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Article History

Received: 15 July 2025

Revised: 21 January 2026

Accepted: 18 February 2026

First Online: 28 February 2026

Competing interests

: Ditte Demontis has received speaker fee from Medice Nordic and Takeda. Anders D. Børglum has received speaker fee from Lundbeck. Zheng Chang has received speaker fees from Takeda Pharmaceuticals. In the past year, Stephen Faraone received income, potential income, travel expenses continuing education support and/or research support from Aardvark, Aardwolf, Otsuka, Collegium, Corium, Supernus, and Mentavi. With his institution, he has US patent US20130217707 A1 for the use of sodium-hydrogen exchange inhibitors in the treatment of ADHD. He receives royalties from books published by Guilford Press: Straight Talk about Your Child’s Mental Health, Oxford University Press: Schizophrenia: The Facts and Elsevier: ADHD: Non-Pharmacologic Interventions. All other authors report no biomedical financial interests or potential conflicts of interest.

: iPSYCH was approved by the Danish Scientific Ethics Committee, the Danish Health Data Authority, the Danish Data Protection Agency, and Danish Newborn Screening Biobank Steering Committee. In accordance with Danish legislation, the Danish Scientific Ethics Committee has waived the need for informed consent in biomedical research based on existing biobanks. All data were de-identified and not recognizable at an individual level. This study did not involve lived experience. iPSYCH was approved by the Ethics Committee initially in 2012, with subsequent amendments in 2013, 2015, and 2018. More details can be found at URL: . New Danish legislation (effective from January 2024) introduces the possibility for participants to opt out of studies that are exempt from active informed consent. After consulting with the Ethics Committees and patient organizations, iPSYCH contacted all participants in the iPSYCH cohort in June 2025 and offered the possibility to opt out of new genetic studies initiated henceforth. Overall, 1.8% of the iPSYCH participants chose to opt out, and their data will be deleted from the active research database. Data included in finalized and ongoing studies will not be removed.