Actually, I don't think that is true. Depression is more about brain chemistry than it is about external events.
You may have a point there. If being 'rich' made people happy, then why do some many of the 'rich and famous' commit suicide in one way or another? Is it because material possessions aren't the key to happiness?
Depression is more about brain chemistry than it is about external events.
I agree that an imbalance in brain chemistry, or defect in it can cause depression. However, if one has no 'medical' problem, they can still be afflicted with depression. That type of depression usually comes from external events.
So... maybe the best answer is that we are both correct, and it depends on the person.