Effects of Nifedipine, a Calcium Channel Antagonist, on Cognitive Function in Schizophrenic Patients with Tardive Dyskinesia

Abstract

We examined whether nifedipine, a calcium channel antagonist, added to a stable regimen of neuroleptic medication would affect cognition in patients with chronic schizophrenia or schizoaffective disorder who had tardive dyskinesia. Fifteen patients with tardive dyskinesia were treated with nifedipine (60 mg daily) or matching placebo for 4 weeks and then were crossed over from nifedipine to placebo or from placebo to nifedipine for another 4 weeks. At the end of each 4-week phase of the study, the patients performed a rotary pursuit test of procedural learning and a dementia scale assessing general cognitive abilities. Nifedipine improved performance in the rotary pursuit test and conceptual abilities in the dementia scale compared with placebo, but only for patients who first were exposed to the tests during the placebo condition. These results provide preliminary evidence that calcium channel antagonists might enhance learning and memory in schizophrenic patients with tardive dyskinesia.