The Song of the Cell: An Exploration of Medicine and the New Human

by Siddhartha Mukherjee

I knew that serotonin, the neurotransmitter, had something to do with it. Paul told me the story of the origin of the “brain chemical” theory of depression. In the autumn of 1951, doctors treating tubercular patients at Sea View Hospital on Staten Island with a new drug—iproniazid—had observed sudden transformations in their patients’ moods and behaviors. The wards, typically glum and silent, with moribund, lethargic patients, were “bright last week with the happy faces of men and women,” a journalist wrote. Energy flooded back and appetites returned. Many patients, ill and catatonic for months, demanded five eggs for breakfast. When Life magazine sent a photographer to the hospital to investigate, the patients were no longer lying numbly in their beds. They were playing cards, or walking briskly in the corridors. Researchers later discovered that iproniazid had, as a side effect, increased serotonin levels in the brain. And the idea that depression was caused by the paucity of the neurotransmitter serotonin, in the neural synapse, gripped psychiatry. There isn’t enough serotonin in the synapse, and so the electrical circuits that respond to the chemical don’t get enough stimulation. The inadequate stimulation of mood-regulating neurons results in depression.