Impact of mental health on retention in OAT
Background: Comorbid substance use disorders and mental health conditions (SUD-MH) are associated with poorer treatment completion. It has been previously suggested that treating opioid use disorder (OUD) with pharmacology, such as opioid agonist therapy (OAT), may reduce the retention gap between people with OUD-MH and OUD only. Noting the high OUD-MH prevalence, we aimed to evaluate the impact of mental health comorbidities on OAT treatment retention through a systematic review and meta-analyses.
Methods: PubMed, EMBASE and PsycINFO databases were searched for studies reporting buprenorphine and methadone treatment retention outcomes among people with OUD. Included studies reported on treatment retention at any time point among participants with OUD-MH and OUD only. Baseline MH groupings were any MH disorders/symptoms, mood disorders/symptoms (e.g., depression), anxiety disorders/symptoms (e.g., PTSD), psychotic disorders/symptoms (e.g., schizophrenia), ADHD and personality disorders. Pooled risk ratios (RR) for buprenorphine and methadone treatment retention were estimated through STATA 17 using random-effects meta-analyses.
Results: In total, 38 papers comprising of 37 cohorts were identified, with 54% being buprenorphine cohorts. Of cohorts reporting 12-month OAT retention, 12 measured any MH and 13 measured a specific MH at baseline. Any MH disorder analyses on 12-month buprenorphine (k=8) and methadone (k=3) retention had the highest number of included studies, with no significant impact found on retention. Only ADHD indicated poorer 12-month buprenorphine retention (k=3; RR=1.182, p=.001) while a personality disorder diagnosis indicated better 12-month methadone retention (k=2; RR=0.894, p=0.008), compared to no diagnosis.
Conclusions: This systematic review synthesises and evaluated global evidence of mental health comorbidity on treatment retention for the first time. There is a lack of evidence indicating that retention is poorer among people with OUD-MH, demonstrating the strength of OAT in retaining people with OUD. However, the small number of cohorts contributing to the majority of analyses should be noted.
