More American Adults Use Marijuana, but Few See the Risks

 More and more Americans admit that they use marijuana, and a new study suggests that this is at least partly due to the growing number of people who no longer believe it is dangerous.

Researchers surveyed nearly 600,000 U.S. adults from 2002 to 2014 about drug use and health. Marijuana use rose during the study period, from 10.4% of adults to 13.3%, researchers reported in The Lancet Psychiatry.   During the same period, the proportion of adults who believed there was great risk of harm associated with smoking marijuana once or twice a week fell from about 50% to 33%.   “Despite scientific evidence of potential harm, adults have become much less convinced of the risks associated with marijuana use,” said study lead author Dr. Wilson Compton, deputy director of the National Institute on Drug Abuse (NIDA).   “These reductions in perceived harm are closely linked to the increase in use,” Compton added in an email.   Marijuana is the most commonly used illegal drug in the United States, according to NIDA.   Use of the drug can have short-term effects including mood changes, impaired movement and thinking, reduced problem-solving ability, and memory difficulties. Over time, the drug may also lead to respiratory problems, increased heart rate, and a range of mood disorders.   Overall, marijuana use among U.S. adults increased by more than 30% over the past dozen years covered by the study, with more people using marijuana in 2014 than in 2002.   Daily or near-daily marijuana use increased even more significantly.   In 2002, 3.9 million adults in the United States reported using marijuana daily or almost daily. By 2014, that figure had more than doubled to 8.4 million.   “Doctors need to understand these changing patterns of marijuana use in order to guide healthcare, and more research is needed on the consequences—both acute and long-term—that may be associated with frequent, heavy use,” Compton said.   Both the prevalence and frequency of marijuana use began rising around 2007, with a notably larger spike after 2011, the study found.   During the study period, more and more U.S. states passed legislation legalizing marijuana for medical purposes and, in some cases, for recreational use.   As of 2015, 24 states and the District of Columbia had passed medical marijuana legislation, the study authors noted.