Original article

Korean Journal of Schizophrenia Research 2009;12(1):10-14.

Atypical Psychoses in Japan

Takuji Hayashi, MD

Abstract

The concept of atypical psychoses was developed in Japan under the influence of Mitsuda’s clinico-genetic studies. According to Mitsuda, atypical psychoses are not mere phenotypical variants of typical schizophrenia and manic-depressive psychosis (MDP), but belong to a genetically different category and are probably heterogeneous. The characteristic features of atypical psychoses emphasize disturbed consciousness and pays attention to the nosological relationship with epilepsy, as well as with schizophrenia and MDP. Thus, in Japan it is generally considered that atypical psychoses are independent of typical major psychoses and are located nosologically in the border area between typical schizophrenia, MDP, and epilepsy. Mitsuda made a study on genotype and phenotype, i.e., the beginning and the end of the disease. However, research on patho-phenogenesis has been performed using various methods. We have been investigating morphological and functional differences between typical schizophrenia and atypical psychoses using brain imaging (CT, SPECT, MRI) and neuro-physiological (ERP, Exploratory eye movement) techniques, and found that atypical psychosis had a different pathogenesis than typical schizophrenia. (Korean J Schizophr Res 2009;12:10-14)

Key Words: Schizophrenia,Atypical psychoses,Epilepsy,Mitsuda,Patogenesis