Psychopharmacology

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Psychopharmacology is the study of drug-induced changes in mood, thinking, and behavior.[1] These drugs may originate from natural sources such as plants and animals, or from artificial sources such as chemical syntheses in the laboratory. These drugs interact with particular target sites or receptors found in the nervous system to induce widespread changes in physiological or psychological functions. The specific interaction between drugs and their target sites or receptors is referred to as drug action. The widespread changes in physiological or psychological function is referred to as drug effect.

The common muscimol-bearing mushroom Amanita muscaria, also known as the Fly Agaric, is frequently regarded as one of the first used psychoactive drugs, it is suspected to be the primary/active ingredient in the sacred drug of ancient India, known as Soma.[1] There are many modern theories citing the discovery of its psychoactive properties as far back as 10,000 BCE. Modern psychopharmacology studies a wide range of substances with various types of psychoactive properties, though the professional and commercial fields of pharmacology/psychopharmacology don't typically focus on psychedelic or recreational drugs, the majority of studies are conducted on medicinal psychoactives. Bar none, studies are conducted on all psychoactives by both fields, psychopharmacology focuses primarily on the psychoactive and chemical interactions with the brain.

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[edit] History

Psychoactive drug use predates recorded history. Hunter-gatherer societies tended to favor hallucinogenic drugs, and today their use can still be observed in many surviving tribal cultures. The exact drug used depends on what the particular ecosystem a given tribe lives in can support, and are typically found growing wild. Such drugs include various hallucinogenic mushrooms and cacti, along with many other plants. These societies generally attach spiritual significance to drug use, and often incorporate it into their religious practices.

With the dawn of the Neolithic and the proliferation of agriculture, new entheogens came into use as a natural by-product of farming. Among them were opium, cannabis, and alcohol 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 was traditionally prescribed in Europe for depression (in addition to use as a general-purpose good-tasting tea), and Chinese medicine developed elaborate lists of herbs and preparations.

With the scientific revolution in Europe and America, the use of traditional herbal remedies fell out of favor with the mainstream medical establishment, although a few people continued to use and maintain knowledge of traditional European herblore. In the early 20th century, scientists began reassessing this rejection of traditional herbs in medicine. A number of important psychiatric drugs have been developed as a byproduct of the analysis of organic compounds present in traditional herbal remedies. The use of psychiatric drugs to restore mental health, or at least limit aberrant behaviour, has only been part of the European and American medical institution since the 1950s, when a number of new classes of drugs were discovered, notably tranquillizers and antidepressants, and LSD was popularized among many psychiatrists as a mental miracle drug capable of curing all manner of problems.

In the latter half of the 20th century, research into new psychopharmacologic drugs exploded, with many new drugs discovered, created, and tested. Many once-popular drugs are now out of favor, and there are fashions in psychiatric drugs, as with any other kind of drug.

[edit] Major Drug Classes that are Studied

In psychopharmacology, researchers are interested in a wide range of drug classes such as antidepressants and stimulants. Drugs are researched for their pharmaceutical properties, physical side effects, and psychological side effects. These 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 of the drug in question. After all of the testing is completed, the drug is proposed to the FDA, and is either commercially introduced to the public, introduced to the public via prescription, or deemed safe enough for over the counter sale.

[edit] Antipsychotics

Main article: Antipsychotics

Antipsychotics are drugs that are used in the treatment of various symptoms of psychosis, such as those caused by Psychotic Disorders or Schizophrenia. Antipsychotics are also sometimes used as mood stabilizers, most frequently to help manage such disorders as Bipolar disorder, even if no symptoms of psychosis are present. Antipsychotics may also be referred to as neuroleptic drugs and some antipsychotics are branded as major tranquilizers.

There are two categories of Antipsychotics, typical antipsychotics and atypical antipsychotics, and due to the nature of the drugs the majority of them require a verifiable prescription from a licensed professional.

Common Antipsychotics[2]:

[edit] Antidepressants

Main article: Antidepressants

Antidepressants are drugs used in the treatment of clinical depression, and are often used in combination with other drugs such as antipsychotics or stimulants, depending on the condition of the patient. Most antidepressants will restrain the metabolism of serotonin and/or norepinephrine. Such drugs are called Selective Serotonin Reuptake Inhibitors (SSRI), and they actively attempt to prevent the aforementioned neurotransmitters from dropping to the levels at which depression is experienced. SSRIs will often take 3-5 weeks to have a noticeable effect, due to the inability of the brain to process the flood of serotonin and it reacts by downregulating the sensitivity of the autoreceptors, which can take up to 5 weeks. Currently, Bi-functional SSRIs are being researched, which will occupy the autoreceptors, bypassing the 'throttling' of serotonin. Another type of antidepressant is an Monoamine oxidase inhibitor, which are thought to block the actions of MAO, an enzyme which assists in the breakdown of serotonin and norepinephrine. MAOI's are typically only used in the event that a tricyclic antidepressant or SSRI fails to prevent or exacerbates depression.

Common Antidepressants[3][4]:

[edit] Mood stabilizers

Main article: Mood stabilizers

In 1949, the Australian John Cade discovered that lithium salts could control mania, reducing the frequency and severity of manic episodes. This introduced the now popular drug Lithium carbonate to the mainstream public, as well as being the first mood stabilizer to be approved by the Food & Drug Administration. Many antipsychotics are used as mood stabilizers, although typically the first resort would be a standard mood stabilizer such as Lithium carbonate. Many mood stabilizers, with the exception of Lithium, are anticonvulsants.

Common Mood Stabilizers[5]:

[edit] Stimulants

Main article: Stimulants

Stimulants are some of the most widely prescribed drugs today. A stimulant is any drug that stimulates the central nervous system. Adderall®, a collection of Amphetamine salts, is one of the most prescribed pharmaceuticals in the treatment of ADHD. Typically prescribed to treat adolescents with Attention Deficit Hyperactivity Disorder and though not FDA approved for Adults, it is very common as a treatment. Patients respond differently to each drug. Most frequently used are Timed-release mediums but if such a method doesn't work there are many options to try. Stimulants have the potential to be addictive and patients with a history of drug abuse are typically monitored closely or even barred from the usage and given an alternative. Discontinuing treatment without tapering the dosage is not advisable.

Common Stimulants[6]:

[edit] Anxiolytics & Hypnotics

Barbiturates were first used as hypnotics and as anxiolytics, but as time went on, safer benzodiazepines (Lowell Randall and Leo Sternbach, 1957) were developed in the 1960s and 1970s. Eventually they led to billions of doses being consumed annually, but as prescriptions were increasing, even more was the abuse of them.

Common Anxiolytics & Hypnotics:

[edit] See also

[edit] References

  1. ^ Meyer, J. S. and Quenzer, L. S. (2004). Psychopharmacology: Drugs, the Brain and Behavior. Sinauer Associates. ISBN 0-87-893534-7
  2. ^ Stephen M. Stahl, M.D., Ph.D.; et al (2004). "A Review of the Neuropharmacology of Bupropion, a Dual Norepinephrine and Dopamine Reuptake Inhibitor" (pdf). Journal of Clinical Psychiatry; 6(04) 159-166 2004 PHYSICIANS POSTGRADUATE PRESS, INC. Retrieved on 2006-09-02.


[edit] Peer-reviewed journals

[edit] External links

Neuroscience subfields:

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Neurobiology | Cognitive Neuroscience | Computational Neuroscience | Neural Engineering | Neuroanatomy | Neurochemistry | Neuroimaging | Neurolinguistics | Neurology | Neuropharmacology | Neurophysiology | Neuropsychology | Psychopharmacology | Systems Neuroscience
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