Abstract Introduction Social vulnerability, encompassing exposure to systemic inequities, reflects the disadvantage that individuals face. It has previously been linked to poorer sleep, disrupted circadian rhythms, and increased prevalence of serious mental illness (SMI). Socially vulnerable populations also face substantial barriers to accessing and engaging in evidence-based psychological treatments, reducing reach and widening mental health disparities. Despite growing recognition of these inequities, little research has examined whether social vulnerability moderates treatment outcomes. The present study evaluates how social vulnerability influences treatment outcomes of the Transdiagnostic Intervention for Sleep and Circadian Dysfunction (TSC) in community mental health centers, including an Adapted version of TSC to reduce treatment burden and fit client contexts. Methods Data were pooled across two randomized controlled trials evaluating Standard and Adapted TSC (N = 636). Participants who met the criteria for SMI and sleep/circadian disturbance completed assessments at pre-treatment, post-treatment, and six-month follow-up. The Social Vulnerability Index (SVI) measured the degree of disadvantage across subdomains: socioeconomic; household composition/disability; minoritized racial group/language; and housing/transportation. Multilevel models assessed whether subdomains moderated treatment effectiveness across time for various clinical outcomes. Results SVI subdomains moderated the effects of Adapted versus Standard TSC on psychiatric symptoms and functional impairment. For psychiatric symptoms, higher socioeconomic (b = 3.95, SE = 1.64, p = .016) and housing/transportation (b = 3.85, SE = 1.75, p = .027) vulnerability were associated with greater variability in outcomes in Standard TSC, whereas Adapted TSC showed more consistent gains across levels of vulnerability over time. Functional impairment showed a similar pattern, with more consistent improvement in Adapted TSC relative to Standard for socioeconomic (b = 1.23, SE = 0.56, p = .029) and housing/transportation (b = 1.64, SE = 0.62, p = .008) vulnerability. Conclusion These findings suggest that social vulnerability subdomains may influence response to TSC in community health settings. While not all subdomains moderated outcomes, the Adapted condition demonstrated more equitable improvements across levels of socioeconomic and housing/transportation vulnerability. This is important because tailoring interventions to better match client contexts may enhance engagement and improve clinical outcomes. Support (if any) The research was funded by the National Institute of Mental Health (R01MH105513 and R01MH120147).
Oliver et al. (2026) studied this question.