Issue 51 | Neurobiology and Eating Disorders
About this resource
Welcome to the fifty first edition of the NEDC e-Bulletin, as we kick off what promises to be an exciting year with our continued focus on developing and maintaining a nationally consistent approach to the prevention, treatment and management of eating disorders in Australia.
In this first e-Bulletin for 2018, we explore growing evidence of the important role played by neurobiological vulnerabilities in the development of eating disorders. Research indicates that differences in brain structure and activity can contribute to differences in appetite, mood and cognition. This month, Dr. Andrea Phillipou provides an overview of current research into the neurobiology of eating disorders, with a specific focus on anorexia nervosa. We also provide a reading list of 12 recent review articles that give a detailed and informative snapshot of emergent research in this field.
We conclude with the introduction of a short digital animation called Eating Disorders 101, which provides a good starting point for raising awareness and initiating conversations in the community, workplace and education settings.
We are also pleased to share the announcement of the expansion of the Butterfly National Helpline 1800 ED HOPE (1800 33 4673).
If you are interested in connecting or collaborating with the NEDC, we encourage you to join and become an NEDC member.
The Neurobiology of Anorexia Nervosa
Dr Andrea Phillipou is a Postdoctoral Research Fellow at Swinburne University and St Vincent’s Hospital. Her research has focused on uncovering the neurobiological mechanisms involved in anorexia nervosa, with an aim to improve treatment outcomes in the future.
Anorexia nervosa is considered a biopsychosocial condition, meaning biological, psychological and sociocultural factors are likely contributors to the development of the illness. Although psychological and sociocultural factors are likely to play a role in anorexia nervosa, most individuals exposed to these factors do not develop the condition. For example, most people exposed to the ‘thin ideal’ portrayed in the media will not develop anorexia nervosa. Therefore, an individual’s biology is an important factor to consider, in regards to predisposition. Specifically, a person’s neurobiology, or the way their brain is structured and functions may predispose them to developing anorexia nervosa.
Research to date has not identified a specific brain area or neurotransmitter (‘brain chemical’) that is responsible for anorexia nervosa. A lot of research has been undertaken in how people with anorexia nervosa’s brains look (the ‘structure’ of the brain) compared to people without the condition. This research has shown that some parts of the brain are smaller in people with anorexia nervosa, but these return to a comparable size to people without the condition during recovery (Castro-Fornieles, et al., 2009). These findings can mean one of two things: either, the size of brain regions ‘normalise’ when someone no longer has anorexia nervosa showing that their brain is also recovering from the condition; or that the difference in brain size when unwell was due to the effects of starvation experienced by someone with anorexia nervosa.
Although the structure of the brain is important, the way that an individual’s brain functions can provide insight into the mechanisms behind disordered behaviours and distorted thoughts. There are a few different ways to observe how someone’s brain is functioning. Two of the most informative ways are to look at which brain areas are ‘activated’ when completing different tasks, and the other is to look at the concentrations of different neurotransmitters.
In terms of brain activity, a number of brain imaging methods can be used, the most common being functional magnetic resonance imaging or fMRI. This scan looks at the amount of blood flow to a brain area when presented with different stimuli, for example when looking at an image of high-calorie food. Similarly to other organs in the human body, blood rushes to regions that are in use or ‘active’, and an fMRI scan highlights the brain areas activating to stimuli. Research in anorexia nervosa has found that some brain areas are not as active and some areas are more active in response to different stimuli. For example, when presented with bodies depicting an underweight state, an area of the brain involved in reward processing, called the ventral striatum, has been found to be more active in individuals with anorexia nervosa (Fladung, et al., 2009). This suggests that looking at an underweight body may be more rewarding to someone with anorexia nervosa, compared to someone without the condition. Another example is when individuals with anorexia nervosa are presented with images of their own face. Research findings have suggested increased activity in regions of the brain involved in the processing of fine details (i.e. the inferior and middle temporal gyri, and the lingual gyrus) in anorexia nervosa, compared to healthy individuals; which may help explain why some individuals with anorexia nervosa have a tendency to focus on the fine details of their physical appearance (Phillipou, et al., 2015).
Levels of different types of neurotransmitters have also been of interest in anorexia nervosa. Neurotransmitters are the chemical messengers that enable the brain to function. The greatest research interest has been in the neurotransmitters dopamine and serotonin because of their roles in regulating eating behaviours and reward. Although these neurotransmitters have been found to be reduced in individuals with anorexia nervosa, similarly to the structural brain findings described earlier, they tend to ‘normalise’ when recovered, suggesting that the reduced levels may be due to the low body weight experienced in anorexia nervosa (Phillipou, et al., 2014a). Recent findings have, however, suggested that a neurotransmitter called gamma-Aminobutyric acid or GABA may be involved in anorexia nervosa, though the exact nature of its involvement is still unclear (Phillipou, et al., 2014b; Phillipou, et al., 2016). Levels of GABA are closely related to anxiety levels, which is why GABA-ergic medications are sometimes used to treat anxiety (Nemeroff, 2002). High levels of anxiety are often characteristic of someone with anorexia nervosa (Swinbourne & Touyz, 2007), and it is thought that altered GABA levels and increased anxiety may be related to some of the behaviours seen in someone with anorexia nervosa, including anxiety around body image and food.
In sum, the research into the neurobiology of anorexia nervosa is still in its early days. Similar research is also being conducted in other eating disorders such as bulimia nervosa, but with less research focus than anorexia nervosa. Findings in bulimia nervosa have, however, indicated some similarities between anorexia and bulimia nervosa, such as reduced activity of the parietal cortex (a ‘spatial awareness’ area of the brain) when looking at one’s own body in both conditions, when compared to individuals without an eating disorder (Vocks, et al., 2010); whereas other research has found different neural responses to images of food in the two conditions (Brooks, et al., 2011). These findings suggest that eating disorders such as anorexia and bulimia nervosa share some similarities in brain function, but differ in other ways, which helps explain why the behaviours in the two conditions often differ.
The research findings in anorexia nervosa so far suggest these individuals may have brains that look and function differently to people without anorexia nervosa, which may predispose them to developing the illness. However, much more research is needed in this area to confirm the brain mechanisms involved in anorexia nervosa so that we are able to develop more effective treatments targeting these altered mechanisms in the future.
In addition, the findings from anorexia nervosa may be later applied to and drive additional research into the neurobiology of other DSM-5 eating disorders (including, BED and OSFED).
Brooks, S. J., Owen, G. O., Uher, R., Friederich, H. C., Giampietro, V., Brammer, M., ... & Campbell, I. C. (2011). Differential neural responses to food images in women with bulimia versus anorexia nervosa. PLoS One, 6(7), e22259.
Castro-Fornieles, J., Bargalló, N., Lázaro, L., Andrés, S., Falcon, C., Plana, M. T., & Junqué, C. (2009). A cross-sectional and follow-up voxel-based morphometric MRI study in adolescent anorexia nervosa. Journal of psychiatric research, 43(3), 331-340.
Fladung, A. K., Grön, G., Grammer, K., Herrnberger, B., Schilly, E., Grasteit, S., Wolf, R.G., Walter, H. & von Wietersheim, J. (2009). A neural signature of anorexia nervosa in the ventral striatal reward system. American Journal of Psychiatry, 167(2), 206-212.
Nemeroff, C. B. (2002). The role of GABA in the pathophysiology and treatment of anxiety disorders. Psychopharmacology bulletin, 37(4), 133-146.
Phillipou, A., Rossell, S. L., & Castle, D. J. (2014a). The neurobiology of anorexia nervosa: a systematic review. Australian and New Zealand Journal of Psychiatry, 48(2), 128-152.
Phillipou, A., Rossell, S. L., Castle, D. J., Gurvich, C., & Abel, L. A. (2014b). Square Wave Jerks and Anxiety as Distinctive Biomarkers for Anorexia Nervosa. Investigative Ophthalmology & Visual Science, 55(12), 8366-8370.
Phillipou, A., Abel, L. A., Castle, D. J., Hughes, M. E., Gurvich, C., Nibbs, R. G., & Rossell, S. L. (2015). Self perception and facial emotion perception of others in anorexia nervosa. Frontiers in Psychology, 6.
Phillipou, A., Rossell, S. L., Gurvich, C., Castle, D. J., & Abel, L. A. (2016). The eyes have it: Eye movements and anorexia nervosa. Australian and New Zealand Journal of Psychiatry, 50(8), 806-807.
Swinbourne, J. M., & Touyz, S. W. (2007). The co‐morbidity of eating disorders and anxiety disorders: a review. European Eating Disorders Review, 15(4), 253-274.
Vocks, S., Busch, M., Grönemeyer, D., & Herpertz, S. (2010). Neural correlates of viewing photographs of one's own body and another woman's body in anorexia and bulimia nervosa: an fMRI study. Journal of psychiatry & neuroscience: JPN, 35(3), 163.
Recent review articles on the neurobiology of eating disorders
The neurobiology of eating disorders is an emerging field of research. Growing evidence suggests the neurobiological model warrants further understanding and refinement as an important approach to improving the treatment of eating disorders.
Below is a sample of 12 recent review articles exploring neurobiology, in relation to the cause and treatment of eating disorders.
1. King, JA, Frank GKW, Thompson PM & Ehlrich S (2018). Structural Neuroimaging of Anorexia Nervosa: Future Directions in the Quest for Mechanisms Underlying Dynamic Alterations. Biological Psychiatry, 83(1), 224-234. https://doi.org/10.1016/j.biopsych.2017.08.011
2. Fuglset, T. S., Landrø, N. I., Reas, D. L., & Rø, Ø. (2016). Functional brain alterations in anorexia nervosa: A scoping review. Journal of eating disorders, 4(1), 32. http://doi.org/10.1186/s40337-016-0118-y
3. Hill, L., Peck, S. K., Wierenga, C. E., & Kaye, W. H. (2016). Applying neurobiology to the treatment of adults with anorexia nervosa. Journal of Eating Disorders, 4(31). http://doi.org/10.1186/s40337-016-0119-x
4. Steinglass, J. E., & Walsh, B. T. (2016). Neurobiological model of the persistence of anorexia nervosa. Journal of Eating Disorders, 4(1), 19. http://doi.org/10.1186/s40337-016-0106-2
5. Sj, B., & The, L. M. (2015). The neurobiology of eating disorders — a clinical perspective. Acta Psychiatrica Scandinavica, 131, 244–255. http://doi.org/10.1111/acps.12335
6. Phillipou, A., Rossell, S. L., & Castle, D. J. (2014). The neurobiology of anorexia nervosa: A systematic review. Australian & New Zealand Journal of Psychiatry, 48(2), 128–152. http://doi.org/10.1177/0004867413509693
7. Mitchison, D., & Hay, P. P. J. (2014). The epidemiology of eating disorders: Genetic, environmental, and societal factors. Clinical Epidemiology, 6(1), 89–97. http://doi.org/10.2147/CLEP.S40841
8. Coman, A., Skårderud, F., Reas, D. L., & Hofmann, B. M. (2014). The ethics of neuromodulation for anorexia nervosa: a focus on rTMS. Journal of Eating Disorders, 2, 10. http://doi.org/10.1186/2050-2974-2-10
9. Van Elburg, A., & Treasure, J. (2013). Advances in the neurobiology of eating disorders. Current Opinion in Psychiatry, 26(6), 556–61. http://doi.org/10.1097/YCO.0b013e328365a2e7
10. Kaye, W. H., Wierenga, C. E., Bailer, U. F., Simmons, A. N., Wagner, A., & Bischoff-Grethe, A. (2013). Does a shared neurobiology for foods and drugs of abuse contribute to extremes of food ingestion in anorexia and bulimia nervosa? Biological Psychiatry, 73(9), 836–842. http://doi.org/10.1016/j.biopsych.2013.01.002
11. Kaye, W. H., Wierenga, C. E., Bailer, U. F., Simmons, A. N., & Bischoff-Grethe, A. (2013). Nothing tastes as good as skinny feels: The neurobiology of anorexia nervosa. Trends in Neurosciences, 36(2), 110–120. http://doi.org/10.1016/j.tins.2013.01.003
12. Keating, C., Tilbrook, A. J., Rossell, S. L., Enticott, P. G., & Fitzgerald, P. B. (2012). Reward processing in anorexia nervosa. Neuropsychologia, 50(5), 567–575. http://doi.org/10.1016/j.neuropsychologia.2012.01.036
Eating Disorders 101
Eating disorders are serious, potentially life threatening mental and physical illnesses, however with appropriate treatment, support and a high level of personal commitment, recovery from an eating disorder is achievable.
Evidence shows that the sooner treatment can commence for an eating disorder, the shorter the recovery process will be. Encouraging your loved one or client you are working with to seek help at the first warning signs is much more effective than waiting until the illness is in full swing.
How familiar are you with eating disorders?
Watch Eating Disorders 101: An animated introduction to eating disorders (Click on the video above!)
If you suspect that you or someone you know has an eating disorder, disordered eating or body image issues, it is important to seek help immediately. See the Helpline section of the NEDC website for further information - www.nedc.com.au/support-and-services/get-help/
Disclaimer: The services and website listings within this section are provided for convenience only. The NEDC cannot guarantee the accuracy, relevancy, timeliness or completeness of the information provided. The inclusion of services is not intended to assign importance to those services listed.
National Helpline - Extended Hours
Butterfly's National Helpline ED HOPE (1800 33 4673) is Australia’s national eating disorders support service. It has extended its hours and is now available from 8:00am to midnight AEST, seven days a week.
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