The study was a 12-week, double-blind, placebo-controlled, cross-over clinical trial of injectable methylcobalamin, after which subjects were given the option of entering a 6-month open-label trial. All subjects received 6 weeks of placebo and 6 weeks of methyl B12 at a dose of 64.5 mcg/kg every three days administered subcutaneously into the buttocks. Blood for GSH analysis and behavioral assessments were obtained at baseline, week 6, and week 12. Thirty (30) subjects completed the 12-week, double-blind study and 22 subjects completed the 6-month extension study. No statistically significant mean differences in behavior tests or in glutathione status were identified between active and placebo groups. However, 9 subjects (30%) demonstrated clinically significant improvement on the Clinical Global Impression Scale and at least two additional behavioral measures. More notably, these responders exhibited significantly increased plasma concentrations of GSH and GSH/GSSG. Although methylcobalamin was found to be ineffective overall in treating behavioral symptoms of autism, methylcobalamin may alleviate symptoms of autism in a subgroup of children. (J Altern Complement Med. 2010 May;16(5):555-60.) PMID: 20804367.
