Key clinical point: “Education is needed to inform the public about the mental health hazards of regular use of high-potency cannabis.”

Major finding: Daily cannabis use is associated with a threefold higher risk of psychotic disorder.

Study details: Multicenter case-control study in 901 patients with a first-psychotic episode and 1,237 controls.

Disclosures: The study was supported by the Medical Research Council, the European Community’s Seventh Framework Program, the São Paulo Research Foundation, the National Institute for Health Research Biomedical Research Centre, and the Wellcome Trust. Five authors declared personal fees and grants from the pharmaceutical industry. No other conflicts of interest were declared.