Poverty And Mental Health
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A
mental disorder A mental disorder, also referred to as a mental illness or psychiatric disorder, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. Such features may be persistent, relapsing and remitti ...
is an impairment of the mind disrupting normal thinking, feeling, mood, behavior, or
social interactions A social relation or also described as a social interaction or social experience is the fundamental unit of analysis within the social sciences, and describes any voluntary or involuntary interpersonal relationship between two or more individuals ...
, and accompanied by significant distress or dysfunction. The causes of mental disorders are very complex and vary depending on the particular disorder and the individual. Although the causes of most mental disorders are not fully understood, researchers have identified a variety of biological, psychological, and environmental factors that can contribute to the development or progression of mental disorders. Most mental disorders result in a combination of several different factors rather than just a single factor.


Research results

Risk factors for mental illness include psychological trauma, adverse childhood experiences, genetic predisposition, and personality traits. Correlations of mental disorders with drug use include almost all psychoactive substances, e.g.,
cannabis ''Cannabis'' () is a genus of flowering plants in the family Cannabaceae. The number of species within the genus is disputed. Three species may be recognized: ''Cannabis sativa'', '' C. indica'', and '' C. ruderalis''. Alternatively ...
,
alcohol Alcohol most commonly refers to: * Alcohol (chemistry), an organic compound in which a hydroxyl group is bound to a carbon atom * Alcohol (drug), an intoxicant found in alcoholic drinks Alcohol may also refer to: Chemicals * Ethanol, one of sev ...
, and
caffeine Caffeine is a central nervous system (CNS) stimulant of the methylxanthine class. It is mainly used recreationally as a cognitive enhancer, increasing alertness and attentional performance. Caffeine acts by blocking binding of adenosine t ...
. Mental illnesses have risk factors, for instance including unequal parental treatment, adverse life events and drug use in depression, migration and discrimination, childhood trauma, loss or separation in families, and cannabis use in
schizophrenia Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social withdra ...
and
psychosis Psychosis is a condition of the mind that results in difficulties determining what is real and what is not real. Symptoms may include delusions and hallucinations, among other features. Additional symptoms are incoherent speech and behavior ...
, and parenting factors, child abuse, family history (e.g. of anxiety), and temperament and attitudes (e.g. pessimism) in
anxiety Anxiety is an emotion which is characterized by an unpleasant state of inner turmoil and includes feelings of dread over anticipated events. Anxiety is different than fear in that the former is defined as the anticipation of a future threat wh ...
. Many psychiatric disorders include problems with impulse and other emotional control. In February 2013, a study found genetic links between five major psychiatric disorders:
autism The autism spectrum, often referred to as just autism or in the context of a professional diagnosis autism spectrum disorder (ASD) or autism spectrum condition (ASC), is a neurodevelopmental condition (or conditions) characterized by difficulti ...
,
ADHD Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterised by excessive amounts of inattention, hyperactivity, and impulsivity that are pervasive, impairing in multiple contexts, and otherwise age-inapp ...
,
bipolar disorder Bipolar disorder, previously known as manic depression, is a mental disorder characterized by periods of depression and periods of abnormally elevated mood that last from days to weeks each. If the elevated mood is severe or associated with ...
,
major depressive disorder Major depressive disorder (MDD), also known as clinical depression, is a mental disorder characterized by at least two weeks of pervasive low mood, low self-esteem, and loss of interest or pleasure in normally enjoyable activities. Introdu ...
, and
schizophrenia Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social withdra ...
. Abnormal functioning of
neurotransmitter A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a synapse. The cell receiving the signal, any main body part or target cell, may be another neuron, but could also be a gland or muscle cell. Neuro ...
systems is also responsible for some mental disorders, including serotonin, norepinephrine, dopamine, and glutamate system's abnormal functioning. Differences have also been found in the size or activity of specific brain regions in some cases. Psychological mechanisms have also been implicated, such as
cognitive Cognition refers to "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, ...
(e.g.
reasoning Reason is the capacity of consciously applying logic by drawing conclusions from new or existing information, with the aim of seeking the truth. It is closely associated with such characteristically human activities as philosophy, science, lang ...
) biases,
emotional Emotions are mental states brought on by neurophysiological changes, variously associated with thoughts, feelings, behavioral responses, and a degree of pleasure or displeasure. There is currently no scientific consensus on a definition. E ...
influences, personality dynamics,
temperament In psychology, temperament broadly refers to consistent individual differences in behavior that are biologically based and are relatively independent of learning, system of values and attitudes. Some researchers point to association of temperam ...
, and
coping Coping refers to conscious strategies used to reduce unpleasant emotions. Coping strategies can be cognitions or behaviours and can be individual or social. Theories of coping Hundreds of coping strategies have been proposed in an attempt to ...
style. Studies have indicated that variation in
genes In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
can play an important role in the evolution of mental disorders, although the reliable identification of connections between specific genes and specific disorders has proven more difficult. Environmental events surrounding
pregnancy Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occurs by sexual intercourse, but ca ...
(such as maternal
hypertension Hypertension (HTN or HT), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms. Long-term high bl ...
,
preeclampsia Pre-eclampsia is a disorder of pregnancy characterized by the onset of high blood pressure and often a significant amount of protein in the urine. When it arises, the condition begins after 20 weeks of pregnancy. In severe cases of the disease ...
, or infection) and
birth Birth is the act or process of bearing or bringing forth offspring, also referred to in technical contexts as parturition. In mammals, the process is initiated by hormones which cause the muscular walls of the uterus to contract, expelling the f ...
have also been implicated.
Traumatic brain injury A traumatic brain injury (TBI), also known as an intracranial injury, is an injury to the brain caused by an external force. TBI can be classified based on severity (ranging from mild traumatic brain injury TBI/concussionto severe traumatic b ...
may increase the risk of developing certain mental disorders. Throughout the years, there have been inconsistent links found to certain viral infections, substance misuse, and general physical health that have been false. Adverse experiences affect a person's
mental health Mental health encompasses emotional, psychological, and social well-being, influencing cognition, perception, and behavior. It likewise determines how an individual handles stress, interpersonal relationships, and decision-making. Mental health ...
, including
abuse Abuse is the improper usage or treatment of a thing, often to unfairly or improperly gain benefit. Abuse can come in many forms, such as: physical or verbal maltreatment, injury, assault, violation, rape, unjust practices, crimes, or other t ...
,
neglect In the context of caregiving, neglect is a form of abuse where the perpetrator, who is responsible for caring for someone who is unable to care for themselves, fails to do so. It can be a result of carelessness, indifference, or unwillingness and ...
,
bullying Bullying is the use of force, coercion, hurtful teasing or threat, to abuse, aggressively dominate or intimidate. The behavior is often repeated and habitual. One essential prerequisite is the perception (by the bully or by others) of an imba ...
,
social stress Social stress is stress that stems from one's relationships with others and from the social environment in general. Based on the appraisal theory of emotion, stress arises when a person evaluates a situation as personally relevant and perceives t ...
, traumatic events, and other overwhelming life experiences. The specific risks and pathways to particular disorders are less clear, however. Aspects of the wider community have also been implicated, including
employment Employment is a relationship between two parties regulating the provision of paid labour services. Usually based on a contract, one party, the employer, which might be a corporation, a not-for-profit organization, a co-operative, or any othe ...
problems,
socioeconomic Socioeconomics (also known as social economics) is the social science that studies how economic activity affects and is shaped by social processes. In general it analyzes how modern societies progress, stagnate, or regress because of their local ...
inequality Inequality may refer to: Economics * Attention inequality, unequal distribution of attention across users, groups of people, issues in etc. in attention economy * Economic inequality, difference in economic well-being between population groups * ...
, lack of social cohesion, problems linked to
migration Migration, migratory, or migrate may refer to: Human migration * Human migration, physical movement by humans from one region to another ** International migration, when peoples cross state boundaries and stay in the host state for some minimum le ...
, and features of particular
societies A society is a group of individuals involved in persistent social interaction, or a large social group sharing the same spatial or social territory, typically subject to the same political authority and dominant cultural expectations. Societi ...
and
cultures Culture () is an umbrella term which encompasses the social behavior, institutions, and norms found in human societies, as well as the knowledge, beliefs, arts, laws, customs, capabilities, and habits of the individuals in these groups.Tyl ...
. Mental stress is a common cause of mental illnesses, so finding a coping solution to cope with mental
stress Stress may refer to: Science and medicine * Stress (biology), an organism's response to a stressor such as an environmental condition * Stress (linguistics), relative emphasis or prominence given to a syllable in a word, or to a word in a phrase ...
would be beneficial. Many solutions that have helped reduce stress are yoga, exercise, and some medications that may help.


Theories


General theories

Several
theories A theory is a rational type of abstract thinking about a phenomenon, or the results of such thinking. The process of contemplative and rational thinking is often associated with such processes as observational study or research. Theories may be s ...
or
models A model is an informative representation of an object, person or system. The term originally denoted the plans of a building in late 16th-century English, and derived via French and Italian ultimately from Latin ''modulus'', a measure. Models c ...
seek to explain the causes (
etiology Etiology (pronounced ; alternatively: aetiology or ætiology) is the study of causation or origination. The word is derived from the Greek (''aitiología'') "giving a reason for" (, ''aitía'', "cause"); and ('' -logía''). More completely, e ...
) of
mental disorder A mental disorder, also referred to as a mental illness or psychiatric disorder, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. Such features may be persistent, relapsing and remitti ...
s. These theories may differ in regards to how they explain the cause of the disorder, how to treat the disorder, and how they classify mental disorders. Theories also differ about the
philosophy of mind Philosophy of mind is a branch of philosophy that studies the ontology and nature of the mind and its relationship with the body. The mind–body problem is a paradigmatic issue in philosophy of mind, although a number of other issues are addre ...
they accept; that is, whether the
mind The mind is the set of faculties responsible for all mental phenomena. Often the term is also identified with the phenomena themselves. These faculties include thought, imagination, memory, will, and sensation. They are responsible for various m ...
and
brain A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a v ...
are identical or not. During most of the 20th century, mental illness was ascribable to problematic relationships between children and their parents. This view was held well into the late 1990s, in which people still believed this child-parent relationship was a large determinant of severe mental illness, such as depression and schizophrenia. In the 21st century, additional factors have been identified such as genetic contributions, though experience also plays a role. So, the perceived causes of mental illness have changed over time and will most likely continue to alter while more research develops throughout the years. Outside the West, community approaches remain a focus. A practical mixture of models will explain particular issues and disorders, although there may be difficulty defining boundaries for indistinct psychiatric
syndromes 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 σύνδρομον, meaning "concurrence". When a syndrome is paire ...
.


Medical or biomedical model

An overall distinction is also commonly made between a "medical model" (also known as a biomedical or disease model) and a "social model" (also known as an empowerment or recovery model) of mental disorder and
disability Disability is the experience of any condition that makes it more difficult for a person to do certain activities or have equitable access within a given society. Disabilities may be Cognitive disability, cognitive, Developmental disability, dev ...
, with the former focusing on hypothesized disease processes and symptoms, along with latter focusing on hypothesized
social constructionism Social constructionism is a theory in sociology, social ontology, and communication theory which proposes that certain ideas about physical reality arise from collaborative consensus, instead of pure observation of said reality. The theory ...
and social contexts.
Biological psychiatry Biological psychiatry or biopsychiatry is an approach to psychiatry that aims to understand mental disorder in terms of the biological Biology is the scientific study of life. It is a natural science with a broad scope but has several uni ...
has tended to follow a
biomedical Biomedicine (also referred to as Western medicine, mainstream medicine or conventional medicine)
model focused on organic or "hardware" pathology of the brain, where many mental disorders are conceptualized as disorders of
brain circuits A neural circuit is a population of neurons interconnected by synapses to carry out a specific function when activated. Neural circuits interconnect to one another to form large scale brain networks. Biological neural networks have inspired the ...
shaped by a complex interplay of genetics and experience. The social and medical models of mental disorders each work to identify and study distinct aspects, solutions, and potential therapies of disorders. The intersection and cross reference between the two models can further be used to develop more holistic models of mental disorders. Many criticisms historically of each model is the exclusivity of the other perspective. Therefore, intersectional research improved the impact and importance of future findings.


Biopsychosocial model

The primary model of contemporary mainstream Western psychiatry is the
biopsychosocial model Biopsychosocial models are a class of trans-disciplinary models which look at the interconnection between biology, psychology, and socio-environmental factors. These models specifically examine how these aspects play a role in topics ranging from ...
(BPS), which integrates biological, psychological, and social factors. The Biopsychosocial model was first conceptualised by George Engel in 1977, suggesting that to understand a person's medical condition it is not simply the biological factors to consider, but also the psychological and social factors . The biopsychosocial approach systematically considers biological, psychological, and social factors and their complex interactions in understanding health, illness, and health care delivery. Biological, psychological, and social factors exist along a continuum of natural systems. The factors within the model contain the following: * Biological (physiological pathology) * Psychological (thoughts emotions and behaviours such as psychological distress, fear/avoidance beliefs, current coping methods and attribution) * Social (socio-economical, socio-environmental, and cultural factors suchs as work issues, family circumstances and benefits/economics) This model is commonly used for case conceptualization of psychological disorders as well as chronic pain, with the view that the pain is a psychophysiological behavior pattern that cannot be categorised into biological, psychological, or social factors alone. A related view, the diathesis-stress model, posits that mental disorders result from genetic dispositions and environmental stressors, combining to cause patterns of distress or dysfunction. The model is one way to explain why some individuals are more vulnerable to mental disorders than others. Additionally, it explains why some people may develop a mental disorder after exposure to stressful life events while others do not.


Psychoanalytic theories

Psychoanalytic PsychoanalysisFrom Greek: + . is a set of theories and therapeutic techniques"What is psychoanalysis? Of course, one is supposed to answer that it is many things — a theory, a research method, a therapy, a body of knowledge. In what might be ...
theories focus on unresolved internal and relational conflicts. These theories have been predicated as explanations of mental disorders. Many psychoanalytic groups are said to adhere to the biopsychosocial model and to accept an eclectic mix of subtypes of psychoanalysis.
Sigmund Freud Sigmund Freud ( , ; born Sigismund Schlomo Freud; 6 May 1856 – 23 September 1939) was an Austrian neurologist and the founder of psychoanalysis, a clinical method for evaluating and treating psychopathology, pathologies explained as originatin ...
developed the psychoanalytic theory. This theory focuses on the impact of unconscious forces on human behavior. According to Freud, a personality has three parts: the id,
ego Ego or EGO may refer to: Social sciences * Ego (Freudian), one of the three constructs in Sigmund Freud's structural model of the psyche * Egoism, an ethical theory that treats self-interest as the foundation of morality * Egotism, the drive to ...
, and
superego The id, ego, and super-ego are a set of three concepts in psychoanalytic theory describing distinct, interacting agents in the psychic apparatus (defined in Sigmund Freud's structural model of the psyche). The three agents are theoretical const ...
. The id operates under the pleasure principle, the ego operates under the
reality principle In Freudian psychology and psychoanalysis, the reality principle (german: Realitätsprinzip) is the ability of the mind to assess the reality of the external world, and to act upon it accordingly, as opposed to acting on the pleasure principle. A ...
, and the superego is the "conscience" and incorporates what is and is not socially acceptable into a person's value system. According to the psychoanalytic theory, there are five stages of psychosexual development that everyone goes through the
oral stage In Freudian psychoanalysis, the term oral stage or hemitaxia denotes the first psychosexual development stage wherein the mouth of the infant is their primary erogenous zone. Spanning the life period from birth to the age of 18 months, the oral s ...
,
anal stage The anal stage is the second stage in Sigmund Freud's theory of psychosexual development, taking place approximately between the ages 18 months and three years. According to Freud, the anus is the primary erogenous zone and pleasure is derived ...
,
phallic stage In Freudian psychoanalysis, the phallic stage is the third stage of psychosexual development, spanning the ages of three to six years, wherein the infant's libido (desire) centers upon their genitalia as the erogenous zone. When children become ...
,
latency stage The latency stage is the fourth stage of Sigmund Freud's model of a child's psychosexual development. Freud believed that the child discharges their libido (sexual energy) through a distinct body area that characterizes each stage. The stages ar ...
, and
genital stage The genital stage in psychoanalysis is the term used by Sigmund Freud to describe the final stage of human psychosexual development. The individual develops a strong sexual interest in people outside of the family. In Freud and later thinkers The ...
. Mental disorders can be caused by an individual receiving too little or too much gratification in one of the psychosexual developmental stages. When this happens, the individual is said to be in that developmental stage.


Attachment theory

Attachment theory Attachment theory is a psychological, evolutionary and ethological theory concerning relationships between humans. The most important tenet is that young children need to develop a relationship with at least one primary caregiver for normal ...
is a kind of evolutionary-psychological approach sometimes applied in the context of mental disorders, which focuses on the role of early caregiver-child relationships, responses to danger, and the search for a satisfying reproductive relationship in adulthood. According to this theory, a child's attachment is to a nurturing adult, the more likely that child will maintain healthy relationships with others in their life. As found by the Strange Situation experiment run by
Mary Ainsworth Mary Dinsmore Ainsworth (; December 1, 1913 – March 21, 1999) was an American-Canadian developmental psychologist known for her work in the development of the attachment theory. She designed the strange situation procedure to observe early emot ...
based on the formulations of
John Bowlby Edward John Mostyn Bowlby, CBE, FBA, FRCP, FRCPsych (; 26 February 1907 – 2 September 1990) was a British psychologist, psychiatrist, and psychoanalyst, notable for his interest in child development and for his pioneering work in attachmen ...
, there are four patterns of attachment:
secure attachment Secure attachment is classified by children who show some distress when their caregiver leaves but are able to compose themselves quickly when the caregiver returns. Children with secure attachment feel protected by their caregivers, and they know ...
, avoidant attachment,
disorganized attachment Attachment theory is a psychological, evolutionary and ethological theory concerning relationships between humans. The most important tenet is that young children need to develop a relationship with at least one primary caregiver for normal ...
, and
ambivalent attachment Attachment theory is a psychological, evolutionary and ethological theory concerning relationships between humans. The most important tenet is that young children need to develop a relationship with at least one primary caregiver for normal ...
. Later research found the fourth pattern of attachment is known as disorganized disoriented attachment. Secure attachments reflect trust in the child-caretaker relationship while insecure attachment reflects mistrust. The security of attachment in a child affects the child's emotional, cognitive, and social competence later in life.


Evolutionary psychology

Evolutionary psychology Evolutionary psychology is a theoretical approach in psychology that examines cognition and behavior from a modern evolutionary perspective. It seeks to identify human psychological adaptations with regards to the ancestral problems they evolv ...
and
evolutionary psychiatry Evolutionary psychiatry, also known as Darwinian psychiatry, is a theoretical approach to psychiatry that aims to explain psychiatric disorders in evolutionary terms. A branch of the field of evolutionary medicine, it is distinct from the medical p ...
posit that mental disorders involve the dysfunctional operation of mental modules adapted to
ancestral An ancestor, also known as a forefather, fore-elder or a forebear, is a parent or (recursively) the parent of an antecedent (i.e., a grandparent, great-grandparent, great-great-grandparent and so forth). ''Ancestor'' is "any person from whom ...
physical or social environments but not necessarily to modern ones. Behavioral abnormalities that resemble human mental illness have been found in related species (
great apes The Hominidae (), whose members are known as the great apes or hominids (), are a taxonomic family of primates that includes eight extant species in four genera: '' Pongo'' (the Bornean, Sumatran and Tapanuli orangutan); ''Gorilla'' (the east ...
). Other theories suggest that mental illness could have evolutionary ''advantages'' for the species, including enhancing creativity and
stress Stress may refer to: Science and medicine * Stress (biology), an organism's response to a stressor such as an environmental condition * Stress (linguistics), relative emphasis or prominence given to a syllable in a word, or to a word in a phrase ...
to enhance survival by activating the
flight-or-fight response The fight-or-flight or the fight-flight-or-freeze response (also called hyperarousal or the acute stress response) is a physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival. It was first des ...
in anticipation of danger.
Schizophrenia Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social withdra ...
could have been beneficial in prehistoric times by improving creativity during stressful times, or by helping to disseminate
delusion A delusion is a false fixed belief that is not amenable to change in light of conflicting evidence. As a pathology, it is distinct from a belief based on false or incomplete information, confabulation, dogma, illusion, hallucination, or some o ...
al tales that would have aided in-group cohesion and finding gullible mates. The paranoia associated with Schizophrenia could have prevented danger from other humans and other animals.
Mania Mania, also known as manic syndrome, is a mental and behavioral disorder defined as a state of abnormally elevated arousal, affect, and energy level, or "a state of heightened overall activation with enhanced affective expression together wit ...
and depression could have benefited from seasonal changes by helping to increase energy levels during times of plenty and rejuvenating energy during times of scarcity. In this way, mania was set in motion during the spring and summer to facilitate energy for hunting; depression worked best during the winter, similar to how bears
hibernate Hibernation is a state of minimal activity and metabolic depression undergone by some animal species. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate. It most ...
to recover their energy levels. This may explain the connection between circadian genes and
Bipolar Disorder Bipolar disorder, previously known as manic depression, is a mental disorder characterized by periods of depression and periods of abnormally elevated mood that last from days to weeks each. If the elevated mood is severe or associated with ...
and explain the relationship between light and
seasonal affective disorder Seasonal affective disorder (SAD) is a mood disorder subset, in which people who have normal mental health throughout most of the year exhibit depressive symptoms at the same time each year. Common symptoms include sleeping too much, having li ...
.


Biological factors

Biological factors consist of anything physical that can cause adverse effects on a person's mental health. Biological factors include genetics, prenatal damage, infections, exposure to toxins, brain defects or injuries, and substance abuse. Many professionals believe that the cause of mental disorders is the biology of the brain and the nervous system. ''Mind'' mentions genetic factors, long-term physical health conditions, and head injuries or epilepsy (affecting behavior and mood) as factors that may trigger an episode of mental illness.


Genetics

Some rare mental disorders are caused only by genetics such as
Huntington's disease Huntington's disease (HD), also known as Huntington's chorea, is a neurodegenerative disease that is mostly inherited. The earliest symptoms are often subtle problems with mood or mental abilities. A general lack of coordination and an unst ...
. Family linkage and some
twin studies Twin studies are studies conducted on identical or fraternal twins. They aim to reveal the importance of environmental and genetic influences for traits, phenotypes, and disorders. Twin research is considered a key tool in behavioral genetics a ...
have indicated that genetic factors often play a role in the heritability of mental disorders. The reliable identification of specific genetic variation can cause indication of higher risk to particular disorders, through
linkage Linkage may refer to: * ''Linkage'' (album), by J-pop singer Mami Kawada, released in 2010 *Linkage (graph theory), the maximum min-degree of any of its subgraphs *Linkage (horse), an American Thoroughbred racehorse * Linkage (hierarchical cluster ...
, Genome Wide Association Scores or
association studies Genetic association is when one or more genotypes within a population co-occur with a phenotypic trait more often than would be expected by chance occurrence. Studies of genetic association aim to test whether single-locus alleles or genotype fr ...
, has proven difficult. This is due to the complexity of interactions between genes, environmental events, and early development or the need for new research strategies. No specific gene results in a complex trait disorder, but specific variations of alleles result in higher risk for a trait. The
heritability Heritability is a statistic used in the fields of breeding and genetics that estimates the degree of ''variation'' in a phenotypic trait in a population that is due to genetic variation between individuals in that population. The concept of h ...
of behavioral traits associated with a mental disorder may be in permissive than in restrictive environments, and susceptibility genes probably work through both "within-the-skin" (physiological) pathways and "outside-the-skin" (behavioral and social) pathways. Investigations increasingly focus on links between genes and endophenotypes because they are more specific traits. Some include neurophysiological, biochemical, endocrinological, neuroanatomical, cognitive, or neuropsychological, rather than disease categories. Concerning a well-known mental disorder,
schizophrenia Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social withdra ...
, it is said with certainty that
alleles An allele (, ; ; modern formation from Greek ἄλλος ''állos'', "other") is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution. ::"The chro ...
(forms of genes) were responsible for this disorder. Some research has indicated only multiple, rare mutations are thought to alter neurodevelopmental pathways that can ultimately contribute to schizophrenia; virtually every rare structural mutation was different in each individual. Research has shown that many conditions are polygenic meaning there are multiple defective genes rather than only one that is responsible for a disorder, and these genes may also be pleiotropic meaning that they cause multiple disorders, not just one.
Schizophrenia Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social withdra ...
and
Alzheimer's Alzheimer's disease (AD) is a neurodegenerative disease that usually starts slowly and progressively worsens. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As t ...
are both examples of hereditary mental disorders. When exonic genes encode for proteins, these proteins do not just affect one trait. The pathways that contribute to complex traits and phenotypes interact with multiple systems, even though proteins have specific functions. brain plasticity (neuroplasticity) raises questions of whether some brain differences may be caused by mental illnesses or by pre-existing and then causing them.


Prenatal damage

Any damage that occurs to a fetus while still in its mother's womb is considered prenatal damage. Mental disorders can develop if the pregnant mother uses drugs or alcohol or is exposed to illnesses or infections during pregnancy. According to research,
autism The autism spectrum, often referred to as just autism or in the context of a professional diagnosis autism spectrum disorder (ASD) or autism spectrum condition (ASC), is a neurodevelopmental condition (or conditions) characterized by difficulti ...
results from a disruption of early fetal brain progression. Environmental events surrounding
pregnancy Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occurs by sexual intercourse, but ca ...
and
birth Birth is the act or process of bearing or bringing forth offspring, also referred to in technical contexts as parturition. In mammals, the process is initiated by hormones which cause the muscular walls of the uterus to contract, expelling the f ...
have increased the development of mental illness in the
offspring In biology, offspring are the young creation of living organisms, produced either by a single organism or, in the case of sexual reproduction, two organisms. Collective offspring may be known as a brood or progeny in a more general way. This ca ...
. Some events may include maternal exposure to
stress Stress may refer to: Science and medicine * Stress (biology), an organism's response to a stressor such as an environmental condition * Stress (linguistics), relative emphasis or prominence given to a syllable in a word, or to a word in a phrase ...
or
trauma Trauma most often refers to: *Major trauma, in physical medicine, severe physical injury caused by an external source *Psychological trauma, a type of damage to the psyche that occurs as a result of a severely distressing event *Traumatic inju ...
, conditions of famine, obstetric birth complications, infections, and gestational exposure to
alcohol Alcohol most commonly refers to: * Alcohol (chemistry), an organic compound in which a hydroxyl group is bound to a carbon atom * Alcohol (drug), an intoxicant found in alcoholic drinks Alcohol may also refer to: Chemicals * Ethanol, one of sev ...
or
cocaine Cocaine (from , from , ultimately from Quechuan languages, Quechua: ''kúka'') is a central nervous system (CNS) stimulant mainly recreational drug use, used recreationally for its euphoria, euphoric effects. It is primarily obtained from t ...
. These factors have been hypothesized to affect areas of neurodevelopment, general development, and restrict
neuroplasticity Neuroplasticity, also known as neural plasticity, or brain plasticity, is the ability of Neural circuit, neural networks in the brain to change through growth and reorganization. It is when the brain is rewired to function in some way that diffe ...
.


Infection, disease and toxins

There have been some findings of links between infection by the parasite
Toxoplasma gondii ''Toxoplasma gondii'' () is an obligate intracellular parasitic protozoan (specifically an apicomplexan) that causes toxoplasmosis. Found worldwide, ''T. gondii'' is capable of infecting virtually all warm-blooded animals, but felids, such as d ...
and schizophrenia.
AIDS Human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV), a retrovirus. Following initial infection an individual m ...
has been linked to some mental disorders. Research shows that infections and exposure to toxins such as
HIV The human immunodeficiency viruses (HIV) are two species of ''Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the immune ...
and
streptococcus ''Streptococcus'' is a genus of gram-positive ' (plural ) or spherical bacteria that belongs to the family Streptococcaceae, within the order Lactobacillales (lactic acid bacteria), in the phylum Bacillota. Cell division in streptococci occurs ...
cause dementia. This HIV infection that makes its way to the brain is called encephalopathy which spreads itself through the brain leading to dementia. The infections or toxins that trigger a change in the brain chemistry can develop into a mental disorder. Depression and emotional liability may be also be caused by
babesiosis Babesiosis or piroplasmosis is a malaria-like parasitic disease caused by infection with a eukaryotic parasite in the order Piroplasmida, typically a ''Babesia'' or ''Theileria'', in the phylum Apicomplexa. Human babesiosis transmission via ti ...
. There is some evidence that there may be a relationship between BoDV-1 infection and psychiatric disease. The research on Lyme disease caused by a deer tick and toxins is expanding the link between bacterial infections and mental illness.


Injury and brain defects

Any damage to the brain can cause a mental disorder. The brain is the control system for the nervous system and the rest of the body. Without it, the body cannot function properly. Increased mood swings, insane behavior, and substance abuse disorders are
traumatic brain injury A traumatic brain injury (TBI), also known as an intracranial injury, is an injury to the brain caused by an external force. TBI can be classified based on severity (ranging from mild traumatic brain injury TBI/concussionto severe traumatic b ...
(TBI) examples. Findings on the relationship between TBI severity and prevalence of subsequent psychiatric disorders have been inconsistent, and occurrence relates to prior mental health problems. Direct neurophysiological effects in a complex interaction with personality, attitude, and
social influences Social influence comprises the ways in which individuals adjust their behavior to meet the demands of a social environment. It takes many forms and can be seen in conformity, socialization, peer pressure, obedience, leadership, persuasion, sale ...
. Head trauma classifies as either open or closed head injury. In
open head injury A penetrating head injury, or open head injury, is a head injury in which the dura mater, the outer layer of the meninges, is breached.University of Vermont College of Medicine"Neuropathology: Trauma to the CNS."Accessed through web archive on Augu ...
, the skull is punctured and the brain tissue is demolished.
Closed head injury Closed-head injury is a type of traumatic brain injury in which the skull and dura mater remain intact. Closed-head injuries are the leading cause of death in children under 4 years old and the most common cause of physical disability and cognitive ...
is more common, the skull is not punctured because there is an impact of the brain against the skull that creates permanent structural damage (
subdural hematoma A subdural hematoma (SDH) is a type of bleeding in which a Hematoma, collection of blood—usually but not always associated with a traumatic brain injury—gathers between the inner layer of the dura mater and the arachnoid mater of the meninges ...
). With both types, symptoms may disappear or persist over time. Typically the longer the length of time spent unconscious and the length of
post-traumatic amnesia Post-traumatic amnesia (PTA) is a state of confusion that occurs immediately following a traumatic brain injury (TBI) in which the injured person is disoriented and unable to remember events that occur after the injury. The person may be unable ...
the worse the prognosis for the individual. The cognitive residual symptoms of head trauma are associated with the type of injury (either an open head injury or closed head injury) and the amount of tissue destroyed. Closed injury head trauma symptoms include; Deficits in abstract reasoning ability, judgment, memory, and marked personality changes. Open injury head trauma symptoms tend to be the experience of classic neuropsychological syndromes like
aphasia Aphasia is an inability to comprehend or formulate language because of damage to specific brain regions. The major causes are stroke and head trauma; prevalence is hard to determine but aphasia due to stroke is estimated to be 0.1–0.4% in th ...
, visual-spatial disorders, and types of memory or perceptual disorders. Brain tumors are classified as either
malignant Malignancy () is the tendency of a medical condition to become progressively worse. Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous ''benign'' tumor in that a malignancy is not s ...
and
benign Malignancy () is the tendency of a medical condition to become progressively worse. Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous benign tumor, ''benign'' tumor in that a malign ...
, and as
intrinsic In science and engineering, an intrinsic property is a property of a specified subject that exists itself or within the subject. An extrinsic property is not essential or inherent to the subject that is being characterized. For example, mass ...
(directly infiltrate the
parenchyma Parenchyma () is the bulk of functional substance in an animal organ or structure such as a tumour. In zoology it is the name for the tissue that fills the interior of flatworms. Etymology The term ''parenchyma'' is New Latin from the word π ...
of the brain) or
extrinsic In science and engineering, an intrinsic property is a property of a specified subject that exists itself or within the subject. An extrinsic property is not essential or inherent to the subject that is being characterized. For example, mass ...
(grows on the external surface of the brain and produces symptoms as a result of pressure on the brain tissue). Progressive cognitive changes associated with brain tumors may include confusion, poor comprehension, and even
dementia Dementia is a disorder which manifests as a set of related symptoms, which usually surfaces when the brain is damaged by injury or disease. The symptoms involve progressive impairments in memory, thinking, and behavior, which negatively affe ...
. Symptoms tend to depend on the location of the tumor in the brain. For example, tumors on the frontal lobe tend to be associated with the sign of impairment of judgment, apathy, and loss of the ability to regulate/modulate behavior. Findings have indicated abnormal functioning of
brainstem The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is cont ...
structures in individuals with mental disorders such as
schizophrenia Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social withdra ...
, and other disorders that have to do with impairments in maintaining sustained attention. Some abnormalities in the average size or shape of some regions of the brain have been found in some disorders, reflecting genes and experiences. Studies of schizophrenia have tended to find enlarged ventricles and sometimes reduced volume of the
cerebrum The cerebrum, telencephalon or endbrain is the largest part of the brain containing the cerebral cortex (of the two cerebral hemispheres), as well as several subcortical structures, including the hippocampus, basal ganglia, and olfactory bulb. In ...
and
hippocampus The hippocampus (via Latin from Greek , 'seahorse') is a major component of the brain of humans and other vertebrates. Humans and other mammals have two hippocampi, one in each side of the brain. The hippocampus is part of the limbic system, a ...
, while studies of (psychotic)
bipolar disorder Bipolar disorder, previously known as manic depression, is a mental disorder characterized by periods of depression and periods of abnormally elevated mood that last from days to weeks each. If the elevated mood is severe or associated with ...
have sometimes found increased
amygdala The amygdala (; plural: amygdalae or amygdalas; also '; Latin from Greek, , ', 'almond', 'tonsil') is one of two almond-shaped clusters of nuclei located deep and medially within the temporal lobes of the brain's cerebrum in complex verteb ...
volume. Findings differ over whether volumetric abnormalities are risk factors or are only found alongside the course of mental health problems, possibly reflecting neurocognitive or emotional stress processes and medication use or substance use. Some studies have also found reduced hippocampal volumes in
major depression Major depressive disorder (MDD), also known as clinical depression, is a mental disorder characterized by at least two weeks of pervasive low mood, low self-esteem, and loss of interest or pleasure in normally enjoyable activities. Introdu ...
, possibly worsening with time depression.


Neurotransmitter systems

Abnormal levels 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 compound, organic chemical of the catecholamine and phenethylamine families. Dopamine const ...
activity correspond with several disorders (reduced in
ADHD Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterised by excessive amounts of inattention, hyperactivity, and impulsivity that are pervasive, impairing in multiple contexts, and otherwise age-inapp ...
and OCD, and increased in schizophrenia). The dysfunction in
serotonin Serotonin () or 5-hydroxytryptamine (5-HT) is a monoamine neurotransmitter. Its biological function is complex and multifaceted, modulating mood, cognition, reward, learning, memory, and numerous physiological processes such as vomiting and vas ...
and other
monoamine Monoamine neurotransmitters are neurotransmitters and neuromodulators that contain one amino group connected to an aromatic ring by a two-carbon chain (such as -CH2-CH2-). Examples are dopamine, norepinephrine and serotonin. All monoamines are ...
neurotransmitters (
norepinephrine Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as both a hormone and neurotransmitter. The name "noradrenaline" (from Latin '' ad'', ...
and
dopamine Dopamine (DA, a contraction of 3,4-dihydroxyphenethylamine) is a neuromodulatory molecule that plays several important roles in cells. It is an organic compound, organic chemical of the catecholamine and phenethylamine families. Dopamine const ...
) correspond with certain mental disorders and their associated neural networks. Some include
major depression Major depressive disorder (MDD), also known as clinical depression, is a mental disorder characterized by at least two weeks of pervasive low mood, low self-esteem, and loss of interest or pleasure in normally enjoyable activities. Introdu ...
, obsessive-compulsive disorder,
phobias A phobia is an anxiety disorder defined by a persistent and excessive fear of an object or situation. Phobias typically result in a rapid onset of fear and are usually present for more than six months. Those affected go to great lengths to avoi ...
,
post-traumatic stress disorder Post-traumatic stress disorder (PTSD) is a mental and behavioral disorder that can develop because of exposure to a traumatic event, such as sexual assault, warfare, traffic collisions, child abuse, domestic violence, or other threats on ...
, and
generalized anxiety disorder Generalized anxiety disorder (GAD) is a mental and behavioral disorder, specifically an anxiety disorder characterized by excessive, uncontrollable and often irrational worry about events or activities. Worry often interferes with daily function ...
. Studies of depleted levels of
monoamine Monoamine neurotransmitters are neurotransmitters and neuromodulators that contain one amino group connected to an aromatic ring by a two-carbon chain (such as -CH2-CH2-). Examples are dopamine, norepinephrine and serotonin. All monoamines are ...
neurotransmitters show an association with depression and other psychiatric disorders, but "... it should be questioned whether 5-HT erotoninrepresents just one of the final and not the main, factors in the neurological chain of events underlying psychopathological symptoms...." Simplistic "chemical imbalance" explanations for mental disorders have never received empirical support; and most prominent psychiatrists, neuroscientists, and psychologists have not espoused such ill-defined, facile etiological theories. Instead, neurotransmitter systems have been understood in the context of the diathesis-stress or biopsychosocial models. The following 1967 quote from renowned psychiatric and neuroscience researchers exemplifies this more sophisticated understanding (in contrast to the woolly "chemical imbalance" notion). Whereas specific genetic factors may be of importance in the etiology of some, and possibly all, depressions, it is equally conceivable that early experiences of the infant or child may cause enduring biochemical changes, that may predispose some individuals to depressions in adulthood. It is not likely that changes in the metabolism of the biogenic amines alone will account for the complex phenomena of normal or pathological affect.


Substance abuse

Substance abuse, especially long-term abuse, can cause or exacerbate many mental disorders.
Alcoholism Alcoholism is, broadly, any drinking of alcohol (drug), alcohol that results in significant Mental health, mental or physical health problems. Because there is disagreement on the definition of the word ''alcoholism'', it is not a recognize ...
is linked to depression while abuse of
amphetamines Substituted amphetamines are a class of compounds based upon the amphetamine structure; it includes all derivative compounds which are formed by replacing, or substituting, one or more hydrogen atoms in the amphetamine core structure with sub ...
and
LSD Lysergic acid diethylamide (LSD), also known colloquially as acid, is a potent psychedelic drug. Effects typically include intensified thoughts, emotions, and sensory perception. At sufficiently high dosages LSD manifests primarily mental, vi ...
can leave a person feeling
paranoid Paranoia is an instinct or thought process that is believed to be heavily influenced by anxiety or fear, often to the point of delusion and irrationality. Paranoid thinking typically includes persecutory beliefs, or beliefs of conspiracy concer ...
and
anxious Anxiety is an emotion which is characterized by an unpleasant state of inner turmoil and includes feelings of dread over anticipated events. Anxiety is different than fear in that the former is defined as the anticipation of a future threat wh ...
. Correlations of mental disorders with drug use include
cannabis ''Cannabis'' () is a genus of flowering plants in the family Cannabaceae. The number of species within the genus is disputed. Three species may be recognized: ''Cannabis sativa'', '' C. indica'', and '' C. ruderalis''. Alternatively ...
, alcohol, and
caffeine Caffeine is a central nervous system (CNS) stimulant of the methylxanthine class. It is mainly used recreationally as a cognitive enhancer, increasing alertness and attentional performance. Caffeine acts by blocking binding of adenosine t ...
. At more than 300 mg,
caffeine Caffeine is a central nervous system (CNS) stimulant of the methylxanthine class. It is mainly used recreationally as a cognitive enhancer, increasing alertness and attentional performance. Caffeine acts by blocking binding of adenosine t ...
may cause
anxiety Anxiety is an emotion which is characterized by an unpleasant state of inner turmoil and includes feelings of dread over anticipated events. Anxiety is different than fear in that the former is defined as the anticipation of a future threat wh ...
or worsen anxiety disorders. Illicit drugs can stimulate particular parts of the brain that can affect development in adolescence. Cannabis has also been found to worsen depression and lessen an individual's
motivation Motivation is the reason for which humans and other animals initiate, continue, or terminate a behavior at a given time. Motivational states are commonly understood as forces acting within the agent that create a disposition to engage in goal-dire ...
. Alcohol has the potential to damage "
white matter White matter refers to areas of the central nervous system (CNS) that are mainly made up of myelinated axons, also called tracts. Long thought to be passive tissue, white matter affects learning and brain functions, modulating the distribution ...
" in the brain that affects
thinking In their most common sense, the terms thought and thinking refer to conscious cognitive processes that can happen independently of sensory stimulation. Their most paradigmatic forms are judging, reasoning, concept formation, problem solving, an ...
and
memory Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembered, ...
. Alcohol is a problem in many countries due to many people participating in excessive drinking or
binge drinking Binge drinking, or heavy episodic drinking, is drinking alcoholic beverages with an intention of becoming intoxicated by heavy consumption of alcohol over a short period of time, but definitions ( see below) vary considerably. Binge drinking ...
.


Life experience and environmental factors

The term "environment" is very loosely defined when it comes to mental illness. Unlike biological and psychological causes, environmental causes are stressors that individuals deal with in everyday life. These stressors range from financial issues to having low self-esteem. Environmental causes are more psychologically based, making them more closely related. Events that evoke feelings of loss or damage are most likely to cause a mental disorder to develop in an individual. Environmental factors include but are not limited to dysfunctional home life, poor relationships with others, substance abuse, not meeting social expectations, low self-esteem, and poverty.
Mind The mind is the set of faculties responsible for all mental phenomena. Often the term is also identified with the phenomena themselves. These faculties include thought, imagination, memory, will, and sensation. They are responsible for various m ...
mentions childhood abuse, trauma, violence or neglect, social isolation, loneliness or discrimination, the death of someone close, stress, homelessness or housing, social disadvantage, poverty or debt, unemployment, caring for a family member or friend, significant trauma as an adult, such as military combat, and being involved in an accident or being the victim of a violent crime as possibly triggering an episode of mental illness. Repeating generational patterns are a risk factor for mental illness.


Life events and emotional stress

Treatment in childhood and adulthood, including
sexual abuse Sexual abuse or sex abuse, also referred to as molestation, is abusive sexual behavior by one person upon another. It is often perpetrated using force or by taking advantage of another. Molestation often refers to an instance of sexual assa ...
,
physical abuse Physical abuse is any intentional act causing injury or trauma to another person or animal by way of bodily contact. In most cases, children are the victims of physical abuse, but adults can also be victims, as in cases of domestic violence or wo ...
,
emotional abuse Emotions are mental states brought on by neurophysiological changes, variously associated with thoughts, feelings, behavioral responses, and a degree of pleasure or displeasure. There is currently no scientific consensus on a definition. E ...
,
domestic violence Domestic violence (also known as domestic abuse or family violence) is violence or other abuse that occurs in a domestic setting, such as in a marriage or cohabitation. ''Domestic violence'' is often used as a synonym for ''intimate partner ...
, and
bullying Bullying is the use of force, coercion, hurtful teasing or threat, to abuse, aggressively dominate or intimidate. The behavior is often repeated and habitual. One essential prerequisite is the perception (by the bully or by others) of an imba ...
, has been linked to the development of mental disorders, through a complex interaction of societal, family, psychological and biological factors. Negative or stressful life events more generally have been implicated in the development of a range of disorders, including mood and anxiety disorders. The main risks appear to be from a cumulative combination of such experiences over time, although exposure to a single major trauma can sometimes lead to psychopathology, including
PTSD Post-traumatic stress disorder (PTSD) is a mental and behavioral disorder that can develop because of exposure to a traumatic event, such as sexual assault, warfare, traffic collisions, child abuse, domestic violence, or other threats on a ...
. Resilience to such experiences varies, and a person may be resistant to some forms of experience but susceptible to others. Features associated with variations in resilience include genetic vulnerability, temperamental characteristics, cognitive set, coping patterns, and other experiences. For
bipolar disorder Bipolar disorder, previously known as manic depression, is a mental disorder characterized by periods of depression and periods of abnormally elevated mood that last from days to weeks each. If the elevated mood is severe or associated with ...
, stress (such as childhood adversity) is not a specific cause but does place genetically and biologically vulnerable individuals at risk for a more severe course of illness.


Poor parenting, abuse and neglect

Poor parenting is a risk factor for depression and anxiety. Separation or bereavement in families, and childhood trauma, be risk factors for psychosis and schizophrenia. Severe psychological trauma, such as abuse, can wreak havoc on a person's life. Children are much more susceptible to psychological harm from traumatic events than adults. Once again, the reaction to the trauma will vary based on the person and the individual's age. Many factors impact these children. Many factors include the type of event, the length of exposure, and how the individual was affected. Study shows that human-induced trauma, such as a tumultuous childhood, affects children even more than natural disasters.
Neglect In the context of caregiving, neglect is a form of abuse where the perpetrator, who is responsible for caring for someone who is unable to care for themselves, fails to do so. It can be a result of carelessness, indifference, or unwillingness and ...
is a type of maltreatment related to the failure to provide needed, age-appropriate care, supervision, and protection. It is not to be confused with
abuse Abuse is the improper usage or treatment of a thing, often to unfairly or improperly gain benefit. Abuse can come in many forms, such as: physical or verbal maltreatment, injury, assault, violation, rape, unjust practices, crimes, or other t ...
, which, in this context, is defined as any action that intentionally harms or injures another person. Neglect most often happens during childhood by the parents or caretakers. Parents who are guilty of neglect were also neglected as children. The long-term effects of neglect are reduced physical, emotional, and mental health in a child and throughout adulthood.


Adverse childhood experiences

Adverse childhood experiences (ACEs) such as physical or emotional neglect or both,
abuse Abuse is the improper usage or treatment of a thing, often to unfairly or improperly gain benefit. Abuse can come in many forms, such as: physical or verbal maltreatment, injury, assault, violation, rape, unjust practices, crimes, or other t ...
, poverty, malnutrition, and
traumatic experiences Psychological trauma, mental trauma or psychotrauma is an emotional response to a distressing event or series of events, such as accidents, rape, or natural disasters. Reactions such as psychological shock and psychological denial are typical. ...
can have long-lasting negative consequences. Adverse experiences in childhood can affect the structural and functional development of the brain, giving structural and functional abnormalities in the future, and adulthood. ACEs and chronic trauma can disrupt the control of immune responses and promote chronic immune system activation giving rise to lasting inflammatory dysregulation. The
Adverse Childhood Experiences Study Adverse childhood experiences (ACEs) encompass various forms of physical and emotional abuse, neglect, and household dysfunction experienced in childhood. The harms of ACEs can be long-lasting, affecting people even in their adulthood. ACEs have be ...
has shown a strong
dose–response relationship The dose–response relationship, or exposure–response relationship, describes the magnitude of the response of an organism, as a function of exposure (or doses) to a stimulus or stressor (usually a chemical) after a certain exposure time. ...
between ACEs and numerous health, social, and behavioral problems throughout a person's lifespan, including suicide attempts and frequency of depressive episodes. Several adverse childhood experiences can give a level of stress known as
toxic stress Early childhood is a critical period in a child's life that includes ages from conception to five years old.Poulsen, Marie K., and Karen M. Finello. "Foundations of Early Childhood Mental Health: Public Health & Life Course Perspectives." Preventi ...
. A child's neurological development can be disrupted when chronically exposed to stressful events such as physical, emotional, or sexual abuse, physical or emotional neglect, witnessing violence in the household, or a parent being incarcerated or having a mental illness. As a result, the child's cognitive functioning or ability to cope with negative or disruptive emotions can diminish. Over time, the child may adopt various harmful coping strategies that contribute to later disease and disability. Childhood adversity is associated with an increased risk of developing severe mental illnesses, including schizophrenia. Studies show that it could contribute to some features of the illness, including cognitive impairment. Findings from several studies have been mixed but some suggest that cognitive impairment is more related to forms of neglect than any other form of adversity. Underlying mechanisms remain unknown.


Familial and close relationships

Relationships and community have been extensively associated with mental health, success, and mental disorders. Home life and parental support impact social and mental development and health of individuals. Parental divorce, death, absence, or lack of continuity appears to increase risk, perhaps only if there is family discord or disorganization. Early social privation, or lack of ongoing, harmonious, secure, committed relationships, has been implicated in the development of mental disorders. How an individual interacts with others as well as the quality of relationships can greatly increase or decrease a person's quality of living. Continuous conflict with friends, support system, and family can all lead to an increased risk of developing or worsening a mental illness or mental health state. A
dysfunctional family A dysfunctional family is a family in which conflict, misbehavior, and often child neglect or abuse and sometimes even all of the above on the part of individual parents occur continuously and regularly, leading other members to accommodate suc ...
may include disobedience, child neglect, and/or one with mental and/or abuse which occurs.
Divorce Divorce (also known as dissolution of marriage) is the process of terminating a marriage or marital union. Divorce usually entails the canceling or reorganizing of the legal duties and responsibilities of marriage, thus dissolving the ...
is also another factor that can take a toll on both children and adults alike. Divorcees may have emotional adjustment problems due to a loss of intimacy and social connections. Newer statistics show that the negative effects of divorce have been overstated. The effects of divorce on children can be impactful on the child's mental health and development.


Social expectations and esteem

How individuals view themselves ultimately determines who they are, their abilities, and what they can be. Having both too low of
self-esteem Self-esteem is confidence in one's own worth or abilities. Self-esteem encompasses beliefs about oneself (for example, "I am loved", "I am worthy") as well as emotional states, such as triumph, despair, pride, and shame. Smith and Mackie (2007) d ...
or too high can be detrimental to an individual's mental health. A person's self-esteem plays a role in their overall happiness and quality of life. Poor self-esteem can result in aggression, violence, self-deprecating behavior, anxiety, and other mental disorders. Not fitting in with the masses can result in bullying and other types of emotional abuse. Bullying can result in depression, feelings of anger, loneliness.


Poverty

Studies show that there is a direct correlation between
poverty Poverty is the state of having few material possessions or little income. Poverty can have diverse social, economic, and political causes and effects. When evaluating poverty in ...
and mental illness. The lower the socioeconomic status of an individual the higher the risk of mental illness. Impoverished people are two to three times more likely to develop mental illness than those of a higher economic class. Low levels of self-efficiency and self-worth are experienced by children of disadvantaged families or those from the economic underclass. Theorists of child development have argued that persistent poverty leads to high levels of psychopathology and poor self-concepts. This increased risk for psychiatric complications remains consistent for all individuals among the impoverished population, regardless of any in-group demographic differences that they may possess. These families must deal with economic stressors like unemployment and lack of affordable housing, which leads to mental health disorders. A person's socioeconomic class outlines the
psychosocial The psychosocial approach looks at individuals in the context of the combined influence that psychological factors and the surrounding social environment have on their physical and mental wellness and their ability to function. This approach is ...
, environmental, behavioral, and
biomedical Biomedicine (also referred to as Western medicine, mainstream medicine or conventional medicine)
risk factors that are associated with mental health. According to findings, there is a strong association between poverty and
substance abuse Substance abuse, also known as drug abuse, is the use of a drug in amounts or by methods which are harmful to the individual or others. It is a form of substance-related disorder. Differing definitions of drug abuse are used in public health, ...
. Substance abuse only perpetuates a continuous cycle. It can make it extremely difficult for individuals to find and keep jobs. As stated earlier, both financial problems and substance abuse can cause mental illnesses to develop.


Communities and cultures

Problems in communities or cultures, including poverty, unemployment or
underemployment Underemployment is the underuse of a worker because a job does not use the worker's skills, is part-time, or leaves the worker idle. Examples include holding a part-time job despite desiring full-time work, and overqualification, in which the em ...
, lack of social cohesion, and migration, have been associated with the development of mental disorders. Stresses and strains related to socioeconomic position (
socioeconomic status Socioeconomic status (SES) is an economic and sociological combined total measure of a person's work experience and of an individual's or family's economic access to resources and social position in relation to others. When analyzing a family's ...
(SES) or
social class A social class is a grouping of people into a set of Dominance hierarchy, hierarchical social categories, the most common being the Upper class, upper, Middle class, middle and Working class, lower classes. Membership in a social class can for ...
) have been linked to the occurrence of major mental disorders, with a lower or more insecure educational, occupational, economic, or social position generally linked to more mental disorders. There have been mixed findings on the nature of the links and on the extent to which pre-existing personal characteristics influence the links. Both personal resources and community factors have been implicated, as well as interactions between individual-level and regional-level income levels. The causal role of different socioeconomic factors may vary by country. Socioeconomic deprivation in neighborhoods can cause worse mental health, even after accounting for genetic factors. Minority
ethnic An ethnic group or an ethnicity is a grouping of people who identify with each other on the basis of shared attributes that distinguish them from other groups. Those attributes can include common sets of traditions, ancestry, language, history, ...
groups, including first or second-generation
immigrants Immigration is the international movement of people to a destination country of which they are not natives or where they do not possess citizenship in order to settle as permanent residents or naturalized citizens. Commuters, tourists, and ...
, are at greater risk for developing mental disorders, which has been attributed to various kinds of life insecurities and disadvantages, including
racism Racism is the belief that groups of humans possess different behavioral traits corresponding to inherited attributes and can be divided based on the superiority of one race over another. It may also mean prejudice, discrimination, or antagonism ...
. The direction of causality is sometimes unclear, and alternative hypotheses such as the
drift hypothesis Drift hypothesis, concerning the relationship between mental illness and social class, is the argument that illness causes one to have a downward shift in social class. The circumstances of one's social class do not cause the onset of a mental dis ...
sometimes need to be discounted.


Psychological and individual factors, including resilience

Some clinicians believe that psychological characteristics alone determine mental disorders. Others speculate that abnormal behavior can be explained by a mix of social and psychological factors. In many examples, environmental and psychological triggers complement one another resulting in emotional stress, which in turn activates a mental illness. Each person is unique in how they will react to psychological stressors. What may break one person may have little to no effect on another. Psychological stressors, which can trigger mental illness, are as follows: emotional, physical, or sexual abuse, loss of a significant loved one, neglect, and being unable to relate to others. The inability to relate to others is also known as
emotional detachment In psychology, emotional detachment, also known as emotional blunting, is a condition or state in which a person lacks emotional connectivity to others, whether due to an unwanted circumstance or as a positive means to coping, cope with anxiety. ...
. Emotional detachment makes it difficult for an individual to empathize with others or to share their feelings.These individuals tend to stress the importance of their independence and tend to struggle relating to others.An emotionally detached person may try to rationalize or apply logic to a situation to which there is no logical explanation. Often, the inability to relate to others stems from a traumatic event. Mental characteristics of individuals, as assessed by both neurological and psychological studies, have been linked to the development and maintenance of mental disorders. This includes cognitive or
neurocognitive Neurocognitive functions are cognitive functions closely linked to the function of particular areas, neural pathways, or cortical networks in the brain, ultimately served by the substrate of the brain's neurological matrix (i.e. at the cellular a ...
factors, such as the way a person perceives, thinks, or feels about certain things; or an individual's overall personality,
temperament In psychology, temperament broadly refers to consistent individual differences in behavior that are biologically based and are relatively independent of learning, system of values and attitudes. Some researchers point to association of temperam ...
, or coping style or the extent of protective factors or "positive illusions" such as optimism, personal control and a sense of meaning.


References

{{Reflist Biology of bipolar disorder
Mental disorders A mental disorder, also referred to as a mental illness or psychiatric disorder, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. Such features may be persistent, relapsing and remitti ...
Biology of attention deficit hyperactivity disorder Biology of obsessive–compulsive disorder