Author Contributions: Drs Volkow and Tomasi had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Volkow.
Acquisition of data: Wang, Vaska, Telang, Alexoff, Wong.
Analysis and interpretation of data: Volkow, Tomasi, Vaska, Fowler, Telang, Logan.
Drafting of the manuscript: Volkow, Wong.
Critical revision of the manuscript for important intellectual content: Volkow, Tomasi, Wang, Vaska, Fowler, Telang, Alexoff, Logan.
Statistical analysis: Tomasi.
Obtained funding: Volkow, Fowler.
Administrative, technical, or material support: Wang, Fowler, Telang, Alexoff, Wong.
Study supervision: Wang, Fowler.
Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.
Funding/Support: This study was carried out at Brookhaven National Laboratory (BNL) and was supported by the Intramural Research Program of the National Institutes of Health (NIH) and by infrastructure support from the Department of Energy.
Role of Sponsor: The funding agencies had no role in the design and conduct of the study; the collection, management, analysis, and interpretation of the data; or the preparation, review, or approval of the manuscript.
Additional Contributions: We are grateful to BNL employees Donald Warner, AA, for positron emission tomography operations; David Schlyer, PhD, and Michael Schueller, PhD, for cyclotron operations; Pauline Carter, RN, and Barbara Hubbard, RN, for nursing care; Payton King, BS, for plasma analysis; and Lisa Muench, MS, Youwen Xu, MS, and Colleen Shea, MS, for radiotracer preparation; and to NIH employees Karen Appelskog-Torres, AA, for protocol coordination; Millard Jayne, RN, for subject recruitment and nursing care; and Linda Thomas, MS, for editorial assistance. We also thank the individuals who volunteered for these studies. None of the individuals acknowledged were compensated in addition to their salaries for their contributions.