You’ve heard that beauty is in the eye of the beholder, but what about weight?

Figure 1. Patients suffering from AN have a distorted view of their own bodies many times thinking they are overweight when in fact they are dangerously underweight. Image from: http://theraphaelproject.com/blog/eating-disorders/

Figure 1. Patients suffering from AN have a distorted view of their own bodies many times thinking they are overweight when in fact they are dangerously underweight. Image from: http://theraphaelproject.com/blog/eating-disorders/

In the media, we often hear about the obesity epidemic. Another weight related problem that is becoming more and more widespread is anorexia nervosa.

According to DSM-IV, Anorexia nervosa (AN) is characterized by an intense fear of gaining weight or becoming fat even though the patient is below normal weight. The patient experiences a disturbance in the way they view their body weight and body shape (Figure 1), often thinking they are overweight when in fact they are critically underweight. Even though patients have a powerful pursuit of weight loss they are also inherently preoccupied with food and eating rituals. They also show an obsessive need to exercise and do so to an extreme point.

AN is one of the most homogenous psychiatric disorders in that the age of onset is very narrow, usually beginning at puberty, and there is a very stereotypic presentation of symptoms associated with the disease. The etiology of AN is unknown however there are many different theories as to what may cause AN.

Like many psychological diseases there seems to be a mix of causative factors that influences the onset and progression of AN. These include biological factors, psychological factors, and environmental factors.

  • Figure 2. A comparison in extracellular serotonin levels as well as serotonin receptor activity in healthy controls and in patients with AN. These abnormalities lead to a dysphoric mood, increased error detection, and increased inhibition in patients suffering from AN.

    Figure 2. A comparison in extracellular serotonin levels as well as serotonin receptor activity in healthy controls and in patients with AN. These abnormalities lead to a dysphoric mood, increased error detection, and increased inhibition in patients suffering from AN.

    Biological factors: It has been found that there might be up to an 80% genetic influence in the development of AN although it is unknown which genes may contribute to this risk. There has also been research on abnormalities in certain brain circuits, neurotransmitter function, and receptor function that may contribute to AN. One observation in patients with AN is that they seem to have an increased amount of extracellular serotonin levels as well as abnormal serotonin receptor activity (Figure 2). These abnormalities together seem to result in an increased feeling of satiety in AN patients as well as an anxious temperament. Serotonin increases with food intake and in patients suffering from AN this leads to an increase in anxiousness. Serotonin levels are reduced during starvation. In healthy controls this leads to an anxious and food driven temperament but in patients with AN, this reduction in serotonin reduces anxiety and leads to continuing food aversion behaviors.

  • Psychological factors: Patients that develop AN tend to present with a certain set of personality traits. These include: negative emotionality, harm avoidance, perfectionism, inhibition, an inherent drive for thinness, and obsessive-compulsiveness. These personality traits make it easier for people to stick to extreme diets even when they are very hungry. It also drives them to lose more and more weight despite already being dangerously thin.
  • Environmental: People are bombarded by media on a regular basis.  TV shows, movies, and magazines are dominated by very thin actors, actresses, and models. Photoshop is used to create body images that are incredibly difficult to reach for the average person, this may be a driving factor in the development of AN.

Treatment for AN can be difficult as many people do not see it as a problem and choose to view it more as a lifestyle choice. Men with AN generally seek treatment less than women do as AN is seen as a “woman’s issue”. The first treatment needed may be medical attention for any issues due to extreme weight loss and starvation. The next steps for treatment are to restore the weight and for the patient to undergo psychotherapy. Medications are typically not effective for patients suffering from AN. The disease is one that is typically fought throughout a lifetime especially during times of increased stress. Patients may need to undergo continuing therapy to continue achieving a healthy weight. AN is a complex psychological disorder. Although it is one of the most homogenous of the psychological disorders there is not one known cause that leads to the onset and progression of AN.

Guest author: Alyson Betcher is a member of the Medical Education department at NeuroScience, Inc. 

References:
Kaye, W., Fudge, J., Paulus, M. (2009). New insights into the symptoms and neurocircuit function of anorexia nervosa. Nature Reviews, 10: 573-584.
http://www.mayoclinic.org/diseases-conditions/anorexia/basics/definition/con-20033002
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