Vitamins in psychiatry. Do they have a role?

Deficiencies of specific vitamins produce consistent symptoms of psychiatric disorder. Thiamine deficiency, which is common in alcoholism, can produce confusion and psychotic symptoms, in addition to neurological signs. Vitamin B12 and folate deficiency may contribute symptoms of disorientation, depression or psychosis; their measurement is a part of routine dementia work-ups. Pyridoxine deficiency results in seizures, although the effects of exogenously administered pyridoxine are not clearly understood in depression and anxiety - the disorders in which it is most frequently used clinically. The use of vitamins has been most prominent in psychiatry in the treatment of schizophrenia, where large doses of nicotinic acid were initially given alone and later combined with other vitamins and minerals. Several theoretical models were described to support the use of vitamins in schizophrenia. These included: the parallels of schizophrenia to the psychiatric symptoms of pellagra; hypotheses of a defect in adrenaline metabolism; and the accumulation of psychotoxic substances which produce psychotic symptoms. Initially, positive results were reported over 30 years ago, but have not been replicated by thorough investigations. An extensive series of comprehensive placebo-controlled trials failed to show efficacy for any of the vitamin therapies tested. Although clearly less effective than antipsychotic drug treatment, vitamin therapy is not without risks - adverse effects have been reported with nicotinic acid, pyridoxine and vitamin C.(ABSTRACT TRUNCATED AT 250 WORDS)