Psychiatric Diagnoses in Parents and Psychiatric, Behavioral, and Psychosocial Outcomes in Their Offspring: A Swedish Population-Based Register Study.

Objective: Associations were examined between six psychiatric diagnoses in parents and a broad range of psychiatric and nonpsychiatric outcomes in their offspring.

Methods: All individuals born in Sweden between 1970 and 2000 were linked to their biological parents (N=3,286,293) through Swedish national registers. A matched cohort design, with stratified Cox regression and conditional logistic regression analyses, was used examine associations between six psychiatric diagnoses in the parents and 32 outcomes in their offspring. All children, including those exposed and those not exposed to parents with psychiatric diagnoses, were followed from their date of birth to the date of emigration from Sweden, death, or December 31, 2013, when the offspring were 14-44 years old.

Results: In terms of absolute risk, most children who had parents with psychiatric diagnoses were not diagnosed in specialist care themselves, and the proportion of offspring having any of the 16 types of psychiatric conditions ranged from 22.17% (of offspring exposed to parental depression) to 25.05% (of offspring exposed to parental drug-related disorder) at the end of follow-up. Nevertheless, in terms of relative risk, exposure to any of the six parental psychiatric diagnoses increased probabilities of the 32 outcomes among the offspring, with hazard ratios that ranged from 1.03 to 8.46 for time-to-event outcomes and odds ratios that ranged from 1.29 to 3.36 for binary outcomes. Some specificities were observed for parental diagnoses of psychosis and substance-related disorders, which more strongly predicted psychotic-like and externalizing-related outcomes, respectively, in the offspring.

Conclusions: The intergenerational transmission of parental psychiatric conditions appeared largely transdiagnostic and extended to nonpsychiatric outcomes in offspring. Given the broad spectrum of associations with the outcomes, service providers (e.g., psychiatrists, teachers, and social workers) should consider clients' broader psychiatric family history when predicting prognosis and planning interventions or treatment.