CHANGES IN THE PREVALENCE OF PSYCHIATRIC-DISORDER IN A COMMUNITY ARE RELATED TO CHANGES IN THE MEAN LEVEL OF PSYCHIATRIC-SYMPTOMS

The paper of Anderson et al. (1993), based on cross-sectional data, sh owed that minor psychiatric disorder in a population is linearly relat ed to the mean number of psychiatric symptoms in the population. The p resent investigation asks whether the same relationship holds longitud inally as well as cross-sectionally. Data from a 7-year follow-up of a general population sample demonstrate, for the first time, that a rel ationship exists between changes in prevalence of psychiatric disorder and changes in the mean number of psychiatric symptoms in a given pop ulation. Moreover, the relationship is linear; a one-point decrease in mean scores on the GHQ-30 is associated with a 6% decrease in prevale nce of disorder.