Effectiveness of digital interventions for people with comorbid heavy drinking and depression: A systematic review and narrative synthesis

Introduction: Heavy drinking and depression frequently co-occur and make a substantial contribution to the global non-communicable disease burden. Positive evidence exists for the use of digital interventions with these conditions alone, but there has been limited assessment of combined approaches. Objective: A systematic review of the effectiveness of combined digital interventions for comorbid heavy drinking and major depression in community-dwelling populations. Methods and analysis: Electronic databases were searched to October 2021 for randomised controlled trials that evaluated any personalised digital intervention for comorbid heavy drinking and depression. Primary outcomes were changes in quantity of alcohol consumed and depressive symptoms. Two reviewers independently assessed study eligibility, extracted data, and undertook risk of bias assessment. Due to the limited number and heterogeneity of studies identified, meta-analysis was not possible, therefore data were synthesised narratively. Results: Of 898 articles identified, 24 papers were reviewed in full, five of which met the inclusion criteria (N = 1503 participants). Three utilised web-based intervention delivery; two computer programmes delivered in a clinic setting. All involved multi-component interventions; treatment length varied from one to ten sessions. Four studies found no evidence for the superiority of combined digital interventions for comorbid heavy drinking and depression over therapist-delivered approaches, single condition interventions (including online), or assessmentonly controls. Positive impacts of integrated online therapy compared to generalist online health advice were reported in a fifth study, but not maintained beyond the 1-month follow-up. Limitations: Few eligible, heterogeneous studies prevented meta-analysis. Conclusion: Limited evidence exists of the effectiveness of combined digital interventions for comorbid heavy drinking and depression in community dwelling populations.