RANDOMIZED, DOUBLE-BLIND, PLACEBO-CONTROLLED STUDY OF FLUOXETINE IN CHRONIC FATIGUE SYNDROME

Background No somatic treatment has been found to be effective for chr onic fatigue syndrome (CFS). Antidepressant therapy is commonly used. Fluoxetine is recommended in preference to tricyclic agents because it has fewer sedative and autonomic nervous system effects. However, the re have been no randomised, placebo-controlled, double-blind studies s howing the effectiveness of antidepressant therapy in CFS. We have car ried out such a study to assess the effect of fluoxetine in depressed and non-depressed CFS patients. Methods In this randomised, double-bli nd study, we recruited 44 patients to the depressed CFS group, and 52 to the non-depressed CFS group. In each group participants were random ly assigned to receive either fluoxetine (20 mg once daily) or placebo for 8 weeks. The effect of fluoxetine was assessed by questionnaires, self-observation lists, standard neuropsychological tests, and a moti on-sensing device (Actometer), which were applied on the day treatment started and on the last day. Findings The two groups were well matche d in terms of age, sex distribution, employment and marital status, an d duration of CFS. There were no significant differences between the p lacebo and fluoxetine-treated groups in the change during the 8-week t reatment period for any dimension of CFS. There was no change in subje ctive assessments of fatigue, severity of depression, functional impai rment, sleep disturbances, neuropsychological function, cognitions, or physical activity in the depressed or the non-depressed subgroup. Int erpretation Fluoxetine in a 20 mg daily dose does not have a beneficia l effect on any characteristic of CFS. The lack of effect of fluoxetin e on depressive symptoms in CFS suggests that processes underlying the presentation of depressive symptoms in CFS may differ from those in p atients with major depressive disorder.