He received his M.D. from the Yale University School of Medicine in 1997 and completed his Fellowship in Adolescent Medicine at the University of California, San Francisco, in 2003. Beginning in 2003, Dr. Rubinstein has collaborated with Dr. Neal Benowitz on a number of projects looking at the impact of the rate nicotine metabolism has on adolescent nicotine addiction. Specifically, he found that faster metabolizers of nicotine reported greater withdrawal symptoms after 24 hours of abstinence compared with slower metabolizers even after adjusting for the number of cigarettes smoked per day. The metabolite ratio was also significantly correlated with self-described level of addiction.