VITAMIN-B-12 TREATMENT FOR DELAYED SLEEP PHASE SYNDROME - A MULTICENTER DOUBLE-BLIND-STUDY

The active form of vitamin B-12 (methylcobalamin) has been reported to be effective on sleep-wake rhythm disorders. Previous studies, howeve r, were performed under open trial, and the effect of vitamin B-12 has not been properly evaluated. The aim of this double-blind study was t o investigate the efficacy of methylcobalamin on delayed sleep phase s yndrome (DSPS). Methylcobalamin (3 mg/day) or placebo was administered for 4 weeks. The subjects were 50 patients with DSPS aged 13-55 years (26.5 +/- 1.3), 27 of whom received the active drug while 23 received the placebo. No significant differences were observed between the 2 g roups in subjective evaluations of mood or drowsiness during the dayti me or in night sleep by sleep-log evaluation. These results indicate t hat 3 mg methylcobalamin administered over 4 weeks is not an effective treatment for DSPS.