Cannabis almost as addictive as opioids among teens, study finds

Teenagers' addiction rates for cannabis are about the same as for prescription opioids, according to a new study of drugs and youth.

A year after first trying cannabis, almost 10.7% of adolescents age 12 to 17 met the criteria of addiction. Those in the same age group who tried prescription opioids had a similar addiction rate of 11.2%, according to the study, published Monday in JAMA Pediatrics.

The findings contradict widely held perceptions that cannabis isn't particularly addictive and may attract attention amid a broad U.S. push to liberalize its use. The rates of addiction were significant, especially since teenagers' brains are still developing, according to Nora Volkow, an author of the study and the current director of the United States' National Institute on Drug Abuse.

For adolescents who experiment with cannabis, the risk is real: "One in 10 teens having a marijuana addiction—that's huge," Volkow said in a phone interview. Using cannabis also gives them a higher chance of becoming addicted to other drugs later, she said.

If users were younger when they first tried cannabis and other drugs, they were more likely to become addicted, the study found. For those in the 18-to-25 age range, only 6.4% developed an addiction a year after first trying cannabis—about half the rate of the younger age group. In the older 18-25 category, opioid addiction rates were similar to marijuana addiction rates after one year, according to the study. Cocaine addiction rates were slightly lower.

The findings underscore how important it is for doctors to ask teenage patients about recreational drug use, something that isn't always emphasized at younger ages, the researchers said.

Emily Einstein, one of the study's authors, said a rise in cannabis' potency in recent years could help to explain the higher addiction rates. She cited separate studies that have found marijuana with higher levels of THC to be more addictive.

The study is based on data from 2015 to 2018 collected by national surveys done by an agency of the U.S. Department of Health and Human Services.

Recreational cannabis is spreading rapidly at the state level and federal lawmakers are debating bills to legalize it nationwide. While states that allow cannabis restrict its use to those age 21 and over, some studies have found that more widespread availability in legalized states is linked to more use by young people.