Single-Session Interventions for Mental Health Problems and Service Engagement: Umbrella Review of Systematic Reviews and Meta-Analyses.

Most people with mental health needs cannot access treatment; among those who do, many access services only once. Accordingly, single-session interventions (SSIs) may help bridge the treatment gap. We conducted the first umbrella review synthesizing research on SSIs for mental health problems and service engagement in youth and adults. Our search yielded 24 systematic reviews of SSIs, which included 415 unique trials. Twenty reviews (83.33%) reported significant, positive effects of SSIs for one or more outcomes (anxiety, depression, externalizing problems, eating problems, substance use, treatment engagement or uptake). Across 12 reviews that meta-analytically examined SSIs' effectiveness relative to controls, SSIs showed a positive effect across outcomes and age groups (standardized mean difference = -0.25, 2 = 43.17%). Per AMSTAR 2 (A Measurement Tool to Assess Systematic Reviews), some methodological concerns emerged across reviews, such as low rates of preregistration. Overall, findings support the clinical utility of SSIs for certain psychological problems and populations. Implementation research is needed to integrate effective SSIs into systems of care.