A randomized, double-blind, placebo-controlled trial of moclobemide in patients with chronic fatigue syndrome

Background: Chronic fatigue syndrome is characterized by prolonged and disa bling fatigue and a range of neuropsychiatric symptoms including depressed and/or irritable mood. To date, no medical or psychotropic therapies have p rovided clear symptomatic benefit. Method: Ninety patients with chronic fatigue syndrome, diagnosed with our s ystem that approximates CDC criteria, participated in a randomized, placebo -controlled, double-blind trial of 450 to 600 mg/day of moclobemide, a nove l reversible inhibitor of monoamine oxidase-A. Results: Fifty-one percent (24/47) of patients receiving moclobemide improv ed compared with 33% (14/43) of patients receiving placebo (odds ratio = 2. 16, 95% confidence interval [CI] = 0.9 to 5.1). Drug response was best char acterized symptomatically by an increase in the subjective sense of vigor a nd energy rather than a reduction in depressed mood. The effect of moclobem ide on subjective energy was detectable within the first 2 weeks of treatme nt and increased across the course of the study. The greatest reduction in clinician-rated disability was in patients with concurrent immunologic dysf unction (mean difference in standardized units of improvement = 0.8, 95% CI = 0.03 to 1.6). Conclusion: Moclobemide produces some improvement in key symptoms experienc ed by patients with chronic fatigue syndrome. This effect is not dependent on the presence of concurrent psychological distress and is likely to be sh ared with other monoamine oxidase inhibitors.