Prenatal origins of hospitalization for personality disorders: the Helsinki birth cohort study.

Although a suboptimal prenatal environment has been linked with schizophrenia and depression, possible associations with personality disorders remain unclear. The aim of this study was to examine the associations of body size at birth and length of gestation with hospitalization for personality disorders in a cohort study of 6506 men and 5857 women born in Helsinki, Finland, between 1934 and 1944. International Classification of Diseases (-8, -9, -10) diagnoses of personality disorders were extracted from the national Finnish Hospital Discharge Register since 1969. 102 men and 80 women had been hospitalized due to any personality disorder. 41 men and 30 women had dramatic personality disorders. Among men, head circumference showed an inverse J-shaped, nonlinear association with hospitalization for personality disorders. Men with a small head circumference were at increased risk. Also in men, a smaller head-to-length ratio linearly predicted personality disorders. Among women, a smaller placental area predicted increased risk of hospitalization for dramatic personality disorders. Vulnerability to personality disorders may be programmed during fetal life.