Cognitive impairments in adolescent drug-abusers.

A basic neuropsychological test battery was given to 64 adolescents (57 males and seven females; mean age = 15.5) divided in two groups: (1) drug-abusers ("experimental group," n = 26), and (2) non drug-abusers ("control group," n = 38). Psychoactive substances included marijuana, "crack," solvent inhalation, gasoline sniffing, and alcohol. The following tests were used: (1) language, (2) perceptual recognition, (3) memory, and (4) praxic abilities. In general, performance was mildly (but nonsignificantly) lower in the experimental than in the control group. Only some neuropsychological test scores correlated with lifetime and amount of psychoactive drugs used. It was proposed that cognitive impairments in this sample of young drug-abusers may have been not evident because: (1) lifetime use was limited, due to the age of the subjects; and (2) in adolescents and pre-adolescents, toxic effects of drug-abuse might be manifested as a decrease in the rate of cognitive development rather than as a general cognitive decline.