I think a lot of the first line remedies for depression (such as exercise, increase social contact, sleep better, etc) highlights the issue with empirical methodologies used to describe experience. Correlation really becomes causation at a certain point.
People who sleep well, have strong social lives, and exercise frequently are rarely depressed. This isn't because of some biochemical reaction, but simply doing the above doesn't fit the definition of depression.
People who sleep well, have strong social lives, and exercise frequently are rarely depressed. This isn't because of some biochemical reaction, but simply doing the above doesn't fit the definition of depression.