Six-month paroxetine treatment of premenstrual dysphoric disorder: continuous versus intermittent treatment protocols

Several trials have proved the efficacy of selective serotonin re-uptake inhibitors (SSRI) in the treatment of premenstrual dysphoric disorder (PMDD) in Western society. The SSRI can be administered continuously throughout the entire cycle or intermittently from ovulation to the onset of menstruation (luteal phase). The purpose of the present study was to compare continuous and intermittent paroxetine treatment in oriental PMDD women during 6 months follow up.

Thirty-six subjects were evaluated and drug free for two menstrual cycles, and they received daily paroxetine (20 mg) for two further full cycles. They were then randomly divided into continuous or intermittent treatment groups (n = 16, 14) over the next four cycles. Responses were assessed every 2 weeks. Outcome measures included scores on the Prospective Record of the Impact and Severity of Menstrual Symptomatology (PRISM) calendar, Hamilton Rating Scale for Depression/Anxiety (HAMD/HAMA), and the Clinical Global Impression scale (CGI).

All these women had significant improvements in the HAMA, HAMD, CGI, and PRISM calendar. The rate of response to paroxetine treatment lay between 50% and 78.6% in the continuous-treatment group, and 37.5-93.8% in the intermittent-treatment group, as determined at the study end-point. Limitations of the present study included the open-label design and the incorporation of a limited sample size.

The present results indicate that paroxetine is effective in both continuous and intermittent treatment of oriental PMDD women, and that the effects of active treatment lasted for six consecutive treatment menstrual cycles.