Childhood and adolescent risk factors for comorbid depression and substance use disorders in adulthood.

The comorbidity of major depression and substance use disorders is well documented. However, thorough understanding of prevalence and early risk factors for comorbidity in adulthood is lacking, particularly among urban African Americans. With data from the Woodlawn Study, which follows a community cohort of urban African Americans from ages 6 to 42, we identify the prevalence of comorbidity and childhood and adolescent risk factors of comorbid depression and substance use disorders, depression alone, and substance use disorders alone. Prevalence of comorbid substance use disorders and major depression in adulthood is 8.3% overall. Comorbidity in cohort men is twice that for women (11.1% vs. 5.7%). Adjusted multinomial regression models found few differences in risk factors for comorbidity compared to either major depression or a substance use disorder on its own. However, results do suggest distinct risk factors for depression without a substance use disorder in adulthood compared to a substance use disorder without depression in adulthood. In particular, low socioeconomic status and family conflict was related to increased risk of developing major depression in adulthood, while dropping out of high school was a statistically significant predictor of adult-onset substance use disorders. Early onset of marijuana use differentiated those with a substance use disorder with or without depression from those with depression without a substance use disorder in adjusted models. In conclusion, comorbid substance use disorders and depression are highly prevalent among these urban African Americans. Insight into the unique childhood and adolescent risk factors for depression compared to substance use disorders is critical to intervention development in urban communities. Results suggest that these programs must consider individual behaviors, as well as the early family dynamic.