Nothing? Something happens in the brain (and body) which is depression, at a lower level of abstraction. The world outside of the brain "causes" depression. S

Nothing? Something happens in the brain (and body) which is depression, at a lower level of abstraction. The world outside of the brain "causes" depression. Sometimes things inside the brain or body (ideas, beliefs, emotions) cause the certain things to happen in the outside world (actions or inaction). Sometimes these form a cycle: undesired life circumstances cause the brain to become depressive, which causes inaction, which prevents the circumstances from changing. Sometimes nature/nurture/nutrition play a part in those internal ideas/beliefs/emotions, causing certain people to tend to get in depressive states more than others. I'm certain 95% of depressions is this, but don't bother coming after me for the last 5%, keep it to yourself.