1. Ten schizophrenic male patients were given large doses of synthetic vitamin B1 orally and intravenously for a period of eight weeks.2. None showed clinical improvement that could be correlated with the medication. No deleterious effects were seen.3. The Stanford-Binet scores showed only random changes.4. No significant changes were observed in blood pressure, pulse rate, oxygen consumption rate, venous carbon dioxide and glutathione levels.5. Decreases in venous oxygen and lactic acid levels were observed.6. Three patients were given in addition four weekly injections of vitamin B1 intrathecally without significant effects.7. Extension of the study with other catalytic agents is regarded as desirable.Abstract Teaser