Schizophrenia as a Long-Term Outcome of Pregnancy, Delivery, and Perinatal Complications: A 28-Year Follow-Up of the 1966 North Finland General Population Birth Cohort

OBJECTIVE: The 1966 North Finland general population birth cohort was studied to determine whether abnormalities during pregnancy, delivery, and the neonatal period are associated with adult-onset schizophrenia. METHOD: The authors included all 11,017 subjects alive in Finland at age 16. For each individual, standardized assessments made during pregnancy, delivery, and infancy were linked to national psychiatric case registers covering the period up to age 28. Subjects with DSM-III-R schizophrenia were identified by using a two-stage screen that included perusal of individual case records. Associations (adjusted odds ratios) between schizophrenia and specific pregnancy, delivery, and neonatal characteristics were calculated. RESULTS: Within this cohort, 76 cases of DSM-III-R schizophrenia arose by age 28 years; 51 (67.1%) of these persons were men. Demographic characteristics and previous obstetric histories of the mothers were similar in the case and unaffected comparison groups, although the former were more likely to have been more depressed than usual during pregnancy. Low birth weight (<2500 g) and the combination of low birth weight and short gestation (<37 weeks) were more common among the schizophrenic subjects. Being small for gestational age (<10th percentile) was not more common. Of 125 survivors of severe perinatal brain damage, six (4.8%) later developed schizophrenia. CONCLUSIONS: The spectrum of adverse outcomes after fetal and perinatal insults unfolded beyond childhood and included adult-onset schizophrenia. The findings have implications for understanding the mechanisms involved in the development of schizophrenia and, possibly, for its prevention.