Incidence of adult onset schizophrenic disorders in the US Military: Patterns by sex, race and age

Background: There are limited data describing the epidemiology of adult-onset schizophrenic disorders in the United States. Although the military is not proportionately comparable in all demographic characteristics to the civilian population, it is drawn from all racial/ethnic subgroups, and members range in age from 17 to > 60 years. We describe the incidence of hospitalization for new onset schizophrenic disorders among military members by sex, race, and age. Methods: Using military inpatient data, we evaluated patterns of initial hospitalizations for schizophrenic disorders among military personnel for 2000-2009, focusing on sex, race, and age. No individual-level data were available. Results: From 2000-2009, 1976 military personnel had a first schizophrenic disorder hospitalization, with an overall incidence rate of 0.14/1000 person-years. There were no consistent changes in rates over time. While overall incidence rates were similar for men and women (incidence rate ratio (IRR) = 1.10), rates were higher among men than women below age 25; after 25-30 rates were higher among women. Incidence was higher among blacks and other racial groups, with IRR = 2.0 and 1.3, respectively. Conclusion: Medical screening of military applicants prevents persons with overt or a reported history of psychosis, and most with serious behavior problems, from enlisting; therefore, first hospitalization is likely to reflect new illness. No pre-military socioeconomic data were available, however, essentially all study subjects were high school graduates; unmeasured differences in socioeconomic status were unlikely to explain the observed results. This report may provide lower bound estimates of the schizophrenic disorder incidence in the United States.