Introduction: Depression is considered a multiproblematic disorder that leads to impairment in interpersonal, academic, social, and occupational functioning. Untreated depression can lead to suicide, which is the second leading cause of death among adolescents and young adults. Antidepressants and psychotherapy have limited effectiveness and are not available worldwide. Alternative and complementary treatments, such as online mindfulness-based interventions (MBIs), are growing. Objective: We examined the effects of online MBIs on depressive symptoms in college and university students and explored the moderating effects of participant, methods, and intervention characteristics. Methods: We systematically searched nine databases from their inception through August 2022 without date restrictions. We included primary studies evaluating MBIs with college and university students with depression measured as an outcome, a comparison group, that were written in English. We used random-effects model to compute effect sizes (ESs) using Hedges' g, a forest plot, and Q and I2 statistics as measures of heterogeneity; we also examined moderator analyses. Results: Fifteen studies included 1886 participants (22.6 ± 3.2 years old). Overall, online MBIs showed significantly improved depression (g = 0.18, 95% confidence interval 0.02 to 0.34, I2 = 61%) compared with controls. With regard to moderators, when depression was measured further from the end of the intervention, there was less reduction in depressive symptoms (β = -0.012, Qmodel = 3.81, p = 0.051). Researchers who reported higher attrition reported less beneficial effects on depressive symptoms (β = -0.013, Qmodel = 9.85, p = 0.001). Researchers who used intention-to-treat reported lower ESs (g = -0.15) compared with not using intention-to-treat (g = 0.32, p < 0.001). No other quality indicators moderated the effects of online MBIs on depression. Conclusions: Online MBIs improved depressive symptoms in college and university students. Thus, it might be used as one treatment in their tool kit for college and university students.
Keywords: college and university students; depression; meta-analysis; mindfulness.