Obstetric complications and schizophrenia: prenatal underdevelopment and subsequent neurodevelopmental impairment.

BACKGROUND Many studies have shown an association between obstetric complications and schizophrenia. AIMS To investigate the possible relationship between prenatal underdevelopment, neurodevelopmental abnormality and subsequent schizophrenia. METHOD The literature was reviewed. In particular, by pooling data from recently published reports, we examined whether low birthweight (< 2500 g) is a risk factor for schizophrenia. RESULTS Low birthweight was significantly more common for subjects with schizophrenia than for control subjects: P < 0.00001, odds ratio 2.6 (95% CI 2.0 to 3.3). Individuals born prematurely are at greater risk of perinatal brain damage and subsequent neurodevelopmental abnormalities, which may constitute vulnerability to the development of schizophrenia. Patients with schizophrenia who had low birthweights also tended to have poor premorbid psychosocial adjustment. CONCLUSIONS Low birthweight is a modest, but definite, risk factor for schizophrenia. Brain damage associated with prenatal underdevelopment has a role in the pathogenesis of poor premorbid functioning and subsequent neurodevelopmental impairment in some cases of schizophrenia.