Depression and anxiety increase with greater frequency of cannabis use in young people, especially women. Patton and colleagues (p 1195) followed a cohort of 1600 Australian adolescents for seven years and show that, especially in girls, smoking cannabis weekly or more often significantly increased later risks. This persisted after adjustment for concurrent use of alcohol, tobacco, and other illicit substances, as well as family disadvantage. In contrast, depression in teenagers did not predict higher cannabis use. The study supports the link between frequent cannabis use and mental health problems and points to a need for strategies to reduce frequent recreational use in young people.
