Cannabis legalization is a growing reality: 20 states permit medical marijuana use, and Colorado and Washington have legalized it for all adults. But as more states line up — and more people light up — Columbia researchers wonder: what’s on the other side?by Paul Hond Published Spring 2014
“I don’t think it is more dangerous than alcohol,” President Barack Obama ’83CC told the New Yorker in a profile published in January. In the seventy-seven-year history of the federal prohibition of cannabis, this was the least antagonistic remark about the substance ever to issue from the White House. Not that Obama was out on a political limb: a 2013 Gallup poll showed that 58 percent of Americans support legalization. The government estimates that 110 million Americans have tried cannabis, and that nineteen million people use it regularly.
Though Obama, a partaker in his Hawaiian youth, also called pot smoking a “vice” and “not something I encourage,” he said it was important for legalization to go forward in Colorado and Washington, citing the racial disparities in punishment that have always been a feature of US drug enforcement. African-Americans, despite having a cannabis usage rate about the same as whites, are nearly four times as likely to be arrested for possession.
But while most people can agree that liberalized laws will alleviate certain injustices, another set of questions looms in the fog: What are the harms to individuals from using cannabis? Will legalization lead to more use? Will the roads be less safe? And what about the kids?
To get answers, Columbia Magazine went uptown to the medical campus, stopped by the New York State Psychiatric Institute and the Mailman School of Public Health, and knocked on some doors.
Smoking for Uncle Sam
Is cannabis addictive? The question has long been a point of contention in the how-harmful-is-it debate. One key criterion would be the presence of a withdrawal syndrome.
Margaret Haney, a professor of clinical neurobiology, is the director of Columbia’s Marijuana Research Laboratory. Every other month, she brings in four chronic users to live for a nine-to-sixteen-day period in the lab’s tiny bedrooms and common space (couch, chairs, DVD-only flat-screen, board games, washer/dryer, books, no clock, no radio, no phone, no windows, no Internet) and has them smoke weed. The product is grown at the government’s pot farm at the University of Mississippi; funding comes from the National Institute on Drug Abuse. “We don’t have a hard time finding volunteers,” Haney says.
Haney has headed the lab since 1999. That year, she and her team conducted an experiment: over a span of twenty-one days, they gave their willingly captive subjects an alternating course of active marijuana and placebos. Then they monitored behavior on closed-circuit TVs: sleep patterns, food intake, shifts in mood.
What they found was compelling. “Sleep disruption is one of the most robust withdrawal symptoms,” Haney says. “The smokers had trouble falling asleep. They woke up in the night. They woke up early. Their mood, too, reflected classic drug-withdrawal symptoms: irritability, anxiety, restlessness. Food intake dropped precipitously. The first two days, they consumed up to a thousand calories less than they did baseline conditions. That recovered fairly quickly, but the disruption in mood and sleep lasted for a week to ten days.”
It was the first empirical demonstration of a withdrawal syndrome for cannabis.
“The consequences of dependence are not as severe as with alcohol, cocaine, and other things,” Haney says. “However, once you’re a daily smoker, your ability to stop becomes as poor as cocaine users’: only 15 to 37 percent are able to maintain abstinence.” The physical withdrawal symptoms don’t compare to those of heroin (diarrhea, sweating, nausea), but to Haney, it’s the psychological part — the anxiety, the craving — that really drives relapse. “These withdrawal symptoms for marijuana are significant,” she says. “They play a role in maintaining heavy drug use.”
It’s that heavy use that concerns Haney. One thing she feels she isn’t hearing much about in the legalization discussion is the consequences of smoking an intoxicant every day.
“There’s going to be a cost for teenagers doing that,” she says. “I do worry about the developing brain and the effect of heavy marijuana use on the brain’s cannabinoid receptors. The CB-1 cannabinoid receptor, where THC binds, is virtually everywhere in our brain, in areas involved with mood and memory and stress response.” (THC is the main psychoactive compound in cannabis.)
“What is the effect on a fifteen-year-old, whose brain is developing, of smoking marijuana every day? What are the long-term consequences?”
Are the Kids All Right?
With Haney’s questions in mind, we drop in on Deborah Hasin ’80SW, ’86PH, an epidemiologist at the Mailman School. In the haze of such data as a 2012 New Zealand study tying adolescent pot smoking to lowered IQ, Hasin wants to know if liberalized cannabis laws will lead to an increase in use among teenagers.
In 2011, she and her colleagues, with funding from the National Institutes of Health, took a national data set and compared rates of adult marijuana use and prevalence of “use disorders” in states with medical-marijuana laws and states without them. According to the American Psychiatric Association, “cannabis use disorder” includes standard addiction signs like “important social, occupational, or recreational activities are given up or reduced” and “a failure to fulfill major role obligations at work, school, or home,” and afflicts 9 percent of pot smokers.