Experiences of serious depression and serious anxiety among individuals receiving injectable opioid agonist treatment (iOAT)

Background: This study aims to provide evidence of factors that impact participant reported serious depression and serious anxiety among individuals receiving injectable opioid agonist treatment (iOAT). Methods: Data from an 18-month longitudinal retrospective cohort of individuals receiving iOAT was utilized. The outcomes of serious depression and serious anxiety were ascertained via self-report in the European Addiction Severity Index. Two Generalized Linear Mixed Models were formulated using Penalized Quasi-Likelihood method. Results: Analyses included 131 participants. Average age was 49.04 years, 31 % self-identified as female, and 30 % self-identified as Indigenous. Adjusted analysis identified the importance of poorer physical health (AOR:1.06; 95 % CI: 1.03, 1.08), illicit opioid use (AOR: 1.03; 95 %CI: 1.01, 1.06), emotional abuse (AOR: 2.01; 95 % CI: 1.17, 3.44), and social isolation (AOR: 1.95; 95 % CI: 1.06, 3.58) with serious depression. Adjusted analysis of serious anxiety identified associations with age (AOR: 0.95; 95 % CI: 0.92, 0.98), illicit benzodiazepine use (AOR:1.31 95 % CI: 1.06, 1.61), poorer physical health (AOR: 1.05; 95 % CI: 1.03, 1.07), and social problems (AOR: 2.09; 95 % CI: 1.18, 3.71). Limitations: Generalizability of study findings may be limited given the criteria used to enroll participants and to define depression and anxiety. Conclusion: Depression and anxiety are highly prevalent among clients receiving iOAT. While both disorders share several factors, there are distinct characteristics associated with each outcome. These include poorer physical health, experiences of abuse, illicit substance use, and social problems. Understanding factors that influence depression and anxiety in iOAT can assist providers in supporting iOAT clients' mental health and developing individualized care plans.