THE CANNABIS COMEBACK The number of marijuana users has more than doubled in the past decade as legalization has spread across the United States. With the trend come a host of public health considerations, and Columbia Mailman School researchers are at the heart of the discussion. By Alla Katsnelson
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he last session on the last day of any scientific conference is always quiet, and professor of Epidemiology (in Psychiatry) Deborah Hasin, PhD, was anticipating a sparse crowd when she took the podium at an American Psychiatric Association meeting in May, 2010. To her astonishment, the room was packed, and at the conclusion of her presentation on marijuana dependence, the attendees asked a seemingly endless stream of questions. “We could barely get people out of the room,” Hasin recalls. Many of the questions were about the new laws legalizing marijuana use that were sweeping the nation, and what their effect might be on usage of the drug. By 2010, 13 states had enacted laws that allowed citizens to use marijuana—or more specifically the leaf of the cannabis plant, or extracts thereof—for medical purposes. A few had passed further legislation to allow recreational marijuana use as well. Since then, medical marijuana has been legalized in 33 states and Washington, D.C.; recreational marijuana is now legal in 11. At press time, a bill to decriminalize marijuana at the federal level was gaining momentum in Congress. And more Columbia Mailman School researchers, including Pia M. Mauro, PhD, assistant professor of Epidemiology, and Silvia Martins, MD, PhD, associate professor of Epidemiology, have published extensively on the public health impacts of marijuana use, and become among the foremost experts on the subject.
