Teenage marijuana use was found to have no link to the development of mental and physical conditions as one grows older.
Researchers studied data on 408 men who, in 1987, were monitored for social and behavioral issues at the age of 14 as part of the Pittsburgh Youth Study.
The group was 54 percent black, 42 percent white and 4 percent other ethnicities.
Each participant was interviewed once a year for 12 years and then once more when he turned 36 years old (on average), UPI reports.
Participants were then put into four groups depending on their levels of marijuana use and when they started smoking.
According to Medical Daily, 46 percent of the men rarely or never used marijuana; 11 percent used it mostly during their teenage years; 21 percent started smoking when they became adults; and 22 percent started smoking at a young age and went on to become regular users.
After comparing the health of each group, researchers were shocked to discover no connection between chronic teenage marijuana use and cancer, asthma, high blood pressure or an array of psychological disorders.
In the published study, the researchers wrote,
[F]indings from this sample indicated that chronic marijuana users were not more likely than late increasing users, adolescence-limited users, or low/nonusers to experience several physical or mental health problems in their mid-30s. In fact, there were no significant differences between marijuana trajectory groups in terms of adult health outcomes, even when models were run without controlling for potential confounds.
It appears the participants who were heavy marijuana users as teens had the same risk of developing health problems as those who didn't smoke at all during this time.
Of the results, lead researcher Dr. Jordan Bechtold said in a press release,
What we found was a little surprising. 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 previous studies, small links were uncovered between marijuana and psychological disorders, cancer and asthma.
The researchers suggested this is because some people simply possess certain qualities -- possibly genetic qualities -- that trigger negative reactions to marijuana.
This study was originally published in Psychology of Addictive Behaviors.