Author Contributions: Dr Costello, as primary investigator, had full access to all of the data in this study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Costello, Angold.
Acquisition of data: Costello, Angold.
Analysis and interpretation of data: Costello, Angold, Erkanli, Copeland.
Drafting of manuscript: Costello, Angold, Copeland.
Critical revision of manuscript for important intellectual content: Costello, Angold, Erkanli, Copeland.
Statistical expertise: Erkanli, Copeland.
Obtained funding: Costello, Angold.
Administrative, technical, or material support: Costello, Angold, Erkanli.
Study supervision: Costello.
Financial Disclosures: None reported.
Funding/Support: The study was supported by grants MH63970, MH63671, and MH48085 from the National Institute of Mental Health, DA11301 and DA023026 from the National Institute on Drug Abuse, and National Alliance for Research on Schizophrenia and Depression. These institutions provided financial support for every aspect of the study.
Role of the Sponsor: The National Institute of Mental Health reviewed and approved the study design but had no role in the conduct of the study; in the collection, management, analysis, or interpretation of the data; or in the preparation, review, or approval of the article.