Factors in the development of psychiatric epidemics
The term “epidemic” is broadly employed to refer to any occurrence of illness that is clearly in excess of normal expectancy. Whenever there is an apparent increase in the number of cases over a relatively short time, there are three possibilities: (1) a true epidemic in which the actual incidence of the disorder is increasing; (2) an increase in the number of previously undiagnosed individuals coming to clinical attention; or (3) a broadening of diagnostic definitions over time. Although reports of greatly increased rates of some psychiatric disorders in the past 30 years suggest possible “epidemics,” a closer examination raises questions about whether any of these truly represent increased incidence of the disorder in the community. In most cases, claims for the existence of an epidemic depend on reports of increased numbers of diagnoses made by mental health providers as opposed to evidence of increased rates of the symptomatic presentation.