When a bipartisan group of top Massachusetts elected officials stood before a bank of cameras this summer and declared their opposition to legalizing marijuana in the state, they kept returning to a familiar argument: The drug too often leads to the opioid abuse destroying many families, reports the Boston Globe. “If you know anyone in the recovery community, talk to them,” said Boston Mayor Martin Walsh, a recovering alcoholic and longtime advocate for those struggling with addiction. “You’ll hear that most of them, many of them, started with marijuana.” Governor Charlie Baker and House Speaker Robert DeLeo echoed fears of marijuana as a “gateway” drug.
Six weeks before voters decide on a referendum legalizing recreational use of marijuana, a review of the scientific literature and interviews with experts shows that, while there is some evidence for the gateway theory, it is not so solid as the state’s political leadership would suggest. “The direct answer” to the question of whether marijuana is a gateway drug, said Susan Weiss, a research director at the federal National Institute on Drug Abuse, “is maybe.” Marijuana is undoubtedly a gateway in one respect: Its use almost always precedes the use of harder drugs. But most marijuana smokers don’t go on to shoot heroin. And it’s not clear that using one somehow causes the use of the other. There are plenty of alternative explanations for why some people move from marijuana to harder drugs. Perhaps underlying forces, like anxiety or a willingness to take risks, lead to the use of both drugs — with most people smoking marijuana first simply because it is more readily available.