TUESDAY, Sept. 2 (HealthDay News) -- Many people believe that marijuana is not addictive, but a new study challenges that theory.
"As more people are able to obtain and consume cannabis legally for medical and, in some states, recreational use, people are less likely to perceive it as addictive or harmful," study co-author John Kelly, a psychiatrist at Massachusetts General Hospital's Center for Addiction Medicine, said in a hospital news release.
"But research shows that cannabis use can have significant consequences, and we know that among adolescents it is second only to alcohol in rates of misuse," he added.
In the new study, Kelly's team followed outcomes for 127 teens, ages 14 to 19, treated at an outpatient substance abuse clinic. Marijuana was the substance used most often by 90 of the teens.
Of those 90 teens, 76 (84 percent) met criteria for marijuana dependence, including increased tolerance for, and use of, marijuana, as well as unsuccessful attempts to reduce or stop using the drug. About two-fifths of the 90 teens also experienced symptoms of withdrawal when they stopped using marijuana -- a sign of drug dependence, according to the study authors.
Teens who exhibited withdrawal symptoms were more likely to experience negative consequences such as trouble at school or on the job, or financial or relationship problems, Kelly's team said.
The teens who developed withdrawal symptoms were also more likely to meet the guidelines for marijuana dependence and for mood disorders, according to the study published recently in the Journal of Addiction Medicine.
People who recognized and accepted that they had a substance abuse problem tied to their marijuana use were more likely to make progress towards abstinence, compared to those who did not think they had a problem, the researchers noted.
"The importance of understanding the addictiveness, risks and harms associated with cannabis use is a major theme of this study's findings," said said Kelly, an associate professor of psychiatry in addiction medicine at Harvard Medical School in Boston. "Recognizing those risks is known to reduce the likelihood that someone will start to use drugs, and better understanding of the role of substances in the problems experienced by patients may help them cut down on future use."
"Unfortunately, the general trend in attitudes in the U.S. is to minimize the risks and not recognize the addictiveness of cannabis," he added.
The study was supported by a grant from the U.S. National Institute of Alcohol Abuse and Alcoholism.
There's more on teens and marijuana at the U.S. National Institute on Drug Abuse.