic link between autism and Tourette's has not been established as of 2017.


Mechanism

The exact mechanism affecting the inherited vulnerability to Tourette's is not well established. Tics are believed to result from dysfunction in cortical and subcortical brain regions: the
thalamus The thalamus (: thalami; from Greek language, Greek Wikt:θάλαμος, θάλαμος, "chamber") is a large mass of gray matter on the lateral wall of the third ventricle forming the wikt:dorsal, dorsal part of the diencephalon (a division of ...
,
basal ganglia The basal ganglia (BG) or basal nuclei are a group of subcortical Nucleus (neuroanatomy), nuclei found in the brains of vertebrates. In humans and other primates, differences exist, primarily in the division of the globus pallidus into externa ...
and frontal cortex. Neuroanatomic models suggest failures in circuits connecting the brain's cortex and subcortex; imaging techniques implicate the frontal cortex and basal ganglia. In the 2010s, neuroimaging and postmortem brain studies, as well as
animal Animals are multicellular, eukaryotic organisms in the Biology, biological Kingdom (biology), kingdom Animalia (). With few exceptions, animals heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, ...
and genetic studies, made progress towards better understanding the neurobiological mechanisms leading to Tourette's. These studies support the basal ganglia model, in which
neuron A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural net ...
s in the
striatum The striatum (: striata) or corpus striatum is a cluster of interconnected nuclei that make up the largest structure of the subcortical basal ganglia. The striatum is a critical component of the motor and reward systems; receives glutamat ...
are activated and inhibit outputs from the basal ganglia. Cortico-striato-thalamo-cortical (CSTC) circuits, or neural pathways, provide inputs to the basal ganglia from the cortex. These circuits connect the basal ganglia with other areas of the brain to transfer information that regulates planning and control of movements, behavior, decision-making, and learning. Behavior is regulated by cross-connections that "allow the integration of information" from these circuits. Involuntary movements may result from impairments in these CSTC circuits, including the sensorimotor, limbic,
language Language is a structured system of communication that consists of grammar and vocabulary. It is the primary means by which humans convey meaning, both in spoken and signed language, signed forms, and may also be conveyed through writing syste ...
and
decision making In psychology, decision-making (also spelled decision making and decisionmaking) is regarded as the cognitive process resulting in the selection of a belief or a course of action among several possible alternative options. It could be either ra ...
pathways. Abnormalities in these circuits may be responsible for tics and premonitory urges. The caudate nuclei may be smaller in subjects with tics compared to those without tics, supporting the hypothesis of pathology in CSTC circuits in Tourette's. The ability to suppress tics depends on brain circuits that "regulate response inhibition and cognitive control of motor behavior". Children with TS are found to have a larger
prefrontal cortex In mammalian brain anatomy, the prefrontal cortex (PFC) covers the front part of the frontal lobe of the cerebral cortex. It is the association cortex in the frontal lobe. The PFC contains the Brodmann areas BA8, BA9, BA10, BA11, BA12, ...
, which may be the result of an adaptation to help regulate tics. It is likely that tics decrease with age as the capacity of the frontal cortex increases. Cortico-basal ganglia (CBG) circuits may also be impaired, contributing to "sensory, limbic and executive" features. The release of
dopamine Dopamine (DA, a contraction of 3,4-dihydroxyphenethylamine) is a neuromodulatory molecule that plays several important roles in cells. It is an organic chemical of the catecholamine and phenethylamine families. It is an amine synthesized ...
in the basal ganglia is higher in people with Tourette's, implicating biochemical changes from "overactive and dysregulated dopaminergic transmissions".
Histamine Histamine is an organic nitrogenous compound involved in local immune responses communication, as well as regulating physiological functions in the gut and acting as a neurotransmitter for the brain, spinal cord, and uterus. Discovered in 19 ...
and the H3 receptor may play a role in the alterations of neural circuitry. A reduced level of histamine in the H3 receptor may result in an increase in other neurotransmitters, causing tics. Postmortem studies have also implicated "dysregulation of neuroinflammatory processes".


Diagnosis

According to the ''Diagnostic and Statistical Manual of Mental Disorders'' (DSM-5), Tourette's may be diagnosed when a person exhibits both multiple motor tics and one or more vocal tics over a period of one year. The motor and vocal tics need not be concurrent. The onset must have occurred before the age of 18 and cannot be attributed to the effects of another condition or substance (such as
cocaine Cocaine is a tropane alkaloid and central nervous system stimulant, derived primarily from the leaves of two South American coca plants, ''Erythroxylum coca'' and ''Erythroxylum novogranatense, E. novogranatense'', which are cultivated a ...
). Hence, other medical conditions that include tics or tic-like movements—for example,
autism Autism, also known as autism spectrum disorder (ASD), is a neurodevelopmental disorder characterized by differences or difficulties in social communication and interaction, a preference for predictability and routine, sensory processing d ...
or other causes of tics—must be ruled out. Patients referred for a tic disorder are assessed based on their family history of tics, vulnerability to ADHD, obsessive–compulsive symptoms, and a number of other chronic medical, psychiatric and neurological conditions. In individuals with a typical onset and a family history of tics or OCD, a basic physical and neurological examination may be sufficient. There are no specific medical or screening tests that can be used to diagnose Tourette's; the diagnosis is usually made based on observation of the individual's symptoms and family history, and after ruling out secondary causes of tic disorders ( tourettism). Delayed diagnosis often occurs because professionals mistakenly believe that TS is rare, always involves coprolalia, or must be severely impairing. The DSM has recognized since 2000 that many individuals with Tourette's do not have significant impairment; diagnosis does not require the presence of coprolalia or a comorbid condition, such as ADHD or OCD. Tourette's may be misdiagnosed because of the wide expression of severity, ranging from mild (in the majority of cases) or moderate, to severe (the rare but more widely recognized and publicized cases). About 20% of people with Tourette syndrome do not realize that they have tics. Tics that appear early in the course of TS are often confused with
allergies Allergies, also known as allergic diseases, are various conditions caused by hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include Allergic rhinitis, hay fever, Food allergy, food al ...
,
asthma Asthma is a common long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wh ...
, vision problems, and other conditions. Pediatricians, allergists and ophthalmologists are among the first to see or identify a child as having tics, although the majority of tics are first identified by the child's parents. Coughing, blinking, and tics that mimic unrelated conditions such as asthma are commonly misdiagnosed. In the UK, there is an average delay of three years between symptom onset and diagnosis.


Differential diagnosis

Tics that may appear to mimic those of Tourette's—but are associated with disorders other than Tourette's—are known as tourettism and are ruled out in the
differential diagnosis In healthcare, a differential diagnosis (DDx) is a method of analysis that distinguishes a particular disease or condition from others that present with similar clinical features. Differential diagnostic procedures are used by clinicians to di ...
for Tourette syndrome. The abnormal movements associated with choreas, dystonias, myoclonus, and dyskinesias are distinct from the tics of Tourette's in that they are more rhythmic, not suppressible, and not preceded by an unwanted urge. Developmental and
autism spectrum Autism, also known as autism spectrum disorder (ASD), is a neurodevelopmental disorder characterized by differences or difficulties in social communication and interaction, a preference for predictability and routine, sensory processing d ...
disorders may manifest tics, other stereotyped movements, and stereotypic movement disorder. The stereotyped movements associated with autism typically have an earlier age of onset; are more symmetrical, rhythmical and bilateral; and involve the extremities (for example, flapping the hands). If another condition might better explain the tics, tests may be done; for example, if there is diagnostic confusion between tics and
seizure A seizure is a sudden, brief disruption of brain activity caused by abnormal, excessive, or synchronous neuronal firing. Depending on the regions of the brain involved, seizures can lead to changes in movement, sensation, behavior, awareness, o ...
activity, an EEG may be ordered. An MRI can rule out brain abnormalities, but such brain imaging studies are not usually warranted. Measuring thyroid-stimulating hormone blood levels can rule out hypothyroidism, which can be a cause of tics. If there is a family history of
liver disease Liver disease, or hepatic disease, is any of many diseases of the liver. If long-lasting it is termed chronic liver disease. Although the diseases differ in detail, liver diseases often have features in common. Liver diseases File:Ground gla ...
, serum copper and ceruloplasmin levels can rule out Wilson's disease. The typical age of onset of TS is before adolescence. In teenagers and adults with an abrupt onset of tics and other behavioral symptoms, a urine drug screen for
stimulants Stimulants (also known as central nervous system stimulants, or psychostimulants, or colloquially as uppers) are a class of drugs that increase alertness. They are used for various purposes, such as enhancing attention, motivation, cognitio ...
might be requested. Increasing episodes of tic-like behavior among teenagers (predominantly adolescent girls) were reported in several countries during the
COVID-19 pandemic The COVID-19 pandemic (also known as the coronavirus pandemic and COVID pandemic), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), began with an disease outbreak, outbreak of COVID-19 in Wuhan, China, in December ...
. Researchers linked their occurrence to followers of certain
TikTok TikTok, known in mainland China and Hong Kong as Douyin (), is a social media and Short-form content, short-form online video platform owned by Chinese Internet company ByteDance. It hosts user-submitted videos, which may range in duration f ...
or
YouTube YouTube is an American social media and online video sharing platform owned by Google. YouTube was founded on February 14, 2005, by Steve Chen, Chad Hurley, and Jawed Karim who were three former employees of PayPal. Headquartered in ...
artists. Described in 2006 as '' psychogenic'', abrupt-onset movements resembling tics are referred to as a '' functional movement disorder'' or ''functional tic-like movements''. Functional tic-like movements can be difficult to distinguish from tics that have an organic (rather than psychological) cause. They may occur alone or co-exist in individuals with tic disorders. These tics are inconsistent with the classic tics of TS in several ways: the premonitory urge (present in 90% of those with tics disorders) is absent in functional tic-like movements; the suppressibility seen in tic disorders is lacking; there is no family or childhood history of tics and there is a female predominance in functional tics, with a later-than-typical age of first presentation; onset is more abrupt than typical with movements that are more suggestible; and there is less co-occurring OCD or ADHD and more co-occurring disorders. Functional tics are "not fully stereotypical", do not respond to medications, do not demonstrate the classic waxing and waning pattern of Tourettic tics, and do not progress in the typical fashion, in which tics often first appear in the face and gradually move to limbs. Other conditions that may manifest tics include Sydenham's chorea;
idiopathic An idiopathic disease is any disease with an unknown cause or mechanism of apparent spontaneous origin. For some medical conditions, one or more causes are somewhat understood, but in a certain percentage of people with the condition, the cause ...
dystonia; and genetic conditions such as
Huntington's disease Huntington's disease (HD), also known as Huntington's chorea, is an incurable neurodegenerative disease that is mostly Genetic disorder#Autosomal dominant, inherited. It typically presents as a triad of progressive psychiatric, cognitive, and ...
, neuroacanthocytosis, pantothenate kinase-associated neurodegeneration, Duchenne muscular dystrophy, Wilson's disease, and
tuberous sclerosis Tuberous sclerosis complex (TSC) is a rare multisystem autosomal dominant genetic disease that causes non-cancerous tumours to grow in the brain and on other vital organs such as the kidneys, heart, liver, eyes, lungs and skin. A combinatio ...
. Other possibilities include chromosomal disorders such as Down syndrome, Klinefelter syndrome, XYY syndrome and
fragile X syndrome Fragile X syndrome (FXS) is a genetic neurodevelopmental disorder. The average IQ in males with FXS is under 55, while affected females tend to be in the borderline to normal range, typically around 70–85. Physical features may include a lo ...
. Acquired causes of tics include drug-induced tics, head trauma,
encephalitis Encephalitis is inflammation of the Human brain, brain. The severity can be variable with symptoms including reduction or alteration in consciousness, aphasia, headache, fever, confusion, a stiff neck, and vomiting. Complications may include se ...
,
stroke Stroke is a medical condition in which poor cerebral circulation, blood flow to a part of the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemor ...
, and
carbon monoxide poisoning Carbon monoxide poisoning typically occurs from breathing in carbon monoxide (CO) at excessive levels. Symptoms are often described as " flu-like" and commonly include headache, dizziness, weakness, vomiting, chest pain, and confusion. Large ...
. The extreme self-injurious behaviors of Lesch-Nyhan syndrome may be confused with Tourette syndrome or stereotypies, but self-injury is rare in TS even in cases of violent tics. Most of these conditions are rarer than tic disorders and a thorough history and examination may be enough to rule them out without medical or screening tests.


Screening for other conditions

Although not all those with Tourette's have comorbid conditions, most presenting for clinical care exhibit symptoms of other conditions along with their tics. ADHD and OCD are the most common, but autism spectrum disorders or
anxiety Anxiety is an emotion characterised by an unpleasant state of inner wikt:turmoil, turmoil and includes feelings of dread over Anticipation, anticipated events. Anxiety is different from fear in that fear is defined as the emotional response ...
, mood,
personality Personality is any person's collection of interrelated behavioral, cognitive, and emotional patterns that comprise a person’s unique adjustment to life. These interrelated patterns are relatively stable, but can change over long time per ...
, oppositional defiant, and conduct disorders may also be present. Learning disabilities and sleep disorders may be present; higher rates of sleep disturbance and migraine than in the general population are reported. A thorough evaluation for comorbidity is called for when symptoms and impairment warrant, and careful assessment of people with TS includes comprehensive screening for these conditions. Comorbid conditions such as OCD and ADHD can be more impairing than tics, and cause greater impact on overall functioning. Disruptive behaviors, impaired functioning, or
cognitive Cognition is the "mental action or process of acquiring knowledge and understanding through thought, experience, and the senses". It encompasses all aspects of intellectual functions and processes such as: perception, attention, thought, ...
impairment in individuals with comorbid Tourette's and ADHD may be accounted for by the ADHD, highlighting the importance of identifying comorbid conditions. Children and adolescents with TS who have learning difficulties are candidates for psychoeducational testing, particularly if the child also has ADHD.


Management

There is no cure for Tourette's. There is no single most effective medication, and no one medication effectively treats all symptoms. Most medications prescribed for tics have not been approved for that use, and no medication is without the risk of significant
adverse effect An adverse effect is an undesired harmful effect resulting from a medication or other intervention, such as surgery. An adverse effect may be termed a "side effect", when judged to be secondary to a main or therapeutic effect. The term compli ...
s. Treatment is focused on identifying the most troubling or impairing symptoms and helping the individual manage them. Because comorbid conditions are often a larger source of impairment than tics, they are a priority in treatment. The management of Tourette's is individualized and involves shared decision-making between the clinician, patient, family and caregivers. Practice guidelines for the treatment of tics were published by the
American Academy of Neurology The American Academy of Neurology (AAN) is a professional society representing over 40,000 neurologists and neuroscientists. As a medical specialty society it was established in 1948 by A.B. Baker of the University of Minnesota to advance the a ...
in 2019. Education, reassurance and psychobehavioral therapy are often sufficient for the majority of cases. In particular, psychoeducation targeting the patient and their family and surrounding community is a key management strategy. Also see Zinner 2000, .
Watchful waiting Watchful waiting (also watch and wait or WAW) is an approach to a medical problem in which time is allowed to pass before medical intervention or therapy is used. During this time, repeated testing may be performed. Related terms include ''expe ...
"is an acceptable approach" for those who are not functionally impaired. Symptom management may include
behavioral Behavior (American English) or behaviour (British English) is the range of actions of individuals, organisms, systems or artificial entities in some environment. These systems can include other systems or organisms as well as the inanimate p ...
, psychological and
pharmacological Pharmacology is the science of drugs and medications, including a substance's origin, composition, pharmacokinetics, pharmacodynamics, therapeutic use, and toxicology. More specifically, it is the study of the interactions that occur between ...
therapies. Pharmacological intervention is reserved for more severe symptoms, while psychotherapy or
cognitive behavioral therapy Cognitive behavioral therapy (CBT) is a form of psychotherapy that aims to reduce symptoms of various mental health conditions, primarily depression, PTSD, and anxiety disorders. Cognitive behavioral therapy focuses on challenging and chang ...
(CBT) may ameliorate depression and
social isolation Social isolation is a state of complete or near-complete lack of contact between an individual and society. It differs from loneliness, which reflects temporary and involuntary lack of contact with other humans in the world. Social isolation c ...
, and improve family support. The decision to use behavioral or pharmacological treatment is "usually made after the educational and supportive interventions have been in place for a period of months, and it is clear that the tic symptoms are persistently severe and are themselves a source of impairment in terms of self-esteem, relationships with the family or peers, or school performance".


Psychoeducation and social support

Knowledge, education and understanding are uppermost in management plans for tic disorders, and psychoeducation is the first step. A child's parents are typically the first to notice their tics; they may feel worried, imagine that they are somehow responsible, or feel burdened by misinformation about Tourette's. Effectively educating parents about the diagnosis and providing
social support Social support is the perception and actuality that one is cared for, has assistance available from other people, and, most popularly, that one is part of a supportive social network. These supportive resources can be emotional (e.g., nurturance), ...
can ease their anxiety. This support can also lower the chance that their child will be unnecessarily medicated or experience an exacerbation of tics due to their parents' emotional state. People with Tourette's may suffer socially if their tics are viewed as "bizarre". If a child has disabling tics, or tics that interfere with social or academic functioning, supportive
psychotherapy Psychotherapy (also psychological therapy, talk therapy, or talking therapy) is the use of Psychology, psychological methods, particularly when based on regular Conversation, personal interaction, to help a person change behavior, increase hap ...
or school accommodations can be helpful. Even children with milder tics may be angry, depressed or have low self-esteem as a result of increased teasing, bullying, rejection by peers or social stigmatization, and this can lead to social withdrawal. Some children feel empowered by presenting a peer awareness program to their classmates. It can be helpful to educate teachers and school staff about typical tics, how they fluctuate during the day, how they impact the child, and how to distinguish tics from naughty behavior. By learning to identify tics, adults can refrain from asking or expecting a child to stop ticcing, because "tic suppression can be exhausting, unpleasant, and attention-demanding and can result in a subsequent rebound bout of tics". Adults with TS may withdraw socially to avoid stigmatization and discrimination because of their tics. Depending on their country's healthcare system, they may receive social services or help from support groups.


Behavioral

Behavioral therapies using
habit reversal training Habit reversal training (HRT) is a "multicomponent behavioral treatment package originally developed to address a wide variety of repetitive behavior disorders". Behavioral disorders treated with HRT include tics, trichotillomania, nail biting, ...
(HRT) and exposure and response prevention (ERP) are first-line interventions in the management of Tourette syndrome, and have been shown to be effective. Because tics are somewhat suppressible, when people with TS are aware of the premonitory urge that precedes a tic, they can be trained to develop a response to the urge that competes with the tic. Comprehensive behavioral intervention for tics (CBIT) is based on HRT, the best researched behavioral therapy for tics. TS experts debate whether increasing a child's awareness of tics with HRT/CBIT (as opposed to ignoring tics) can lead to more tics later in life. When disruptive behaviors related to comorbid conditions exist, anger control training and parent management training can be effective. CBT is a useful treatment when OCD is present.
Relaxation technique A relaxation technique (also known as relaxation training) is any method, process, procedure, or activity that helps a person to relax; attain a state of increased calmness; or otherwise reduce levels of pain, anxiety, stress or anger. Relaxat ...
s, such as exercise, yoga and meditation may be useful in relieving the stress that can aggravate tics. Beyond HRT, the majority of behavioral interventions for Tourette's (for example, relaxation training and
biofeedback Biofeedback is the technique of gaining greater awareness of many physiology, physiological functions of one's own body by using Electronics, electronic or other instruments, and with a goal of being able to Manipulation (psychology), manipulate ...
) have not been systematically evaluated and are not empirically supported.


Medication

Children with tics typically present when their tics are most severe, but because the condition waxes and wanes, medication is not started immediately or changed often. Tics may subside with education, reassurance and a supportive environment. When medication is used, the goal is not to eliminate symptoms. Instead, the lowest dose that manages symptoms without adverse effects is used, because adverse effects may be more disturbing than the symptoms being treated with medication. The classes of medication with proven efficacy in treating tics— typical and atypical neuroleptics—can have long-term and short-term adverse effects. Some antihypertensive agents are also used to treat tics; studies show variable efficacy but a lower side effect profile than the neuroleptics. The antihypertensives clonidine and guanfacine are typically tried first in children; they can also help with ADHD symptoms, but there is less evidence that they are effective for adults. The neuroleptics
risperidone Risperidone, sold under the brand name Risperdal among others, is an atypical antipsychotic used to treat schizophrenia and bipolar disorder, as well as aggressive and self-injurious behaviors associated with autism spectrum disorder. It is t ...
and aripiprazole are tried when antihypertensives are not effective, and are generally tried first for adults. Because of lower side effects, aripiprazole is preferred over other antipsychotics. The most effective medication for tics is haloperidol, but it has a higher risk of side effects.
Methylphenidate Methylphenidate, sold under the brand names Ritalin ( ) and Concerta ( ) among others, is a central nervous system (CNS) stimulant used in the treatment of attention deficit hyperactivity disorder (ADHD) and narcolepsy. It may be taken Oral adm ...
can be used to treat ADHD that co-occurs with tics, and can be used in combination with clonidine. Selective serotonin reuptake inhibitors are used to manage anxiety and OCD.


Other

Complementary and alternative medicine approaches, such as dietary modification, neurofeedback and allergy testing and control have popular appeal, but they have no proven benefit in the management of Tourette syndrome. Despite this lack of evidence, up to two-thirds of parents, caregivers and individuals with TS use dietary approaches and alternative treatments and do not always inform their physicians. There is low confidence that tics are reduced with
tetrahydrocannabinol Tetrahydrocannabinol (THC) is a cannabinoid found in cannabis. It is the principal psychoactive constituent of ''Cannabis'' and one of at least 113 total cannabinoids identified on the plant. Although the chemical formula for THC (C21H30O2) de ...
, and insufficient evidence for other
cannabis ''Cannabis'' () is a genus of flowering plants in the family Cannabaceae that is widely accepted as being indigenous to and originating from the continent of Asia. However, the number of species is disputed, with as many as three species be ...
-based medications in the treatment of Tourette's. There is no good evidence supporting the use of
acupuncture Acupuncture is a form of alternative medicine and a component of traditional Chinese medicine (TCM) in which thin needles are inserted into the body. Acupuncture is a pseudoscience; the theories and practices of TCM are not based on scientif ...
or
transcranial magnetic stimulation Transcranial magnetic stimulation (TMS) is a noninvasive neurostimulation technique in which a changing magnetic field is used to induce an electric current in a targeted area of the brain through electromagnetic induction. A device called a st ...
; neither is there evidence supporting
intravenous immunoglobulin Immunoglobulin therapy is the use of a mixture of antibodies (normal human immunoglobulin) to treat several health conditions. These conditions include primary immunodeficiency, immune thrombocytopenic purpura, chronic inflammatory demyelinat ...
, plasma exchange, or antibiotics for the treatment of PANDAS. Deep brain stimulation (DBS) has become a valid option for individuals with severe symptoms that do not respond to conventional therapy and management, although it is an experimental treatment. Selecting candidates who may benefit from DBS is challenging, and the appropriate lower age range for surgery is unclear; it is potentially useful in less than 3% of individuals. The ideal brain location to target has not been identified as of 2019.


Pregnancy

A quarter of women report that their tics increase before
menstruation Menstruation (also known as a period, among other colloquial terms) is the regular discharge of blood and Mucous membrane, mucosal tissue from the endometrium, inner lining of the uterus through the vagina. The menstrual cycle is characterized ...
; however, studies have not shown consistent evidence of a change in frequency or severity of tics related to pregnancy or hormonal levels. Overall, symptoms in women respond better to haloperidol than they do for men. Most women find they can withdraw from medication during pregnancy without much trouble. When needed, medications are used at the lowest doses possible. During pregnancy, neuroleptic medications are avoided when possible because of the risk of pregnancy complications. When needed, olanzapine,
risperidone Risperidone, sold under the brand name Risperdal among others, is an atypical antipsychotic used to treat schizophrenia and bipolar disorder, as well as aggressive and self-injurious behaviors associated with autism spectrum disorder. It is t ...
and quetiapine are most often used as they have not been shown to cause fetal abnormalities. One report found that haloperidol could be used during pregnancy, to minimize the side effects in the mother, including low blood pressure, and
anticholinergic Anticholinergics (anticholinergic agents) are substances that block the action of the acetylcholine (ACh) neurotransmitter at synapses in the central nervous system, central and peripheral nervous system. These agents inhibit the parasympatheti ...
effects, although it may cross the
placenta The placenta (: placentas or placentae) is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation. It plays critical roles in facilitating nutrient, gas, and waste exchange between ...
. If severe tics might interfere with administration of local anesthesia, other anesthesia options are considered. Neuroleptics in low doses may not affect the breastfed infant, but most medications are avoided. Clonidine and amphetamines may be present in breast milk.


Prognosis

Tourette syndrome is a spectrum disorder—its severity ranges from mild to severe. Symptoms typically subside as children pass through adolescence. In a group of ten children at the average age of highest tic severity (around ten or eleven), almost four will see complete remission by adulthood. Another four will have minimal or mild tics in adulthood, but not complete remission. The remaining two will have moderate or severe tics as adults, but only rarely will their symptoms in adulthood be more severe than in childhood. Regardless of symptom severity, individuals with Tourette's have a normal life span. Symptoms may be lifelong and chronic for some, but the condition is not degenerative or life-threatening.
Intelligence Intelligence has been defined in many ways: the capacity for abstraction, logic, understanding, self-awareness, learning, emotional knowledge, reasoning, planning, creativity, critical thinking, and problem-solving. It can be described as t ...
among those with pure TS follows a normal curve, although there may be small differences in intelligence in those with comorbid conditions. The severity of tics early in life does not predict their severity in later life. There is no reliable means of predicting the course of symptoms for a particular individual, but the
prognosis Prognosis ( Greek: πρόγνωσις "fore-knowing, foreseeing"; : prognoses) is a medical term for predicting the likelihood or expected development of a disease, including whether the signs and symptoms will improve or worsen (and how quickly) ...
is generally favorable. By the age of fourteen to sixteen, when the highest tic severity has typically passed, a more reliable prognosis might be made. Tics may be at their highest severity when they are diagnosed, and often improve as an individual's family and friends come to better understand the condition. Studies report that almost eight out of ten children with Tourette's experience a reduction in the severity of their tics by adulthood, and some adults who still have tics may not be aware that they have them. A study that used video to record tics in adults found that nine out of ten adults still had tics, and half of the adults who considered themselves tic-free displayed evidence of mild tics.


Quality of life

People with Tourette's are affected by the consequences of tics and by the efforts to suppress them. Head and eye tics can interfere with reading or lead to headaches, and forceful tics can lead to repetitive strain injury. Severe tics can lead to pain or injuries; as an example, a rare cervical disc herniation was reported from a neck tic. Some people may learn to camouflage socially inappropriate tics or channel the energy of their tics into a functional endeavor. A supportive family and environment generally give those with Tourette's the skills to manage the disorder. Outcomes in adulthood are associated more with the perceived significance of having tics as a child than with the actual severity of the tics. A person who was misunderstood, punished or teased at home or at school is likely to fare worse than a child who enjoyed an understanding environment. The long-lasting effects of bullying and teasing can influence self-esteem, self-confidence, and even employment choices and opportunities. Comorbid ADHD can severely affect the child's well-being in all realms, and extend into adulthood. Factors impacting
quality of life Quality of life (QOL) is defined by the World Health Organization as "an individual's perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards ...
change over time, given the natural fluctuating course of tic disorders, the development of
coping Coping refers to conscious or unconscious strategies used to reduce and manage unpleasant emotions. Coping strategies can be cognitions or behaviors and can be individual or social. To cope is to deal with struggles and difficulties in life. It ...
strategies, and a person's age. As ADHD symptoms improve with maturity, adults report less negative impact in their occupational lives than do children in their educational lives. Tics have a greater impact on adults' psychosocial function, including financial burdens, than they do on children. Adults are more likely to report a reduced quality of life due to depression or anxiety; depression contributes a greater burden than tics to adults' quality of life compared to children. As coping strategies become more effective with age, the impact of OCD symptoms seems to diminish.


Epidemiology

Tourette syndrome is a common but underdiagnosed condition that reaches across all social, racial and ethnic groups. It is three to four times more frequent in males than in females. Observed
prevalence In epidemiology, prevalence is the proportion of a particular population found to be affected by a medical condition (typically a disease or a risk factor such as smoking or seatbelt use) at a specific time. It is derived by comparing the number o ...
rates are higher among children than adults because tics tend to remit or subside with maturity and a diagnosis may no longer be warranted for many adults. Up to 1% of the overall population experiences tic disorders, including chronic tics and transient (provisional or unspecified) tics in childhood. Chronic tics affect 5% of children and transient tics affect up to 20%. Many individuals with tics do not know they have tics, or do not seek a diagnosis, so epidemiological studies of TS "reflect a strong
ascertainment bias In statistics, sampling bias is a bias (statistics), bias in which a sample is collected in such a way that some members of the intended statistical population, population have a lower or higher sampling probability than others. It results in a b ...
" towards those with co-occurring conditions. The reported prevalence of TS varies "according to the source, age, and sex of the sample; the ascertainment procedures; and diagnostic system", with a range reported between 0.15% and 3.0% for children and adolescents. Sukhodolsky, et al. wrote in 2017 that the best estimate of TS prevalence in children was 1.4%. Both Robertson and Stern state that the prevalence in children is 1%. The prevalence of TS in the general population is estimated as 0.3% to 1.0%. According to turn of the century census data, these prevalence estimates translated to half a million children in the US with TS and half a million people in the UK with TS, although symptoms in many older individuals would be almost unrecognizable. Tourette syndrome was once thought to be rare: in 1972, the US
National Institutes of Health The National Institutes of Health (NIH) is the primary agency of the United States government responsible for biomedical and public health research. It was founded in 1887 and is part of the United States Department of Health and Human Service ...
(NIH) believed there were fewer than 100 cases in the United States, and a 1973 registry reported only 485 cases worldwide. However, numerous studies published since 2000 have consistently demonstrated that the prevalence is much higher. Recognizing that tics may often be undiagnosed and hard to detect, newer studies use direct classroom observation and multiple informants (parents, teachers and trained observers), and therefore record more cases than older studies. As the diagnostic threshold and assessment methodology have moved towards recognition of milder cases, the estimated prevalence has increased. Because of the high male prevalence of TS, there is limited data on females from which conclusion about gender-based differences can be drawn; caution may be warranted in extending conclusions to females regarding the characteristics and treatment of tics based on studies of mostly males. A 2021 review stated that females may see a later peak than males in symptoms, with less remission over time, along with a higher prevalence of anxiety and mood disorders.


History

A French doctor, Jean Marc Gaspard Itard, reported the first case of Tourette syndrome in 1825, describing the Marquise de Dampierre, an important woman of nobility in her time. In 1884, Jean-Martin Charcot, an influential French physician, assigned his student and intern Georges Gilles de la Tourette, to study patients with movement disorders at the Salpêtrière Hospital, with the goal of defining a condition distinct from hysteria and chorea. In 1885, Gilles de la Tourette published an account in ''Study of a Nervous Affliction'' of nine people with "convulsive tic disorder", concluding that a new clinical category should be defined. The
eponym An eponym is a noun after which or for which someone or something is, or is believed to be, named. Adjectives derived from the word ''eponym'' include ''eponymous'' and ''eponymic''. Eponyms are commonly used for time periods, places, innovati ...
was bestowed by Charcot after and on behalf of Gilles de la Tourette, who later became Charcot's senior resident. Following the 19th-century descriptions, a psychogenic view prevailed and little progress was made in explaining or treating tics until well into the 20th century. The possibility that movement disorders, including Tourette syndrome, might have an organic origin was raised when an encephalitis lethargica epidemic from 1918 to 1926 was linked to an increase in tic disorders.Blue T (2002)
Tourette syndrome.
''Essortment,'' Pagewise Inc. Retrieved on August 10, 2009.
During the 1960s and 1970s, as the beneficial effects of haloperidol on tics became known, the psychoanalytic approach to Tourette syndrome was questioned. The turning point came in 1965, when Arthur K. Shapiro—described as "the father of modern tic disorder research"—used haloperidol to treat a person with Tourette's, and published a paper criticizing the psychoanalytic approach. In 1975, ''
The New York Times ''The New York Times'' (''NYT'') is an American daily newspaper based in New York City. ''The New York Times'' covers domestic, national, and international news, and publishes opinion pieces, investigative reports, and reviews. As one of ...
'' headlined an article with "Bizarre outbursts of Tourette's disease victims linked to chemical disorder in brain", and Shapiro said: "The bizarre symptoms of this illness are rivaled only by the bizarre treatments used to treat it." During the 1990s, a more neutral view of Tourette's emerged, in which a genetic predisposition is seen to interact with non-genetic and environmental factors. The fourth revision of the DSM ( DSM-IV) in 1994 added a diagnostic requirement for "marked distress or significant impairment in social, occupational, or other important areas of functioning", which led to an outcry from TS experts and researchers, who noted that many people were not even aware they had TS, nor were they distressed by their tics; clinicians and researchers resorted to using the older criteria in research and practice. In 2000, the
American Psychiatric Association The American Psychiatric Association (APA) is the main professional organization of psychiatrists and trainee psychiatrists in the United States, and the largest psychiatric organization in the world. It has more than 39,200 members who are in ...
revised its diagnostic criteria in the fourth text revision of the DSM ( DSM-IV-TR) to remove the impairment requirement, recognizing that clinicians often see people who have Tourette's without distress or impairment.


Society and culture

Not everyone with Tourette's wants treatment or a cure, especially if that means they may lose something else in the process. The researchers Leckman and Cohen believe that there may be latent advantages associated with an individual's genetic vulnerability to developing Tourette syndrome that may have adaptive value, such as heightened awareness and increased attention to detail and surroundings. Accomplished musicians, athletes, public speakers and professionals from all walks of life are found among people with Tourette's. The athlete Tim Howard, described by the ''Chicago Tribune'' as the "rarest of creatures—an American soccer hero", and by the Tourette Syndrome Association as the "most notable individual with Tourette Syndrome around the world", says that his neurological makeup gave him an enhanced perception and an acute focus that contributed to his success on the field.
Samuel Johnson Samuel Johnson ( – 13 December 1784), often called Dr Johnson, was an English writer who made lasting contributions as a poet, playwright, essayist, moralist, literary critic, sermonist, biographer, editor, and lexicographer. The ''Oxford ...
is a historical figure who likely had Tourette syndrome, as evidenced by the writings of his friend
James Boswell James Boswell, 9th Laird of Auchinleck (; 29 October 1740 ( N.S.) – 19 May 1795), was a Scottish biographer, diarist, and lawyer, born in Edinburgh. He is best known for his biography of the English writer Samuel Johnson, '' Life of Samuel ...
. Johnson wrote '' A Dictionary of the English Language'' in 1747, and was a prolific writer, poet, and critic. There is little support for speculation that Mozart had Tourette's: Also see: Simkin, Benjamin. ''Medical and musical byways of Mozartiana.'' Fithian Press. 2001.
Review
, Retrieved on May 14, 2007.
the potentially coprolalic aspect of vocal tics is not transferred to writing, so Mozart's
scatological In medicine and biology, scatology or coprology is the study of faeces. Scatological studies allow one to determine a wide range of biological information about a creature, including its diet (nutrition), diet (and thus habitat (ecology), where ...
writings are not relevant; the composer's available medical history is not thorough; the side effects of other conditions may be misinterpreted; and "the evidence of motor tics in Mozart's life is doubtful". Likely portrayals of TS or tic disorders in fiction predating Gilles de la Tourette's work are "Mr. Pancks" in
Charles Dickens Charles John Huffam Dickens (; 7 February 1812 – 9 June 1870) was an English novelist, journalist, short story writer and Social criticism, social critic. He created some of literature's best-known fictional characters, and is regarded by ...
's '' Little Dorrit'' and "Nikolai Levin" in
Leo Tolstoy Count Lev Nikolayevich Tolstoy Tolstoy pronounced his first name as , which corresponds to the romanization ''Lyov''. () (; ,Throughout Tolstoy's whole life, his name was written as using Reforms of Russian orthography#The post-revolution re ...
's '' Anna Karenina''. The entertainment industry has been criticized for depicting those with Tourette syndrome as social misfits whose only tic is coprolalia, which has furthered the public's misunderstanding and stigmatization of those with Tourette's. The coprolalic symptoms of Tourette's are also fodder for radio and television talk shows in the US and for the British media. High-profile media coverage focuses on treatments that do not have established safety or efficacy, such as deep brain stimulation, and alternative therapies involving unstudied efficacy and side effects are pursued by many parents.


Research directions

Research since 1999 has advanced knowledge of Tourette's in the areas of genetics,
neuroimaging Neuroimaging is the use of quantitative (computational) techniques to study the neuroanatomy, structure and function of the central nervous system, developed as an objective way of scientifically studying the healthy human brain in a non-invasive ...
,
neurophysiology Neurophysiology is a branch of physiology and neuroscience concerned with the functions of the nervous system and their mechanisms. The term ''neurophysiology'' originates from the Greek word ''νεῦρον'' ("nerve") and ''physiology'' (whic ...
, and neuropathology, but questions remain about how best to classify it and how closely it is related to other movement or psychiatric disorders. Modeled after genetic breakthroughs seen with large-scale efforts in other neurodevelopmental disorders, three groups are collaborating in research of the genetics of Tourette's: *The Tourette Syndrome Association International Consortium for Genetics (TSAICG) *Tourette International Collaborative Genetics Study (TIC Genetics) *European Multicentre Tics in Children Studies (EMTICS) Compared to the progress made in
gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
discovery in certain neurodevelopmental or mental health disorders—autism,
schizophrenia Schizophrenia () is a mental disorder characterized variously by hallucinations (typically, Auditory hallucination#Schizophrenia, hearing voices), delusions, thought disorder, disorganized thinking and behavior, and Reduced affect display, f ...
and
bipolar disorder Bipolar disorder (BD), previously known as manic depression, is a mental disorder characterized by periods of Depression (mood), depression and periods of abnormally elevated Mood (psychology), mood that each last from days to weeks, and in ...
—the scale of related TS research is lagging in the United States due to funding.


Notes


References


Book sources

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Further reading

* {{Authority control Articles containing video clips Mental disorders diagnosed in childhood Neurogenetic disorders