- Although there is great progress in the treatment of positive symptoms in schizophrenic patients and movement disorders induced by neuroleptics, it is still a problem for clinicians. In this study vitamin B6 treatment was provided to 15 patients who suffered from schizophrenia and schizoaffective disorder with positive psychotic symptoms and tardive dyskinesia. This study was a double-blind crossover controlled during 9 weeks. Each patient was treated with up to 400 mg/day vitamin B6 versus placebo. Every week the patients' conditions were evaluated with Positive and Negative Symptoms Scale (PANSS), Extrapyramidal Symptoms Rating Scale (ESRS) and a blood sample of level pyridoxal was taken. The results did not show any therapeutic effect of psychotic symptoms from vitamin B6 added to antipsychotic agents, which patients received on a constant base. On the other hand, there was significant improvement in tardive dyskinesia and parkinsonian symptoms. There was no direct correlation between pathological symptoms and the serum baseline level of vitamin B6 nor its level during the treatment. The authors suggest that vitamin B6 may be efficient as the treatment for tardive dyskinesia and parkinsonism induced by neuroleptic agents. There is a need for further studies with larger samples and higher doses of vitamin B6 in order to examine the possibility of a positive therapeutic effect as an augmentation agent for the treatment of psychotic symptoms.