Although drugs have been used for decades to fight mental illness, scientists have not really understood how they worked. Now all that is changing. A miraculous pharmacopoeia is being explored to deal with every kind of ailment in the mind and body. Not too far off may be tailor-made drugs that will lull insomniacs into peaceful sleep, dull the throbbing of pain, organize a schizophrenic's thoughts and perhaps even simulate the pleasures of sex.
This revolution has been gradually brewing. Until they discovered in the 1930s that the disease pellagra was caused simply by...