Submitted for Publication: October 16, 2013; final revision received January 24, 2014; accepted February 25, 2014.
Published Online: June 25, 2014. doi:10.1001/jamapsychiatry.2014.363.
Study concept and design: Ljung, Lichtenstein, Larsson.
Acquisition, analysis, or interpretation of data: All authors.
Drafting of the manuscript: Ljung.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Ljung.
Obtained funding: Lichtenstein, Larsson.
Administrative, technical, or material support: Ljung, Lichtenstein.
Study supervision: Lichtenstein, Larsson.
Conflict of Interest Disclosures: None reported.
Funding/Support: This work was supported by grant 061817-01A1 from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, grant 2012-1678 from the Swedish Council for Working Life and Social Research, and grants 2010-3184 and 2013-2280 from the Swedish Research Council.
Role of the Sponsor: The funders 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.