Patterns of Substance Use and Mental Health Treatment among U.S. Adults with Substance Use Disorder

Abstract Background U.S. adults with substance use disorders (SUD) underutilize substance use treatment (SUT) and are more likely to use mental health treatment (MHT) than SUT. Understanding how SUD severity and mental illness (MI) severity are associated with different treatment configurations may help explain why some individuals receive mental health services without concurrent substance use treatment. We examined clinical and other factors associated with four behavioral health service configurations: no treatment, both SUT and MHT, SUT only, and MHT only. Methods Data came from the 2022 and 2023 National Survey on Drug Use and Health (N = 19,555, age 18 + with past-year SUD). Multinomial and binary logistic regression models were fitted to examine associations between treatment use patterns and SUD and MI severity as need factors, while controlling for predisposing, enabling, and other need factors. Results The findings show that 59.3% of U.S. adults with SUD did not use SUT or MHT in the past year, 10.7% used both SUT and MHT, 3.7% used SUT only, and 26.4% used MHT only. Severe SUD (RRR = 2.77, 95% CI = 2.13–3.60), compared with mild SUD, and all levels of MI severity (RRR = 7.27, 95% CI = 5.41–9.79 for serious MI) were associated with a higher likelihood of receiving both SUT and MHT. Both moderate and severe SUD, but not MI severity, were associated with receiving SUT only. All levels of MI severity were also associated with a higher likelihood of receiving MHT only (RRR = 7.30, 95% CI = 6.17–8.64 for serious MI). The findings were similar in analyses restricted to users of any treatment or SUT. Conclusions Receipt of both SUT and MHT is concentrated among individuals with the highest clinical severity in both SUD and MI. These findings underscore the importance of both treatments and the coordination of SUT and MHT in healthcare service systems