[The diagnostic questionnaires and their use in epidemiological studies in psychiatry].

The paper presents diagnostic instruments employed in psychiatric; brief history of their development with regard to their importance for progress in psychiatric epidemiology, the characteristic of the most important diagnostic questionnaire (Present State Examination--PSE, Composite International Diagnostic Interview--CIDI, Schedules for Clinical Assessment In Neuropsychiatry--SCAN, Structured Clinical Interview for DSM IV--SCID, Schedule for Affective Disorders and Schizophrenia--SADS, Diagnostic Interview Schedule--DIS). It also describes some features that should be considered while choosing a proper instrument for a given study. The authors call attention to some differences between instruments, e.g., those related to the structure of the questionnaire, involving diagnostic categories, the sort of information that an instrument allows to collect, competence of interviewers and their training, and also population for which the instrument is assigned. Presenting advantages and disadvantages of instruments, the authors emphasize that there is no best instrument. The choice of questionnaire depends, first of all, on the purpose of the study and the funds that the researches have at their disposal.