The present state of psychiatric epidemiology.

The seven uses of epidemiology identified by Morris all have direct relevance for mental disorders. But psychiatric epidemiology has a number of distinguishing features: it has to depend on a nosology that may lack validity; it depends largely on subjective symptoms for its data; the morbidity it deals with is really a continuum, and not a dichotomy of cases and unaffected persons; the measurement of morbidity using scales or standardised interviews is open to considerable error; and the unbiased assessment of environmental exposures proves to be technically challenging. Some of these features have been the basis of interesting research developments. The main milestones in the progress of psychiatric epidemiology are reviewed, together with some of the current issues of general interest, including activities in Australasia.