On the Efficacy of Self-Induced Vomiting (Purging)

A single in-lab assessment of caloric consumption, loss, and retention during binge-purge episodes in individuals with bulimia nervosa (BN) is frequently cited as evidence that purging via self-induced vomiting is an ineffective strategy for calorie disposal and weight control (Kaye, Weltzin, Hsu, McConaha, & Bolton, 1993). These findings have been widely interpreted to mean that, on average, purging  rids the body of only about half of the calories consumed, regardless of total quantity.

However, a closer examination of the study does NOT support the notion that purging is an ineffective compensatory behavior. Indeed, the findings of Kaye et al. (1993) would appear to have been both misunderstood and overgeneralized in the subsequent decades. This has important implications for therapeutic alliance in clinical practice as well as for understanding the nature of symptoms, metabolic processes, and physiological alterations in EDs.

THE STUDY

The study included 17 individuals, all of … Continue reading →

Endophenotypes and Biomarkers in Eating Disorders: Genetic Underpinnings, Personality Traits, Vulnerabilities – Part 2

This post continues the discussion of the chapter on eating disorders by Carolina Lopez, Marion Roberts, and Janet Treasure from The Handbook of Neuropsychiatric Biomarkers, Endophenotypes and Genes (2009). Part 1 focused on neurotransmitter biomarkers, and this second part will focus on the neuropsychological biomarkers.

NEUROPSYCHOLOGICAL BIOMARKERS

Attentional biases

Attentional bias is the tendency for individuals to attend to or be distracted by emotionally relevant stimuli over neutral stimuli. Attentional biases have been observed in several studies:

  • Current AN and BN individuals showed bias towards food, body-related stimuli.
  • Past AN but not past BN showed bias towards body shape concerns.
  • Both current and “long-term recovered” AN showed “abnormally higher activation in the medial prefrontal and anterior cingulate cortices in response to food stimuli using fMRI [brain imaging]” (232)

These biases can be minimal but annoying: waiting in line at the pharmacy, staring into space and finding your focus … Continue reading →

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

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
Continue reading →

Who Gets Treatment? Your Ethnicity Matters

In 2010, I wrote a literature review on eating disorders in women of color in North America. I expected to find only a few articles on this subject – every lecture in my undergrad psychology classes, every piece of information targeted to the public, every discussion I had, it seemed, either omitted the existence of EDs in non-stereotypical (white, female, heterosexual, adolescent, upper/middle-class) populations altogether – or glossed over it with a footnote on “acculturation” that reductively attributed the disorder to a misguided desire to fit into the dominant culture, much as other women might aspire to look like the images of female bodies in mass media. (Acculturative stress is actually far more complex than this, and furthermore is not necessarily the sole or even the primary cause of EDs for all people of color.)

[Some people] think that I hate being Asian and want to look

Continue reading →

Etiology of Eating Disorders: A Model of "Empirical Structure"

Hello all, Saren here. I’m honored that Tetyana asked me to be her co-contributor to ScienceofEDs, and am looking forward to collaborating on the project. My interests and background tend more towards the clinical; I don’t have the neuroscience training that she does, so I hope to bring a slightly different perspective while remaining committed to the research focus of the site. I can be reached at saren[@]scienceofeds[.]org with any questions, critiques or suggestions – I’d love to hear from you!

For my first post, I’m going to focus on one of the basic areas that much of the recent ED research aims to address:

WHAT CAUSES EATING DISORDERS?

We hear a lot about how eating disorders are complex syndromes with multiple causes. Articles in the popular press run the gamut from asserting genetic risk factors to proclaiming that Facebook causes eating disorders. In addition, disordered eating practices and poor … Continue reading →