The stronger marijuana available nowadays means teenagers who smoke it are now 11 times likelier to develop mental health problems than those who abstain, according to a study published in the journal Psychological Medicine. “The association between cannabis and psychotic disorders may be stronger than indicated by previous research, which has relied largely on older data when cannabis was less potent than today,” the researchers said, warning that teens are especially vulnerable to the effects of cannabis. From the University of Toronto, The Centre for Addiction and Mental Health and ICES – f…