Background: Tardive dyskinesia (TD) is a significant clinical problem. Vitamin B(6) is a potent antioxidant and takes part in almost all of the possible mechanisms that are suggested as being associated with appearance of TD. The aims of this study were (1) to reexamine the efficacy and safety of higher doses of vitamin B(6) versus placebo in a greater sample of patients for a longer time and (2) to evaluate the carryover effect of vitamin B(6).
Method: A 26-week, double-blind, placebo-controlled trial was conducted in a university-based research clinic from August 2002 to January 2005 on 50 inpatients with DSM-IV diagnoses of schizophrenia or schizoaffective disorder and TD. In a double-blind crossover paradigm, all study subjects were randomly assigned to start treatment with either vitamin B(6) (daily dose of 1200 mg) or placebo. After 12 weeks of treatment and then a 2-week washout, subjects were crossed over to receive the other treatment for 12 weeks. The primary outcome measure was the change from baseline in Extra-pyramidal Symptom Rating Scale (ESRS) scores.
Results: The mean decrease in ESRS clinical global impression scores from baseline to endpoint was 2.4 points in patients treated with vitamin B(6) and 0.2 points in patients treated with placebo (p < .0001). The mean decrease in the parkinsonism subscale score was 18.5 points and 1.4 points, respectively (p < .00001), and the mean decrease in the dyskinesia subscale score was 5.2 points and -0.8 points, respectively (p < .0001).
Conclusion: Vitamin B(6) appears to be effective in reducing symptoms of TD. The specific mechanisms by which vitamin B(6) attenuates symptoms of TD are not clear.