A double-blind crossover comparison of antiparkinson drug therapy: amantadine versus anticholinergics in 90 normal volunteers, with an emphasis on differential effects on memory function.

Anticholinergic antiparkinson drugs administered orally at standard clinically prescribed doses impaired new memory acquisition and mood in normal volunteer subjects, based on tests of free recall, recognition memory, and time production, self-rating of memory function, and an evaluation of mood states. Elderly subjects were more severely impaired than were young adults. Amantadine did not impair new memory acquisition, and on self-report measures, it was significantly better tolerated than were anticholinergics. Among patients being treated for psychotic illness, there are two groups in which an effort to avoid anticholinergic therapy is especially worthwhile because of the severe consequences of memory dysfunction. These individuals are young neuroleptic-responsive patients who are in an early stage of their disease and elderly patients. For these two groups, amantadine should be considered as the initial mode of treatment, with low-dose anticholinergics being used for those patients who do not achieve adequate relief from extrapyramidal side effects with amantadine.