Comorbidity of substance use disorders and other psychiatric disorders among adolescents: evidence from an epidemiologic survey.

This paper extends our knowledge of comorbidity of substance use disorders (SUDs) and other psychiatric disorders by examining comorbidity of specific types of SUDs and risk of comorbidity separately for abuse and dependence. The research question is whether there is specificity of risk for comorbidity for different SUDs and whether greater comorbidity is associated with dependence. Data are presented from a probability sample of 4175 youths aged 11-17 assessed with the NIMH DISC-IV and self-administered questionnaires. SUDs outcomes are alcohol, marijuana and other substances in past year. Mean number of other comorbid disorders ranged from 1.9 for marijuana abuse to 2.2 for other substance abuse and 1.9 for marijuana dependence to 2.8 for other substance dependence. None of the abuse SUDs does not increase risk of anxiety disorders, but dependence does. Both abuse and dependence increased risk of comorbid mood disorders. Similar results were observed for disruptive disorders. Patterns of comorbidity varied by substance, by abuse versus dependence, and by category of other psychiatric disorders. In general, there was greater association of comorbidity with other disorders for dependence versus abuse. Marijuana is somewhat less associated with other disorders than alcohol or other substances. The strongest association is for comorbid disruptive disorders, regardless of SUDs category. Having SUDs and comorbid other psychiatric disorders was associated with substantial functional impairment. Females with SUDs tended to have higher rates of comorbid disorders, as did older youths. There were no differences observed among ethnic groups. When comorbidity of SUDs with other disorders was examined, controlling for other non-SUDs disorders for each specific disorder examined, the greater odds for dependence versus abuse essentially disappeared for all disorders except disruptive disorders, suggesting larger number of comorbid non-SUDs in part account for the observed effects for dependence.