30 years after Prozac arrived, we still buy the lie that chemical imbalances cause depression

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.