Clinical studies of pervasive developmental disorders in Japan.

Articles on pervasive developmental disorders (PDD) published mainly by Japanese child psychiatrists in international journals for the last 20 years were reviewed for the purpose of clarifying the accomplishment and aims of Japanese PDD research. Although Japanese child psychiatrists investigated PDD in various specialties, their contributions to international archives were much fewer than those of Japanese professionals in other branches of medical sciences. This may be accounted for by the absence of an authorized education system of child psychiatrists and strong clinical orientation together with some reluctance of Japanese child psychiatrists to perform research. However, the epidemiology of PDD subtypes, the speech loss in PDD and the psychopathology of persons with high-functioning PDD seem to be providing promising research areas for Japanese child psychiatrists based on their clinical experiences.