Medications and other substances, whether used for legitimate medical purposes, as a habit (for example, caffeine), or recreationally, are an integral part of everyday life for many people (see table Drugs with Both Medical and Recreational Uses Drugs With Medical and Recreational Uses ).
Substance misuse and other substance-related disorders can arise when drugs that directly activate the brain's reward system are taken for the feelings of pleasure they induce. The pleasurable sensations vary with the drug. The drugs are divided into 10 different classes based on the different effects they produce in the body:
Cannabis (including marijuana Marijuana Marijuana (cannabis) is a drug made from the plants Cannabis sativa and Cannabis indica that contain a psychoactive chemical called delta-9-tetrahydrocannabinol (THC). Marijuana... read more and synthetic cannabinoids Marijuana, Synthetic Cannabis is a term for marijuana. Tetrahydrocannabinol (THC) is the main active ingredient in marijuana. Synthetic cannabinoids are man-made drugs that are similar to THC. They are usually sprayed... read more )
Hallucinogens Hallucinogens Hallucinogens are a class of drugs that cause profound distortions in people's perceptions. Hallucinogens distort and intensify sensations, but the actual effects are variable and unpredictable... read more (including LSD, phencyclidine, psilocybin, 3,4-methylenedioxymethamphetamine [MDMA])
Stimulants (including amphetamines Amphetamines Amphetamines are stimulant drugs that are used to treat certain medical conditions but are also subject to abuse. Amphetamines increase alertness, enhance physical performance, and produce euphoria... read more and cocaine Cocaine Cocaine is an addictive stimulant drug made from leaves of the coca plant. Cocaine is a strong stimulant that increases alertness, causes euphoria, and makes people feel powerful. High doses... read more )
Other (including anabolic steroids Anabolic Steroids Anabolic steroids are synthetic (man-made) versions of testosterone that are used to increase muscle size. Anabolic steroids are hormones that promote muscle growth and increase strength and... read more and other commonly abused substances Other Commonly Abused Substances Recreational drug use typically involves mind-altering drugs, but it may also involve drugs or medications taken for other purposes, usually losing weight or enhancing athletic performance.... read more )
Substance-related disorders can develop whether or not a drug is legal, is socially acceptable, or has an accepted medical use (with or without a prescription). Details about specific drugs and their effects are discussed elsewhere in THE MANUAL.
In discussions about controlled substances and drug use, the term "narcotics" is often used. This term refers to drugs that cause loss of feeling, a sense of numbness, and drowsiness, specifically opioids Opioids Opioids, a class of drugs derived from the opium poppy (including synthetic variations), are pain relievers with a high potential for misuse. Opioids are used to relieve pain, but they also... read more (drugs that bind to opiate receptors on cells). However, the term "narcotics" is also used in a broader (and inaccurate) sense to include any drug that is illegal or used illegitimately.
Substance use disorders generally involve behavior patterns in which people continue to use a substance despite having problems caused by its use. There may also be physiologic manifestations, including changes in brain circuitry. The common terms "addiction," "abuse," and "dependence" are too loosely and variably defined to be very useful in systematic diagnosis; "substance use disorder" is more comprehensive and has fewer negative connotations.
Drugs in the 10 classes vary in how likely they are to cause a substance use disorder. The likelihood is termed addiction liability and depends upon a combination of factors including
How the drug is used
How strongly the drug stimulates the brain's reward pathway
How quickly the drug works
The drug's ability to induce tolerance Intoxication and/or symptoms of withdrawal Withdrawal Substance use disorders generally involve behavior patterns in which people continue to use a substance (for example, a recreational drug) despite having problems caused by its use. The substances... read more
The Comprehensive Drug Abuse Prevention and Control Act (Controlled Substances Act) was implemented in the United States in 1970 and modified over the years to regulate the manufacture and distribution of certain classes of drugs, or controlled substances (see table Some Examples of Controlled Substances Some Examples of Controlled Substances* ).
Controlled substances are divided into 5 schedules (or classes) based on their potential for abuse, how accepted they are for medical use, and how safe they are when used under medical supervision. Schedule I drugs are considered the most harmful and therefore have the tightest controls. Schedule V drugs are considered the least harmful and are widely available. State and federal schedules may differ (see also US Drug Enforcement Administration Drug Schedules).
The following English-language resources may be useful. Please note that THE MANUAL is not responsible for the content of these resources.
Drug Enforcement Administration (DEA) Diversion Control Division: Home page of the main US government agency responsible for oversight of legal and illegal use of controlled substances. Contains links to a variety of information, including specific drug information, regulations and requirements, and various forms and applications.
United States Drug Enforcement Administration (DEA), Drug Scheduling: This link leads to further detail on the examples of controlled substances mentioned in this section.