The master switch

摘要

Late last year, researchers at pharmaceutical giant Eli Lilly's labs in Indianapolis, Indiana, suffered a rude shock. Mice involved in tests of one of the company's most promising drugs - a new treatment for anxiety- were having seizures. Lilly put the drug on hold and suspended a clinical trial involving 1900 people. It is still trying to work out what went wrong, and whether trials of the drug can be revived. Talk to Lilly and you could be forgiven for thinking that the drug's woes came as a huge surprise. But perhaps the real surprise is that the drug ever got so far. The compound Lilly was testing was designed to plug into a brain circuit that pharmacologists have long considered a no-go area. Fiddle with it, the orthodoxy goes, and all you get for your troubles is hallucinations, psychosis and seizures. Yet Lilly, and most of its competitors, now believe that this circuit is the key to a new class of molecule that will revolutionise the treatment of mental illness - including many currently intractable or poorly treated diseases such as addiction, anxiety, schizophrenia, epilepsy and chronic pain. Almost every major pharmaceutical company is developing similar molecules. And while none is yet close to the market, some neuroscientists believe they will be the biggest shake-up in central nervous system medicine for decades.