Dr. A. Thomas McLellan

A. Thomas McLellan, Ph.D., was a Professor of Psychiatry at the University of Pennsylvania and the founder and director of the Treatment Research Institute prior to his tenure as Deputy Director of the Office of National Drug Control Policy from 2009–2010. McLellan was the principal developer of the Addiction Severity Index and the Treatment Services Review, measurement instruments that characterize the multiple dimensions of substance abusing patients and treatments. McLellan’s work has also promoted better understanding of the factors that lead to treatment success, and has fostered greater understanding of addiction as a chronic illness, reduced its stigma, and provided means for earlier identification and prevention.

McLellan has published more than 400 articles and chapters on addiction research and has served as editor in chief of the Journal of Substance Abuse Treatment and on the editorial boards and as a reviewer of numerous medical and scientific journals. He has served as an advisor to many government and nonprofit scientific organizations, including the National Practice Laboratory of the American Psychiatric Association, the Swiss National Science Foundation, the World Health Organization, and the Greek government. Among McLellan’s many honors and awards are the Life Achievement Award of the American Society of Addiction Medicine in 2003 and the 2002 award for Distinguished Contribution in Addiction Medicine from the Swedish Medical Association. McLellan received his B.A. from Colgate University and his M.S. and Ph.D. from Bryn Mawr College. He received postgraduate training in psychology at Oxford University in England.