Psychopharmacology
Psychopharmacology (from Greek ψῡχή, psȳkhē, 'breath, life, soul'; φάρμακον, pharmakon, 'drug'; and -λογία, -logia) is the scientific study of the effects drugs have on mood, sensation, thinking, behavior, judgment and evaluation, and memory.
[1] The field of psychopharmacology studies a wide range of substances with various types of psychoactive properties, focusing primarily on the chemical interactions with the brain.
Psychoactive drugs interact with particular target sites or receptors found in the nervous system to induce widespread changes in physiological or psychological functions.
Not often mentioned or included in the field of psychopharmacology today are psychoactive substances not identified as useful in modern mental health settings or references.
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.
For example, St. John's wort was traditionally prescribed in parts of Europe for depression (in addition to use as a general-purpose tea), and Chinese medicine developed elaborate lists of herbs and preparations.
[4] 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.
[citation needed] Psychoactive drugs exert their sensory and behavioral effects almost entirely by acting on neurotransmitters and by modifying one or more aspects of synaptic transmission.
Other effects include reduced coordination, which leads to slurred speech, impaired fine-motor skills, and delayed reaction time.
Alcohol inhibits glutamate (a major excitatory neurotransmitter in the nervous system) neurotransmission by reducing the effectiveness at the NMDA receptor, which is related to memory loss associated with intoxication.
[9] Despite its longstanding prominence in pharmaceutical advertising, the myth that low serotonin levels cause depression is not supported by scientific evidence.
The most serious and troublesome side effects of these classical antipsychotics are movement disorders that resemble the symptoms of Parkinson's disease, because the neuroleptics antagonize dopamine receptors broadly, also reducing the normal dopamine-mediated inhibition of cholinergic cells in the striatum.
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.
[16] 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.
[20] Salvia divinorum, a plant native to Mexico, has strong dissociative and hallucinogenic properties when the dry leaves are smoked or chewed.
This hormone appears to be excreted by the pineal gland early during the sleep cycle and may contribute to human circadian rhythms.
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 they induce.
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.
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.
Descending neurons originating in the periaqueductal gray give rise to two pathways that further block pain signals in the spinal cord.
[1] Opioids are more likely to produce physical dependence worse than that of other classes of psychoactive drugs, and can lead to painful withdrawal symptoms if discontinued abruptly after regular use.
It commonly causes heightened alertness, increased confidence, feelings of exhilaration, reduced fatigue, and a generalized sense of well-being.
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 catecholamines, dopamine and norepinephrine, as well as serotonin.
Various forms of amphetamine are commonly used to treat the symptoms of attention deficit hyperactivity disorder (ADHD) and narcolepsy, or are used recreationally.
There is evidence that dopamine receptors play a central role in the behavioral responses of animals to cocaine, amphetamines, and other psychostimulant drugs.
[citation needed] In psychopharmacology, researchers are interested in any substance that crosses the blood–brain barrier and thus has an effect on behavior, mood, or cognition.
Researchers in psychopharmacology study a variety of different psychoactive substances, including alcohol, cannabinoids, club drugs, psychedelics, opiates, nicotine, caffeine, psychomotor stimulants, inhalants, and anabolic–androgenic steroids.
After all of the testing is completed, the drug is proposed to the concerned regulatory authority (e.g. the U.S. FDA), and is either commercially introduced to the public via prescription, or deemed safe enough for over-the-counter sale.
A somewhat controversial application of psychopharmacology is "cosmetic psychiatry": persons who do not meet criteria for any psychiatric disorder are nevertheless prescribed psychotropic medication.
