Access without Adequacy: Co-Occurring Mental Health Burden and Unmet Need In Sexual Minority Adults with Substance Use Disorder

Background and Purpose: Substance use disorder rarely occurs in isolation, yet research often approaches treatment access as though it does. This becomes more complicated when considering sexual minority populations, where elevated psychological distress is consistently documented. What happens once individuals are already connected to systems of care? This study examines whether sexual minority adults with substance use disorder experience greater co-occurring mental health burden than their heterosexual counterparts and whether that burden is associated with unmet mental health treatment need, alongside differences in mental health treatment use.

Methods: This study uses cross-sectional data from the 2023 National Survey on Drug Use and Health (NSDUH), a nationally representative survey of U.S. adults. The analytic sample was restricted to respondents aged 18 and older who met criteria for past-year substance use disorder. Sexual identity was categorized as heterosexual or sexual minority. Mental health was assessed using NSDUH model-based indicators of any mental illness and serious mental illness, along with psychological distress measured by the K6 scale. Unmet mental health treatment need was defined as self-reported perceived need without receipt of care, and treatment use was measured as receipt of mental health services in the past year. Survey-weighted logistic regression models were estimated to examine differences in mental health, unmet need, and treatment use, adjusting for age, sex, and race or ethnicity. Sequential models were used to assess whether psychological distress and co-occurring mental health burden accounted for observed differences by sexual identity.

Results: Among adults with substance use disorder, sexual minority respondents had higher odds of co-occurring mental health burden compared to heterosexual respondents, including any mental illness (OR = 2.15, p < .001) and serious mental illness (OR = 2.68, p < .001). Among adults with SUD, unmet need was reported by 13.2% of sexual minority adults compared with 8.5% of heterosexual adults. At the same time, sexual minority respondents were more likely to receive mental health treatment (OR = 1.45, p = .021), indicating that greater service use occurred alongside greater unmet need. After psychological distress and co-occurring mental health burden were added to the model, the association between sexual minority status and unmet need was reduced (OR = 1.85 to 1.32); however, this reduction was not statistically significant. This pattern suggests that differences in unmet need may be more closely related to the intensity of mental health burden than to sexual identity alone.

Conclusion and Implications: These findings indicate that unmet mental health need among sexual minority adults with substance use disorder is not explained by lack of service contact. Instead, higher unmet need co-occurs with greater treatment engagement, reflecting a disconnect between service access and meaningful response. Individuals may be receiving care that does not match the type or intensity of their needs or effectively address their co-occurring mental health burden. These results point to the need for approaches that better align care with the level of co-occurring mental health burden.