Perceived correctly, and agreed upon by both Western European and Asian systems of psychology; is the observation that it is not really people who become mentally disturbed, it is only their egos which thus suffer.
From here the two systems diverge radically.
Asian accumulated wisdom of 6000 years is that the ego/self/center of a person is merely a mental construct, culturally induced. At such times as a person forgets this fact, and suffers from having taken their ego/self/center too seriously, healing occurs through remembrance and realization of this fact.
Western European wisdom of 150 years is that the Asian view may possibly be correct but this is irrelevant to the western European mind which cherishes its ego above all else. Since such a mind is hardly likely to view its ego as merely an abstraction, healing of injury must take some other form.
The form taken is the Strengthening of the Ego through various developed psychological techniques and beliefs taught to the patients in order to give them a tougher mental skin. Such techniques are a quick fix of limited utility, and generally have to be backed up with an arsenal of biochemical drugs. But such treatment fits the patients and their culture well, since at moments of doubt the patients are taught to believe that something must be wrong with them, not their therapists or treatment or culture.
Tougher mental skin is accompanied of course by increased insulation and isolation from the external world, and thus increased insensitivity. This is regarded as a definite plus since the less the external world is able to reach the ego, the less the ego is likely to get hurt. In extreme cases those with damaged egos conceive that there are really only two entities in the universe, themselves and all-others; divided by the surface of their skin.
Such a view incidentally results in a much easier way to deal with life, since it is no longer necessary when the ego considers itself under attack to determine the exact direction. There being only one external entity, (and the object of the exercise being the Strengthening of the Ego rather than fair treatment of all-others,) an attack believed to be coming somewhere from an unclear distance can be effectively countered by a response to any conveniently closer target. It is irrelevant that sometimes the attack is only a paranoid delusion, since the maintenance of strong and quick defenses is worth any cost.
The ancient asian method used to restore mental health to the depressed or unbalanced mind and to reeducate it as to the true nature of the mind; is to ask it to consider very deeply and at great length, exactly "Who" it is that asks the question. That is, what is the precise deliniation, boundary, extent, breadth, width, content, particulars, and characteristics of that entity which is truely Who the questioner really is. Or, more concisely, that which is the essential self, the core, the center, the ego, the soul.
With a prolonged serious study of the mind by itself into precisely Who it is, the very least which results is that unhealthy aspects are identified and discarded. The very best is that the mind actually perceives within itself, at least to some definite degree (and not merely as an intellectual theory), that that which it regarded as the essential self was merely a culturally-induced internal mental construct, less apt as a basic foundation than shifting sand. Such awareness eliminates that mind's dependence for a psychological foundation upon that mentally-constructed self from which all depression and insanity has sprung.