EFFECTS OF VITAMIN-B12 ON PERFORMANCE AND CIRCADIAN-RHYTHM IN NORMAL SUBJECTS

This preliminary study investigates effects of methyl- and cyanocobala min on circadian rhythms, well-being, alertness, and concentration in healthy subjects. Six women (mean age 35 years) and 14 men (mean age 3 7 years) were randomly assigned to treatment for 14 days with 3 mg cya no-(CB12) ou methylcobalamin (MB12) after 9 days of pre-treatment obse rvation. Levels in the CB12 group increased rapidly in the first, then slowly in the second treatment week, whereas increase in the MB12 gro up pms linear. Urinary aMT6s excretion was reduced by both forms of vi tamin B12 over 24 hours with a significant decrease between 0700-1100 hours, whereas urinary excretion of potassium ams significantly increa sed between 0700-1100 hours. Activity from 2300-0700 hours increased s ignificantly under both forms of vitamin B12. Sleep time was significa ntly reduced under MB12 intake. In this group the change in the visual analogue scales items ''sleep quality,'' ''concentration,'' and ''fee ling refreshed'' between pretreatment and the first week of treatment showed significant correlations with vitamin B12 plasma levels. Cortis ol excretion and temperature were not affected by either medication., We conclude that vitamin B12 exerts a direct influence on melatonin. O nly MB12 has a positive psychotropic alerting effect with a distributi on of the sleep-wake cycle toward sleep reduction. (C) 1996 American C ollege of Neuropsychopharmacology