Intergenerational transmission of psychiatric disorders: the 1987 Finnish Birth Cohort study

The causes of mental disorders are multifactorial including genetic and environmental exposures, parental psychopathology being the greatest risk factor for their offspring. We set out to quantify the risk of parental psychiatric morbidity with the incidence of mental disorders among their offspring before the age of 22 years and study the sex- and age-specific associations. The present study utilises the 1987 Finnish Birth Cohort (FBC) data, which is a register-based follow-up of all 60,069 children born in Finland 1987 and followed-up until 2008. Data on psychiatric morbidity are based on inpatient care episodes of parents and both inpatient and outpatient visits of offspring and were collected from the Finnish Hospital Discharge Register which covers all Finnish citizens accessing specialized care. Altogether 7.6% of the cohort members had a parent or both parents treated at psychiatric inpatient care during the follow-up. Parental psychiatric morbidity increased the offspring's risk for psychiatric diagnoses two to threefold versus those children without parental psychiatric hospitalization, mother's morbidity comprising a greater risk than that of father's. The risk was prominent for both sexes of the offspring throughout childhood and adolescence. Psychiatric disorders possess significant intergenerational continuum. It is essential to target preventive efforts on the high-risk population that comprises families with a parent or both having mental disorders. It also implies developing appropriate social and health care interventions to support the whole family.