Abstract: Thirty-one RCTs were included in the review. They compared fluoxetine, paroxetine, sertraline, escitalopram and citalopram versus placebo. SSRIs reduced overall self-rated symptoms significantly more effectively than placebo. The effect size was moderate when studies reporting end scores were pooled (for moderate dose SSRIs: SMD -0.65, 95% CI -0.46 to -0.84, nine studies, 1276 women; moderate heterogeneity (I2 = 58%), low quality evidence). The effect size was small when studies reporting change scores were pooled (for moderate dose SSRIs: SMD -0.36, 95% CI -0.20 to -0.51, four studies, 657 women; low heterogeneity (I2=29%), moderate quality evidence). SSRIs were effective for symptom relief whether taken only in the luteal phase or continuously, with no clear evidence of a difference in effectiveness between these modes of administration. However, few studies directly compared luteal and continuous regimens and more evidence is needed on this question. Withdrawals due to adverse effects were significantly more likely to occur in the SSRI group (moderate dose: OR 2.55, 95% CI 1.84 to 3.53, 15 studies, 2447 women; no heterogeneity (I2 = 0%), moderate quality evidence). The most common side effects associated with a moderate dose of SSRIs were nausea (NNH = 7), asthenia or decreased energy (NNH = 9), somnolence (NNH = 13), fatigue (NNH = 14), decreased libido (NNH = 14) and sweating (NNH = 14). In secondary analyses, SSRIs were effective for treating specific types of symptoms (that is psychological, physical and functional symptoms, and irritability). Adverse effects were dose-related. The overall quality of the evidence was low to moderate, the main weakness in the included studies being poor reporting of methods. Heterogeneity was low or absent for most outcomes, though (as noted above) there was moderate heterogeneity for one of the primary analyses. SSRIs are effective in reducing the symptoms of PMS, whether taken in the luteal phase only or continuously. Adverse effects are relatively frequent, the most common being nausea and asthenia. Adverse effects are dose-dependent.

Plain-language summary: The review included 31 randomised controlled trials which compared SSRIs with placebo in a total of 4372 women who were clinically diagnosed with PMS. SSRIs were found to be effective for reducing the overall symptoms of PMS and also for reducing specific types of symptoms (psychological, physical and functional symptoms, and irritability). SSRIs were usually taken for about two weeks before the start of the menstrual period (the luteal phase) or every day (continuously). Both regimens appeared to be equally effective, although more research is needed to confirm this. Adverse effects were more common in the women taking SSRIs than in those taking placebo. The most commonly occurring side effects were nausea and decreased energy. The review authors calculated that nausea is likely to occur as a drug side effect in approximately one out of seven women with PMS taking a moderate dose of SSRIs, and lack of energy is likely to occur as a drug side effect in approximately one out of every nine women. The overall quality of the evidence was rated as low to moderate, the main weakness being poor reporting of methods in the included studies. At least 21 of the studies received funding from pharmaceutical companies.