Sleeping manThere are some small studies that show that vitamin B12 supplementation may be beneficial to patients with problems sleeping. One study that appeared in the Japanese Journal of Psychiatry and Neurobiology (1991;45(1):165-166) looked at five patients between the ages of 14 and 60 with a variety of sleep problems, including insomnia, delayed sleep-phase syndrome, non-24-hour sleep-wake rhythm disorder and depression. The patients were successfully treated with 4.5 milligrams of vitamin B12 per day, divided into three equal doses. Vitamin B12 levels increased two to four fold during the therapy. Another study, that was presented at the 5th World Congress of Biological Psychiatry in 1991, had eight subjects between the ages of 12 and 63, with a variety of sleep-wake rhythm disorders. Two of the patients had 24-hour sleep-wake rhythm disorder, four had delayed sleep-phase syndrome and two had insomnia. Patients were given 1.5 milligrams of vitamin B12 three times per day. Symptoms improved in the patients with the sleep-wake rhythm disorder, in the patients with insomnia and in one of the patients with the delayed sleep-phase syndrome. In 1 case phototherapy was utilized at 2500 lux every morning for 2 hours when vitamin B12 therapy was not beneficial during the first month. The light therapy produced a significant improvement in the sleep disorder. The authors of the second study noted that patients with sleep issues who respond to B12 therapy are not necessarily deficient in vitamin B12. It is also noted that the sleep-wake rhythm disorder relapsed several days or a few weeks after discontinuation of the medication.