Temporal patterns of drug use by heroin addicts.

Judgements were obtained from 26 subjects being treated for heroin use concerning the time of day they most commonly used heroin, marijuana, and alcohol. Heroin chipping, or occasional use, showed a peak time, 6 P.M. to 10 P.M., coinciding with the most common time for use of a variety of substances in several populations. However, the habitual use of heroin is most common upon awakening--apparently to ward off withdrawal symptoms. The results also suggest that the use of marijuana and alcohol does not deviate significantly from the recreational pattern of drug use demonstrated by other populations for other nonprescribed drugs.