[Epidemiological research in autism: an integrative view].
INTRODUCTION: Sixty years after the first descriptions of Autism, the same diagnostic criteria based on clinical observation used then are still valid today. Two years ago, the Instituto de Salud Carlos III set up the Grupo de Estudio en los Trastornos del Espectro Autista (Autism Spectrum Disorders Study Group) with the aim of evaluating the current state of research in autism spectrum disorders (ASD) in Spain. This group established collaborative links with different associations and set up a way of working that was more coordinated and closer to the real day-to-day situation experienced by the families involved. AIMS AND DEVELOPMENT: The aim of this review is to update certain areas of knowledge concerning the distribution of the factors that determine ASD, that is to say, about the epidemiology of these disorders. At the same time, it intends to arouse a greater degree of interest among professionals who are more directly involved in the study of pervasive developmental disorders. The latest diagnostic tools offer a higher degree of certainty in the complicated process of evaluating a case with symptoms of autism. Nevertheless, given the effectiveness of early attention and how it affects the prognosis, population-based ASD screening programmes must be implemented. These would have to include the use of Modified Check List for Autism in Toddlers (M-CHAT)-type questionnaires, followed by several levels of diagnosis, in order to reduce the number of false positives while at the same time increasing the true positives.