From the @swansont's link above:
There are criteria in the disorder definitions that are aimed to distinguish between these situations.
This is very wrong, from my experience.
In a normally functioning system, including human's body, different parts should cooperate with each other. When parts of the system are in conflict, there is a disorder. When a system or its parts are in conflict with the outside world, it is not a sign of disorder.
When a person has a disorder, good neighbors help the person to live as happily as possible.