Lots of what we now consider symptoms were thought of as diseases until the underlying problem was better understood. It wasn’t that long ago that your fever ex

Lots of what we now consider symptoms were thought of as diseases until the underlying problem was better understood. It wasn’t that long ago that your fever example was how people thought. The fever was the disease regardless of the unknown underlying cause. That depression is considered a disease by itself and not a symptom of many, possibly related, problems suggests how little we understand it.