Effectiveness of online cognitive behavioral interventions that include mindfulness for clinically-diagnosed anxiety and depressive disorders: A systematic review and meta-analysis

Background: Online cognitive behavioral interventions that include mindfulness techniques have attracted considerable attention given the demonstrated mental health benefits of mindfulness and the availability of scalable opportunities for increased therapeutic use. However, comparatively little is known about the effectiveness of these types of interventions when they are delivered to clinician-diagnosed populations receiving psychiatric treatment. Aims: This review evaluates therapeutic interventions that included a mindfulness component aimed at reducing anxiety and depression symptoms in clinician-diagnosed samples. Methods: Randomized control trials (RCTs) published between January 1990 to September 2020 assessing the effects of online cognitive behavioral interventions that include a mindfulness component were searched across five databases (Medline, PsychINFO, PubMed, CINAHL, Web of Science). Results: Eleven studies met inclusion criteria with sample sizes ranging from 37 to 84 per study. Findings revealed an overall statistically significant moderate between-group difference at post-intervention for depression (Hedges' g = -0.47) and anxiety (Hedges' g = -0.40) outcomes favoring the online treatment groups. Further analyses revealed larger effect sizes among RCTs employing waitlist control (WLC) comparisons, and reductions in depression symptoms within the intervention groups to be above the minimal clinically important difference (MCID) for BDI-II. Conclusions: Findings from this meta-analytic review provide preliminary support for including mindfulness practices within existing therapeutic programs to reduce depression and anxiety symptoms in clinician-diagnosed populations. Research implications and priorities for online mindfulness-based cognitive behavioral programming are discussed.