Forensic psychiatry and epidemiology: introduction.

Epidemiology is concerned with the distribution and determinants of disease frequency in human populations (Daniels, Flanders, Eley, & Boring, 1993) Basic to an understanding of Epidemiology is the tenet that disease does not affect everybody equally or at random, but that there are determinants that place some people at a higher risk of developing a disease because of genetic predisposition, environmental factors, or personality characteristics. Epidemiologist, while aware of the biological causes of disease, contend that these are not sufficient to unleash the disease, but that a social perspective is also required. Thus, the epidemiological approach is not concerned about the individual and his disease, but about the group that he belongs to, the place where the group resides, and the factors that impinge in the health of its members at a particular time. Epidemiology, therefore, relies on observations of naturally or socially occurring phenomena related to disease events, and epidemiologists go about recording their frequency or analyzing their determinants. Although epidemiological studies in psychiatry did not advance as rapidly as they did in other areas of medicine for reasons specific to the nosological and classificatory systems inherent in the study of mental conditions, epidemiology has contributed to the understanding of social determinants of these conditions since the end of last century. In fact, three distinct phases can be described on the use of epidemiology in psychiatry. The first involved descriptive studies of inpatient populations which, at the time, were mostly consisting of mental patients in large mental hospitals. These inpatient treated prevalence studies advanced at the beginning of this century to include the relatives of the patient and even important ‘‘other informants’’ in the community such as clergymen or the police. By definition, these ‘‘community studies’’ were not diagnostic in as much as the diagnosis according to existing classifications and etiological constructs had already been made in the hospital, but researchers were interested in knowing more about the life and circum-