The DSM-III-R applies a single definition across substance use disorders. Dependence is defined by the presence of 3 or more symptoms from a list of 9 covering cognitive, behavioral, and physiological problems that characterize compulsive use of a psychoactive substance. The DIS ascertains drug A/D for the following classes of drugs used on one's own to get high: stimulants, sedatives or tranquilizers, marijuana, cocaine, heroin or other opiates, and hallucinogens. Prescribed psychoactive drug A/D was based on symptoms of A/D due to the following: (1) extramedical use of 3 classes of drugs that often are prescribed stimulants (eg, amphetamines), sedatives, and tranquilizers (eg, barbiturates, sleeping pills, Seconal, Valium, Librium, Quaalude, and Xanax) and opiates other than heroin (eg, codeine, Demerol, morphine, Percodan, methadone, Darvon, and Dilaudid); and (2) use as prescribed of a tranquilizer, sedative, pain pill, antidepressant, or headache medicine every day for 2 weeks or more. The second type of prescribed drug A/D defines cases of A/D despite adherence to medical instructions. Nicotine dependence in the National Institute of Mental Health DIS requires 3 symptoms from a list of 7. The 2 criterion symptoms excluded from the DIS diagnosis of nicotine dependence are (1) a great deal of time spent in activities necessary to get the substance and (2) frequent intoxication or withdrawal symptoms when expected to fulfill major role obligations. The exclusion of these symptoms from the assessment of nicotine dependence in the DIS is based on observations that they do not characterize tobacco dependence. Substance abuse is a residual category, defined by continued use despite knowledge of health, psychological, or social problems caused by the substance or recurrent use in situations in which use is hazardous. In the DSM-III-R (and the DSM-IV), there is no category of nicotine abuse.