Effects of Biperiden and Amantadine on Memory in Medicated Chronic Schizophrenic Patients

BACKGROUND: The effects on memory of an anticholinergic (biperiden) and a dopaminergic (amantadine) anti-Parkinsonian agent were compared. METHOD: Twenty-six chronically medicated schizophrenic (DSM-III-R) in-patients received amantadine (200 mg/day) or biperiden (4 mg/day) for two weeks in a double-blind cross-over design. RESULTS: Biperiden treatment was associated with significantly lower scores on Benton Visual Retention Test (P < 0.003) and the visual subscale of Wechsler Memory Scale (WMS) (P < or = 0.02), with a trend to poorer scores on WMS total (P = 0.086) and the digit span (P = 0.07) and logical memory (P = 0.06) subscales. CONCLUSIONS: In usual clinical doses, biperiden interferes with memory, particularly visual, more than amantadine.