Despite its growing acceptance, marijuana use is being linked to a number of negative effects, especially on teenagers whose brains are still developing. A recent large study in The Lancet Psychiatry shows that these effects include a significant increase in the high-school drop-out rate, as well as attempted suicides among teens who use marijuana compared to those who don't use it.
The study is a meta-analysis of three large, long-running longitudinal studies, using data from almost 4,000 people. Researchers from Australia and New Zealand examined links between frequency of marijuana use and seven specific developmental outcomes through age 30, reports CNN. What they found in the study was that marijuana use negatively impacts the future of young people. Also, the more they used, the worse the effects.
People who were daily marijuana users by age 17 were found to be more than 60 percent less likely to complete high school or get a college degree by age 25 than those who never used pot. They were 18 times more likely to become dependent upon marijuana and eight times more likely to use other drugs in their 20s.
They were also found to be seven times more likely to attempt suicide in their adolescence than their drug-free counterparts.
The study also found a correlation between marijuana use and depression and welfare dependence. However, after adjusting for confounding factors, this correlation was not found to be significant.
For the rest of the effects, the correlation remained consistent, even after factoring in a wide range of things that could have affected the outcome, according to the lead author of the study, Dr. Edward Silins, PhD, of the National Drug and Alcohol Research Center, University of New South Wales, Sydney, Australia. Researchers accounted for 53 different factors, including ethnicity, mental health, and socioeconomic factors, reports Medscape.
Although daily use was connected with the most significant outcomes, the study found that even occasional marijuana use, less than once a month, affected teenagers adversely. Dr. Silins told a group at a media briefing, "The more frequently adolescents used cannabis, the more likely they were to experience adverse outcomes in young adult life."
The findings are such as to support, though not prove, direct causation, not just correlation, which Dr. Silins says is "biologically plausible." This is consistent with other research that, he says, "suggests that heavy cannabis use in adolescence can have an effect on central nervous system development. For example, in relation to education, it's feasible that this could decrease cognitive function."
Previously, The Inquisitr reported that another recent study linked marijuana with lowering the IQ of frequent users.
The study researchers seemed particularly concerned that, with the growing acceptance and sometimes legalization of marijuana, young people will increasingly have access to the drug at a time in their lives when they are particularly vulnerable to its adverse effects.
Newsmax reports similar concerns expressed by Michael Bloomfield, a psychiatrist at University College, London.
"This new study ties in well with previous research into the mental health effects of heavy cannabis smoking during adolescence, a period where the mind and brain are still developing."This most recent study on marijuana use by teens stands as a cautionary tale to politicians and policy makers as they wrestle with the concept of legalizing marijuana, because, contrary to much popular belief, the drug is not benign. Indeed, based on this and other recent studies, marijuana use appears to present much greater danger to youth than was previously believed.