Dr. Atul Ambekar is an Addiction Psychiatrist working as a Professor at the prestigious National Drug Dependence Treatment Centre (NDDTC), AIIMS, New Delhi, India. He has been a member of many international and expert bodies in the field of drug addiction including the Expert Advisory Panel on Drug Dependence (World Health Organization, Geneva), Strategic Advisory Group (IDU and HIV) of the United Nations, National Consultative Committee on Drug Demand Reduction and Rehabilitation (NCCDDR) of the Ministry of Social Justice and Empowerment, Govt. of India. He is a fellow of the School of Criminology, Hong Kong University. He has published a number of research papers, practice guidelines, and training manuals in the field of addiction psychiatry. As the principal investigator, Dr. Atul has led the National Survey on Extent and Pattern of Substance Use in India, one of the largest epidemiological study of substance use in the world. Currently, he is member, Board of Directors of International Society of Addiction Medicine (ISAM).