This avenue of research-as opposed to research into the damage done by recreational drug use-came to a halt in the 1970s when drug prohibition became politically popular first in America and then in the rest of the world. Though the "war on drugs" continues, the approach is gradually becoming less dogmatic and more pragmatic. Even so, research into therapeutic uses of banned drugs is fraught with political considerations, often with bizarre results. For instance, though medical marijuana is now recognised in many parts of the world-in California more than 20,000 people are registered to use it-there are few studies into its benefits.

Fun has its uses

MDMA was first synthesised almost a century ago but was little noticed until the 1960s when young American chemists began to ingest it. Alexander Shulgin, a chemist at Dow Chemical in California who had invented Zectran, the first biodegradable insecticide, had been experimenting-in every sense-with mescaline and its chemical relatives. Then one of his students suggested that he try MDMA. "By golly", he recalls, "she was absolutely right: this was an interesting compound."

Mr Shulgin left Dow to pursue psychoactive chemistry full-time. Over a couple of decades he synthesised hundreds of chemicals, all of which he tried first on himself and a small group of volunteers. One of his collaborators was his wife, Ann. In the late 1970s the Shulgins introduced MDMA to Leo Zeff, a Californian psychotherapist who had developed LSD therapies in the 1960s when that drug was still legal. Dr Zeff was so impressed that he postponed retirement and became an enthusiastic proponent of the drug (which he called Adam), introducing it to hundreds of other therapists in America and Europe.

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