A study led by McMaster University has found a growing connection between cannabis use and detrimental effects on mental health. The study, which compared the mental health outcomes and marijuana use of over 35,000 Canadians aged 15 and up for a decade, found that users of cannabis are more likely to meet criteria for anxiety and depressive disorders and more likely than non-users to report suicidality. The number of people using cannabis multiple times a week more than doubled, and the number of reported using cannabis in the last year increased to nearly 21%. The findings call for improved prevention efforts and easier access to services that treat substance use and mental health issues together.