Neuropsychological deficit in polydrug users. A preliminary report of the findings of the collaborative neuropsychological study of polydrug users.

The Collaborative Neuropsychological Study of Polydrug Users performed extensive neuropsychological assessments on 15 polydrug users 3 weeks after their enrollment in each of eight polydrug demonstration programs. Fifty-six (37%) of these subjects exhibited neuropsychological deficit. This deficit was partially related to increasing age, poor education and premorbid medical risk factors. The deficit was also associated with extensive and intensive use of two classes of drugs: sedatives (sleeping pills and minor tranquilizers) and opiates (heroin and other narcotic drugs). Seventeen (26%) of a comparison group of 66 psychiatric in-patients and day patients also demonstrated age- and education-correlated neuropsychological deficit. For these patients impairment was also related to lifetime experience with antipsychotic drugs and (perhaps) with clinical diagnosis of schizophrenia. Although both polydrug users and psychiatric patients revealed serious psychopathology as measured by the MMPI, the pattern of the neuropsychological test findings suggested that psychopathology alone did not account for impairment. The 3 month follow-up which is in progress should delineate further the time course and enduring features of neuropsychological deficit among polydrug users, and may establish more clearly the relationship of sedative and opiate use to such impairment. Changes in psychopathological status of both polydrug users and psychiatric patients should also help to clarify the influence of this variable on neuropsychological findings.