Is marijuana addictive?
Yes. Over time, overstimulation of the endocannabinoid system by marijuana use can cause changes in the brain that lead to addiction, a condition in which a person cannot stop using a drug even though it interferes with many aspects of his or her life. It is estimated that 9 percent of people who use marijuana will become dependent on it.10,11 The number goes up to about 17 percent in those who start using young (in their teens) and to 25 to 50 percent among daily users.12,13 According to the 2013 NSDUH, marijuana accounted for 4.2 million of the estimated 6.9 million Americans dependent on or abusing illicit drugs.3
Marijuana addiction is linked to a mild withdrawal syndrome. Frequent marijuana users often report irritability, mood and sleep difficulties, decreased appetite, cravings, restlessness, and/or various forms of physical discomfort that peak within the first week after quitting and last up to 2 weeks.14,15
Marijuana potency, as detected in confiscated samples, has steadily increased over the past few decades.2 In the early 1990s, the average THC content in confiscated cannabis samples was roughly 3.7 percent for marijuana and 7.5 percent for sinsemilla (a higher potency marijuana from specially tended female plants). In 2013, it was 9.6 percent for marijuana and 16 percent for sinsemilla.16 Also, newly popular methods of smoking or eating THC-rich hash oil extracted from the marijuana plant (a practice called “dabbing”) may deliver very high levels of THC to the user. The average marijuana extract contains over 50 percent THC, with some samples exceeding 80 percent. These trends raise concerns that the consequences of marijuana use could be worse than in the past, particularly among new users or in young people, whose brains are still developing (see “What are marijuana’s long-term effects on the brain?”).
Researchers do not yet know the full extent of the consequences when the body and brain (especially the developing brain) are exposed to high concentrations of THC or whether the recent increases in emergency department visits by people testing positive for marijuana are related to rising potency. The extent to which marijuana users adjust for increased potency by using less or by smoking it differently is also unknown. Recent studies suggest that experienced users may adjust the amount they smoke and how much they inhale based on the believed strength of the marijuana they are using, but are not able to fully compensate for variations in potency.17,18
This series of reports simplifies the science of research findings for the educated lay public, legislators, educational groups, and practitioners. The series reports on research findings of national interest.