C-reactive protein and substance use disorders in adolescence and early adulthood: a prospective analysis.

BACKGROUND Dysregulated immune function and elevated inflammation markers are seen in adults with chronic diseases, including some psychiatric disorders, but evidence on inflammation in the case of drug abuse is conflicting. OBJECTIVE To test the concurrent and predictive relations between C-reactive protein (CRP) and use and abuse of alcohol, nicotine and cannabis in a longitudinal, population sample of adolescents and young adults, at the period of highest increase in drug use. METHODS Data from the prospective population-based Great Smoky Mountains Study (N=1420) were used, covering children in the community assessed at ages 9-16, 19, and 21. Structured interviews were used to assess substance abuse symptoms and DSM-IV substance use disorders. Bloodspots were collected at each assessment and assayed for CRP. RESULTS CRP levels were higher in the presence of nicotine, alcohol, and cannabis use and nicotine dependence. In prospective analyses, higher CRP levels predicted cannabis use and nicotine dependence, and nicotine use predicted higher CRP levels, once covariates were included in the models. Significant covariates were age, race (American Indian), and obesity. CONCLUSIONS The inter-relationship of CRP and substance abuse has implications for the later health risks associated with early drug and alcohol use and abuse.