Marijuana Addiction: An Overlooked Risk of Increasingly Liberalized Marijuana Laws

In recent years, the potency of marijuana has increased considerably, as have the number of people of all ages who perceive marijuana as not particularly harmful or addictive. There are more ways now to use marijuana than ever before (e.g., smoked, vaporized, edible), and the number of people in the U.S. who report that they have used marijuana within the past month has increased by 50 percent over the course of a decade. As of June 2016, 25 states and Washington, DC have legalized medical marijuana and four states and DC have legalized recreational marijuana use. Many other states are considering following suit.

Against this backdrop of growing public acceptance and accessibility of marijuana and calls for national legalization is an addiction treatment system that is not able to meet the demand for treatment among those who already have addiction; only about 1 in 10 people with addiction receives treatment for it. And despite the fact that admissions to addiction treatment for marijuana account for three-quarters of all adolescent admissions to treatment, the perception of marijuana as non-addictive remains prevalent.

But just how likely is it that someone who uses marijuana will become addicted to the drug? Are only certain groups of people vulnerable to developing clinical dependence or only those people who use the drug very frequently or at very high levels? These are critical questions to answer if our nation is to have a reasoned debate about marijuana that is based in the facts rather than in business interests and individual opinions or passions.

Researchers at the National Center on Addiction and Substance Abuse were interested in determining the rate of addiction among those who use marijuana, but found that the available data on this topic either were quite old or limited in the populations represented (e.g., adults only). A closer examination of the addiction risk of marijuana use is especially needed given the dramatic increase in its potency (i.e., THC concentration) and the decreased prohibition against use over the past few years.

Now, a new paper by researchers from the Center, published in The American Journal of Drug and Alcohol Abuse, reports that more than one in seven (15 percent) individuals, aged 12 and older, who report having used marijuana in the past month meet clinical criteria for a marijuana use disorder diagnosis. Particularly striking was the finding that marijuana use disorder is at least twice as common among youth who use marijuana as among adults who do so, regardless of the time frame in which marijuana is used or the extent or intensity of use. 

Other key findings from the study were:

• More than one in four teens (26 percent), aged 12-17, who report using marijuana at least once in the past month have a marijuana use disorder (this is compared to 13 percent of adults, aged 21 and older)
• More than one in three youth (35 percent), aged 12-20, who report near daily or daily marijuana use (i.e., 21-30 days in the past month) have a marijuana use disorder
• The rate of marijuana use disorder among youth who report relatively infrequent marijuana use (i.e., 1-10 days in the past month) is nearly the same as the rate of marijuana use disorder among adults who report near daily or daily marijuana use (i.e., 21-30 days in the past month): 17 percent vs. 20 percent
• People who use tobacco products or who have an alcohol or other drug use disorder are especially likely to have a marijuana use disorder, even if they use marijuana relatively infrequently (i.e., 1-10 days in the past month)

Addiction is this country’s largest preventable health problem. Although the focus in the past few years has been on the rising rates of addiction and death due to the opioid epidemic, we cannot afford to gloss over the reality that another drug with addictive potential is becoming increasingly available. Although, clearly, it is not as dangerous as heroin or other opioids, decades of research – and this recent study – demonstrate unequivocally that marijuana is not a harmless drug, especially to youth. 

Linda Richter, PHD

Linda Richter is Director of Policy Research and Analysis at the National Center on Addiction and Substance Abuse

Brandie Pugh, MA

Brandie Pugh is a Research Associate at the National Center on Addiction and Substance Abuse