Co-occurring substance use and mental disorders among adults with opioid use disorder

Background: Co-occurring substance use and mental disorders among people with opioid use disorder (OUD) increase risk for morbidity and mortality. Addressing these co-occurring conditions is critical for improving treatment and health outcomes. There is limited recent research on the prevalence of co-occurring disorders, demographic characteristics associated with co-occurring disorders, and receipt of mental health and substance use treatment services among those with OUD. This limits the development of targeted and resourced policies and clinical interventions. Methods: Using 2015-2017 National Survey on Drug Use and Health data, prevalence of co-occurring substance use and mental disorders and receipt of mental health and substance use treatment services was estimated for adults aged 18-64 with OUD. Multivariable logistic regression assessed demographic and substance use characteristics associated with past-year mental illness (AMI) and serious mental illness (SMI) among adults with OUD as well as treatment receipt. Results: Among adults with OUD, prevalence of specific co-occurring substance use disorders ranged from 26.4% (95% CI:23.6%-29.4%) for alcohol to 10.6% (95% CI:8.6%-13.0%) for methamphetamine. Prevalence of AMI was 64.3% (95% CI:60.4%-67.9%) and SMI was 26.9% (95% CI:24.2%-29.8%). Receiving both mental health and substance use treatment services in the past year was reported by 24.5% (95% CI:21.5%-29.9%) of adults with OUD and AMI and 29.6% (95% CI:23.3%-36.7%) of adults with OUD and SMI. Conclusions: Co-occurring substance use and mental disorders are common among adults with OUD. Expanding access to comprehensive service delivery models that address the substance use and mental health co-morbidities of this population is urgently needed.