Aim: To perform a clinical trial of selegiline in 25 patients with chronic fatigue syndrome (CFS) where patients were told they would receive placebo or active agent at different times during the 6-week trial. We chose selegiline, a specific monoamine oxidase (MAO) B receptor inhibitor, because a prior trial of lowdose phenelzine, a nonspecific MAO inhibitor, showed a small but significant therapeutic effect.
Methods: Questionnaires comprised of 19 tests of mood, fatigue, functional status and symptom severity were collected at the start and end of the trial as well as 2 weeks after its start. The trial was done in three 2-week blocks: in the first, 2 placebo pills were given per day; in the next, one 5-mg tablet of agent and one placebo were given per day, and in the last, a 5-mg tablet of agent was given twice a day. The plan was to compare the changes in the 19 tests during the placebo phase to those found in the active treatment phase in 19 patients completing the trial.
Findings: Significant improvement in 3 variables-tension/anxiety, vigor and sexual relations-was found. A significant pattern of improvement compared to worsening was found for the 19 self-report vehicles during active treatment as compared with placebo treatment. Evidence for an antidepressant effect of the drug was not found.
Conclusions: Selegiline has a small but significant therapeutic effect in CFS which appears independent of an antidepressant effect.