Psychopharmacology (from
Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
grc,
ψῡχή, psȳkhē, breath, life, soul, label=none; grc,
φάρμακον, pharmakon, drug, label=none; and grc,
-λογία,
-logia
''-logy'' is a suffix in the English language, used with words originally adapted from Ancient Greek ending in ('). The earliest English examples were anglicizations of the French '' -logie'', which was in turn inherited from the Latin '' -logi ...
, label=none) is the scientific study of the effects
drug
A drug is any chemical substance that causes a change in an organism's physiology or psychology when consumed. Drugs are typically distinguished from food and substances that provide nutritional support. Consumption of drugs can be via insuffla ...
s have on
mood,
sensation
Sensation (psychology) refers to the processing of the senses by the sensory system.
Sensation or sensations may also refer to:
In arts and entertainment In literature
*Sensation (fiction), a fiction writing mode
*Sensation novel, a British ...
,
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 ...
,
behavior
Behavior (American English) or behaviour (British English) is the range of actions and mannerisms made by individuals, organisms, systems or artificial entities in some environment. These systems can include other systems or organisms as wel ...
,
judgment
Judgement (or US spelling judgment) is also known as ''adjudication'', which means the evaluation of evidence to decision-making, make a decision. Judgement is also the ability to make considered decisions. The term has at least five distinct u ...
and
evaluation
Evaluation is a
systematic determination and assessment of a subject's merit, worth and significance, using criteria governed by a set of standards. It can assist an organization, program, design, project or any other intervention or initiative ...
, 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, ...
. It is distinguished from
neuropsychopharmacology
Neuropsychopharmacology, an interdisciplinary science related to psychopharmacology (study of effects of drugs on the mind) and fundamental neuroscience, is the study of the neural mechanisms that drugs act upon to influence behavior. It entails ...
, which emphasizes the correlation between drug-induced changes in the functioning of
cells
Cell most often refers to:
* Cell (biology), the functional basic unit of life
Cell may also refer to:
Locations
* Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...
in the
nervous system
In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes th ...
and changes in
consciousness
Consciousness, at its simplest, is sentience and awareness of internal and external existence. However, the lack of definitions has led to millennia of analyses, explanations and debates by philosophers, theologians, linguisticians, and scien ...
and behavior.
The field of psychopharmacology studies a wide range of substances with various types of
psychoactive
A psychoactive drug, psychopharmaceutical, psychoactive agent or psychotropic drug is a chemical substance, that changes functions of the nervous system, and results in alterations in perception, mood, consciousness, cognition or behavior.
Th ...
properties, focusing primarily on the chemical interactions with the brain. The term "psychopharmacology" was likely first coined by
David Macht
David Israel Macht (February 14, 1882 – October 14, 1961) was a pharmacologist and Doctor of Hebrew Literature, responsible for many contributions to pharmacology during the first half of the 20th century.
Born in Moscow in 1882, Macht moved to ...
in 1920. Psychoactive drugs interact with particular target sites or receptors found in the
nervous system
In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes th ...
to induce widespread changes in physiological or psychological functions. The specific interaction between drugs and their receptors is referred to as "
drug action
The action of drugs on the human body (or any other organism's body) is called pharmacodynamics, and the body's response to drugs is called pharmacokinetics. The drugs that enter an individual tend to stimulate certain receptors, ion channels, act ...
", and the widespread changes in physiological or psychological function is referred to as "
drug effect". These drugs may originate from natural sources such as plants and animals, or from artificial sources such as
chemical synthesis
As a topic of chemistry, chemical synthesis (or combination) is the artificial execution of chemical reactions to obtain one or several products. This occurs by physical and chemical manipulations usually involving one or more reactions. In moder ...
in the laboratory.
Historical overview
Early psychopharmacology
Not often mentioned or included in the field of psychopharmacology today are
psychoactive
A psychoactive drug, psychopharmaceutical, psychoactive agent or psychotropic drug is a chemical substance, that changes functions of the nervous system, and results in alterations in perception, mood, consciousness, cognition or behavior.
Th ...
substances not identified as useful in modern
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 ...
settings or references. These substances are naturally occurring, but nonetheless psychoactive, and are compounds identified through the work of
ethnobotanists
Ethnobotany is the study of a region's plants and their practical uses through the traditional knowledge of a local culture and people. An ethnobotanist thus strives to document the local customs involving the practical uses of local flora for m ...
and
ethnomycologists (and others who study the native use of naturally occurring psychoactive drugs). However, although these substances have been used throughout history by various cultures, and have a profound effect on mentality and brain function, they have not always attained the degree of scrutinous evaluation that lab-made compounds have. Nevertheless, some, such as
psilocybin
Psilocybin ( , ) is a naturally occurring psychedelic prodrug compound produced by more than 200 species of fungi. The most potent are members of the genus ''Psilocybe'', such as '' P. azurescens'', '' P. semilanceata'', and '' P.&nbs ...
and
mescaline
Mescaline or mescalin (3,4,5-trimethoxyphenethylamine) is a naturally occurring psychedelic protoalkaloid of the substituted phenethylamine class, known for its hallucinogenic effects comparable to those of LSD and psilocybin.
Biological sou ...
, have provided a basis of study for the compounds that are used and examined in the field today.
Hunter-gatherer
A traditional hunter-gatherer or forager is a human living an ancestrally derived lifestyle in which most or all food is obtained by foraging, that is, by gathering food from local sources, especially edible wild plants but also insects, fungi, ...
societies tended to favor
hallucinogen
Hallucinogens are a large, diverse class of psychoactive drugs that can produce altered states of consciousness characterized by major alterations in thought, mood, and perception as well as other changes. Most hallucinogens can be categorized ...
s, and today their use can still be observed in many surviving
tribal
The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide usage of the term in English is in the discipline of anthropology. This definition is contested, in part due to conflic ...
cultures. The exact drug used depends on what the particular
ecosystem
An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...
a given tribe lives in can support, and are typically found growing wild. Such drugs include various
psychoactive mushroom
A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil, or on its food source. ''Toadstool'' generally denotes one poisonous to humans.
The standard for the name "mushroom" is th ...
s containing psilocybin or
muscimol
Muscimol (also known as agarin or pantherine) is one of the principal psychoactive constituents of ''Amanita muscaria'' and related species of mushroom. Muscimol is a potent and selective orthosteric agonist for the GABAA receptors and displays ...
and
cacti
A cactus (, or less commonly, cactus) is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 known species of the order Caryophyllales. The word ''cactus'' derives, through Latin, from the Ancient Greek ...
containing mescaline and other chemicals, along with myriad other
plants containing psychoactive chemicals. These societies generally attach spiritual significance to such drug use, and often incorporate it into their religious practices.
With the dawn of the
Neolithic
The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several parts ...
and the proliferation of agriculture, new psychoactives came into use as a natural by-product of farming. Among them were
opium
Opium (or poppy tears, scientific name: ''Lachryma papaveris'') is dried latex obtained from the seed capsules of the opium poppy ''Papaver somniferum''. Approximately 12 percent of opium is made up of the analgesic alkaloid morphine, which i ...
,
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 ...
, and
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 ...
derived from the fermentation of cereals and fruits. Most societies began developing
herblores, lists of herbs which were good for treating various physical and mental ailments. For example,
St. John's wort
''Hypericum perforatum'', known as St. John's wort, is a flowering plant in the family Hypericaceae and the type species of the genus ''Hypericum''.
Possibly a hybrid between '' H. maculatum'' and '' H. attenuatum'', the species can be found a ...
was traditionally prescribed in parts of Europe for depression (in addition to use as a general-purpose tea), and
Chinese medicine
Traditional Chinese medicine (TCM) is an alternative medical practice drawn from traditional medicine in China. It has been described as "fraught with pseudoscience", with the majority of its treatments having no logical mechanism of action ...
developed elaborate lists of
herbs
In general use, herbs are a widely distributed and widespread group of plants, excluding vegetables and other plants consumed for macronutrients, with savory or aromatic properties that are used for flavoring and garnishing food, for medicinal ...
and preparations. These and various other substances that have an effect on the brain are still used as remedies in many cultures.
Modern psychopharmacology
The dawn of contemporary psychopharmacology marked the beginning of the use of psychiatric drugs to treat psychological illnesses. It brought with it the use of opiates and barbiturates for the management of acute behavioral issues in patients. In the early stages, psychopharmacology was primarily used for sedation. With the 1950s came the establishment of
lithium
Lithium (from el, λίθος, lithos, lit=stone) is a chemical element with the symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense solid el ...
for
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 ...
,
chlorpromazine
Chlorpromazine (CPZ), marketed under the brand names Thorazine and Largactil among others, is an antipsychotic medication. It is primarily used to treat psychotic disorders such as schizophrenia. Other uses include the treatment of bipolar dis ...
for
psychoses
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 t ...
, and then in rapid succession, the development of tricyclic antidepressants, monoamine oxidase inhibitors, and benzodiazepines, among other antipsychotics and antidepressants. A defining feature of this era includes an evolution of research methods, with the establishment of
placebo-controlled
Placebo-controlled studies are a way of testing a medical therapy in which, in addition to a group of subjects that receives the treatment to be evaluated, a separate control group receives a sham "placebo" treatment which is specifically designed ...
,
double-blind
In a blind or blinded experiment, information which may influence the participants of the experiment is withheld until after the experiment is complete. Good blinding can reduce or eliminate experimental biases that arise from a participants' expec ...
studies, and the development of methods for analyzing blood levels with respect to clinical outcome and increased sophistication in clinical trials. The early 1960s revealed a revolutionary model by
Julius Axelrod
Julius Axelrod (May 30, 1912 – December 29, 2004) was an American biochemist. He won a share of the Nobel Prize in Physiology or Medicine in 1970 along with Bernard Katz and Ulf von Euler. The Nobel Committee honored him for his work on the re ...
describing nerve signals and
synaptic transmission
Neurotransmission (Latin: ''transmissio'' "passage, crossing" from ''transmittere'' "send, let through") is the process by which signaling molecules called neurotransmitters are released by the axon terminal of a neuron (the presynaptic neuron), ...
, which was followed by a drastic increase of biochemical brain research into the effects of psychotropic agents on brain chemistry. After the 1960s, the field of psychiatry shifted to incorporate the indications for and efficacy of pharmacological treatments, and began to focus on the use and toxicities of these medications. The 1970s and 1980s were further marked by a better understanding of the synaptic aspects of the action mechanisms of drugs. However, the model has its critics, too – notably
Joanna Moncrieff
Joanna Moncrieff is a British psychiatrist and academic. She is Professor of Critical and Social Psychiatry at University College London and a leading figure in the Critical Psychiatry Network. She is a prominent critic of the modern 'psychophar ...
and the
Critical Psychiatry Network The Critical Psychiatry Network (CPN) is a psychiatric organization based in the United Kingdom. It was created by a group of British psychiatrists who met in Bradford, England in January 1999 in response to proposals by the British government to am ...
.
Chemical signaling
Neurotransmitters
Psychoactive drugs exert their sensory and behavioral effects almost entirely by acting on
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 ...
s and by modifying one or more aspects of synaptic transmission. Neurotransmitters can be viewed as chemicals through which
neuron
A neuron, neurone, or nerve cell is an electrically excitable cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all animals except sponges and placozoa. N ...
s primarily communicate; psychoactive drugs affect the mind by altering this communication. Drugs may act by 1) serving as a
precursor
Precursor or Precursors may refer to:
*Precursor (religion), a forerunner, predecessor
** The Precursor, John the Baptist
Science and technology
* Precursor (bird), a hypothesized genus of fossil birds that was composed of fossilized parts of unr ...
to a neurotransmitter; 2) inhibiting neurotransmitter synthesis; 3) preventing storage of neurotransmitters in the pre
synaptic vesicle
In a neuron, synaptic vesicles (or neurotransmitter vesicles) store various neurotransmitters that are released at the synapse. The release is regulated by a voltage-dependent calcium channel. Vesicles are essential for propagating nerve impulse ...
; 4) stimulating or inhibiting neurotransmitter release; 5) stimulating or blocking post-synaptic receptors; 6) stimulating
autoreceptor
An autoreceptor is a type of receptor located in the membranes of nerve cells. It serves as part of a negative feedback loop in signal transduction. It is only sensitive to the neurotransmitters or hormones released by the neuron on which the aut ...
s, inhibiting neurotransmitter release; 7) blocking autoreceptors, increasing neurotransmitter release; 8) inhibiting neurotransmission breakdown; or 9) blocking neurotransmitter
reuptake
Reuptake is the reabsorption of a neurotransmitter by a neurotransmitter transporter located along the plasma membrane of an axon terminal (i.e., the pre-synaptic neuron at a synapse) or glial cell after it has performed its function of transm ...
by the presynaptic neuron.
Hormones
The other central method through which drugs act is by affecting communications between cells through
hormone
A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are required ...
s. Neurotransmitters can usually only travel a microscopic distance before reaching their target at the other side of the
synaptic cleft
Chemical synapses are biological junctions through which neurons' signals can be sent to each other and to non-neuronal cells such as those in muscles or glands. Chemical synapses allow neurons to form circuits within the central nervous syste ...
, while hormones can travel long distances before reaching target cells anywhere in the body. Thus, the
endocrine system
The endocrine system is a messenger system comprising feedback loops of the hormones released by internal glands of an organism directly into the circulatory system, regulating distant target organs. In vertebrates, the hypothalamus is the neu ...
is a critical focus of psychopharmacology because 1) drugs can alter the secretion of many hormones; 2) hormones may alter the behavioral responses to drugs; 3) hormones themselves sometimes have psychoactive properties; and 4) the secretion of some hormones, especially those dependent on the
pituitary gland
In vertebrate anatomy, the pituitary gland, or hypophysis, is an endocrine gland, about the size of a chickpea and weighing, on average, in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain. The ...
, is controlled by neurotransmitter systems in the brain.
Psychopharmacological substances
Alcohol
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 ...
is a
depressant
A depressant, or central depressant, is a drug that lowers neurotransmission levels, which is to depress or reduce arousal or stimulation, in various areas of the brain. Depressants are also colloquially referred to as downers as they lower the ...
, the effects of which may vary according to dosage amount, frequency, and chronicity. As a member of the sedative-hypnotic class, at the lowest doses, the individual feels relaxed and less anxious. In quiet settings, the user may feel drowsy, but in settings with increased sensory stimulation, individuals may feel uninhibited and more confident. High doses of alcohol rapidly consumed may produce
amnesia
Amnesia is a deficit in memory caused by brain damage or disease,Gazzaniga, M., Ivry, R., & Mangun, G. (2009) Cognitive Neuroscience: The biology of the mind. New York: W.W. Norton & Company. but it can also be caused temporarily by the use ...
for the events that occur during intoxication. Other effects include reduced coordination, which leads to slurred speech, impaired fine-motor skills, and delayed reaction time. The effects of alcohol on the body's neurochemistry are more difficult to examine than some other drugs. This is because the chemical nature of the substance makes it easy to penetrate into the brain, and it also influences the
phospholipid bilayer
The lipid bilayer (or phospholipid bilayer) is a thin polar membrane made of two layers of lipid molecules. These membranes are flat sheets that form a continuous barrier around all cells. The cell membranes of almost all organisms and many vir ...
of neurons. This allows alcohol to have a widespread impact on many normal cell functions and modifies the actions of several neurotransmitter systems. Alcohol inhibits
glutamate
Glutamic acid (symbol Glu or E; the ionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can syn ...
(a major excitatory neurotransmitter in the nervous system) neurotransmission by reducing the effectiveness at the
NMDA
''N''-methyl--aspartic acid or ''N''-methyl--aspartate (NMDA) is an amino acid derivative that acts as a specific agonist at the NMDA receptor mimicking the action of glutamate, the neurotransmitter which normally acts at that receptor. Unlike ...
receptor, which is related to memory loss associated with intoxication. It also modulates the function of
GABA, a major inhibitory amino acid neurotransmitter. Abuse of alcohol has also been correlated with thiamine deficiencies within the brain, leading to lasting neurological conditions that affect primarily the ability of the brain to effectively store memories.
One such neurological condition is called
Korsakoff's syndrome
Korsakoff syndrome (KS) is a disorder of the central nervous system characterized by amnesia, deficits in explicit memory, and confabulation. This neurological disorder is caused by a deficiency of thiamine (vitamin B1) in the brain, and it is ...
, for which very few effective treatment modalities have been found.
The reinforcing qualities of alcohol leading to repeated use – and thus also the mechanisms of withdrawal from chronic alcohol use – are partially due to the substance's action on the
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 ...
system. This is also due to alcohol's effect on the
opioid
Opioids are substances that act on opioid receptors to produce morphine-like effects. Medically they are primarily used for pain relief, including anesthesia. Other medical uses include suppression of diarrhea, replacement therapy for opioid us ...
systems, or
endorphins
Endorphins (contracted from endogenous morphine) are chemical signals in the brain that block the perception of pain and increase feelings of wellbeing. They are produced and stored in an area of the brain known as the pituitary gland.
Hist ...
, that have opiate-like effects, such as modulating pain, mood, feeding, reinforcement, and response to stress.
Antidepressants
Antidepressant
Antidepressants are a class of medication used to treat major depressive disorder, anxiety disorders, chronic pain conditions, and to help manage addictions. Common side-effects of antidepressants include dry mouth, weight gain, dizziness, hea ...
s reduce symptoms of mood disorders primarily through the regulation of
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
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 ...
(particularly the
5-HT receptor
5-HT receptors, 5-hydroxytryptamine receptors, or serotonin receptors, are a group of G protein-coupled receptor and ligand-gated ion channels found in the central and peripheral nervous systems. They mediate both excitatory and inhibitory neur ...
s). After chronic use, neurons adapt to the change in biochemistry, resulting in a change in pre- and postsynaptic receptor density and second messenger function.
The use of antidepressants originates from the Monoamine Theory of Depression and Anxiety, which states that the disruption of the activity of nitrogen containing neurotransmitters (i.e. serotonin, norepinephrine, and dopamine) is strongly correlated with the presence of depressive symptoms.
Monoamine oxidase inhibitor
Monoamine oxidase inhibitors (MAOIs) are a class of drugs that inhibit the activity of one or both monoamine oxidase enzymes: monoamine oxidase A (MAO-A) and monoamine oxidase B (MAO-B). They are best known as effective antidepressants, espe ...
s (MAOIs) are the oldest class of antidepressants. They inhibit
monoamine oxidase
Monoamine oxidases (MAO) () are a family of enzymes that catalyze the oxidation of monoamines, employing oxygen to clip off their amine group. They are found bound to the outer membrane of mitochondria in most cell types of the body. The first ...
, the enzyme that metabolizes the monoamine neurotransmitters in the presynaptic terminals that are not contained in protective synaptic vesicles. The inhibition of the enzyme increases the amount of neurotransmitter available for release. It increases norepinephrine, dopamine, and 5-HT, thus increasing the action of the transmitters at their receptors. MAOIs have been somewhat disfavored because of their reputation for more serious side effects.
Tricyclic antidepressant
Tricyclic antidepressants (TCAs) are a class of medications that are used primarily as antidepressants, which is important for the management of depression. They are second-line drugs next to SSRIs. TCAs were discovered in the early 1950s and wer ...
s (TCAs) work through binding to the presynaptic transporter proteins and blocking the reuptake of norepinephrine or 5-HT into the presynaptic terminal, prolonging the duration of transmitter action at the synapse.
Selective serotonin reuptake inhibitor
Selective serotonin reuptake inhibitors (SSRIs) are a class of drugs that are typically used as antidepressants in the treatment of major depressive disorder, anxiety disorders, and other psychological conditions.
SSRIs increase the extracell ...
s (SSRIs) selectively block the reuptake of serotonin (5-HT) through their inhibiting effects on the sodium/potassium
ATP-dependent serotonin transporter in presynaptic neurons. This increases the availability of 5-HT in the synaptic cleft.
The main parameters to consider in choosing an antidepressant are side effects and safety. Most SSRIs are available generically and are relatively inexpensive. Older antidepressants such as TCAs and MAOIs usually require more visits and monitoring, which may offset the low expense of the drugs. SSRIs are relatively safe in overdoses and better tolerated than TCAs and MAOIs for most patients.
Antipsychotics
All proven antipsychotics are postsynaptic dopamine receptor blockers (dopamine
antagonist
An antagonist is a character in a story who is presented as the chief foe of the protagonist.
Etymology
The English word antagonist comes from the Greek ἀνταγωνιστής – ''antagonistēs'', "opponent, competitor, villain, enemy, riv ...
s). For an antipsychotic to be effective, it generally requires a dopamine antagonism of 60%–80% of dopamine D
2 receptors.
First generation (typical) antipsychotics: Traditional
neuroleptics
Antipsychotics, also known as neuroleptics, are a class of psychotropic medication primarily used to manage psychosis (including delusions, hallucinations, paranoia or disordered thought), principally in schizophrenia but also in a range of oth ...
modify several neurotransmitter systems, but their clinical effectiveness is most likely due to their ability to antagonize dopamine transmission by competitively blocking the receptors or by inhibiting dopamine release. The most serious and troublesome side effects of these classical antipsychotics are movement disorders that resemble the symptoms of
Parkinson's disease
Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...
, because the neuroleptics antagonize dopamine receptors broadly, also reducing the normal dopamine-mediated inhibition of
cholinergic
Cholinergic agents are compounds which mimic the action of acetylcholine and/or butyrylcholine. In general, the word "choline" describes the various quaternary ammonium salts containing the ''N'',''N'',''N''-trimethylethanolammonium cation. F ...
cells in the
striatum
The striatum, or corpus striatum (also called the striate nucleus), is a nucleus (a cluster of neurons) in the subcortical basal ganglia of the forebrain. The striatum is a critical component of the motor and reward systems; receives glutamate ...
.
Second-generation (atypical) antipsychotics: The concept of "atypicality" is from the finding that second generation antipsychotics (SGAs) have a greater serotonin/dopamine ratio than earlier drugs, and might be associated with improved efficacy (particularly for the
negative symptoms
Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showin ...
of psychosis) and reduced
extrapyramidal side effects
Extrapyramidal symptoms (EPS) are symptoms that are archetypically associated with the extrapyramidal system of the brain's cerebral cortex. When such symptoms are caused by medications or other drugs, they are also known as extrapyramidal side ...
. Some of the efficacy of atypical antipsychotics may be due to 5-HT
2 antagonism or the blockade of other dopamine receptors. Agents that purely block 5-HT
2 or dopamine receptors other than D
2 have often failed as effective antipsychotics.
Benzodiazepines
Benzodiazepine
Benzodiazepines (BZD, BDZ, BZs), sometimes called "benzos", are a class of depressant drugs whose core chemical structure is the fusion of a benzene ring and a diazepine ring. They are prescribed to treat conditions such as anxiety disorders, ...
s are often used to reduce anxiety symptoms, muscle tension, seizure disorders, insomnia, symptoms of alcohol withdrawal, and panic attack symptoms. Their action is primarily on specific benzodiazepine sites on the GABA
A receptor. This receptor complex is thought to mediate the
anxiolytic
An anxiolytic (; also antipanic or antianxiety agent) is a medication or other intervention that reduces anxiety. This effect is in contrast to anxiogenic agents which increase anxiety. Anxiolytic medications are used for the treatment of anxi ...
, sedative, and
anticonvulsant
Anticonvulsants (also known as antiepileptic drugs or recently as antiseizure drugs) are a diverse group of pharmacological agents used in the treatment of epileptic seizures. Anticonvulsants are also increasingly being used in the treatment of b ...
actions of the benzodiazepines.
Use of benzodiazepines carries the risk of tolerance (necessitating increased dosage), dependence, and abuse. Taking these drugs for a long period of time can lead to
severe withdrawal symptoms upon abrupt discontinuation.
Hallucinogens
Classical Serotonergic Psychedelics
Psychedelics
Psychedelics are a subclass of hallucinogenic drugs whose primary effect is to trigger non-ordinary states of consciousness (known as psychedelic experiences or "trips").Pollan, Michael (2018). ''How to Change Your Mind: What the New Science of ...
cause perceptual and cognitive distortions without delirium. The state of intoxication is often called a "trip". Onset is the first stage after an individual ingests (
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 ...
,
psilocybin
Psilocybin ( , ) is a naturally occurring psychedelic prodrug compound produced by more than 200 species of fungi. The most potent are members of the genus ''Psilocybe'', such as '' P. azurescens'', '' P. semilanceata'', and '' P.&nbs ...
,
ayahuasca
AyahuascaPronounced as in the UK and in the US. Also occasionally known in English as ''ayaguasca'' (Spanish-derived), ''aioasca'' (Brazilian Portuguese-derived), or as ''yagé'', pronounced or . Etymologically, all forms but ''yagé'' descen ...
, and
mescaline
Mescaline or mescalin (3,4,5-trimethoxyphenethylamine) is a naturally occurring psychedelic protoalkaloid of the substituted phenethylamine class, known for its hallucinogenic effects comparable to those of LSD and psilocybin.
Biological sou ...
) or smokes (
dimethyltryptamine
''N'',''N''-Dimethyltryptamine (DMT or ''N'',''N''-DMT, SPL026) is a substituted tryptamine that occurs in many plants and animals, including human beings, and which is both a derivative and a structural analog of tryptamine. It is used as a ...
) the substance. This stage may consist of visual effects, with an intensification of colors and the appearance of geometric patterns that can be seen with one's eyes closed. This is followed by a plateau phase, where the subjective sense of time begins to slow and the visual effects increase in intensity. The user may experience
synesthesia
Synesthesia (American English) or synaesthesia (British English) is a perceptual phenomenon in which stimulation of one sensory or cognitive pathway leads to involuntary experiences in a second sensory or cognitive pathway. People who re ...
, a crossing-over of sensations (for example, one may "see" sounds and "hear" colors). These outward sensory effects have been referred to as the "mystical experience", and current research suggests that this state could be beneficial to the treatment of some mental illnesses, such as depression and possibly addiction. In instances where some patients have seen a lack of improvement from the use of antidepressants, serotonergic hallucinogens have been observed to be rather effective in treatment.
In addition to the sensory-perceptual effects, hallucinogenic substances may induce feelings of depersonalization, emotional shifts to a euphoric or anxious/fearful state, and a disruption of logical thought. Hallucinogens are classified chemically as either
indolamines
Indolamines are a family of neurotransmitters that share a common molecular structure (namely, indolamine). Indolamines are a classification of monoamine neurotransmitter, along with catecholamines and ethylamine derivatives. A common example of ...
(specifically
tryptamines
Substituted tryptamines, or serotonin analogues, are organic compounds which may be thought of as being derived from tryptamine itself. The molecular structures of all tryptamines contain an indole ring, joined to an amino (NH2) group via an ethy ...
), sharing a common structure with serotonin, or as
phenethylamines
Substituted phenethylamines (or simply phenethylamines) are a chemical class of organic compounds that are based upon the phenethylamine structure; the class is composed of all the derivative compounds of phenethylamine which can be formed by ...
, which share a common structure with norepinephrine. Both classes of these drugs are
agonist
An agonist is a chemical that activates a receptor to produce a biological response. Receptors are cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an antagonist blocks the action of the ago ...
s at the 5-HT
2 receptors; this is thought to be the central component of their hallucinogenic properties. Activation of 5-HT
2A may be particularly important for hallucinogenic activity. However, repeated exposure to hallucinogens leads to rapid tolerance, likely through down-regulation of these receptors in specific target cells.
Research suggests that hallucinogens affect many of these receptor sites around the brain and that through these interactions, hallucinogenic substances may be capable of inducing positive introspective experiences.
The current research implies that many of the effects that can be observed occur in the occipital lobe and the frontomedial cortex; however, they also present many secondary global effects in the brain that have not yet been connected to the substance's biochemical mechanism of action.
Dissociative Hallucinogens
Another class of hallucinogens, known as
dissociative
Dissociatives, colloquially dissos, are a subclass of hallucinogens which distort perception of sight and sound and produce feelings of detachment – dissociation – from the environment and/or self. Although many kinds of drugs are capable of ...
s, includes drugs such as
ketamine
Ketamine is a dissociative anesthetic used medically for induction and maintenance of anesthesia. It is also used as a recreational drug. It is one of the safest anesthetics, as, in contrast with opiates, ether, and propofol, it suppresses ne ...
,
phencyclidine
Phencyclidine or phenylcyclohexyl piperidine (PCP), also known as angel dust among other names, is a dissociative anesthetic mainly used recreationally for its significant mind-altering effects. PCP may cause hallucinations, distorted perceptio ...
(PCP), and ''
Salvia divinorum
''Salvia divinorum'' (Latin: "sage of the diviners"; also called ska maría pastora, seer's sage, yerba de la pastora, magic mint or simply salvia) is a plant species with transient psychoactive properties when its leaves are consumed by che ...
''. Drugs such as these are thought to interact predominantly with glutamate recpetors within the brain. Specifically, ketamine is thought to block NMDA receptors that are responsible for signalling in the glutamate pathways.
Ketamine's more tranquilizing effects can be seen in the central nervous system through interactions with parts of the thalamus by inhibition of certain functions.
Ketamine has become a major drug of research for the treatment of depression.
These antidepressant effects are thought to be related to the drug's action on the glutamate receptor system and the relative spike in glutamate levels, as well as its interaction with mTOR, which is an enzymatic protein involved in catabolic processes in the human body.
Phencyclidine's biochemical properties are still mostly unknown; however, its use has been associated with dissociation, hallucinations, and in some cases seizures and death. ''Salvia divinorum'', a plant native to Mexico, has strong dissociative and hallucinogenic properties when the dry leaves are smoked or chewed.
The qualitative value of these effects, whether negative or positive, has been observed to vary between individuals with many other factors to consider.
Hypnotics
Hypnotic
Hypnotic (from Greek ''Hypnos'', sleep), or soporific drugs, commonly known as sleeping pills, are a class of (and umbrella term for) psychoactive drugs whose primary function is to induce sleep (or surgical anesthesiaWhen used in anesthesia ...
s are often used to treat the symptoms of insomnia or other sleep disorders. Benzodiazepines are still among the most widely prescribed sedative-hypnotics in the United States today. Certain non-benzodiazepine drugs are used as hypnotics as well. Although they lack the chemical structure of the benzodiazepines, their sedative effect is similarly through action on the GABA
A receptor. They also have a reputation of being less addictive than benzodiazepines.
Melatonin
Melatonin is a natural product found in plants and animals. It is primarily known in animals as a hormone released by the pineal gland in the brain at night, and has long been associated with control of the sleep–wake cycle.
In vertebrates ...
, a naturally-occurring hormone, is often used over the counter (OTC) to treat insomnia and jet lag. This hormone appears to be excreted by the pineal gland early during the sleep cycle and may contribute to human
circadian rhythm
A circadian rhythm (), or circadian cycle, is a natural, internal process that regulates the sleep–wake cycle and repeats roughly every 24 hours. It can refer to any process that originates within an organism (i.e., Endogeny (biology), endogeno ...
s. Because OTC melatonin supplements are not subject to careful and consistent manufacturing, more specific melatonin agonists are sometimes preferred. They are used for their action on melatonin receptors in the
suprachiasmatic nucleus
The suprachiasmatic nucleus or nuclei (SCN) is a tiny region of the brain in the hypothalamus, situated directly above the optic chiasm. It is responsible for controlling circadian rhythms. The neuronal and hormonal activities it generates regula ...
, responsible for sleep-wake cycles. Many barbiturates have or had an FDA-approved indication for use as sedative-hypnotics, but have become less widely used because of their limited safety margin in overdose, their potential for dependence, and the degree of
central nervous system depression
Central nervous system (CNS) depression is a physiological state that can result in a decreased rate of breathing, decreased heart rate, and loss of consciousness possibly leading to coma or death.
It is the result of inhibited or suppressed brai ...
they induce. The amino-acid
L-tryptophan
Tryptophan (symbol Trp or W)
is an α-amino acid that is used in the biosynthesis of proteins. Tryptophan contains an Alpha_and_beta_carbon , α-amino group, an α-carboxylic acid group, and a side chain indole, making it a polar molecule with ...
is also available OTC, and seems to be free of dependence or abuse liability. However, it is not as powerful as the traditional hypnotics. Because of the possible role of serotonin in sleep patterns, a new generation of 5-HT
2 antagonists are in current development as hypnotics.
Cannabis and the cannabinoids
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 ...
consumption produces a dose-dependent state of intoxication in humans. There is commonly increased blood flow to the skin, which leads to an increased heart rate and sensations of warmth or flushing. It also frequently induces increased hunger.
Iversen (2000) categorized the subjective and behavioral effects often associated with cannabis into three stages. The first is the "buzz", a brief period of initial responding where the main effects are lightheadedness or slight dizziness, in addition to possible tingling sensations in the extremities or other parts of the body. The "high" is characterized by feelings of euphoria and exhilaration characterized by mild psychedelia as well as a sense of disinhibition. If the individual has taken a sufficiently large dose of cannabis, the level of intoxication progresses to the stage of being "stoned", and the user may feel calm, relaxed, and possibly in a dreamlike state. Sensory reactions may include the feeling of floating, enhanced visual and auditory perception, visual illusions, or the perception of the slowing of time passage, which are somewhat psychedelic in nature.
There exist two primary CNS cannabinoid receptors, on which marijuana and the cannabinoids act. Both the
CB1 receptor
Cannabinoid receptor type 1 (CB1), also known as cannabinoid receptor 1, is a G protein-coupled cannabinoid receptor that in humans is encoded by the ''CNR1'' gene. The human CB1 receptor is expressed in the peripheral nervous system and central ...
and
CB2 receptor
The cannabinoid receptor type 2, abbreviated as CB2, is a G protein-coupled receptor from the cannabinoid receptor family that in humans is encoded by the ''CNR2'' gene. It is closely related to the cannabinoid receptor type 1 (CB1), which is la ...
are found in the brain. The CB2 receptor is also found in the immune system. CB
1 is expressed at high densities in the
basal ganglia
The basal ganglia (BG), or basal nuclei, are a group of subcortical nuclei, of varied origin, in the brains of vertebrates. In humans, and some primates, there are some differences, mainly in the division of the globus pallidus into an extern ...
,
cerebellum
The cerebellum (Latin for "little brain") is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as or even larger. In humans, the cerebel ...
,
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 ...
, and
cerebral cortex
The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. The cerebral cortex mostly consists of the six-layered neocortex, with just 10% consisting of ...
. Receptor activation can inhibit
cAMP
Camp may refer to:
Outdoor accommodation and recreation
* Campsite or campground, a recreational outdoor sleeping and eating site
* a temporary settlement for nomads
* Camp, a term used in New England, Northern Ontario and New Brunswick to descri ...
formation, inhibit voltage-sensitive calcium ion channels, and activate potassium ion channels. Many CB
1 receptors are located on axon terminals, where they act to inhibit the release of various neurotransmitters. In combination, these chemical actions work to alter various functions of the central nervous system, including the motor system, memory, and various cognitive processes.
Opioids
The
opioid
Opioids are substances that act on opioid receptors to produce morphine-like effects. Medically they are primarily used for pain relief, including anesthesia. Other medical uses include suppression of diarrhea, replacement therapy for opioid us ...
category of drugs – including drugs such as
heroin
Heroin, also known as diacetylmorphine and diamorphine among other names, is a potent opioid mainly used as a recreational drug for its euphoric effects. Medical grade diamorphine is used as a pure hydrochloride salt. Various white and brow ...
,
morphine
Morphine is a strong opiate that is found naturally in opium, a dark brown resin in poppies (''Papaver somniferum''). It is mainly used as a analgesic, pain medication, and is also commonly used recreational drug, recreationally, or to make ...
, and
oxycodone
Oxycodone, sold under various brand names such as Roxicodone and OxyContin (which is the extended release form), is a strong, semi-synthetic opioid used medically for treatment of moderate to severe pain. It is highly addictive and a commonly ...
– belong to the class of
narcotic
The term narcotic (, from ancient Greek ναρκῶ ''narkō'', "to make numb") originally referred medically to any psychoactive compound with numbing or paralyzing properties. In the United States, it has since become associated with opiates ...
analgesic
An analgesic drug, also called simply an analgesic (American English), analgaesic (British English), pain reliever, or painkiller, is any member of the group of drugs used to achieve relief from pain (that is, analgesia or pain management). It ...
s, which reduce pain without producing unconsciousness but do produce a sense of relaxation and sleep, and at high doses may result in coma and death. The ability of opioids (both
endogenous
Endogenous substances and processes are those that originate from within a living system such as an organism, tissue, or cell.
In contrast, exogenous substances and processes are those that originate from outside of an organism.
For example, es ...
and
exogenous
In a variety of contexts, exogeny or exogeneity () is the fact of an action or object originating externally. It contrasts with endogeneity or endogeny, the fact of being influenced within a system.
Economics
In an economic model, an exogeno ...
) to relieve pain depends on a complex set of neuronal pathways at the spinal cord level, as well as various locations above the spinal cord. Small
endorphin
Endorphins (contracted from endogenous morphine) are chemical signals in the brain that block the perception of pain and increase feelings of wellbeing. They are produced and stored in an area of the brain known as the pituitary gland.
Hist ...
neurons in the spinal cord act on receptors to decrease the conduction of pain signals from the spinal cord to higher brain centers. Descending neurons originating in the
periaqueductal gray
The periaqueductal gray (PAG, also known as the central gray) is a brain region that plays a critical role in autonomic function, motivated behavior and behavioural responses to threatening stimuli. PAG is also the primary control center for d ...
give rise to two pathways that further block pain signals in the spinal cord. The pathways begin in the locus coeruleus (noradrenaline) and the nucleus of raphe (serotonin). Similar to other abused substances, opioid drugs increase dopamine release in the
nucleus accumbens
The nucleus accumbens (NAc or NAcc; also known as the accumbens nucleus, or formerly as the ''nucleus accumbens septi'', Latin for "nucleus adjacent to the septum") is a region in the basal forebrain rostral to the preoptic area of the hypotha ...
.
Opioids are more likely to produce
physical dependence
Physical dependence is a physical condition caused by chronic use of a tolerance-forming drug, in which abrupt or gradual drug withdrawal causes unpleasant physical symptoms. Physical dependence can develop from low-dose therapeutic use of certai ...
than any other class of psychoactive drugs, and can lead to painful withdrawal symptoms if discontinued abruptly after regular use.
Stimulants
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 ...
is one of the more common stimulants and is a complex drug that interacts with various neurotransmitter systems. It commonly causes heightened alertness, increased confidence, feelings of exhilaration, reduced fatigue, and a generalized sense of well-being. The effects of cocaine are similar to those of amphetamines, though cocaine tends to have a shorter duration of effect. In high doses or with prolonged use, cocaine can result in a number of negative effects, including irritability, anxiety, exhaustion, total insomnia, and even psychotic symptomatology. Most of the behavioral and physiological actions of cocaine can be explained by its ability to block the reuptake of the two
catecholamine
A catecholamine (; abbreviated CA) is a monoamine neurotransmitter, an organic compound that has a catechol (benzene with two hydroxyl side groups next to each other) and a side-chain amine.
Catechol can be either a free molecule or a subst ...
s, dopamine and norepinephrine, as well as serotonin. Cocaine binds to transporters that normally clear these transmitters from the synaptic cleft, inhibiting their function. This leads to increased levels of neurotransmitter in the cleft and transmission at the synapses.
Based on in-vitro studies using rat brain tissue, cocaine binds most strongly to the serotonin transporter, followed by the dopamine transporter, and then the norepinephrine transporter.
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 ...
tend to cause the same behavioral and subjective effects of cocaine. Various forms of amphetamine are commonly used to treat the symptoms of
attention deficit hyperactivity disorder
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-inap ...
(ADHD) and
narcolepsy
Narcolepsy is a long-term neurological disorder that involves a decreased ability to regulate sleep–wake cycles. Symptoms often include periods of excessive daytime sleepiness and brief involuntary sleep episodes. About 70% of those affec ...
, or are used recreationally. Amphetamine and
methamphetamine
Methamphetamine (contracted from ) is a potent central nervous system (CNS) stimulant that is mainly used as a recreational drug and less commonly as a second-line treatment for attention deficit hyperactivity disorder and obesity. Methamph ...
are indirect agonists of the catecholaminergic systems. They block catecholamine reuptake, in addition to releasing catecholamines from nerve terminals. There is evidence that dopamine receptors play a central role in the behavioral responses of animals to cocaine, amphetamines, and other psychostimulant drugs. One action causes the dopamine molecules to be released from inside the vesicles into the cytoplasm of the nerve terminal, which are then transported outside by the
mesolimbic
The mesolimbic pathway, sometimes referred to as the reward pathway, is a dopaminergic pathway in the brain. The pathway connects the ventral tegmentum, ventral tegmental area in the midbrain to the ventral striatum of the basal ganglia in the for ...
dopamine pathway to the nucleus accumbens. This plays a key role in the rewarding and reinforcing effects of cocaine and amphetamine in animals, and is the primary mechanism for amphetamine dependence.
Psychopharmacological research
In psychopharmacology, researchers are interested in any substance that crosses the
blood–brain barrier
The blood–brain barrier (BBB) is a highly selective semipermeable membrane, semipermeable border of endothelium, endothelial cells that prevents solutes in the circulating blood from ''non-selectively'' crossing into the extracellular fluid of ...
and thus has an effect on behavior, mood, or cognition. Drugs are researched for their physiochemical properties, physical
side effects
In medicine, a side effect is an effect, whether therapeutic or adverse, that is secondary to the one intended; although the term is predominantly employed to describe adverse effects, it can also apply to beneficial, but unintended, consequence ...
, and psychological side effects. Researchers in psychopharmacology study a variety of different psychoactive substances, including alcohol, cannabinoids,
club drug
Club drugs, also called rave drugs or party drugs, are a loosely defined category of recreational drugs which are associated with discothèques in the 1970s and nightclubs, dance clubs, electronic dance music (EDM) parties, and raves in the 198 ...
s, psychedelics, opiates,
nicotine
Nicotine is a natural product, naturally produced alkaloid in the nightshade family of plants (most predominantly in tobacco and ''Duboisia hopwoodii'') and is widely used recreational drug use, recreationally as a stimulant and anxiolytic. As ...
,
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 ...
,
psychomotor stimulants,
inhalant
Inhalants are a broad range of household and industrial chemicals whose volatile vapors or pressurized gases can be concentrated and breathed in via the nose or mouth to produce intoxication, in a manner not intended by the manufacturer. They ...
s, and
anabolic–androgenic steroid
Anabolic steroids, also known more properly as anabolic–androgenic steroids (AAS), are steroidal androgens that include natural androgens like testosterone as well as synthetic androgens that are structurally related and have similar effects t ...
s. They also study drugs used in the treatment of affective and anxiety disorders, as well 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 ...
.
Clinical studies are often very specific, typically beginning with animal testing and ending with human testing. In the human testing phase, there is often a group of subjects: one group is given a placebo, and the other is administered a carefully measured
therapeutic dose
The therapeutic index (TI; also referred to as therapeutic ratio) is a quantitative measurement of the relative safety of a drug. It is a comparison of the amount of a therapeutic agent that causes the therapeutic effect to the amount that causes ...
of the drug in question. After all of the testing is completed, the drug is proposed to the concerned regulatory authority (e.g. the U.S.
FDA
The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food s ...
), and is either commercially introduced to the public via
prescription, or deemed safe enough for
over-the-counter
Over-the-counter (OTC) drugs are medicines sold directly to a consumer without a requirement for a prescription from a healthcare professional, as opposed to prescription drugs, which may be supplied only to consumers possessing a valid prescr ...
sale.
Though particular drugs are prescribed for specific symptoms or syndromes, they are usually not specific to the treatment of any single mental disorder.
A somewhat controversial application of psychopharmacology is "cosmetic psychiatry": persons who do not meet criteria for any psychiatric disorder are nevertheless prescribed psychotropic medication. The antidepressant
bupropion
Bupropion, sold under the brand names Wellbutrin and Zyban among others, is an atypical antidepressant primarily used to treat major depressive disorder and to support smoking cessation. It is also popular as an add-on medication in the case ...
is then prescribed to increase perceived energy levels and assertiveness while diminishing the need for sleep. The antihypertensive compound
propranolol
Propranolol, sold under the brand name Inderal among others, is a medication of the beta blocker class. It is used to treat high blood pressure, a number of types of irregular heart rate, thyrotoxicosis, capillary hemangiomas, performance anx ...
is sometimes chosen to eliminate the discomfort of day-to-day anxiety.
Fluoxetine
Fluoxetine, sold under the brand names Prozac and Sarafem, among others, is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. It is used for the treatment of major depressive disorder, obsessive–compulsive disorde ...
in nondepressed people can produce a feeling of generalized well-being.
Pramipexole
Pramipexole, sold under the brand Mirapex among others, is medication used to treat Parkinson's disease (PD) and restless legs syndrome (RLS). In Parkinson's disease it may be used alone or together with levodopa. It is taken by mouth. Pramipex ...
, a treatment for restless leg syndrome, can dramatically increase libido in women. These and other off-label lifestyle applications of medications are not uncommon. Although occasionally reported in the medical literature, no guidelines for such usage have been developed. There is also a potential for the misuse of prescription psychoactive drugs by elderly persons, who may have multiple drug prescriptions.
See also
*
Pharmacology
Pharmacology is a branch of medicine, biology and pharmaceutical sciences concerned with drug or medication action, where a drug may be defined as any artificial, natural, or endogenous (from within the body) molecule which exerts a biochemica ...
*
Neuropsychopharmacology
Neuropsychopharmacology, an interdisciplinary science related to psychopharmacology (study of effects of drugs on the mind) and fundamental neuroscience, is the study of the neural mechanisms that drugs act upon to influence behavior. It entails ...
*
Psychiatry
Psychiatry is the medical specialty devoted to the diagnosis, prevention, and treatment of mental disorders. These include various maladaptations related to mood, behaviour, cognition, and perceptions. See glossary of psychiatry.
Initial psych ...
*
History of pharmacy
The history of pharmacy as an independent science dates back to the first third of the 19th century. Before then, pharmacy evolved from antiquity as part of medicine. The history of pharmacy coincides well with the history of medicine, but it's im ...
*
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 ...
*
Recreational drug use
Recreational drug use indicates the use of one or more psychoactive drugs to induce an altered state of consciousness either for pleasure or for some other casual purpose or pastime by modifying the perceptions and emotions of the user. When a ...
*
Nathan S. Kline
References
Further reading
*, an introductory text with detailed examples of treatment protocols and problems.
*, a general historical analysis.
*
*
Peer-reviewed journals
* ''
Experimental and Clinical Psychopharmacology
''Experimental and Clinical Psychopharmacology'' is a peer-reviewed scientific journal published by the American Psychological Association. It was established in 1993 and covers research in clinical psychology. The current editor-in-chief is Willia ...
'',
American Psychological Association
The American Psychological Association (APA) is the largest scientific and professional organization of psychologists in the United States, with over 133,000 members, including scientists, educators, clinicians, consultants, and students. It ha ...
* ''
Journal of Clinical Psychopharmacology
The ''Journal of Clinical Psychopharmacology'' is a peer-reviewed medical journal published by Lippincott Williams & Wilkins covering clinical psychopharmacology. It was founded by Richard I. Shader, MD in 1981 as the first journal of an interna ...
'', Lippincott Williams & Wilkins
* ''
Journal of Psychopharmacology
The ''Journal of Psychopharmacology'' is a monthly peer-reviewed scientific journal published by Sage Publications on behalf of the British Association for Psychopharmacology. It was established in 1987 and is a member of the Committee on Public ...
'', British Association for Psychopharmacology, SAGE Publications
* ''
Psychopharmacology
Psychopharmacology (from Greek grc, ψῡχή, psȳkhē, breath, life, soul, label=none; grc, φάρμακον, pharmakon, drug, label=none; and grc, -λογία, -logia, label=none) is the scientific study of the effects drugs have on m ...
'', Springer Berlin/Heidelberg
External links
''Psychopharmacology: The Fourth Generation of Progress''American College of Neuropsychopharmacology(ACNP)
Bibliographical history of Psychopharmacology and Pharmacopsychology— Advances in the History of Psychology,
York University
York University (french: Université York), also known as YorkU or simply YU, is a public university, public research university in Toronto, Ontario, Canada. It is Canada's fourth-largest university, and it has approximately 55,700 students, 7,0 ...
Monograph ''Psychopharmacology Today''British Association for Psychopharmacology(BAP)
Psychopharmacology Institute Video lectures and tutorials on psychotropic medications.
{{Authority control
Neuropharmacology