Transmethylation and affective disorders

Summary osyl-L-methionine (SAMe) is a naturally occurring metabolite and a major source of methyl groups in the brain. Methylation processes are important in the expression of mood and the failure of methylation may underlie some affective disorders. The administration of SAMe is associated with an increase in both 5-OH-indoleacetic acid and homovanillic acid, being the metabolites of serotonin and dopamine, respectively. SAMe indices mood elevation in depressed patients. Until 1995, 1,400 patients treated with SAMe were investigated in open or controlled trials. The efficacy of SAMe in treating depressive disorders is superior to placebo and comparable to standard tricyclic antidepressants. SAMe demonstrates a particularly low side effect profile. The increase of anxiety is the most common side effect. The addition of SAMe to standard antidepressants may shorten the time of treatment response compared to the use of antidepressants alone, especially in parenteral use (400–800 mg/day, iv.).