Submitted for Publication: September 3, 2013; final revision received and accepted December 20, 2013.
Published Online: March 26, 2014. doi:10.1001/jamapsychiatry.2014.16.
Study concept and design: Pedersen, Mors, Bertelsen, Waltoft, Agerbo, Mortensen.
Acquisition, analysis or interpretation of data: All authors.
Drafting of the manuscript: Pedersen, McGrath, Eaton.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Pedersen, Waltoft, Agerbo.
Obtained funding: Mortensen.
Administrative, technical, or material support: McGrath, Mortensen, Eaton.
Study supervision: Mors, Bertelsen, Waltoft, Agerbo.
Conflict of Interest Disclosures: None reported.
Funding/Support: This study was supported by the Stanley Medical Research Institute; by grants from The Lundbeck Foundation; by John Cade Fellowship APP105692 from the National Health and Medical Research Council (Dr McGrath); and by grant DA026652 from the National Institute on Drug Abuse (Dr Eaton).
Role of the Sponsors: The funding sources had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
Additional Contributions: Søren Dalsgaard, PhD, National Centre for Register-Based Research, Business and Social Sciences, Aarhus University, assisted with the diagnostic classification of attention-deficit/hyperactivity disorder during the International Classification of Diseases, 8th Revision period. No financial compensation was given.