Possible Relations Between Disorders in Circadian Rhythmicity and Mental Disorders

Abstract

The human circadian system is governed by strong principles which keep the dynamics of the rhythms within remarkably narrow limits. This is at least true for data from healthy and young subjects; consequently, in rhythms of these subjects numerous significant correlations can be observed, between different parameters of the same rhythm, between different rhythms in the same condition, and between changes in the rhythm in changing experimental conditions among different subjects. However, when rhythms of ill patients or aged subjects are analyzed, various systematic deviations from these correlations can be observed. It might be suggested, therefore, that there are realtionships between disorders in the structure of the circadian system, on the one hand, and health disorders and, in particular, mental disorders, on the other hand. It remains, however, an open question whether or not there is a causal relationship between rhythm and health disorders, and, if so, in what direction it operates.