Suicide prevention using self-guided digital interventions: a systematic review and meta-analysis of randomised controlled trials

Background
Digital interventions that deliver psychological self-help provide the opportunity to reach individuals at risk of suicide who do not access traditional health services. Our primary objective was to test whether direct (targeting suicidality) and indirect (targeting depression) digital interventions are effective in reducing suicidal ideation and behaviours, and our secondary analyses assessed whether direct interventions were more effective than indirect interventions.
Methods
In this systematic review and meta-analysis, we searched online databases MEDLINE, PubMed, PsycINFO, and Cochrane CENTRAL for randomised controlled trials published between database inception to May 21, 2019. Superiority randomised controlled trials of self-guided digital interventions (app or web based, which delivered theory-based therapeutic content) were included if they reported suicidal ideation, suicidal plans, or suicide attempts as an outcome. Non-inferiority randomised controlled trials were excluded to ensure comparability of the effect. Data were extracted from published reports, and intention-to-treat data were used if available. The primary outcome was the difference in mean scores of validated suicidal ideation measures (Hedges’ g) with the associated 95% CI for the analysis of digital intervention effectiveness on suicidal ideation. We also present funnel plots of the primary outcome measure (suicidal ideation) for direct and indirect interventions to assess for publication bias. We calculated I2 (with I2 CI) values to test heterogeneity. We used random-effects modelling for the meta-analyses to assess the primary and secondary outcomes. This study is registered with PROSPERO, CRD42018102084.
Findings
The literature search yielded 739 articles (including manual searching) for suicidality and 8842 articles for depression. After screening, 14 papers reporting on 16 studies were included in the narrative review and meta-analysis. The 16 studies (ten on direct interventions and six on indirect interventions) provided baseline data for 4398 participants. The primary outcome of overall post-intervention effect for suicidal ideation was small but significant immediately following the active intervention phase (Hedges’ g −0·18, 95% CI −0·27 to −0·10, p<0·0001; I2=0%, I2 CI 0·0–47·9). The secondary objective, comparing direct and indirect interventions, showed that direct interventions (targeting suicidality) significantly reduced suicidal ideation at post-intervention (g −0·23, 95% CI −0·35 to −0·11, p<0·0001; I2=17·6%, I2 CI 0·0–58·6), but indirect interventions (targeting depression) failed to reach significance (g −0·12, 95% CI −0·25 to 0·01, p=0·071; I2=0%, I2 CI 0·0–30·7).
Interpretation
Self-guided digital interventions directly targeting suicidal ideation are effective immediately post-intervention. Indirect interventions were not significant for reducing suicidal ideation. Our findings suggest that digital interventions should be promoted and disseminated widely, especially where there is a lack of, or minimal access to, health services.