Moderators and Mediators of Treatments for Suicidal Thoughts and Behaviors: A Review of More Than 50 Years of Randomized Controlled Trials

Abstract

Psychosocial treatments for suicidal thoughts and behaviors (STBs) are in need of improvement, as suicide rates have substantially increased in the last 20 years and current interventions show limited efficacy. One way to potentially boost response rates is to personalize treatments by identifying what works how and for whom to maximize impact across different individuals. A scoping review of all suicide treatment randomized controlled trials was performed on PubMed, PsycInfo, and GoogleScholar through May 2024 to identify moderators and mediators of suicide treatment. Forty-six studies including moderators and 15 studies including mediators were identified and evaluated by at least two independent researchers. The most frequently tested moderators across both adults and adolescents include age, gender/sex, history of STBs, therapeutic alliance, comorbid depression, and comorbid borderline personality disorder diagnoses or symptoms, with the strongest support found for therapeutic alliance in adults. No mediator was tested in more than one trial or research group, but hopelessness, avoidance, mentalization, and number of treatment contacts in adolescents and resilience, anxiety sensitivity, acceptance, and therapeutic relationship in adults showed positive signals. Overall, additional work is needed as heterogeneity, lack of replication attempts, and concerns about moderator and mediator quality currently limit confidence in findings.