Psychoactive substance use and substance use disorders (SUDs) continue to be major problems around the world, taking a toll on global health and on social and economic functioning. The United Nations Office on Drugs and Crime (UNODC) reports that, in 2015, about 250 million people between ages 15 and 64 used illicit substances at least once. Of those who use psychoactive substances, a significant number will develop substance use problems or SUDs. The 2015 UNODC survey found that about 29.5 million substance users suffer from SUDs, which means their use is harmful to the point they may...