Familial and environmental factors in schizophrenia: interest of the premorbid personality

According to the neurodevelopmental hypothesis, antenatal aggressions (hypoxia and seasonal viral infections) could increase the risk of schizophrenia in adulthood as shown by an excess of obstetric complications and births in winter - spring in schizophrenic patients. As schizoid and schizotypal personality disorders are genetically linked to schizophrenia, we wanted to verify whether such disorders in the premorbid period in schizophrenic patients could be markers of a more genetic and less environmental sub-type of schizophrenia. Therefore, the aim of this study was to assess schizoid and schizotypal premorbid personality disorders (PPD) in 60 schizophrenic patients, and to assess the weight of familial and environmental factors according to the diagnosis of PPD. 41,7 % of patients (25/60) had a schizoid or schizotypal PPD. Compared with patients without PPD, patients with PPD had more often schizophrenia spectrum disorders in first degree relatives (33,3 % vs 14,7 %, NS), less often obstetric complications (20,8% vs 50,0%, p < 0,05) and were less often born in the first half-year (44,0 % vs 68,6 %, p = 0,05). So, we showed a non significant positive association between schizoid - schizotypal PPD and Family history of schizophrenia spectrum disorders, and a significant negative association between PPD and environmental factors : obstetric complications (OC) and birth in winter-spring. So, the absence of PPD could enable us to identify a sub-group of patients in whom environmental factors play a major role. Moreover, the relations between genetic factors and PPD seem to be complicated. Neverthless, the notion of PPD could give information about the kind of genetic factors implicated in schizophrenia.