title: Psychiatric illness following traumatic brain injury in an adult health maintenance organization population.
abstract: BACKGROUND
  Psychiatric illness after traumatic brain injury (TBI) has been shown to be prevalent in hospitalized and tertiary care patient populations.
  
  
  OBJECTIVE
  To determine the risk of psychiatric illness after TBI in an adult health maintenance organization population.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  Large staff-model health maintenance organization.
  
  
  METHODS
  Nine hundred thirty-nine health plan members diagnosed as having TBI in 1993 and enrolled in the prior year, during which no TBI was ascertained. Three health plan members per TBI-exposed subject were randomly selected as unexposed comparisons, matched for age, sex, and reference date.
  
  
  METHODS
  Psychiatric illness in the 3 years after the TBI reference date, determined using computerized records of psychiatric diagnoses according to the International Classification of Diseases, Ninth Revision, Clinical Modification, prescriptions, and service utilization.
  
  
  RESULTS
  Prevalence of any psychiatric illness in the first year was 49% following moderate to severe TBI, 34% following mild TBI, and 18% in the comparison group. Among subjects without psychiatric illness in the prior year, the adjusted relative risk for any psychiatric illness in the 6 months following moderate to severe TBI was 4.0 (95% confidence interval [CI], 2.4-6.8) and following mild TBI was 2.8 (95% CI, 2.1-3.7; P<.001) compared with those without TBI. Among subjects with prior psychiatric illness, the adjusted relative risk for any psychiatric illness in the 6 months following moderate to severe TBI was 2.1 (95% CI, 1.3-3.3) and following mild TBI was 1.6 (95% CI, 1.2-2.0; P =.005). Prior psychiatric illness significantly modified the relationship between TBI and subsequent psychiatric illness (P =.04) and was a significant predictor (P<.001). Persons with mild TBI and prior psychiatric illness had evidence of persisting psychiatric illness.
  
  
  CONCLUSIONS
  Both moderate to severe and mild TBI are associated with an increased risk of subsequent psychiatric illness. Whereas moderate to severe TBI is associated with a higher initial risk, mild TBI may be associated with persistent psychiatric illness.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98105-6560, USA. fann@u.washington.edu
authors.forename: Jesse R
authors.initials: JR
authors.lastname: Fann
authors.forename: Bart
authors.initials: B
authors.lastname: Burington
authors.forename: Alexandra
authors.initials: A
authors.lastname: Leonetti
authors.forename: Kenneth
authors.initials: K
authors.lastname: Jaffe
authors.forename: Wayne J
authors.initials: WJ
authors.lastname: Katon
authors.forename: Robert S
authors.initials: RS
authors.lastname: Thompson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001930:Brain Injuries / Q000150:complications* / Q000453:epidemiology* / Q000523:psychology; D020208:Brain Injury, Chronic / Q000150:complications / Q000453:epidemiology / Q000523:psychology; D015984:Causality; D015331:Cohort Studies; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006279:Health Maintenance Organizations / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology* / Q000523:psychology; D008875:Middle Aged; D019965:Neurocognitive Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology* / Q000523:psychology; D011446:Prospective Studies; D012016:Reference Values; D012306:Risk; D014861:Washington