An open trial of methyltetrahydrofolate in elderly depressed patients.

5-methyltetrahydrofolate (MTHF) is a naturally occurring substance involved in the synthesis of s-adenosyl-l-methionine (SAMe), a major source of methyl groups in the brain. To assess the efficacy of a gastro-resistant, oral preparation of MTHF, 20 elderly patients with a DSM-III-R diagnosis of depressive disorder and a HAM-D-21 score > or = 18 underwent 6-weeks of open-label treatment with 50 mg per day of oral MTHF. Of these 20 patients, 16 completed at least 4 weeks of treatment and showed a markedly significant improvement in their depressive symptoms at endpoint, with 81% of them being considered responders. There were no clinically relevant changes in the routine laboratory tests during the study, and no adverse events considered to be definitely drug-related were reported.