Teenage boys who smoke marijuana heavily in their adolescence are not more likely to develop problems such as depression, cancer or other health issues later in life, a new study published today (4 August 2015) has revealed. A report published in the journal Psychology of Addictive Behaviors, conducted by University of Pittsburgh Medical Center and Rutgers University researchers, tracked 408 US males from their teenage years through to their mid-30s.

The men were separated into four groups: low or non-users (46%); early chronic users (22%); participants who only smoked marijuana during adolescence (11%); and the remaining 21%, who started smoking marijuana in their teens and continued using it through their 20s. Mitigating factors were taken into consideration during the course of the experiment, such as cigarette smoking, other drug use and access to US health insurance.

"What we found was a little surprising," said lead researcher Jordan Bechtold, a psychology research fellow at the University of Pittsburgh Medical Center. "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."

In the late 1980s, a group of 14-year-old males were tracked as part of the Pittsburgh Youth Study, which tracked public-school children in the Pennsylvania city to analyse health and social issues. This current study is an offshoot of the Pittsburgh Youth Study in which the same teenagers were surveyed every 6 or 12 months, for 12 years, in order to track their marijuana use and health issues. Some 408 of these people were given a follow up survey in 2009-2010, when they were 36 years old, in order to document how marijuana use in their teens had effected them.

The research paper said that according to their findings, there was no link between teen marijuana use in men and the onset of psychotic symptoms, cancer, asthma or respiratory problems, nor lifetime depression, anxiety, allergies, headaches or high blood pressure.