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

•Depression and anxiety were reported in 32 % and 41 % of observations, respectively.•Serious depression and anxiety were associated with poorer physical health and concerns about health.•Serious depression was associated with recent illicit opioid use, emotional abuse, and spending free time alone.•Serious anxiety was associated younger age, recent illicit benzodiazepine use, smoking, and experiencing social problems.•Although depression and anxiety share several key factors, there are distinctive characteristics associated with each outcome.