Treatment engagement for substance use disorder and mental illness in the United States

Given high rates of comorbidity between any mental illness (AMI) and substance use disorder (SUD), and low rates of SUD treatment seeking among people with SUD, the objective was to quantify conditional prevalence rates of treatment seeking for AMI and SUD among those with AMI only, SUD only, and dual AMI+SUD.

We used data from U.S. adults aged 18 or older (N = 92,233) who took part in the National Survey on Drug Use and Health (NSDUH), an annual cross-sectional survey representative of the U.S. population, in 2022 or 2023. Respondents answered questions to determine prevalence of DSM-5 SUD, AMI, 12-month SUD treatment engagement and 12-month AMI treatment engagement.

Among the full population, 4.6% and 22.3% of adults had sought treatment for SUD and AMI, respectively. Among people with SUD, prevalence of any past year treatment for SUD was lower (14.4%) than treatment for AMI (37.0%), and 29.9% of those receiving AMI treatment also had a SUD. Those with dual SUD and AMI were approximately three times more likely to seek treatment for AMI (56.8%) compared to SUD (21.3%).

Across levels of care, people with SUD are more likely to seek treatment for mental illness than SUD, suggesting a potential target to engage people in substance-related cascades of care and highlighting the importance of integrated comorbidity care.