There are correlations between cannabis use and mental health issues, but studies have yet to show causation. The more provable consensus is that people who are already at risk of mental health issues are more likely to suffer adverse effects from cannabis use. Though cannabis is not a physically addictive substance in the way tobacco or harder drugs are—withdrawal symptoms are minimal—it is possible to develop a dependency. The risk of dependence among those who use cannabis is nine percent compared to 16 percent for alcohol. But that risk almost doubles for people who begin consuming as teenagers.
Macleans. “What are the mental health risks of marijuana use?” http://www.macleans.ca. 17ju September 2018 Web. 9 October 2018