Biological Explanation of Anorexia

The biological explanation for Anorexia Nervosa focuses on the role of neurotransmitters. It suggests disturbances in the levels of serotonin and dopamines are characteristic of anorexia. Bailer et al compared serotonin activity in women recovering from restricting anorexia with those recovering from purging type anorexia with a healthy control group. They found that the group recovering from purging type anorexia had higher serotonin activity. They also found the highest levels of serotonin in women who showed the most anxiety. They concluded that this suggests that the disruption of serotonin levels might result in increased anxiety which is one of the clinical characteristics of anorexia. However it can be argued that anxiety might be caused by anorexia rather than causing anorexia. Despite the evidence, a problem with the serotonin explanation for anorexia is that SSRIs have been found to be ineffective in treating anorexic patients. However, Kaye et al found SSRIS were effective with those recovering from anorexia because they prevented relapse. The explanation for this is that SSRIs only work once weight returns to normal because the malnutrition resulting from anorexia changed serotonin function.
Kaye et al have looked at the role of another neurotransmitter in anorexia. They used a PET scan to compare a control group of healthy women with a group of recovering female anorexics. They found an over activity of dopamine receptors in the basal ganglia of women recovering from anorexia. They concluded that increased dopamine levels in the basal ganglia alters the way people interpret rewards and that anorexics might find it difficult to associate good feelings with food. Further support comes from a study by Wang et al who found that obese individuals had low levels of dopamine. This contrasts with the high levels found in anorexics suggesting dopamine is inversely related to body weight. However it is unclear whether levels of dopamine cause anorexia or the