Plasma levels and urinary vitamin C excretion in schizophrenic patients

Vitamin C status was determined in schizophrenic subjects using fasting plasma levels and the urinary dose response after an oral load of 1.0 g ascorbic acid. The study was carried out in 20 schizophrenic patients and 15 controls with the diagnosis of neurosis who were on the same hospital diet for at least 2 months. The schizophrenic subjects had significantly lower fasting plasma vitamin C levels (P less than 0.05) and 6-h urinary vitamin C excretion after an ascorbic acid load test (P less than 0.01). Since urinary vitamin C excretion in both groups was significantly associated with differences in fasting vitamin C plasma levels (P less than 0.001), a new group of 15 schizophrenics and 15 controls was supplemented with 70 mg of ascorbic acid daily for 4 weeks in order to optimize and standardize their vitamin C plasma levels before the ascorbic acid loading test. The results showed that after 4 weeks of supplementation the average fasting plasma vitamin C levels were almost identical in both examined groups, but the urinary vitamin C excretion was again significantly lower in schizophrenic patients (P less than 0.05). These results are in agreement with the hypothesis that schizophrenia may be associated with impaired ascorbic acid metabolism.