Anorexia may not only be psychiatric, it could be genetic: study

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Anorexia nervosa — an eating disorder characterized by a fear of gaining weight and other life-threatening symptoms — has previously been understood as a psychiatric illness, but that may not be the whole story.

A new study published in Nature Genetics found that problems with metabolism may also be to blame.

Researchers at King’s College London and the University of North Carolina at Chapel Hill worked together to compare the DNA of nearly 17,000 people with anorexia. They found multiple genes which linked those with anorexia to DNA involved with burning fat and being physically active.

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More research is needed, but if this is the case, then Dr. Cynthia Bulik believes both the diagnosis and treatment of anorexia nervosa will need an upgrade. She’s one of the lead researchers on this study and the founding director of the University of Northern Carolina Center of Excellence for Eating Disorders.

Bulik uses the example of hyperactivity — a common side effect of anorexia — to illustrate her point.

“We’ve been psychologizing that symptom forever, saying that have a drive for thinness or they’re trying to work off the calories,” she said. “And while that might be true, that they might be genetically prone to high physical activity, as well.”

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If this is true and researchers are able to pin down biological causes of anorexia, it may be possible to include medication in the treatment plan.

“We’re going to have to get more samples first to get even more confident in these findings… but then, what we hope is that we can engage our psychologist, neuroscientist and pharmacogenetic friends to start figuring out how we can target those pathways and potentially develop medication,” said Bulik.

Currently, there is no medication proven to work in the treatment of anorexia nervosa. “Right now, it’s all re-nourishment and psychotherapy,” she said. “Our patients deserve the next generation of treatments.”

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Researchers also found eight genes which linked anorexia to anxiety, depression and obsessive-compulsive disorder (OCD) — which came as no surprise.

“ there’s a high positive genetic correlation between anorexia and other psychiatric disorders, and that’s no surprise because… that’s what we see in the clinic,” said Bulik.

“We see anorexia and OCD go hand-in-hand so often… this is genetic confirmation that what we see in treatment is actually based in biology.”

The difference between a psychiatric and physical illness

For many years, anorexia nervosa was understood to be “some sort of choice” or a “socio-cultural phenomenon,” said Bulik. “Actually, being codified as an illness (even a psychiatric one) is really important.”

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However, the data from this study suggest that the long-time classification of anorexia as a psychiatric disorder still misses a key part of the illness: the biology.

“It’s sort of a false distinction that there’s one set of disorders that happen above the neck and another set that happen below the neck,” she said. “We actually need to stop thinking about things this way because… they’re so interconnected, we can’t pull them apart.”

Dr. Michele Laliberte is cautiously optimistic about this data. She’s the clinical lead of the St. Joseph’s Hospital eating disorders program.

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“Maybe this can help us explain why for some patients, it’s very difficult to help some people weight restore or why it seems like some people go right back to a lower weight,” she said, but she emphasized that more research is needed.

“Metabolic reasons are not going to be the whole explanation for everyone,” she said.

“A person who has anorexia who has just weight-restored are also experiencing a tremendous amount of anxiety at that time and they make actual behavioural changes to their eating which leads them to lose weight… the idea that that’s all explained at the metabolic level doesn’t make sense, either.”

The signs and symptoms of anorexia

According to the Canadian Mental Health Association (CMHA), between 0.5 and four per cent of people in Canada have anorexia nervosa; 90 per cent are women.

It most often affects young people, typically beginning during teenage or young adult years, and it runs in families.

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People who diet and people with body-focused careers (like models, dancers and athletes) are also at a higher risk for developing anorexia.

The most common sign of the disorder is dangerously low body weight, but additional symptoms are often present and are different from person to person.

“ an intriguing lack of recognition of the seriousness of their low body weight,” said Bulik.

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People with anorexia may also feel overweight regardless of their actual weight.

An extremely low body weight can cause heart and kidney problems, low blood iron, bone loss, digestive problems and more.

Treatment for anorexia nervosa typically involves some kind of counselling (most commonly, cognitive behavioural therapy). The CMHA also recommends support groups as a good way to share experiences and recovery strategies with other anorexia patients.

Patients are also often referred to nutritional therapy, where they work with a dietitian or a nutritionist to learn healthy eating habits.

If you or someone you know is in crisis and needs help, resources are available. In case of an emergency, please call 911 for immediate help.

The Canadian Association for Suicide Prevention, Depression Hurts and Kids Help Phone 1-800-668-6868 all offer ways of getting help if you, or someone you know, may be suffering from mental health issues.

Meghan.Collie@globalnews.ca

© 2019 Global News, a division of Corus Entertainment Inc.

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