Background: The prevalence of illicit drug abuse in persons with schizophrenia is greater then in the general population and has been attributed to self-medication of the symptoms of the illness; however, limited data indicate that drug abuse is already prevalent before the manifestation of psychosis, consistent with the possibility that drug abuse might be associated with increased risk for schizophrenia.
Methods: The Israeli Draft Board screens the entire, unselected population of 16- to 17-year-old male adolescents for behavioral or personality disturbances. In a cohort of 270,000 male adolescents screened, 50,413 adolescents were suspected of having behavioral or personality disturbances and were questioned about drug use and abuse. These adolescents were followed for hospitalization for schizophrenia using a national, population-based psychiatric hospitalization registry; 268 of 50,413 (.5%) were hospitalized for schizophrenia over the following 5-11 years.
Results: The prevalence of self-reported drug abuse in adolescents later hospitalized for schizophrenia was 12.4%, compared with 5.9% prevalence of drug abuse in adolescents not later hospitalized; adjusted RR = 2.016, 95% confidence interval: 1.309-3.104.
Conclusions: In this cohort of male adolescents with behavior disturbances, these results further support the hypothesis that drug abuse may be associated with increased risk for future schizophrenia.