A biomarker and endophenotype for anorexia nervosa?
Why is this research important?
This research is a major step forward in understanding the neurobiological contributions to anorexia nervosa. The authors found that the rate of an atypical eye movement known as ‘square wave jerks’, together with trait anxiety (anxiety as a personality trait which is relatively stable over time compared with anxiety in a specific moment in time i.e., state anxiety), were a promising biological marker for anorexia nervosa. Further research is needed, however these findings may help to identify people at risk of anorexia nervosa and assist in the development of treatments that specifically target the underlying neurobiology of the illness.
Authors: Andrea Phillipou, Susan L Rossell, Caroline Gurvich, David J Castle, Denny Meyer and Larry A Abel
Objective: Recent research has suggested that a type of atypical eye movement, called square wave jerks, together with anxiety, may distinguish individuals with anorexia nervosa from those without anorexia nervosa and may represent a biomarker and endophenotype for the illness. The aim of this study was to identify the presence of this proposed marker in individuals currently with anorexia nervosa relative to healthy controls, and to identify the state independence and heritability of this putative marker by exploring whether it also exists in individuals who are weight-restored from anorexia nervosa and first-degree relatives (i.e. sisters of people with anorexia nervosa).
Methods: Data from 80 female participants (20/group: current anorexia nervosa, weight-restored from anorexia nervosa, sisters of people with anorexia nervosa and healthy controls) were analysed. Square wave jerk rate was acquired during a fixation task, and anxiety was measured with the State Trait Anxiety Inventory.
Results: Current anorexia nervosa, weight-restored from anorexia nervosa and sisters of people with anorexia nervosa groups made significantly more square wave jerks than healthy controls, but did not differ from one another. Square wave jerk rate and anxiety were found to discriminate groups with exceptionally high accuracy (current anorexia nervosa vs healthy control = 92.5%; weight-restored from anorexia nervosa vs healthy control = 77.5%; sisters of people with anorexia nervosa vs healthy control = 77.5%; p < .001).
Conclusion: The combination of square wave jerk rate and anxiety was found to be a promising two-element marker for anorexia nervosa, and has the potential to be used as a biomarker or endophenotype to identify people at risk of anorexia nervosa and inform future treatments.
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Citation: Phillipou, A., Rossell, S. L., Gurvich, C., Castle, D. J., Meyer, D., & Abel, L. A. (2021). A biomarker and endophenotype for anorexia nervosa?. Australian & New Zealand Journal of Psychiatry, 00048674211047189.