Know how to use "fewer" and "less"? Find out.
drug abuse n.
Habitual use of drugs to alter one's mood, emotion, or state of consciousness.
the excessive, maladaptive, or addictive use of drugs for nonmedical purposes despite social, psychological, and physical problems that may arise from such use. Abused substances include such agents as anabolic steroids, which are used by some athletes to accelerate muscular development and increase strength and which can cause heart disease, liver damage, and other physical problems; and psychotropic agents, substances that affect the user's mental state and are used to produce changes in mood, feeling, and perception. The latter category, which has a much longer history of abuse, includes opium (and such derivatives as heroin), hallucinogens, barbiturates, cocaine, amphetamines, tranquilizers, the several forms of cannabis, and alcohol. A brief treatment of drug abuse follows. For full treatment, see drug use. See also steroid.