Eating Disorders

Demystifying the Genetics of Eating Disorders – Part II

Tetyana

In my last post I talked about some methods that scientists use to study the genetics of eating disorders. I focused on a subfield of genetics called behavioural genetics (which you can think of as a field that attempts to understand, in part, the interplay of genetics and environment in behaviour). In this post I’ll shift gears and focus on molecular genetics. I’ll be working of the same review paper by Drs. Zerwas and Bulik (2011). Molecular geneticists study the structure and function of genes on a molecular level. For example, they try to understand how different mutations or alterations in the genetic code can affect protein function and lead to disease states.

GENETIC ASSOCIATION STUDIES

Genetic association studies are hypothesis driven. This means that researchers make a list of genes that are known to be involved in biological mechanisms or behaviours that are affected in eating disorders, such … Continue reading →

Demystifying the Genetics of Eating Disorders – Part I

Tetyana 9 Comments

Today I thought I’d take the time to do an overview of what researchers know about the genetics of eating disorders and try to clear up some common misconceptions. The bulk of the content in this blog post comes from a very nice review paper published in 2011 by Drs. Stephanie Zerwas and Cynthia Bulik on the genetics and epigenetics of eating disorders. In an effort to keep blog posts short, this will be a multi-part mini-series.

When it comes to the genetics of eating disorders, there are two main questions that research ask: What is the relative contribution of genetic factors to eating disorder behaviours? And what are those genetic factors? I’ll talk about research attempting to answer the first question in this post and the second question in my next post.

In order to understand the role that genetics plays in influencing eating disorder behaviours, researchers use family, … Continue reading →

Avoiding Refeeding Syndrome in Anorexia Nervosa

Tetyana 25 Comments

Refeeding syndrome (RS) is a rare but potentially fatal condition that can occur during refeeding of severely malnourished individuals (such as anorexia nervosa patients). After prolonged starvation, the body begins to use  fat and protein to produce energy because there are not enough carbohydrates. Upon refeeding, there’s a surge of insulin (because of the ingested carbohydrates) and a sudden shift from fat to carbohydrate metabolism. This sudden shift can lead to a whole set of problems that characterize the refeeding syndrome.

For example, one of the key features of RS is hypophosphotemia: abnormally low levels of phosphate in the blood. This occurs primarily because the insulin surge during food ingestion leads to a cellular uptake of phosphate. Phosphate is a very important molecule and its dysregulation affects almost every system in the body and can lead to “rhabdomyolysis, leucocyte dysfunction, respiratory failure, cardiac failure, hypotension, arrhythmias, seizures, coma, and … Continue reading →

Deep Brain Stimulation for Severe Anorexia Nervosa

Tetyana 15 Comments

This week, a team of researchers from the University of Toronto published a paper in The Lancet describing the results of a small study using deep brain stimulation (DBS) to treat severe/chronic anorexia nervosa. Major news outlets, including the BBC, reported on the findings. A few people emailed and messaged me asking me to do a post about it (which is cool! I love it!). So here it is.

DBS is a surgical procedure that involves implanting an electrode that delivers electrical signals to the brain. DBS is used to treat Parkinson’s disease and other movement disorders with good success, and has recently been implicated in the treatment of OCD and depression as well. (This is a pretty good video explaining how DBS works for movement disorders. There’s lots of information online about how DBS works, so I won’t go into detail here.)

This is not the first … Continue reading →

Your Body’s Response to Chewing & Spitting: The Role of Ghrelin and Obestatin

Shelly 3 Comments

Shelly’s follow-up post on chewing and spitting, an often overlooked symptom in eating disorders. In her first post, Shelly discussed the prevalence of chewing and spitting among eating disorder patients. In this post, Shelly discusses some of the physiological effects of chewing and spitting. Enjoy! – Tetyana

Your body responds to food long before it reaches your stomach. The taste, smell, even the mere sight of food all act to trigger a physiological response, “priming” the gut by stimulating various enzymes required for proper digestion and absorption of nutrients. This is called the “cephalic response”, and it is mediated by a part of the nervous system that’s generally not under conscious control (the autonomic nervous system). Keep in mind, the actual consumption of food is NOT necessary to trigger this reflex.

As you may have already guessed, the act of chewing and spitting (CHSP) out … Continue reading →

Living in a Large City: A Risk Factor for Bulimia Nervosa?

Tetyana 7 Comments

The link between urban living and mental disorders such as schizophrenia and depression has been known for quite some time (Sundquist et al., 2004). In one study, Sundquist et al found that individuals living in a densely populated area had a 68-77% higher risk of developing psychosis and 12-22% higher risk of developing depression.

The question then arises, do eating disorders follow a similar pattern? And if yes, what are some possible explanations? Certainly we know that both genetic and environmental factors are involved in the development of eating disorders, but what specific factors and to what extent remains unclear.

In this study, Gabrielle E. van Son and colleagues set out to explore whether increasing urbanization was an environmental risk factor for the development of eating disorders.

In order to answer this question, the researchers had a network general practitioners (GPs) record each newly diagnosed case of anorexia … Continue reading →

Framing Eating Disorders As "Brain Diseases" Might Lead to More Stigma

Tetyana 12 Comments

Many–myself included–assume that emphasizing the biological basis of mental disorders will reduce mental health stigma. The idea is that it will place less blame and personal responsibility on the affected individual.

Still, when it comes to raising awareness and reducing stigma, we need to make sure that our assumptions hold up to the evidence, otherwise we run the risk of playing a game of broken telephone. Given that this is Eating Disorder Awareness Week in the United States, the topic is particularly timely. Those of us involved in some aspect of mental health awareness don’t want to be saying “x” only to have be interpreted as “y.”

So, the question is–does a biological or genetic framing of eating  disorders lead individuals to hold more positive views of eating disorder sufferers and place less blame on “weak will”?

This is precisely what Matthias Angermeyer and colleagues asked almost 1,350 individuals … Continue reading →

Rigid Food Rules in Eating Disorders: Is Perfectionism to Blame?

Tetyana 12 Comments

I remember cutting baby carrots into 6 pieces. Rushing home to eat because I wasn’t “allowed” to eat after 7 pm. Eating the exact portion size–no more, no less. (Oh the rules. I don’t miss them.) Rigid food rules are very common among eating disorder sufferers. These rules can be about anything: the foods you are allowed to eat, how you are allowed to eat them, the time you are allowed to eat them, and so on.

But where do they come from? Why do some individuals have more rules and more ritualistic behaviours than others?

It is a complex question, but a recent study suggests that perfectionism might play a role. Specifically, the authors explored the idea that perfectionism mediates adherence to food rules in disordered eating behaviours. In order words, food rules might be a way in which perfectionism “expresses itself” in eating disorders.

Why perfectionism… Continue reading →

Chewing and Spitting: A Neglected Symptom in Eating Disorders?

Shelly 23 Comments

Eating disorders come in all shapes and sizes, but all of them are characterized by the same goal: to avoid weight gain or induce weight loss. While behaviours such as food restriction, purging, and laxative abuse are relatively well studied, chewing and spitting (CHSP) is not. A simple Google search, however, reveals over 1.5 million results for the term “chewing and spitting.” Results often links to blog posts or Tumblr pages where CHSP sufferers confess their guilt, disgust and obsession with the behaviour.

What is chewing and spitting? How does it relate to other disordered eating behaviours  such as restrictive eating or binge eating?

Chewing and spitting describes the pathological eating behaviour where the individual chews a variety of enjoyable foods, and spits it out to avoid undesirable consequences of weight gain (Mitchell et al, 1988). This seemingly “smart” workaround allows them to enjoy the taste of foods … Continue reading →

Lifetime Prevalence of Eating Disorders Among Eating Disorder Professionals

Tetyana 15 Comments

How many professionals that treat eating disorders have a personal history of struggling with an eating disorder? It is a crucial question to ask (and answer) because there are important implications for patient treatment and for the health of the afflicted professionals. It is true that many (or most?) individuals who go into mental health do so because of personal experiences–whether due to their own personal history or the experiences of a loved one–so it is useful to ask, just how common are eating disorders among ED treatment professionals?

This is the question that Nicole Barbarich asked in a survey mailed to 823 members of the Academy for Eating Disorders.

Barbarich developed a 14-item self-report questionnaire that assessed everything from basic demographics to personal eating disorder history and their employer’s hiring policies. Out of 823 potential participants, 399 completed the questionnaire.

SUMMARY OF MAIN FINDINGS

Demographics of Survey Responders… Continue reading →