Machine derived contents note: 1. Introduction -- 2. Cannabis the drug -- 3. Patterns of use -- 4. The acute effects of cannabis intoxication -- 5. The chronic health effects of cannabis use -- 6. The effects of cannabis use on adolescent development -- 7. Psychological effects of chronic cannabis use -- 8. The benefits of cannabis use -- 9. An overall appraisal of the health risks and benefits of cannabis use -- 10. The harms caused by cannabis prohibition -- 11. Proposals for cannabis law reform -- 12. Reducing the harm of cannabis use under prohibition