A study by Great Britain's Independent Scientific Committee on Drugs, published in the November 1 issue of The Lancet, compared the harmfulness of 20 drugs based on 16 criteria, ranging from the drug's lethality to the ecological costs of production and distribution. Alcohol scored highest, with a 72 on a 100-point scale. Heroin came in a distant second place at 55.
Psilocybin mushrooms finished last, with a measly six harm points, all of them for "drug-specific impairment of mental functioning." Shrooms weren't the only drug researchers determined to have virtually no social costs; the study found that both LSD and MDMA (seven and nine points, respectively) did not impose a significant burden on others.
The study was led by committee founder David Nutt, a University of Bristol psychopharmacologist who was forced out of his job as the British government's chief drug control adviser after suggesting that current legal distinctions between cannabis and alcohol are not scientifically justified. While Nutt's comparisons between psychoactive substances provide ammunition to opponents of the war on drugs, they can also be used in service of less libertarian arguments: He and his co-authors suggest alcohol is underregulated, concluding that "aggressively targeting alcohol harms is a valid and necessary public health strategy."