Olivia Goldhill in Quartz:
Some 2,000 years ago, the Ancient Greek scholar Hippocrates argued that all ailments, including mental illnesses such as melancholia, could be explained by imbalances in the four bodily fluids, or “humors.” Today, most of us like to think we know better: Depression—our term for melancholia—is caused by an imbalance, sure, but a chemical imbalance, in the brain.
This explanation, widely cited as empirical truth, is false. It was once a tentatively-posed hypothesis in the sciences, but no evidence for it has been found, and so it has been discarded by physicians and researchers. Yet the idea of chemical imbalances has remained stubbornly embedded in the public understanding of depression.
Prozac, approved by the US Food and Drug Administration 30 years ago today, on Dec. 29, 1987, marked the first in a wave of widely prescribed antidepressants that built on and capitalized off this theory. No wonder: Taking a drug to tweak the biological chemical imbalances in the brain makes intuitive sense. But depression isn’t caused by a chemical imbalance, we don’t know how Prozac works, and we don’t even know for sure if it’s an effective treatment for the majority of people with depression.
More here. [Thanks to Yohan J. John.]