Why are some people able to stop after one drink while others keep drinking until the bottle’s empty? Understanding the difference between these two types of brains is the key to helping alcoholics, drug users, gamblers and other addicts. Rita Z. Goldstein researches addiction at the Icahn School of Medicine at Mount Sinai, and she joins host Krys Boyd to talk about the latest addiction research, which is featured in the September issue of National Geographic magazine.