Kevin P Hill1, Tony P George2. 1. Division of Addiction Psychiatry, Harvard Medical School, Boston, MA, USA; Beth Israel Deaconess Medical Center, Boston, MA 02215, USA. Electronic address: khill1@bidmc.harvard.edu. 2. Department of Psychiatry, University of Toronto, Toronto, ON, Canada; Addictions Division, Centre for Addiction and Mental Health, Toronto, ON, Canada.