Submitted for Publication: October 21, 2014; final revision received February 3, 2015; accepted March 15, 2015.
Published Online: May 6, 2015. doi:10.1001/jamapsychiatry.2015.0469.
Study concept and design: Pingault, Viding, Plomin, Rijsdijk.
Acquisition, analysis, or interpretation of data: Pingault, Viding, Galéra, Greven, Zheng, Plomin.
Drafting of the manuscript: Pingault, Viding, Rijsdijk.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Pingault, Rijsdijk.
Obtained funding: Pingault, Plomin.
Study supervision: Viding, Greven, Rijsdijk.
Conflict of Interest Disclosures: Dr Galéra reported receiving support from the industry to attend scientific congresses in the past. No other disclosures were reported.
Funding/Support: The Twins Early Development Study is supported by grant G0901245 (and previously G0500079) from the UK Medical Research Council. Dr Pingault is supported by Marie Curie Intra-European Fellowship 330699 from the European Commission. Dr Viding is supported by a Royal Society Wolfson Research Merit Award from the Royal Society and the Wolfson Foundation. Dr Plomin is supported by research professorship award G19/2 from the Medical Research Council and by advanced investigator award 295366 from the European Research Council.
Role of the Funder/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.
Additional Contributions: We gratefully acknowledge the ongoing contribution of the participants in the Twins Early Development Study and their families.