Neuropsychology is currently the most scientific and most advanced of all schools of thought within psychology. It uses techniques and machines like PET and fMRI scans to measure and observe what is happening in the brain when people are in certain mental states and, through doing this, it can identify which parts of the brain are implicated in psychological conditions like anorexia nervosa and bulimia nervosa.
What causes an eating disorder?
Various parts of the brain have been implicated in eating disorders and, more generally, in eating behaviour. For example, two parts of the hypothalamus have been identified as being important in the sensation of hunger and the decision to eat: the ventro-medial hypothalamus is seen as playing an important role in telling when we feel full, and the lateral hypothalamus is seen as playing an important role in telling us when we are hungry.
As well as looking at which parts of the brain are important in eating behaviour, neuropsychology also tells us which brain chemicals, or neurotransmitters, are important as well. The two most important neurotransmitters in explaining conditions like anorexia nervosa and bulimia nervosa are serotonin and dopamine.
Serotonin is associated with mood regulation and appetite regulation: if something went wrong with the serotonin system in your brain, it might result in you experiencing difficulties in appetite regulation and anxiety or obsessive behaviours. Studies have shown that people currently suffering from both anorexia nervosa and bulimia nervosa do have alterations in the way their brains deal with serotonin, although these effects are more pronounced in anorexics than in bulimics.
Eating disorders are also associated with dopamine regulation. In a study looking at how dopamine was processed in the brains of bulimics, Broft et al. found that the way a bulimic brain deals with dopamine is similar to what one would expect to see from someone suffering with an addiction, suggesting that, in some ways at least, bulimia nervosa resembles an addiction.
Where can I go to find out more?
If you go to a doctor or a psychiatrist, chances are s/he will be familiar with the neuropsychological approach to eating disorders and might prescribe a Selective Serotonin Re-uptake Inhibitor (SSRI), which is a kind of drug that works to alter the way the brain deals with serotonin so as to correct the abnormalities that have caused the eating disorder. Unfortunately, the effectiveness of these drugs in dealing with eating disorders is questionable at best, possibly because they neglect the social and environmental factors that have contributed to the creation of the eaing disorder in the first place.
Chapters in books: Duvvuri, V., et al., 2010. "Altered Serotonin Function in Anorexia and Bulimia Nervosa", p.715 in: Müller, C & Hacobs, B., (eds.) 2010, Handbook of Behavioural Neurobiology of Serotonin, Elsevier B.V. Journal Articles: Broft A., et al., 2012. "Striatal Dopamine in Bulimia Nervosa: a PET Imaging Study", International Journal of Eating Disorders, 45(5), 648-656