Researchers investigate the genetics of eating disorders

genetics of eating disorders, depression
© Inna Zaichenko

An international research team have discovered that the genetics of eating disorders and some psychiatric disorders have some similarities, raising new questions about treatment for both

In Western Europe, four in ten people will experience anorexia nervosa, bulimia nervosa and binge-eating disorder at some point in their lifetimes.

A recent study in the UK found that 61% of people felt that their struggles with eating had become harder to manage over the pandemic lockdown, leaving these individuals more at risk of relapse or worsening symptoms than in ordinary times.

Virtual reality therapy for eating disorders is a treatment that has made recent breakthroughs. Dr Maria Matsangidou, Research Associate at RISE Ltd, said: “Multi-User Virtual Reality is an innovative medium for psychotherapeutic interventions that allows for the physical separation of therapist and patient, providing thus more ‘comfortable’ openness by the patients.”

While treatments continue to evolve, what about the understanding of why conditions take root in the first place? A family history of depression can strongly suggest the potential of depression, so what about eating disorders?

To answer this question, researchers examined 20,000 people in the UK.

‘Lift the veil on certain aspects of how eating disorders develop’

“Previous studies, which highlighted a genetic association between a high risk of anorexia nervosa and a low risk of obesity, have begun to lift the veil on certain aspects of how eating disorders develop that had been mostly neglected until then,” said Professor Nadia Micali, Department of Psychiatry at UNIGE Faculty of Medicine and Head of the Division of child and adolescent psychiatry at the HUG, who directed this work.

The team was a coalition from the University of Geneva (UNIGE), the University Hospitals of Geneva (HUG), King’s College London, the University College London, the University of North Carolina (UNC) and The Icahn School of Medicine at Mount Sinai.

“However, the same work has not been done for the two other major eating disorders: bulimia nervosa and binge-eating disorder. The goal of our study was to understand similarities and differences amongst all eating disorders in the role of genes governing body weight.”

‘We calculated polygenic scores for psychiatric disorders’

First author, Dr Christopher Hübel, from King’s College London said: “We were able to access volunteer’s DNA, their basic health data (weight, age, etc.) and responses to health questionnaires, including possible psychiatric disorders and their eating disorder history. We are grateful for this access as we were able to conduct multifactorial analyses and calculate more than 250 polygenic scores for each person.

“Each polygenic score sums the risk genes involved in a specific trait, such as depression, for example. We calculated polygenic scores for psychiatric disorders, such as schizophrenia and obsessive-compulsive disorder, and metabolic and physical traits, including insulin sensitivity, obesity and high BMI.”

‘Strong psychiatric component’

Professor Nadia Micali further explained: “The similarities lie in the association with psychiatric risks: anorexia nervosa, bulimia nervosa and binge-eating disorder share genetic risk with certain psychiatric disorders, in particular for schizophrenia and depression, thus confirming the strong psychiatric component of these diseases.

“However, the big difference concerns the associated genetics of body weight regulation, which are opposite between anorexia on the one hand, and bulimia nervosa and binge-eating disorder on the other, the latter being linked to a high genetic risk of obesity, and high BMI.”

Basically, if a person is genetically more likely to naturally embody a heavier weight versus a “light” weight – this could be the factor that pushes people (who share the same genetic risk of mental health problems) to contract different eating disorders.

When it comes to body types, variation is human and incredibly normal. But perception filters out everything but the envisioned ‘ideal’ – which can be slightly different for each individual with an eating disorder.

There is also a connection between ADHD and binge-eating disorder

“The metabolic and physical component would therefore direct the individual either towards anorexia nervosa or towards bulimia nervosa or binge-eating disorder,” explained Professor Nadia Micali.

“Moreover, this study confirms a clear genetic relationship between binge-eating disorder and attention deficit hyperactivity disorder (ADHD), that was already clinically observed, which might be linked to greater impulsivity, which is shared by these disorders.”

Read the full study here.


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