Sudden death of father or sibling in early childhood increases risk for psychotic disorder

ObjectiveTo determine if exposure to a severe, acute stressor during early development is associated with an increased incidence of schizophrenia and bipolar disorder compared to exposure to a chronic stressor.DesignWe identified all those born in Helsinki between 1960 and 1990 whose father or sibling died between their conception and 5-years-of-age through linking two national registers: the Finnish Population Register and the Cause of Death Register. The reason for the death was also extracted from the Cause of Death Register. A third register, the Finnish Hospital Discharge Register, was used to determine psychiatric outcomes in adulthood.Sample11,855 individuals whose father or sibling had died before they were 5-years-old. In total, 129 individuals had an ICD 8, 9 or 10 diagnosis of schizophrenia and 165 had a diagnosis of bipolar disorder. 6136 individuals had a father or sibling who died from a sudden, external cause (e.g. accident or suicide) and 5719 individuals had father or sibling who died from a non-external, illness-associated cause.ResultsSudden loss of a father or sibling led to a significantly greater risk of developing bipolar disorder or schizophrenia in adulthood compared to loss of a father or sibling from illness. These associations are independent of sex, parental history of psychiatric illness, age at exposure to loss and age at follow-up.ConclusionOur findings are in keeping with accumulating evidence which indicates that exposure to stress during early development can increase the risk of psychotic illness among those exposed.