[Diagnosis and nosographic classification in the child-psychiatric epidemiology].

Psychiatric epidemiology is founded on clinical experience and scientific research; these two spheres are not contradictory but complementary. Different aspects need to be examined thoroughly; for instance, diagnosis, considered as the result of a rather complicated process has hardly ever been studied. This should not lead us to give up or to act in a pseudo-scientific way as if we could control all the problems. The existing results show us that diagnosis is getting significant only with complementary and specific items. From the methodological point of view, video-tape and discussions about case histories allow us to study the diagnosis process. Field researches, comparative studies about systematic case data of different services, clinical and longitudinal investigations contribute ot epidemiological knowledge and facilitate interdisciplinary and international cooperation. Any linear and causal explanations on epidemiological phenomena appear unreliable.