From the results of the investigations of 148 patients afflicted with mental alienation in our national sanatorium situated in Nagoya City, 12, 600 patients abstracted from all the forced patients in Japan and 10, 539 patients in all the lunatic asylums in Kanagawa Prefecture, the following conclusions were drawn. 1) By age-group, of the 148 patients in our national sanatorium those of 20's stand first in number (45.3%) and those of 30's stand second (20.9%), while of the 12, 600 forced patients those of 30's stand first (35.3%) and those of 20's stand second (23.2%). And of the 10, 539 patients in Kanagawa Prefecture those of 30's stand first (35.3%) and those of 20's stand second (23.6%). As stated above, young age-groups, 20's and 30's, have more sufferers in Japan, while the aged group above 65 years has more sufferers in foreign countries, a striking contrast between the two. Accordingly, we presume that aged sufferers from mental alienation will increase in Japan, too, in future with the aging of our population. 2) By sex, of the patients in our sanatorium 79 are male and 69 are female (=100 : 87.3) ; of the forced patients 7, 721 are male and 4, 879 are female (100: 63.2) ; of the patients in Kanagawa Prefecture 6, 067 are male and 4.472 are female (=100 :73.7). Namely, there are more male sufferers than female ones in Japan, while there are more female sufferers in foreign countries. In this, Japan is, as it were, antipodal to them. 3) Of the psychoses, schizophrenia is most prevalent, from which 63.5% of the patients in our sanatorium, 77.6% of the forced patients and 67.2% of the patients in Kanagawa Prefecture are suffering. 4) From the hereditary point of view, only 6.8% of the patients in our sanatorium and 10.8% of the new patients in the whole country come of psychopathic stock. But this rema ins to be investigated more minutely. 5) The result of clinical examination is that as many as 33.1% of the patients in our sanatorium ire sufferers from an impediment in liver function. This is probably due to administration of too much psychotropica. How to cope with this: 1) to strengthen and establish the structure of local medical facilities. 2) to enforce and promote the rehabilitation system. 3) to consolidate special hospitals and send specialists to mental hospitals.