Association between parental psychiatric disorders and risk of offspring autism spectrum disorder: a Swedish and Finnish population-based cohort study.

Background: Roughly more than one in six adults worldwide suffer from psychiatric conditions. Sporadic studies have associated parental psychiatric disorders with autism spectrum disorder in offspring. Comprehensively examining the association between parental psychiatric disorders and offspring autism spectrum disorder is needed to guide health policies, and to inform etiologic studies.
Methods: We included all children born in Sweden and Finland 1997-2016. Diagnoses were clinically ascertained from National Registers through 2017. We calculated adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for autism spectrum disorder in offspring of fathers and mothers with psychiatric disorders, in both parents jointly and across co-occurring conditions.
Findings: Among 2,505,842 children, 33,612 were diagnosed with autism spectrum disorder, of which 20% had a parent with psychiatric disorders. The risk of autism spectrum disorder was increased across all psychiatric disorders in fathers (Sweden: aHR = 2.02, 95% CI = 1.92-2.12; Finland: aHR = 1.63, 95% CI = 1.50-1.77), mothers (Sweden: aHR = 2.34, 95% CI = 2.24-2.43; Finland aHR = 2.12, 95% CI = 1.92-2.28), or both parents (Sweden: aHR = 3.76, 95% CI = 3.48-4.07; Finland aHR = 3.61, 95% CI = 3.20-4.07), compared to neither parents. Co-occurrence of parental psychiatric disorders further increased risk (e.g., Sweden: for one, two or ≥three different diagnostic categories compared to no diagnosis, in fathers aHR = 1.81, 2.07, 2.52; in mothers aHR = 2.05, 2.63, 3.57).
Interpretation: Psychiatric disorders in both parents conveyed the highest risk of offspring autism spectrum disorder, followed by mothers and then fathers. The risk increased with number of co-occurring disorders. All parental psychiatric disorders were associated with increased the risk of autism spectrum disorder. To reliably assess the risk of autism spectrum disorder in children, a comprehensive history incorporating the full range of parental psychiatric disorders is needed beyond solely focusing on familial autism spectrum disorder.
Funding: Swedish-Research-Council-2021-0214.
Competing Interests: Dr. Yin reports funding from KI Research Foundation Grant 2022–02021. Dr. Kolevzon reports support from American Psychiatric Publishing, Phelan-McDermid Syndrome Foundation – Spain and Phelan-McDermid Syndrome Foundation – Brazil, consulting fees from RitrovaTherapeutics, CureSHANK, Aelis Farma, Acadia, Alkermes, Jaguar Therapeutics, GW Pharmaceuticals, Neuren Pharmaceuticals, Clinilabs Drug Development Corporation, Scioto Biosciences, Biogen, PYC Therapeutics, stock or stock options from Ovid Therapeutics, and payment for expert testimony from Anthone v Franciscan Health System (Deposition) FAVROS LAW 701 Fifth Avenue, Suite 4750, Seattle, WA 98104, Ting v. Christina Ring, MD (Deposition) CARDONE & RUTBERG, PC, 3773 Cherry Creek North Drive, Suite 680W, Denver, Colorado, 80,209, Palmquist v. Hain Celestial Group (Trial only), COVINGTON & BURLING LLP, One CityCenter, 850 Tenth Street, NW, Washington, DC 20001–4956, Anderson v. The Johns Hopkins System (Deposition), GOODELL, DEVRIES, LEECH, & DANN, LLP, One South Street, 20th Floor, Baltimore, MD, and Acetaminophen – ASD-ADHD Product Liability Litigation (Deposition), BUTLER SNOW LLP, 810 7th Avenue, Suite 1105, New York, NY, 10,019. Dr. Kolevzon also reports participation in Vagal nerve stimulation in eating and weight disorders. Dr. Ludvigsson has coordinated an unrelated study on behalf of the Swedish IBD quality register (SWIBREG). That study received funding from Janssen corporation. Dr Ludvigsson has also received financial support from MSD developing a paper reviewing national healthcare registers in China. Dr Ludvigsson has an ongoing research collaboration on celiac disease with Takeda. Dr. Kajantie reports support from Academy of Finland, European Commission, Sigrid Jusélius Foundation, Foundation for Pediatric Research, Signe and Ane Gyllenberg Foundation, Yrjö Jahnsson Foundation, Novo Nordisk Foundation, Jalmari and Rauha Ahokas Foundation and Finnish Medical Foundation. Dr. Sandin reports funding from Swedish Research council Grant #2021–0214 and payment for acting as opponent at PhD defense in University of Oslo, Norway. Dr Sandin is a member of DSMB for Vagus Nerve Stimulation for Treatment of Eating Disorders at Mount Sinai Hospital, New York STUDY-21-01790. All authors confirm the independence of researchers from funders. Transparency statement The guarantor of this study affirms that this manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained. Ethical approval The study was approved by the national Swedish ethics review board, Sweden (2017/1875–31/1; 2018/1864–32; 2019–06314) and the Institutional review board of The Finnish Institute for Health and Welfare (THL/1984/6.02.01/2018 and THL/4309/6.02.01/2022). No individual level consent was required, and all data used were anonymized. Patient and public involvement statement Patients or the public were not involved in the design, conduct, or reporting, or dissemination of our research. Availability of data and material Data cannot be shared publicly because of restrictions by law. Access to the Swedish data can be requested from the Swedish registers (https://www.socialstyrelsen.se/en/statistics-and-data/registers/; socialstyrelsen@socialstyrelsen.se). Access to the Finnish data can be requested from Finnish Social and Health Data Permit Authority Findata (info@findata.fi).
(© 2024 The Author(s).)