Psychoactive drug
From Wikipedia, the free encyclopedia
A psychoactive drug or psychotropic substance is a chemical substance that acts primarily upon the central nervous system where it alters brain function, resulting in temporary changes in perception, mood, consciousness and behavior.
These drugs may be used recreationally to purposefully alter one's consciousness (such as coffee, alcohol, cocaine or cannabis), as entheogens for spiritual purposes (such as the mescaline-containing peyote cactus or psilocybin-containing mushrooms), as medication (such as the use of narcotics in controlling pain, and also as psychiatric medication (such as stimulants to treat narcolepsy and attention disorders, as well as anti-depressants and anti-psychotics for treating neurological and psychiatric illnesses).
Many of these substances (especially the stimulants and depressants) can be habit-forming, causing chemical dependency and may lead to substance abuse. Conversely, others (namely the psychedelics) can help to treat and even cure such addictions.[1][2]
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[edit] History
Drug use is a practice that dates to prehistoric times. There is archaeological evidence of the use of psychoactive substances dating back at least 10,000 years, and historical evidence of cultural use over the past 5,000 years.[3] While medicinal use seems to have played a very large role, it has been suggested that the urge to alter one's consciousness is as primary as the drive to satiate thirst, hunger or sexual desire.[4] Others suggest that marketing, availability or the pressures of modern life are why humans use so many psychoactives in their daily lives. However the long history of drug use and even children's desire for spinning, swinging, sliding indicates that the drive to alter one's state of mind is universal.[5]
This relationship is not limited to humans. A number of animals consume different psychoactive plants and animals, berries and even fermented fruit, and become intoxicated as for instance, cats after consuming catnip. Traditional legends of sacred plants often contain references to animals that introduced humankind to their use.[6] Biology suggests an evolutionary connection between psychoactive plants and animals, as to why these chemicals and their receptors exist within the nervous system.[7]
The 20th century has seen governments initially responding to many drugs by banning them and making their use, supply or trade a criminal offence. A notable example of this is the Prohibition era in the United States, where alcohol was made illegal for 13 years. However, many governments have concluded that illicit drug use cannot be sufficiently stopped through criminalization. In some countries, there has been a move toward harm reduction by health services, where the use of illicit drugs is neither condoned nor promoted, but services and support are provided to ensure users have the negative effects of their illicit drug use minimized. This can go hand-in-hand with supply reduction strategies by law-enforcement agencies.
[edit] Current uses
Psychoactive drugs are used in many contexts, including for medical treatment of mental illness,[8] for recreation,[9] and for ritual or spiritual purposes.[10]
[edit] Addiction
Psychoactive drugs are often associated with addiction. Addiction can be divided into two types: psychological addiction, by which a user feels compelled to use a drug despite negative physical or societal consequence, and physical dependence, by which a user must use a drug to avoid medically harmful withdrawal.[11] Not all drugs are physically addictive, but any activity that stimulates the brain's dopaminergic reward system — typically, any pleasurable activity[12] — can lead to psychological addiction.[11] Drugs that are most likely to cause addiction are drugs that directly stimulate the dopaminergic system, like cocaine and amphetamines. Drugs that only indirectly stimulate the dopaminergic system, such as psychedelics, are not as likely to be addictive.
Because so many consumers want to reduce or eliminate their own use of psychoactive drugs,[13] many professionals, self-help groups, and businesses specialize in that field, with varying degrees of success. Many parents attempt to influence the actions and choices of their children regarding psychoactives.
[edit] Legality and ethics
For thousands of years, people have studied psychoactive drugs, both by observation and ingestion. However, humanity remains bitterly divided regarding psychoactive drugs, and their value and use has long been an issue of major philosophical and moral contention, even to the point of war (the Opium Wars being a prime example of a war being fought over psychoactives, though moreover it was a prime example of British Imperialism and exploitation of China). A majority of youths and adults consume one or more psychoactive drugs. In the West, the most common by numbers of users are caffeine, alcohol, and nicotine, in that order. Most people accept restrictions on some and the prohibition of others, especially the "hard" drugs, which are generally illegal in most countries.[14][15][16] It is interesting to note that some of the most popular recreational drugs such as alcohol or tobacco are legal, despite being considered hard drugs by many. At the same time many soft drugs such as cannabis or psilocybin are illegal and in many cases the most tightly controlled (in the US for example both cannabis and psilocybin are Schedule I drugs, a section reserved for the most dangerous of drugs). This has led many to believe that current prohibition laws are more political in nature.
Debate continues over whether each psychoactive drug being considered is or is not spiritual, sinful, therapeutic, poisonous, ethical, immoral, effective, risky, responsible, recreational, a weapon to use against enemies, a boost to the economy, etc. These attitudes can often be deeply rooted in philosophical and/or religious beliefs, making it difficult to reach consensus on acceptable moral, philosophical, and pragmatic stances regarding psychoactive drugs. A major point of contention regards the role of government: should it (for each drug) remain neutral, prohibit, require a prescription, regulate trade, restrict advertising, promote abstention, promote moderation, and/or educate for safety, as well as whether any existing penalties or enforcement should be changed.
[edit] Effects
[edit] Drug effects on neurons
There are many ways in which psychoactive drugs can affect the brain (see neuropsychopharmacology). Each drug has a specific action on one or more neurotransmitter or neuroreceptor in the brain.
The following is a classification of notable drugs by their primary effects on their respective neurotransmitters or receptors. However, it should be noted that most drugs act on more than one transmitter or receptor in the brain.[citation needed]
Neurotransmitter/receptor | Classification | Examples |
---|---|---|
Serotonin | Serotonin receptor agonists | LSD, psilocybin, mescaline, DMT |
Selective serotonin reuptake inhibitors (SSRIs) | fluoxetine, sertraline | |
Serotonin releasers | MDMA (ecstasy) | |
GABA | GABA receptor agonists | ethanol, barbiturates, diazepam, thujone |
GABA reuptake inhibitors | tiagabine | |
GABA receptor selective agonists | muscimol, ibotenic acid | |
Opioid receptor | μ-opioid receptor agonists | morphine, heroin, oxycodone |
μ-opioid receptor inverse agonists | naloxone, naltrexone | |
κ-opioid receptor agonists | salvinorin A, butorphanol, nalbuphine | |
Dopamine | Dopamine protein transporter blockers | cocaine |
Dopamine receptor antagonists | haloperidol, droperidol | |
Monoamine oxidase (MAO) | Monoamine oxidase inhibitors (MAOIs) | phenelzine, iproniazid |
bind to MAO protein transporter | amphetamine, methamphetamine | |
NMDA receptor | NMDA receptor antagonists | ketamine, PCP, DXM |
Norepinephrine | Norepinephrine reuptake inhibitors | amoxapine, atomoxetine |
Norepinephrine releasers | mianserin | |
Cannabinoid receptor | Cannabinoid receptor agonists | THC |
Acetylcholine | Cholinergics (acetylcholine agonists) | nicotine, piracetam |
Anticholinergics (acetylcholine antagonists) | scopolamine, dimenhydrinate, diphenhydramine | |
Adenosine | Methlyxanthines (adenosine receptor antagonists[17]) | caffeine |
AMPA receptor | AMPA receptor antagonists | kynurenic acid, NBQX |
Melanocortin receptor | Melanocortin receptor agonists | bremelanotide |
[edit] Effects on humans
The following Venn diagram attempts to organize and provide a basic overview of the most common psychoactive drugs into intersecting groups and subgroups based upon the the subjective and behavioral effects they cause in humans as well as by their pharmacological classification.[18][19][20][21][22] Items within each subgroup are close to those of most similar method of action, and also follow a general placement in accordance with the legend below the diagram. Primary intersections are represented via color mixing.
[edit] Legend
[edit] Primary groups
- Blue: Stimulants generally increase in potency to the upper left.
- Red: Depressants generally increase in potency to the lower right.
- Green: Hallucinogens are psychedelic to the left, dissociative to the right, generally less predictable down and to the right, and generally more potent towards the bottom.
- Pink: Antipsychotics are generally more sedative/tranquilizing to the right.
[edit] Secondary groups
- Cyan (light blue): Overlap of Stimulants (Blue) and Psychedelic hallucinogens (Green) — Primary psychedelics exhibit a stimulant effect
- Yellow : Overlap of Depressants (Red) and Dissociative hallucinogens (Green) — Primary dissociatives exhibit a depressant effect
- Lavender: Overlap of Stimulants (Blue) and Antipsychotics (Pink) - The modern non-sedating antidepressants.
- Salmon: Overlap of Depressants (Red) and Antipsychotics (Pink) - The older sedating antidepressants and anxiolytics.
[edit] Tertiary groups
- Magenta (purple): Overlap of Stimulants (Blue) and Depressants (Red) — Example: nicotine exhibits effects of both.
- White: Overlap of Stimulants, Depressants and Hallucinogens — Example: THC exhibits effects of all three sections.
- Sky-blue: Overlap of Stimulants, Psychedelic hallucinogens and Antipsychotics - The empathogens / entactogens.
- Peach: Overlap of Depressants, Dissociative hallucinogens and Antipsychotics
[edit] Quaternary group
- Light-pink: Center overlap of all four sections (Stimulants, Depressants, Hallucinogens and Antipsychotics) - Cannabis, containing both THC and CBD, exhibits a mix of all sections, leaning towards the hallucinogen section due to THC being the primary constituent.
[edit] See also
[edit] References
- ^ Psychedelics Could Treat Addiction Says Vancouver Official. Retrieved on March 26, 2007.
- ^ Ibogaine research to treat alcohol and drug addiction. Retrieved on March 26, 2007.
- ^ Merlin, M.D. "Archaeological Evidence for the Tradition of Psychoactive Plant Use in the Old World". Economic Botany 57 (3): 295–323.
- ^ Siegel, Ronald K (2005). Intoxication: The Universal Drive for Mind-Altering Substances. Park Street Press, Rochester, Vermont. ISBN 1-59477-069-7.
- ^ Weil, Andrew (2004). The Natural Mind : A Revolutionary Approach to the Drug Problem (Revised edition). Houghton Mifflin, 15. ISBN 0-618-46513-8.
- ^ Samorini, Giorgio (2002). Animals And Psychedelics: The Natural World & The Instinct To Alter Consciousness. Park Street Press. ISBN 0-89281-986-3.
- ^ Albert, David Bruce, Jr. (1993). Event Horizons of the Psyche. Retrieved on February 2, 2006.
- ^ Ford-Martin, Paula. Psychoactive Drugs. Psychology Encyclopedia. ISBN 1557981876
- ^ Neuroscience of Psychoactive Substance Use and Dependence by the WHO
- ^ Carod-Artal F, Vázquez-Cabrera C. "Mescaline and the San Pedro cactus ritual: archaeological and ethnographic evidence in northern Peru". Rev Neurol 42 (8): 489-98. PMID 16625512.
- ^ a b Johnson, Brian. (2002) Psychological Addiction, Physical Addiction, Addictive Character, and Addictive Personality Disorder: A Nosology of Addictive Disorders. [1]
- ^ Zhang J, Xu M (2001). "Toward a molecular understanding of psychostimulant actions using genetically engineered dopamine receptor knockout mice as model systems". J Addict Dis 20 (3): 7-18. PMID 11681595.
- ^ More Promising Research Findings. Brief Interventions Help Heavy Drinkers and Alcoholics. Retrieved on July 12, 2006.
- ^ What's your poison?. Caffeine. Retrieved on July 12, 2006.
- ^ Griffiths, RR (1995). Psychopharmacology: The Fourth Generation of Progress (4th edition). Lippincott Williams & Wilkins, 2002. ISBN 0-7817-0166-X.
- ^ Edwards, Griffith (2005). Matters of Substance : Drugs--and Why Everyone's a User. Thomas Dunne Books, 352. ISBN 0-312-33883-X.
- ^ Ford: Clinical Toxicology, 1st ed.,Copyright © 2001 W. B. Saunders Company, Chapter 36 - Caffeine and Related Nonprescription Sympathomimetics
- ^ McKim, William A (2002). Drugs and Behavior: An Introduction to Behavioral Pharmacology (5th Edition). Prentice Hall, 400. ISBN 0-13-048118-1.
- ^ Information on Drugs of Abuse. Commonly Abused Drug Chart. Retrieved on December 27, 2005.
- ^ Erowid Psychoactive Vaults. Retrieved on December 27, 2005.
- ^ Stafford, Peter (1992). Psychedelics Encycloedia. ISBN 0914171518.
- ^ Kent, James. Psychedelic Information Theory - Shamanism in the Age of Reason. [2]
[edit] External links
- Erowid – Extensive portal primarily relating to psychoactive drugs (Wikipedia article about the website – Erowid)
- The Lycæum – Lycaeum Synaesthesia (similar website)
- Neuroscience of Psychoactive Substance Use and Dependence by the WHO –