Perinatal risk factors in offenders with severe personality disorder: a population-based investigation.

Although perinatal factors are associated with the development of several psychiatric disorders, it is unknown whether these factors are linked with personality disorder. Cases of personality disorder were drawn from a national registry of all forensic psychiatric evaluations (n = 150). Two control groups were used: (1) A sample of forensic evaluations without any psychiatric disorder (n = 97) allowing for a nested case-control investigation; and (2) A population-based sample matched by age and gender with no history of psychiatric hospitalization (n = 1498). Prematurity (<37 weeks of completed gestation) was significantly associated with a diagnosis of personality disorder, both in the nested and the population-based case-control comparisons with adjusted odds ratios (OR) for this risk factor ranging from 2 to 4. Asphyxia (adjusted OR = 2.4, 95% CI: 1.4-4.1) and complicated delivery (adjusted OR = 1.5, 1.0-2.1) were associated with personality disorder in the population-based study, and the former remained significant in multivariate models. Overall, perinatal complications were found to be associated with a later diagnosis of personality disorder in this selected sample. As with other psychiatric disorders where such associations have been demonstrated, changes during the perinatal period may lead to abnormal brain development and function.