Intellectual and neuropsychological functions in young men with heavy and long-term patterns of drug abuse

The authors attempted to determine the long-term effects of heavy drug abuse in 87 male prisoners. The sample was divided into the following groups: 1) nondrug users; 2) users of cannabis and hallucinogens; 3) users of cannabis, hallucinogens, and amphetamines; and 4) users of cannabis, hallucinogens, amphetamines, and opiates. Intellectual and neuropsychological tests sensitive to brain dysfunction revealed no intergroup differences. This finding casts some doubt on other reports suggesting that long-term drug abuse results in neuropsychological disorders. However, the authors caution that one should not conclude that no organic changes occurred in their sample.