In my research on the history of psychiatry and psychopharmacology, I can’t get away from mercury. Edgar Allan Poe, three months before he died in a delirious state, had been treated with mercury-laden calomel pills after exposure to cholera during an outbreak in Philadelphia; high levels were later found in samples of his hair. Although the possible contributory effects on Poe's condition are uncertain, some researchers suspect that figures as diverse as Abraham Lincoln, Charles Darwin, and Louisa May Alcott may have manifested symptoms of mercury toxicity. Since ancient times, mercury has been considered to be helpful for depression, and conversely, in relatively recent times environmental mercury—and even dental fillings containing it—has been suspected to be a cause of mood disorders.
The history of mercury as a medicine—and awareness of its toxicity in higher quantities—goes back to antiquity in Egypt and China. Qin Shi Huang, a Chinese emperor of the third century BC, whose physicians fed him large amounts as the key to immortality, reportedly went mad and suffered an early death at age 49. Even in the end, he was a believer; he was buried in a bejeweled tomb with mercury pools, which to this day cannot be opened because of concerns of toxic contamination.
Cinnabar (mercury sulfide), the ore from which most pure mercury is extracted, has had a place in Chinese traditional medicine for sedation for over 2000 years. It was widely used by the classical Greeks and throughout the Western world through medieval times for a variety of conditions including melancholy, venereal diseases, parasites, trachoma, and constipation. Mercury turned the stools black, and it was thought that this resulted from removing an excess of bile, one of the four ‘humors’ whose appropriate balance was believed to........