Association of family history of schizophrenia and history of obstetric complications at birth: relationship with age at onset and psychopathology dimensions in a Nigerian cohort

Background: The nature of the association between obstetric complications (OCs) at birth and the genetic aetiology of schizophrenia remains unclear, as some authors suggest that it is an independent risk factor while others support either interactionism or an epiphenomenon perspective.
Objective: To examine the association of family history of schizophrenia (FHS) with history of OCs, with a view to assessing whether this relationship moderates clinical phenotypes such as symptom dimensions and age at onset of illness.
Methods: This study examined OCs among schizophrenia probands using the Obstetric Complications Scale. An inquiry into family history was performed using the Family history method. Psychopathological symptom dimensions were assessed using standard scales. Data were analyzed to examine the interaction of FHS and history of OCs with age at onset and symptom dimensions, using ANCOVA.
Results: FHS was significantly associated with the disorganized symptoms dimension (p=0.03). History of OCs was significantly associated with earlier age at onset (p=0.007). However, in ANCOVA, the effect of the interaction between FHS and history of OCs was not significant for age at onset and symptom dimensions (P = 0.059).
Conclusion: FHS was significantly associated with disorganization syndrome, and OCs was significantly associated with age at onset.

Keywords
Family history; schizophrenia; obstetric complications; symptom dimensions; age at onset.