Effects of Trazodone on Sleep: A Systematic Review and Meta-analysis

Background and objectives Sleep problems and insomnia are common, challenging to treat, and transcend specific diagnoses. Although trazodone is a popular choice, robust meta-analytic evidence is lacking. This systematic review and meta-analysis investigates the efficacy and safety of trazodone for sleep disturbances, reflecting recent updates in insomnia diagnosis and treatment. Methods We searched Medline, Embase, APA PsycINFO, the Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) up to 1 May 2024, for Randomized Controlled Trials (RCTs) comparing trazodone with placebo and reporting sleep-related outcomes. The minimum pharmacotherapy duration was 5 days. Included were all RCTs regardless of blinding (open-label or single- or double-blind), while quasi-randomized studies were excluded. The Cochrane Risk of Bias Tool for Randomized Trials assessed bias. Analyses used a random-effects model on an intention-to-treat (ITT) basis. Risk ratio (RR) was used for dichotomous outcomes and weighted mean difference (WMD) for continuous outcomes. When different units or scales were used, Hedge's adjusted g standardized mean difference (SMD) was calculated. Subgroup and preplanned sensitivity analyses explored heterogeneity and evaluated findings' strength and consistency. Results In total, 44 RCTs with 3935 participants were included. Trazodone did not significantly impact subjective total sleep time (TST) [WMD = 0.73 min, 95% confidence interval (CI) - 24.62; 26.07, p = 0.96] but improved sleep quality (SQ) (SMD = - 0.58, 95% CI - 0.87; - 0.28, p < 0.01) and secondary outcomes. These included the number of nocturnal awakenings (SMD = - 0.57, 95% CI - 0.85; - 0.30], p < 0.01), nocturnal time awake after sleep onset (WMD = - 13.47 min, 95% CI - 23.09; - 3.86], p < 0.01), objective TST by polysomnography (WMD = 27.98 min, 95% CI 4.02; 51.95, p = 0.02), and sleep efficiency (WMD = 3.32, 95% CI 0.53; 1.57, p = 0.02). Tolerability issues included more dropouts owing to adverse effects (RR = 2.30, 95% CI 1.45; 3.64, p < 0.01), any sleep-related adverse effects (RR = 3.67, 95% CI 1.07; 12.47, p = 0.04), more adverse effects in general (RR = 1.18, 95% CI 1.03; 1.33, p = 0.02), and more sleep-related adverse effects (RR = 4.31, 95% CI 2.29; 8.13, p < 0.01). Conclusion Trazodone extends total sleep time but does not affect perceived sleep duration. It may improve sleep quality and continuity but has minor effects on sleep latency, efficiency, and daytime impairment. Trazodone is associated with adverse effects, necessitating a careful risk-benefit assessment. Limited data restrict generalizability, underscoring the need for more research.