April 24 (HealthDay News) -- Some teens are smoking marijuana not just for recreation but to self-medicate emotional problems, sleep difficulties and pain, a new study shows.

Researchers conducted in-depth interviews with 63 adolescents who smoked marijuana regularly. About a third of the teens said they used the drug as a medication rather than as a means of getting high.

The findings appear in the April 22 issue of Substance Abuse, Treatment, Prevention and Policy.

The most common complaints were emotional problems, including depression, anxiety and stress, sleep difficulties, and problems with concentration and pain.

"Youth who reported they had been prescribed drugs such as Ritalin, Prozac or sleeping pills stopped using them because they did not like how these drugs made them feel or found them ineffective," the authors said in a news release from the journal publisher. "For these kids, the purpose of smoking marijuana was not specifically about getting high or stoned."

The teens' experiences with the medical system were uniformly negative, according to the study.

"Marijuana is perceived by some teens to be the only available alternative for those experiencing difficult health problems when legitimate medical treatments have failed or when they lack access to appropriate health care," said Joan Bortoff, who worked on the study with a team of researchers from the University of British Columbia.

In contrast to the unpleasant side effects of prescribed medications and long and ineffective but legal therapies, marijuana provided the adolescents with immediate relief for a variety of health concerns, according to the study.

"It's not good for you, but then again, neither is McDonald's and a lot of other things," one teen told the researchers.

SOURCE: BioMed Central, news release, April 22, 2009