| This study aimed to conduct a systematic review and meta-analysis of dropout among Service Members and Veterans initiating psychotherapy. Specifically, the objectives of this metaanalysis included (1) obtaining an average, weighted psychotherapy dropout rate and (2) examining covariates and moderators of dropout. Overall, 338 articles met study inclusion criteria. These articles comprised data from over 60 years of published research and 735,771 Service Members and Veterans initiating psychotherapy. The average dropout rate, using a random effects model, was 23.40%, 95% CI [20.5%, 26.6%]. Using mixed effects models, dropout was not significantly linked with a number of client demographic (age, employment status, education levels, female gender, race/ethnicity), client military (sample type, service branch, rank, combat deployment history, service era, service connection), client diagnostic (prevalence of a range of mental health diagnoses, traumatic brain injury), therapist (female gender), treatment (theoretical orientation, manualized interventions, treatment format, intensity of services ranging from outpatient to inpatient settings, in person versus telehealth), and research (publication year, effectiveness versus efficacy studies, search strategy, country) variables. However, higher dropout was linked to having fewer clients in committed relationships and having more clients who were in the reserve component. Studies utilizing both experienced and trainee therapists yielded higher dropout rates than those utilizing experienced therapists only. Higher dropout rates were associated with interventions delivered in Department of Veterans Affairs (VA) versus civilian settings as well as approaches that had a low or no time limit versus a high time limit. Articles defining dropout using therapist report yielded higher dropout rates than articles defining dropout using failure to complete a protocol. Lower dropout rates were observed in articles that did not define dropout compared to articles that defined dropout using any method (therapist report, failure to complete a protocol, stopped attending sessions, and other). Taken together, approximately one of four Service Members and Veterans prematurely terminate psychotherapy. These findings highlight the utility of targeting treatment engagement among military populations that are not in committed relationships, are affiliated with the reserve component, receive care from trainee therapists, seek treatment from VA settings, and are engaged in time-limited psychotherapies. |