Relations between mental health diagnoses, mental health treatment, and substance use in homeless youth

Background Youth experiencing homelessness have elevated rates of mental illness and substance use compared to the general population. However, the extent to which underlying mental health issues may contribute to substance use as a way to manage symptoms and whether mental health treatment may reduce risk for substance use is unclear. This paper investigated these relations in a community sample of homeless youth. Methods Youth ages 13–24 (N = 416) were interviewed as part of a community count and survey of homeless youth in Houston, Texas. A path analysis examined relations among lifetime diagnoses of ADHD, bipolar disorder, and depression; past-month marijuana, alcohol, and synthetic marijuana use, and hypothesized mediators of past-year mental health treatment and perceived unmet need for treatment. Results Rates of prior mental disorder diagnoses were high, with extensive comorbidity across the three diagnoses (n = 114, 27.3% had all three diagnoses). Relations varied by diagnoses and substances. ADHD was positively related to current marijuana use (β = 0.55 (0.16), p < 0.001), a relation that mental health treatment did not mediate. Depression was positively related to synthetic marijuana use through unmet need (β = 0.25 (0.09), p = 0.004) and to alcohol use through unmet need (β = 0.20 (0.10), p = 0.04) Conclusions This study provides new information about relations between prior mental health diagnoses and substance use in homeless youth. Findings support the need to consider prior mental disorder diagnoses in relation to current substance use and to assess for whether youth perceive they have unmet needs for mental health treatment.