Drug abuse


Drug abuse is the use of illegal drugs, or the misuse of prescription or over-the-counter drugs for at least a year with negative consequences.

See also:

Alternative Names

Substance abuse; Illicit drug abuse; Narcotic abuse; Hallucinogen abuse



Marijuana is also called "grass," "pot," "reefer," "joint," "hashish," "cannabis," "weed," and "Mary Jane."

About 2 in 5 Americans have used marijuana at least once in their life.

Marijuana comes from a plant called hemp (cannabis sativa). The main, active ingredient in marijuana is THC (short for delta-9-tetrahydrocannabinol). This and other ingredients, called cannabinoids, are found in the leaves and flowering parts of the marijuana plant. Hashish is a substance taken from the tops of female marijuana plants. It contains the highest amount of THC.

How fast you feel the effects of marijuana depend on how you use it:

Marijuana acts on your central nervous system. Low-to-moderate amounts of the drug may cause:

Other effects can include:

Regular users may have withdrawal effects when they stop marijuana use. These may include:


The medical use of marijuana is controversial, yet it's active ingredient (THC) is legal for medical purposes in at least 16 states. (Whole marijuana is illegal, even for medical use.)

THC has been approved by the U.S. Food and Drug Administration (FDA) for the following medical purposes:

PHENCYCLIDINE (PCP, "angel dust")

PCP is an illegal drug that comes as a white powder, which can be dissolved in alcohol or water. PCP may be smoked, shot into a vein, or taken by mouth. How quickly it affects you depends on how you take it.

Different doses of PCP will cause different effects:

Because of the pain-killing (analgesic) properties of PCP, users who get seriously injured may not feel any pain.


A number of other illegal drugs have become popular and available in recent years, including:


LSD (lysergic acid diethylamide) is a very strong hallucinogen. Only tiny amounts are needed to cause effects, such as hallucinations. Other commonly abused hallucinogens include:

LSD use may cause:

Hallucinogens can lead to extreme anxiety and lack of reality, called "bad trips". These experiences can come back as a "flashback," even without using the drug again. Such experiences typically occur during times of increased stress, and tend to occur less often and intensely after stopping the drugs.


The abuse of cocaine increased dramatically in the late 1980s and early 1990s, but is now on the decline. Other names to describe different forms of cocaine include "crack," "coke," "snow," and "speedball."

Cocaine may be taken in different ways:

Smoking cocaine produces a nearly instant and intense sense of joy (euphoria), which is attractive to abusers. Other effects include:

Regular users of cocaine may need larger amounts of the drug to feel these effects. Regular users of cocaine may have:

Heavy use may cause paranoia, which can lead to violence.


Amphetamines are stimulants. Other names used to desrribe amphetamines or methamphetamines include "crystal," "go," "crank," and "cross-tops." See: Methamphetamine overdose

Amphetamines are very addictive. Prescription amphetamines are considered controlled substances. Over-the-counter (OTC) amphetamine look-alike drugs are often abused. These drugs typically contain caffeine and other stimulants, and are sold as appetite suppressants or stay-awake/stay-alert aids.

Signs and symptoms of stimulant use:


Inhalant use became popular with young teens in the 1960s with "glue sniffing." Since then, a greater variety of inhalants have become popular. Inhalant use typically involves younger teens or school-age children.

Commonly abused inhalants include:

Negative effects of inhalant abuse include:


Opiates come from opium poppies. These drugs include morphine and codeine. Opioids are artificial substances that have the same effect as morphine or codeine. The term "narcotic" refers to either type of drug.

Narcotics are powerful painkillers that cause drowsiness (sedation) and sometimes, feelings of euphoria.

These drugs include:

Signs and symptoms of narcotic use:

Because heroin is commonly injected into a vein (used intravenously), there are health concerns about sharing contaminated needles among IV drug users. Complications of sharing contaminated needles include hepatitis, HIV infection, and AIDS.


These substances produce a sedative and anxiety-reducing effect, which can lead to dependence.

These types of drugs include:

Signs and symptoms of alcohol or other depressant use:



There are a number of different support groups available to help those with drug abuse. They include:

See also:


Samet JH. Drug abuse and dependence. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 32.

Review Date: 3/20/2011
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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