Increased marijuana use for recreational purposes among adolescents and young adults is a growing concern in the United States. To tackle this problem, it is important to understand why such individuals resort to using marijuana. A new study by researchers from Boston Children's Hospital found that young adults and adolescents usually resort to marijuana use to deal with negative moods.

"Young people who use marijuana frequently experience an increase in negative affect in the 24 hours leading up to a use event, which lends strong support to an affect-regulation model in this population," the study's lead author, Lydia A. Shrier of the division of adolescent and young adult medicine at Boston Children's Hospital, said in a press statement. "One of the challenges is that people often may use marijuana to feel better but may feel worse afterward. Marijuana use can be associated with anxiety and other negative states. People feel bad, they use, and they might momentarily feel better, but then they feel worse. They don't necessarily link feeling bad after using with the use itself, so it can become a vicious circle."

Researchers examined 40 people, aged between 15 and 24 years. All participants used marijuana at least twice a week with an average usage of 9.7 times a week. They were trained to use a handheld computer that signaled them at a random time within three-hour intervals (four to six times per day) for two weeks. Each time they were signaled, the participants were asked about their mood, companionship, perceived availability of marijuana and recent marijuana use. Researchers found that negative effects increased significantly during the 24 hours before marijuana use compared with other periods. However, the positive ones didn't vary before marijuana use compared with other times.

Researchers also noted that the availability of marijuana or the presence of friends didn't modify the likelihood that chronic users would use marijuana following a period of negative affect.

"There are a host of limitations with retrospective assessments, such as asking people 'the last time you used marijuana, why did you use it?'" Shrier said. "We weren't asking people to predict anything or to recall anything - we were just asking them to give us reports about how they were feeling right now. We were able to put under a microscope the association between those feelings and subsequent marijuana use."

The findings were published online in the Journal of Studies on Alcohol and Drugs.