The diagnosis of organic mental disorders stands out from a number of other diagnoses used by contemporary psychiatrists in this way that it assumes the knowledge of the aetiology of disorder. Even if this assumption is usually too optimistic, the tradition to establish such diagnoses is firmly consolidated and an example of its presence on the area of child psychiatry is MBD (minimal brain damage/dysfunction). Admittedly, the diagnosis of MBD is from today's viewpoint rather of historic value but clinical features of this kind are still met in our medical and psychological practice although under other names. The subject of the paper is the influence of so-called microorganicity on the personality development and thus on mental and social functioning of the child and the adult. Besides this, the paper concerns the use of psychotherapeutic treatment in this group of patients and describes specific problems and limitations of such therapy. The issues raised acquire special importance in the light of broadening of our knowledge regarding the influence of psychotherapy on the function, not only of the mind, but also of the brain.