Organic impairment in polydrug users: risk factors.

In a national collaborative study to assess the neuropsychological status of 151 polydrug users, the Halstead-Reitan Neuropsychological Battery showed deficits in 37% two to three weeks after they entered treatment and in 34% at three-month follow-up. Comparative rates for a group of psychiatric patients were 26% and 27%, and for nonpatients, 8% and 4%. Extensive and intensive use of CNS depressants and opiates correlated positively with neuropsychological deficit. Older, less-educated subjects with adverse medical or developmental histories were more likely to show polydrug-related organic impairment. Although there is some evidence that such impairment is reversible, the condition appears to be of at least intermediate duration and may be long lasting.