Maternal stress, prenatal medical illnesses and obstetric complications: Risk factors for schizophrenia spectrum disorder, bipolar disorder and major depressive disorder.

Maternal stress and medical illnesses during early life are well-documented environmental indicators of an increased risk of schizophrenia. Few studies, conversely, have confirmed an association with major affective disorders. The present study examined the impact of maternal stress, medical illnesses and obstetric complications on the development of severe mental disorder in 240 patients with a diagnosis of schizophrenia spectrum disorder, bipolar disorder, or major depressive disorder and matched with 85 controls. Mothers of participants were asked about stressful events during pregnancy using the Social Readjustment Scale; information on prenatal/perinatal illnesses were acquired from medical records. Schizophrenia spectrum disorder was positively associated with maternal stress (OR = 2.16), infections (OR = 7.67), inadequate weight gain (OR = 9.52) during pregnancy, and peripartum asphyxia (OR = 4.00). An increased risk of bipolar disorder was associated with head circumference < 32 cm at birth (OR = 5.40) and inversely with inadequate weight gain (OR = 0.29). Major depressive disorder diagnosis was inversely related to inadequate weight gain (OR = 0.22). These results support a role for maternal stress, medical illnesses and obstetric complications as risk factors for subsequent severe mental illness in adulthood. Further research is needed, especially with regard to affective disorders.