"The problem with you," she explained, "is that you have a chemical imbalance. It's biological, just like diabetes, but it's in your brain. This chemical in your brain called serotonin is too, too low. There's not enough of it, and that's what's causing the chemical imbalance. We need to give you medication to correct that."
Alix Spiegel of NPR, on the misleading "chemical imbalance" story of depression.