Effectiveness of online psychological and psychoeducational interventions to prevent depression: Systematic review and meta-analysis of randomized controlled trials.

Although evidence exists for the efficacy of interventions to prevent depression, little is known about its prevention through online interventions. We aim to assess the effectiveness of online psychological and psychoeducational interventions to prevent depression in heterogeneous populations. A systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted based on literature searches in eight electronic data bases and other sources from inception to 22 July 2019. Of the 4181 abstracts reviewed, 501 were selected for full-text review, and 21 RCTs met the inclusion criteria, representing 10,134 participants from 11 countries and four continents. The pooled SMD was -0·26 (95%CI: -0·36 to -0·16; p < 0.001) and sensitivity analyses confirmed the robustness of this result. We did not find publication bias but there was substantial heterogeneity (I = 72%; 95%CI, 57% to 82%). A meta-regression including three variables explained 81% of the heterogeneity. Indicated prevention and interactive website delivery were statistically associated with higher effectiveness, and no association was observed with risk of bias. Online psychological and psychoeducational interventions have a small effect in reducing depressive symptoms in non-depressed and varied populations, and the quality of evidence is moderate. Given that these types of interventions are very accessible and can be applied on a wide scale, they should be further developed and implemented. Registration details: Registration number (PROSPERO): CRD42014014804.