It is considered that the mental disease starts when somebody cannot maintain the correct balance between himself and the real world.
But it is implicitly suggested that to preserve your mental health means to ignore that both your self and the world are the primary sources of the maladjustment which finally injure the psychic state.
Both the world and the self lie on an insurmountable contradiction for the individuals.
Firstly, because any positive implication into the world affairs is opposed the individual who has a limited life to the unlimited duration of the world. If the positive implication tends to build a stable social position, the limited lifespan of the human beings proves that any social achievement strikingly contradicts its ephemeral authors.
Secondly, we cannot be aware of our self if we do not pay attention to our bodily constitution which is its most graspable form. However, the body betrays the social self through its sexual function. We cannot express our most intimate sexuality into the social space without risking to be judged as abnormal persons.
Therefore, the normality does not really belong to the individual, but it is a social invention. The preservation of mental health supposes the admission of a great portion of unhealthy ignorance for the individuals. And we may wonder if the perfect mental health is not in fact more important to the society than to the individuals.