Teenagers 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 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.
Researchers found no difference in the mental or physical health of adults who had smoked cannabis as a teenager, and those who had not.
"What we found was a little surprising," Jordan Bechtold, the lead researcher of the study, said. "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."
The research paper said that according to their findings, there was no link between teen marijuana use and the onset of psychotic symptoms, cancer, asthma or respiratory problems, nor lifetime depression, anxiety, allergies, headaches or high blood pressure.
There were no differences in the findings based on race or ethnicity.
Based on previous studies, the researchers expected to find a link between teenage marijuana use and the development of psychotic symptoms (for example delusions and hallucinations), cancer, asthma or respiratory problems later, but they found none.
But the reaserchers pointed out they they only made one study regarding this issue.
"We wanted to help inform the debate about legalisation of marijuana, but it's a very complicated issue and one study should not be taken in isolation," said Dr Bechtold.
Early long-term users of the drug reported much higher use of marijuana, which rapidly increased during their teenage years to a peak of more than 200 days per year on average when they were 22 years old.
Their marijuana use then declined somewhat as they got older, scientists noted.
Since the study included only males, there were no findings or conclusions about women.
