The association of preceding traumatic brain injury with mental disorders, alcoholism and criminality: the Northern Finland 1966 Birth Cohort Study.

The purpose of this study was to test the hypothesis that traumatic brain injury (TBI) during childhood and adolescence is associated with psychiatric disorders, heavy alcohol use and criminal offenses in adulthood. We made use of an unselected, general population birth cohort (n=12058) in Northern Finland, which was followed up prospectively up to the age of 31. The data on TBIs of the cohort members were collected from the hospital case notes of the outpatient clinics of the hospitals in the region and from the Finnish Hospital Discharge Registers (FHDR). The data on mental disorders including alcohol diagnoses were also collected from the FHDR after a careful validation process. The Ministry of Justice provided information on criminal offenses for all subjects. The final number of subjects in our study was 5589 males and 5345 females. We found that after controlling for confounders, TBI during childhood or adolescence increased the risk of developing mental disorders two-fold (OR 2.1, 95% CI 1.1-3.6) and TBI was significantly related to later mental disorder with coexisting criminality in male cohort members (OR 4.1, 95% CI 1.2-13.6). The results support the TBI's association with psychiatric morbidity, which should not be overlooked when treating psychiatric patients, especially those with comorbid criminality.