Since we there is no exact definition of what a mentally healthy human being is, in the same way that those specifications would be available for a machine for example, the definitions of mental problems have obviously been developed mostly in other ways.

Conditions where a person causea problems for himself or his surroundings are then labeled as mental health problems. Naturally, the opposite conditions may be benign. The person may be overly obedient, or overly trusting (opposite of paranoia), irrationally peaceful (opposite of depression) and so on, and this may indeed be caused by the same mechanism that causes the opposite condition, but as it does not cause problems, it is not considered a disease.