Efficacy of selective serotonin-reuptake inhibitors in premenstrual syndrome: a systematic review

Background Selective serotonin-reuptake inhibitors (SSRIs) are increasingly being used as first-line therapy for severe premenstrual syndrome (PMS). We undertook a meta-analysis on the efficacy of SSRIs in this disorder. Methods We searched medical and scientific databases, approached pharmaceutical companies, and reviewed citations of relevant articles to identify 29 studies of the use of SSRIs in PMS. 14 were excluded (no placebo group, preliminary report of included trial, or low quality). 15 randomised placebo-controlled trials were included. Information on study design, participants, drugs used and dosing regimens, outcome measures, side-effects, and sources of funding was extracted. Standardised mean differences between treatment and placebo groups were calculated to obtain an overall estimate of efficacy. The primary outcome measure was a reduction in overall PMS symptoms. Findings The primary analysis included data on 904 women (570 assigned active treatment and 435 assigned placebo, including 101 in crossover trials). The overall standardised mean difference was -1.066 (95% CI -1.381 to -0.750), which corresponds to an odds ratio of 6.91 (3.90 to 12.2) in favour of SSRIs. SSRIs were effective in treating physical and behavioural symptoms. There was no significant difference in symptom reduction between continuous and intermittent dosing or between trials funded by pharmaceutical companies and those independently funded. Withdrawal due to side-effects was 2.5 times more likely in the active-treatment group than in the placebo group. Interpretation SSRIs are an effective first-line therapy for severe PMS. The safety of these drugs has been demonstrated in trials of affective disorder, and the side-effects at low doses are generally acceptable.