The relationship between circadian rhythms and eating disorders

A paper examining the relationship between anorexia nervosa and morning chronotype has been published in the journal JAMA Netw Open.

Anorexia nervosa, an eating disorder (AN), occurs in less than 1% of people in Western societies (women are much more common than men), and the incidence of anorexia is increasing among adolescent girls.

The circadian clock is an internal biological system that produces 24-hour cyclical processes called circadian rhythms. Circadian rhythms affect a wide range of human physiology, including body temperature cycles and sleep and wakefulness patterns. Chronotype-a preference for morning or evening time-is a correlate of circadian rhythms and a person's propensity for earlier or later bedtimes and other activities and has been linked to psychological, neurological, gastrointestinal, and respiratory disorders.

The likelihood of various RPPs is related to circadian rhythms, this fact was found for bulimia and overeating: these disorders are more characteristic of "owls" (as well as depression and increased anxiety). The results of this study suggest that, unlike other metabo-psychiatric disorders, anorexia is more common in larks, predominantly in individuals with morning insomnia.

There is also some evidence suggesting a circadian system link to eating disorders, most notably the association between overeating disorder and evening chronotype compared to other psychiatric disorders.