What is mentally disturbed behavior?

When can we actually speak about a mental disorder or at which point can we call a behavior mentally disturbed? Many authors are providing a different definition for this question in their psychological books.

But there are 4 characteristics, which have many of these definitions in common:

1. Deviance
2. Impairment
3. Suffering
4. Endangerment

Therefore, when we are talking about mentally disturbed behavior or a mental disorder, these 4 points should be more or less applicable. This means that the person concerned, should in some form show deviant, abnormal behavior (deviance), this behavior should affect or strain the person in their life or in their everyday situations (impairment and suffering) and maybe, the person should compromise theirself or others with this behavior.

Example

Accordingly, we would not speak about a mental disorder at a crazy artist or quirky professor, although both certainly show a not normal behavior. But in their cases, this behavior is not suffering, affecting or a risk.

But, on the other hand, when we consider a person with a cleaning compulsion (deviance) and this person is not leaving the house because of this and this person can no longer cope with the everyday life and the profession (impairment) and the person thus has not even time for friends (suffering), we can speak of a mental disorder.