Perinatal risk factors for schizophrenia: diagnostic specificity and relationships with maternal psychopathology

Although a growing body of evidence supports the hypothesis that exposure to obstetric complications (OCs) increases the vulnerability for schizophrenia, some questions remain unanswered regarding the diagnostic specificity and the etiological significance of this association. Associations with a history of OCs have been reported for other severe psychiatric disorders, such as autism, anorexia nervosa, or psychotic affective disorder. Thus, OCs may increase in a relatively non-specific way the vulnerability for a range of severe mental disorders, the expression of this vulnerability depending on the interaction between OCs and other risk factors, such as the genetic liability for specific psychiatric disorder, or exposure to later environmental risk factors. The causal pathway between OCs, maternal psychopathology, and psychotic outcome in the offspring is not fully elucidated. The directions of the associations are often bi-directional, and the mediating variables, if any, are not clearly identified. OCs may have a direct negative impact on fetal brain development, may be on the causal pathway between prepartum maternal depression/exposure to stress and increased risk of schizophrenia, or may indirectly increase the risk of child's later psychiatric disorder by acting as risk factors for maternal postpartum depression. The links and possible interactions between somatic perinatal risk factors and maternal psychopathology in the association with offspring's increased vulnerability for psychosis have to be further explored.