We've covered the study by former UK drug czar David Nutt that found alcohol to be the most dangerous drug in the country by far when 20 drugs were rated on how much harm each caused to users and to others.

Nutt just came out with a new book, Drugs Without the Hot Air: Minimizing the Harms of Legal and Illegal Drugs, and last week told the Guardian that research into mental illness is hampered by the prohibition of drugs such as psilocybin and LSD.

This chart from Nutt's study is pretty staggering: