Serotonin 3 receptor antagonists for obsessive-compulsive disorder: A systematic review and pairwise meta-analysis.

The benefits of serotonin 3 receptor antagonists (5-HT3R-As) in obsessive-compulsive disorder (OCD) treatment remain unclear. Thus, this study aimed to perform a systematic review and a random-effects meta-analysis, including double-blind, randomized, placebo-controlled trials (DBRPCTs). The outcomes include the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) total score (primary), Y-BOCS obsession subscale score, Y-BOCS compulsive subscale score, treatment response, remission rate, all-cause discontinuation, and incidence of individual adverse events (nervousness/restlessness/anxiety, insomnia, headache, dizziness/lightheadedness, decreased appetite, constipation, nausea/vomiting, diarrhea, dry mouth, sweating/increased perspiration, itching/pruritus, tremor, and sexual dysfunction/decreased libido). The mean differences (MD) for continuous outcomes and risk ratios for dichotomous outcomes with 95% confidence intervals (CIs) were calculated. Our study included 10 DBRPCTs (n = 628). Pooled 5-HT3R-As outperformed placebo regarding Y-BOCS total score (MD = -5.08, 95% CI = -7.04, -3.12, N = 9, n = 560), Y-BOCS obsession subscale score, Y-BOCS compulsive subscale score, treatment response, and remission rate. Individually, all 5-HT3R-As outperformed placebo regarding Y-BOCS total score (granisetron: MD = -5.59, 95% CI = -8.79, -2.39, N = 3, n = 178, ondansetron: MD = -5.72, 95% CI = -8.06, -3.37, N = 6, n = 331, tropisetron: MD = -2.87, 95% CI = -5.19, -0.550, N = 1, n = 96). However, all-cause discontinuation and incidence of individual adverse events between pooled 5-HT3R-As and placebo were not significantly different. In conclusion, our meta-analysis suggested 5-HT3R-As as efficacious for symptom improvement in individuals with OCD. However, the number of individuals included in each study was small; thus, a replication randomized trial of 5-HT3R-As should be conducted using a larger sample size.