2012

Are There Any Meaningful Differences Between Subthreshold and Full Syndrome Anorexia Nervosa?

Tetyana 11 Comments

I see this on a daily basis: patients with subthreshold eating disorders feeling invalidated and “not sick enough.” They are struggling so much, but maybe they still have their periods, or maybe their weight isn’t quite low enough, and so they often (but not always, thankfully) get dismissed by doctors, other healthcare professionals, and insurance companies. Do you think you really need this treatment, maybe you can just focus on eating healthier? You know you are not fat, you are perfectly healthy! Just be happy! Or, Sorry, we can’t cover this psychological treatment because you don’t fit the full diagnostic criteria. 

Why do we draw a line between ‘threshold’ and ‘subthreshold’ at arbitrary numerical criteria?

No doubt numbers are important for medical treatment: someone with a very low BMI might have considerably more physical complications that need to be taken into account during treatment than someone with a not-so-low … 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 →

Shared Genetics Between Disordered Eating and Periods (Menses)

Tetyana 5 Comments

Puberty at an early age increases the risk for disordered eating behaviours such as bingeing and purging (Jacobi et al., 2004; Kaltiala-Heino et al., 2001). What’s more, the hormone estradiol moderates the risk of disordered eating behaviours. More precisely, in a group of twins with low estradiol levels, differences in disordered eating are likely due to environmental factors (such as family, school, friends), but in a group of twins with high estradiol levels, the differences in disordered eating are more likely due to genetic factors. (I blogged about it here.)

Essentially, estradiol partially moderates the extent to which genes affect disordered eating.

This is interesting because the estrogen system has a role in regulating body weight and food intake, influences eating behaviours during the menstrual cycle, and obviously plays an important role during puberty. Moreover, one study showed that estrogen receptor genes (proteins that bind estrogen) are associated … Continue reading →

Over-Exercise is Associated With Suicidality in Individuals with Disordered Eating

Tetyana 6 Comments

Last week, I blogged about a study that examined personality traits and clinical variables associated with excessive exercise in eating disorder patients. In that study, 2 out of 5 participants engaged in excessive exercise. Today, I’m going to discuss a study that suggests over-exercise in disordered eating patients is associated with suicide behaviour.

Suicide rates in eating disorder patients are high. One meta-analysis suggested that out of all eating disorder related deaths, 1 in 5 are suicides. (Keep in mind, these numbers are really hard to pin down as they depend a lot on the sample population, sample size, and how the authors did their statistics, among other things.)

Another analysis found that the standardized mortality ratio (ratio of observed deaths in the study sample/expected deaths in the population of the same age but without the disease/disorder you are studying) for suicide in eating disorders was 31 for patients with … Continue reading →

Dopamine and Anorexia Nervosa: Tackling the Myths – Part IV (Treatment with Antipsychotics)

Tetyana 6 Comments

This is part IV in my mini-series on the role of dopamine in anorexia nervosa. In part I, I did a a little introduction on dopamine and dopamine signalling in the brain. In part II, I discussed preclinical studies using animal models to study the role of dopamine in AN. Finally, in part III, I talked about clinical studies using patients with AN to assess dopamine function. In this final post, I’ll review the evidence for using drugs that modulate the dopamine system in order to treat anorexia nervosa.

It is going to be short, because there’s really not that much evidence that any pharmacological agents help in treating anorexia nervosa. To quote the authors of this review study,

No single psychological intervention has shown clear superiority in treating adults with AN.

Most importantly,

… the first line of treatment for underweight patients with AN should be

… Continue reading →

Dopamine and Anorexia Nervosa: Tackling the Myths – Part III (Clinical Studies)

Tetyana 1 Comment

This is part III of my series on the role of dopamine in anorexia nervosa. In my first post I did a little introduction on dopamine and dopaminergic signalling. In the second post I talked about preclinical studies that used animal models of anorexia nervosa. In this post I’ll briefly go over some of the research that has used patients with anorexia nervosa to understand the role of dopamine in this disorder.

I’ve got to be honest here: I wish things were simpler. I wish the research wasn’t so contradictory–but it often is. When you first start to explore a topic, and you are not even sure you are asking exactly the right question, things often look messy. I find this is true for my own research as well, and as a graduate student, it is hard to accept contradictory results. Yet, it is also hard as a science blogger … Continue reading →

Dopamine and Anorexia Nervosa: Tackling the Myths – Part II (Contradictory Findings in Preclinical Studies)

Tetyana 2 Comments

This is part II in my series of posts on the role of dopamine in anorexia nervosa. (You can find the first part, which covers the basics of dopamine signalling, here.) In this post I’m going to discuss the findings from preclinical studies (studies in animal models).

I don’t think I’ve talked about animal models of anorexia nervosa before on the blog, but believe or not, they exist. The most well-known one is called activity-based anorexia (ABA). ABA works like this: rats are simultaneously restricted in the amount of food they can eat and given access to a running wheel. As the rats experience a reduction in their caloric intake, they begin to spend more and more time running on the wheel. A similar model with basically the same premise is called starvation-induced hyperactivity. These models are thought to mimic both the restriction/weight-loss and excessive exercise components of anorexia … Continue reading →

Dopamine and Anorexia Nervosa: Tackling the Myths – Part I (Intro)

Tetyana 4 Comments

There is this prevalent myth on Tumblr eating disorder blogs that increased dopamine (DA) receptor activity or increased DA signalling causes anorexia nervosa. It has left me quite perplexed, as I have never come across a single paper that has shown increased DA activity causes anorexia nervosa. My research for this post also left me empty-handed. I have no idea where this myth comes from, but I thought I’d blog about what research on DA activity in anorexia has shown. This topic will take me a few (not necessarily successive) posts to cover. This first post is a very brief introduction to DA signalling.

First, what is dopamine?

DA is a neurotransmitter–a molecule that one neuron releases to another in order to send a signal. Dopamine is released from one cell (the presynaptic neuron) and binds to its receptors on the other (postsynaptic) neuron. There are five different DA receptors … Continue reading →

Extreme Medical Negligence: Failure to Feed Patients with Anorexia Nervosa

Tetyana 15 Comments

They are crazy stories, really. It is hard to believe they are true.

A 28-year-old woman with anorexia nervosa complained about weakness and nausea following the insertion of a feeding tube. Her gastroenterologist sent her to the emergency room (ER). The woman was in the emergency room for two days without receiving any food. She was discharged home after she was told her lab tests and X-rays came back normal.  Unfortunately, her X-rays weren’t normal. Her gastroenterologist determined she had a bowel obstruction and sent her back to the hospital. She lost a substantial amount of weight in those 3 days.

The second story is even worse.

A 26-year-old woman with a feeding tube was discharged prematurely from a residential facility. She began to feel dizzy and weak, and was admitted to a hospital. She did not receive any food for the 6 days she was there, despite extremely … Continue reading →

Anorexia Nervosa: Can We Blame The Season Of Birth?

Tetyana

You might have heard that individuals born between the months of June – August (or sometimes March – August) have a higher chance of developing anorexia nervosa. But is it true? A lot of studies have been done to investigate the question of whether a season of birth (or a month) correlates with a higher risk of anorexia or bulimia nervosa. The results are inconsistent, weak, and fraught with methodological problems.

But first, how could seasons (or the average temperature during birth, or conception) have an effect on the etiology of eating disorders? What’s the hypothesis?

There seem to be two main ideas (summarized in Winje et al., 2012):

  1. alterations in neuropsychological function as a result of sunlight exposure during gestation or postpartum, maternal infections during pregnancy, or nutritional changes (seasonal variation in nutrients, vitamins)
  2. alterations in fertility/reproductive patterns of the parents due to cultural influences, disordered eating in the
… Continue reading →