The authors appeared to include 25 placebo controlled RCTs (n=unclear) in the review, of which five (n=757) were included in the relapse prevention meta-analysis.
Definitions of response and remission varied between studies. RCTs reported a range of thresholds on the Yale-Brown Obsessive Compulsive Scale (Y-BOCS).
Five placebo-controlled RCTs evaluated the long-term efficacy of serotonin reuptake inhibitors. One RCT reported fluvoxamine to be superior to placebo over eight weeks follow-up, but only for depression. One RCT reported superior response for clomipramine over 52-weeks follow-up. One RCT reported improvements for fluoxetine at doses of 20, 40 and 60 mg over 24 weeks; the 60 mg group improved significantly more than others. One RCT reported significant improvement in OCD symptoms for sertraline over 40 weeks follow up. The final RCT found significant benefits of escitalopram 10 mg, escitalopram 20 mg and paroxetine 40 mg compared to placebo over 24 weeks follow up, with highly significant differences for escitalopram 20 mg and paroxetine.
Five placebo-controlled RCTs (n=757) reported relapse prevention outcomes. These trials evaluated paroxetine, fluoxetine, sertraline and escitalopram. When combined in a meta-analysis, the pooled relative risk ratio of relapse was significantly lower in the serotonin reuptake inhibitor than placebo groups (relative risk ratio was 0.52, 95% CI: 0.41 to 0.66, p<0.00001).