By Robert Preidt, HealthDay Reporter

(HealthDay)

TUESDAY, Aug. 4, 2015 (HealthDay News) -- Regular marijuana use doesn't appear to put teens at increased risk for depression, lung cancer or other physical and mental health problems later in life, contends a new study that challenges previous research.

"What we found was a little surprising," lead researcher Jordan Bechtold, a psychology research fellow at the University of Pittsburgh Medical Center, said in a news release from the American Psychological Association.

"There were no differences in any of the mental or physical health outcomes that we measured regardless of the amount or frequency of marijuana used during adolescence," Bechtold explained.

The study included more than 400 males in Pittsburgh who were followed from age 14 to 36. Fifty-four percent were black, 42 percent were white and 4 percent were from other racial/ethnic groups.

The participants were divided into four groups based on their marijuana use: low or non-users (46 percent); early regular users (22 percent); those who only smoked marijuana when they were teens (11 percent); and those who started using marijuana later in their teens and continued using the drug (21 percent).

Early regular users had much higher marijuana use. The study found their use rapidly increased during their teens to a peak of more than 200 days per year on average by the time they were 22 years old. After that, their marijuana use fell slightly, the study authors said.

Because only males were included in the study, the researchers could not draw any conclusions about women and marijuana use.

"We wanted to help inform the debate about legalization of marijuana, but it's a very complicated issue and one study should not be taken in isolation," Bechtold said.

Some previous studies have suggested that teens who use marijuana are at increased risk for cancer, delusions, hallucinations and other psychotic symptoms, asthma and other respiratory problems later in life, but this study found no such links.

Bechtold and colleagues also found no association between teen marijuana use and depression, anxiety, allergies, headaches or high blood pressure later in life.

The study was published online Aug. 3 in the journal Psychology of Addictive Behaviors.

More information

The U.S. National Institute on Drug Abuse has more about marijuana.