EFFECTS OF BIPERIDEN AND AMANTADINE ON MEMORY IN MEDICATED CHRONIC-SCHIZOPHRENIC PATIENTS - A DOUBLE-BLIND CROSS-OVER STUDY

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 less than or equal to 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.