Neuroscience

Endophenotypes and Biomarkers in Eating Disorders: Genetic Underpinnings, Personality Traits, Vulnerabilities – Part 1

Saren

There have been some interesting discussions on the F.E.A.S.T. Facebook group over the past month regarding the role of genetics, personality traits, environmental factors and their role (or lack thereof) in the development of eating disorders and their prognosis. A parent group may seem like an unlikely forum for several hundred-odd comment threads on etiology; however, what we (caregivers, patients or clinicians) believe to underlie these disorders naturally informs our attitudes, decisions and choices with regards to treatment and our relationship to the disorders themselves:

Is this something they will have to manage their entire life?
Does anyone ever fully recover?
I had bulimia as a young adult and now my son has an eating disorder, too – did I pass on “bad genes”, bad habits, or is it a coincidence?
Is her rigidity and anxiety merely a side affect of starvation, or should we treat those as an underlying … Continue reading →

Serotonin Function in Bulimia Nervosa – Brain Circuits & Behaviour

Tetyana 15 Comments

Serotonin (5-hydroxytryptamine, 5-HT) is a neurotransmitter that is involved in just about everything. It helps ensure proper cell growth, maturation and migration during development. Serotonin is also important in regulating emotions, cognitive functions, appetite, pain, circadian rhythms, and our endocrine system in adulthood. It is hardly a surprise then, that the serotonergic system seems to be important in bulimia nervosa (BN).

I’ve written previously about serotonin in restricting-type anorexia nervosa, so for this post I’m going to be shifting focus and talk about bulimia and binge-purge type anorexia nervosa (AN-BP).

The information in this post isn’t coming from a review paper. Instead, I’m going to be summarizing and explaining information from a chapter in a book titled Behavioural Neurobiology of Eating Disorders. In the chapter on serotonin and bulimia, Howard Steiger and colleagues propose a model for serotonin action in bulimia nervosa which takes into account “diverse … Continue reading →

Benefits of Starving and Why You Don’t Have a “Chemical Imbalance”

Tetyana 9 Comments

Most people hate starving, hate prolonged hunger and suck at dieting. Patients with anorexia nervosa (AN), on the other hand, excel in these areas. How can someone like being hungry? How are they able to exert such “self-control”  (as many non-ED people often say) over their food intake? Part of the answer might lie with serotonin. But don’t worry, there’s no “chemical imbalance” – it is much more complex than that.

In this post, I’m going to continue discussing the review article in Nature Neuroscience (2009) by Kaye et al., focusing on what is currently known or hypothesized about the role of serotonin in anorexia (reminder, findings Kaye et al focuses are specific to restricting-type AN and may not apply to AN-BP or BN).

BUT FIRST, A LITTLE NEUROSCIENCE

Serotonin (aka 5-hydroxytryptamine or 5-HT) is a neurotransmitter, meaning that it is a chemical messenger that cells in … Continue reading →

Symptoms in Anorexia: Cause or Consequence?

Tetyana 4 Comments

In 2009, Dr. Walter Kaye and colleagues published an article in the prestigious journal, Nature Neuroscience Reviews, titled “New insights into symptoms and neurocircuit function of anorexia nervosa”. [By anorexia nervosa, Kaye et al. limited themselves to restricting-type anorexics (AN-R), so some but not all findings may extend to bingeing-purging anorexics and bulimics] This review, which is lengthy and will take me a few posts to cover thoroughly, focuses on the “findings from pharmacological, behavioural and neuroimaging studies that contribute to the understanding of appetite regulation, reward, neurotransmitters and neurocircuits that are associated with AN.”

A striking feature of anorexia nervosa is the incredibly uniformity of traits and symptoms that patients experience, as well as the narrow range of onset. While the course of the illness varies from person to person, during the AN-R state, individuals exhibit very stereotypic presentation (and that, of course, may be due to malnutrition … Continue reading →

The Anorexia Nervosa Brain: A Summary of Neuroimaging Studies – Part 1

Tetyana 1 Comment

Journalists like to report on novel and exciting findings regardless of how likely they are to be replicated or how well they fit with everything else known about the topic. It is an all too common occurrence that a small pilot study which has favourable results, creates a buzz and gets into our heads, only to produce negative results once the sample size is increased. But the latter, negative finding, rarely makes it to the printing press. So, we are left thinking the results of the pilot study are correct, when they might be an outlier or a false positive.

Given this, I wanted to summarize an article that provides a critical overview of the current neuroimaging studies in anorexia nervosa. We can use this as an introduction to neuroimaging in AN: to get a sense of the scientific consensus, the trends that emerge and what can be learned from … Continue reading →

The Genetics of Anorexia Nervosa

Tetyana 11 Comments

Is it the culture of thinness, obsession with dieting or just bad mothering? When it comes to determining the causes of anorexia nervosa, the answer appears to be none of the above. Increasingly, the evidence is pointing to genetics playing an important role in predisposing individuals to anorexia nervosa. Among clinicians and researchers, the notion that genetic factors are important in the development of anorexia nervosa seems uncontested. In this short review, Dr. Cynthia Bulik and colleagues summarize some of the findings in the genetics of anorexia nervosa.

Currently (DSM-IV), to be diagnosed with anorexia nervosa, a patient must show:

  • An inability to maintain normal weight (<85% of what is expected)
  • Intense fear of weight gain and/or becoming fat, though underweight
  • Obsession with body weight and shape, giving it undue importance in evaluating self-esteem/self-worth
  • Amenorrhea (missing 3 or more consecutive periods)
  • There are two AN-subtypes: restricting type (AN-R) and
… Continue reading →