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Psychoactive drug

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Main article: Drugs
Pyschoactive Drugs

An assortment of psychoactive drugs

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 behaviour. These drugs may be used recreationally to purposefully alter one's consciousness, as entheogens for ritual or spiritual purposes, as a tool for studying or augmenting the mind, or therapeutically as medication.

Because psychoactive substances bring about subjective changes in consciousness and mood that the user may find pleasant (e.g. euphoria) or advantageous (e.g. increased alertness), many psychoactive substances are abused, that is, used excessively, despite risks or negative consequences. With sustained use of some substances, physical dependence may develop, making the cycle of abuse even more difficult to interrupt. Drug rehabilitation can involve a combination of psychotherapy, support groups and even other psychoactive substances to break the cycle of dependency.

In part because of this potential for abuse and dependency, the ethics of drug use are the subject of a continuing philosophical debate. Many governments worldwide have placed restrictions on drug production and sales in an attempt to decrease drug abuse.


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.[1] 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.[2] 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, or sliding indicates that the drive to alter one's state of mind is universal.[3]

This relationship is not limited to humans. A number of animals consume different psychoactive plants, animals, berries and even fermented fruit, becoming intoxicated, such as cats after consuming catnip. Traditional legends of sacred plants often contain references to animals that introduced humankind to their use.[4] Biology suggests an evolutionary connection between psychoactive plants and animals, as to why these chemicals and their receptors exist within the nervous system.[5]

During the 20th century, many governments across the world initially responded to the use of recreational drugs by banning them and making their use, supply or trade a criminal offense. 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.[How to reference and link to summary or text] This can go hand-in-hand with supply reduction strategies by law-enforcement agencies.

Uses of psychoactive substances



Main article: Anesthesia

General anesthetics are a class of psychoactive drug used on patients to block pain and other sensations. Most anesthetics induce unconsciousness, which allows patients to undergo medical procedures like surgery without physical pain or emotional trauma.[7] To induce unconsciousness, anesthetics affect the GABA and NMDA systems. For example, halothane is a GABA agonist,[8] and ketamine is an NMDA receptor antagonist.[9]


Main article: Analgesics

Psychoactive drugs are often prescribed to manage pain. As the subjective experience of pain is regulated by endorphins, neurochemicals that are endogenous opioids, pain can be managed using psychoactives that operate on this neurotransmitter system. This class of drugs includes narcotics, like morphine and codeine,[10] and also NSAIDs (which don't affect endorphins) such as aspirin and ibuprofen.

Psychiatric medications

Main article: Psychiatric medications
Zoloft bottles

Zoloft, an antidepressant (and anti-anxiety) medication

Psychiatric medications are prescribed for the management of mental and emotional disorders. There are 6 major classes of psychiatric medications:

Recreational drugs

Main article: Recreational drug use

Many psychoactive substances are used for their mood and perception altering effects, including those with accepted uses in medicine and psychiatry. Classes of drugs frequently used recreationally include:

  • Stimulants, which elevate the central nervous system. These are used recreationally for their euphoric effects.
  • Hallucinogens (psychedelics, dissociatives and deliriants), which induce perceptual and cognitive distortions.
  • Hypnotics, which are used recreationally because they induce inebriation.
  • Analgesics, which are used recreationally because of their euphoric effects.
  • Inhalants, in the forms of gas aerosols, or solvents, which are inhaled as a vapor because of their stupefying effects. Many inhalants also fall into the above categories (such as Nitrous Oxide which is also an anelgesic)

Examples include caffeine, alcohol, cocaine, LSD, and cannabis.[12]

In some sub-cultures, drug usage is seen as a status symbol. Recreational drugs are seen as status symbols at events such as at nightclubs and parties.[13] This is true of many cultures throughout history; drugs have been viewed as status symbols since ancient times. For example, in ancient Egypt, gods were commonly pictured holding hallucinogenic plants.[14]

Because there is controversy about regulation of recreational drugs, there is an ongoing debate about drug prohibition. Critics of prohibition believe that regulation of recreational drug use is a violation of personal autonomy and freedom.[15] In the United States, critics have noted that prohibition or regulation of recreational and spiritual drug use might be unconstitutional.[16]

Ritual and spiritual use

Main article: Entheogens

Certain psychoactives, particularly hallucinogens, have been used for religious purposes since prehistoric times. Native Americans have used mescaline-containing peyote cacti for religious ceremonies for as long as 5700 years.[17] The muscimol-containing Amanita muscaria mushroom was used for ritual purposes throughout prehistoric Europe.[18] Various other hallucinogens, including jimsonweed, psilocybin mushrooms, and cannabis have been used in religious ceremonies for centuries.[19]





File:Synapse Illustration2 tweaked.svg
Main article: Neuropsychopharmacology


Drugs that increase activity in particular neurotransmitter systems are called agonists. They act by increasing the synthesis of one or more neurotransmitters or reducing its reuptake from the synapses. Drugs that reduce neurotransmitter activity are called antagonists, and operate by interfering with synthesis or blocking postsynaptic receptors so that neurotransmitters cannot bind to them.[23]


Affected neurotransmitter systems


Neurotransmitter/receptor Classification Examples

Cholinergics (acetylcholine agonists) nicotine, piracetam
Anticholinergics (acetylcholine antagonists) scopolamine, dimenhydrinate, diphenhydramine, atropine, most tricyclics
Adenosine receptor antagonists[26] caffeine, theobromine, theophylline

Dopamine reuptake inhibitors (DRIs) cocaine, methylphenidate, amphetamine, bupropion
Dopamine releasers amphetamine
Dopamine agonists pramipexole, L-DOPA (prodrug)
Dopamine receptor antagonists haloperidol, droperidol, many antipsychotics

GABA reuptake inhibitors tiagabine
GABA receptor agonists ethanol, barbiturates, diazepam and other benzodiazepines, muscimol, ibotenic acid
GABA antagonists thujone, bicuculline
Noradrenaline chemical structure

Norepinephrine reuptake inhibitors most non-SSRI antidepressants such as amoxapine, atomoxetine, bupropion, venlafaxine and the tricyclics
Norepinephrine releasers mianserin
Serotonin receptor agonists LSD, psilocybin, mescaline, DMT
Serotonin reuptake inhibitors most antidepressants including tricyclics such as amitryptyline and SSRIs such as fluoxetine and sertraline
Serotonin releasers MDMA (ecstasy)
AMPA receptor
AMPA receptor antagonists kynurenic acid, NBQX
Cannabinoid receptor
Cannabinoid receptor agonists THC
Melanocortin receptor
Melanocortin receptor agonists bremelanotide
NMDA receptor
NMDA receptor antagonists ketamine, PCP, DXM
Opioid receptor
μ-opioid receptor agonists morphine, heroin, oxycodone
μ-opioid receptor inverse agonists naloxone, naltrexone
κ-opioid receptor agonists salvinorin A, butorphanol, nalbuphine
κ-opioid receptor inverse agonists buprenorphine
Monoamine oxidase
Monoamine oxidase inhibitors (MAOIs) phenelzine, iproniazid
bind to MAO protein transporter amphetamine, methamphetamine


Main article: Addiction
Bayer Heroin bottle

Heroin bottle

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.[27] Not all drugs are physically addictive, but any activity that stimulates the brain's dopaminergic reward system — typically, any pleasurable activity[28] — can lead to psychological addiction.[27] 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.


Common forms of rehabilitation include psychotherapy, support groups and pharmacotherapy, which uses psychoactive substances to reduce cravings and physiological withdrawal symptoms while a user is going through detox. Methadone, itself an opioid and a psychoactive substance, is a common treatment for heroin addiction. Recent research on addiction has shown some promise in using psychedelics to treat and even cure addictions, although this has yet to become a widely accepted practice.[30][31]



In the United States, the Food and Drug Administration (FDA) has authority over all drugs, including psychoactive drugs. The FDA regulates which psychoactive drugs are over the counter and which are only available with a prescription.[34] However, certain psychoactive drugs, like alcohol, tobacco, and drugs listed in the Single Convention on Narcotic Drugs are subject to criminal laws. The Controlled Substances Act of 1970 regulates the recreational drugs outlined in the Single Convention on Narcotic Drugs.[35] Alcohol is regulated by state governments, but the federal National Minimum Drinking Age Act penalizes states for not following a national drinking age.[36] Tobacco is also regulated by all fifty state governments.[37] Most people accept such restrictions and prohibitions of certain drugs, especially the "hard" drugs, which are illegal in most countries.[38][39][40]



See also


  1. Merlin, M.D (2003). Archaeological Evidence for the Tradition of Psychoactive Plant Use in the Old World. Economic Botany 57 (3): 295–323.
  2. Siegel, Ronald K (2005). Intoxication: The Universal Drive for Mind-Altering Substances, Park Street Press, Rochester, Vermont. ISBN 1-59477-069-7.
  3. Weil, Andrew (2004). The Natural Mind: A Revolutionary Approach to the Drug Problem (Revised edition), 15, Houghton Mifflin. ISBN 0-618-46513-8.
  4. Samorini, Giorgio (2002). Animals And Psychedelics: The Natural World & The Instinct To Alter Consciousness, Park Street Press. ISBN 0-89281-986-3.
  5. Albert, David Bruce, Jr. (1993). Event Horizons of the Psyche.
  6. Lovett, Richard (24 September 2005). Coffee: The demon drink?. New Scientist (2518).
  7. Medline Plus. Anesthesia. Accessed on July 16, 2007.
  8. Li X, Pearce RA (2000). Effects of halothane on GABA(A) receptor kinetics: evidence for slowed agonist unbinding. J. Neurosci. 20 (3): 899–907.
  9. Harrison N, Simmonds M (1985). Quantitative studies on some antagonists of N-methyl D-aspartate in slices of rat cerebral cortex. Br J Pharmacol 84 (2): 381–91.
  10. Quiding H, Lundqvist G, Boréus LO, Bondesson U, Ohrvik J (1993). Analgesic effect and plasma concentrations of codeine and morphine after two dose levels of codeine following oral surgery. Eur. J. Clin. Pharmacol. 44 (4): 319–23.
  11. Schatzberg, A.F. (2000). New indications for antidepressants. Journal of Clinical Psychiatry 61 (11): 9–17.
  12. Neuroscience of Psychoactive Substance Use and Dependence by the WHO. Retrieved on July 5, 2007.
  13. Anderson TL (1998). Drug identity change processes, race, and gender. III. Macrolevel opportunity concepts. Substance use & misuse 33 (14): 2721–35.
  14. Bertol E, Fineschi V, Karch S, Mari F, Riezzo I (2004). Nymphaea cults in ancient Egypt and the New World: a lesson in empirical pharmacology. Journal of the Royal Society of Medicine 97 (2): 84–5.
  15. Hayry M (2004). Prescribing cannabis: freedom, autonomy, and values. Journal of medical ethics 30 (4): 333–6.
  16. Barnett, Randy E. The Presumption of Liberty and the Public Interest: Medical Marijuana and Fundamental Rights. Retrieved on July 4, 2007.
  17. El-Seedi HR, De Smet PA, Beck O, Possnert G, Bruhn JG (2005). Prehistoric peyote use: alkaloid analysis and radiocarbon dating of archaeological specimens of Lophophora from Texas. Journal of ethnopharmacology 101 (1-3): 238–42.
  18. Vetulani J (2001). Drug addiction. Part I. Psychoactive substances in the past and presence. Polish journal of pharmacology 53 (3): 201–14.
  19. Hall, Andy. Entheogens and the Origins of Religion. Retrieved on May 13, 2007.
  20. Becker HS (1967). History, culture and subjective experience: an exploration of the social bases of drug-induced experiences. Journal of health and social behavior 8 (3): 163–76.
  21. Bullis RK (1990). Swallowing the scroll: legal implications of the recent Supreme Court peyote cases. Journal of psychoactive drugs 22 (3): 325–32.
  22. United States Food and Drug Administration. CDER Data Standards Manual. Retrieved on May 15, 2007.
  23. Seligman, Martin E.P. (1984). Abnormal Psychology, W. W. Norton & Company.
  24. University of Texas, Addiction Science Research and Education Center.
  25. Lüscher C, Ungless M (2006). The mechanistic classification of addictive drugs. PLoS Med. 3 (11): e437.
  26. Ford, Marsha. Clinical Toxicology. Philadelphia: Saunders, 2001. Chapter 36 - Caffeine and Related Nonprescription Sympathomimetics. ISBN 0721654851
  28. 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.
  29. Hops H, Tildesley E, Lichtenstein E, Ary D, Sherman L (1990). Parent-adolescent problem-solving interactions and drug use. The American journal of drug and alcohol abuse 16 (3-4): 239–58.
  30. Psychedelics Could Treat Addiction Says Vancouver Official.
  31. Ibogaine research to treat alcohol and drug addiction.
  32. United Nations Single Convention on Narcotic Drugs. Retrieved on June 20, 2007.
  33. MacCoun R, Reuter P (1997). Interpreting Dutch cannabis policy: reasoning by analogy in the legalization debate. Science 278 (5335): 47–52.
  34. History of the Food and Drug Administration. Retrieved at FDA's website on June 23, 2007.
  35. United States Controlled Substances Act of 1970. Retrieved from the DEA's website on June 20, 2007.
  36. Title 23 of the United States Code, Highways. Retrieved on June 20, 2007.
  37. State Excise Tax Rates on Cigarettes. Retrieved on June 20, 2007.
  38. What's your poison?. Caffeine.
  39. Griffiths, RR (1995). Psychopharmacology: The Fourth Generation of Progress (4th edition), 2002, Lippincott Williams & Wilkins. ISBN 0-7817-0166-X.
  40. Edwards, Griffith (2005). Matters of Substance: Drugs--and Why Everyone's a User, 352, Thomas Dunne Books. ISBN 0-312-33883-X.
  41. Mosher, Clayton James; Scott Akins (2007). Drugs and Drug Policy: The Control of Consciousness Alteration, Sage.
  42. Dworkin, Ronald. Artificial Happiness. New York: Carroll & Graf, 2006. pp.2-6. ISBN 0786719338
  43. Manninen BA (2006). Medicating the mind: a Kantian analysis of overprescribing psychoactive drugs. Journal of medical ethics 32 (2): 100–5.

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