‘Eating disorder’ is the umbrella term used to describe different patterns of eating that are disordered due to dysfunctional attitudes and emotions towards food and weight.
According to the Diagnostic Statistical Manual of Mental Disorders (DSM-IV), eating disorders are classified as Axis I disorders, which represent clinical syndromes (i.e. clinical symptomology that can cause significant impairment).
Anorexia nervosa and bulimia nervosa are the two most common types of eating disorder.
The criteria for a diagnosis of anorexia nervosa comprises:
an intense fear of weight gain
a refusal to maintain body weight above 85% of expected weight
three consecutive missed menses (periods)
lack of recognition of the seriousness of the weight loss.
There are two subtypes of anorexia:
the restrictive type (i.e. food restriction)
the binge eating and purging type (i.e. some episodes of overeating or purging).
The criteria for a diagnosis of bulimia nervosa, which is only made when the behaviour is not part of anorexia, comprises:
the presence of episodes of binge eating (i.e. an episode of overeating that is perceived to be uncontrollable)
compensated for by excessive or inappropriate methods of avoiding weight gain, such as the misuse of laxatives, diuretics or slimming pills.
As with anorexia, there are two subtypes of bulimia nervosa:
the purging type (i.e. self-induced vomiting)
the non-purging type, where an individual may partake in excessive exercise or fasting (food abstinence) to counteract a binge.
There are other categories of eating disorder, such as:
Binge Eating (i.e. eating large amounts of food over a discreet time period, accompanied by perceived lack of control but no compensatory behaviour)
Eating Disorder Not Otherwise Specified (EDNOS) (i.e. disordered eating patterns that do not fit the criteria used to diagnose anorexia or bulimia).
Approximately one-third of people with eating disorders fully recover, whilst one-third continue to experience some symptoms and another one-third remain chronic (Devlin, Jahraus, & Dobrow, 2005).
Long-term follow-up studies on anorexia demonstrate recovery rates ranging from 44-76%, with mortality in approximately 20% of sufferers (mainly from cardiac arrest or suicide).
There is a less research on the long-term follow-up of people with bulimia, but short-term success rates of 50-70% have been reported, with 6-month relapse rates of between 30-50%.
People with bulimia generally have a better prognosis compared to anorexia, although the fact that bulimia often goes unrecognised can place women with this disorder at great risk.
Causes of Eating Disorders
There are a number of theories as to the cause and maintenance of eating disorders, including those that are biological, social, or psychological in nature.
Genetic factors have been found to have a significant influence on the development of anorexia:
It has been estimated that approximately 58% of people with anorexia have inherited the disorder (Wade, Bulik, Neale, & Kendler, 2000).
In terms of social explanations, there has been a large focus on media influence and the thin ideal.
Research on the psychological factors underlying eating disorders indicates that:
more than half of people with anorexia have experienced sexual abuse or some other major trauma.
There are also cognitive theories of eating disorders (Spranger, 2001), including that they are caused by:
Information Processing Errors
If you have any experience of eating disorders, please feel free to share your own insight into the causes. It would also be good to hear what has helped you overcome an eating disorder.
Devlin, M., Jahraus, J., & Dobrow I. (2005). Eating disorders. Levenson. J. (ed). Textbook of Psychosomatic Medicine, (pp. 311-334). Washington, DC: American Psychiatric Association.
Spranger, S.C., Waller, G., & Bryant-Waugh, R. (2001). Schema avoidance in bulimic and non-eating disordered women. International Journal of Eating Disorders. 29, 302–306.
Wade, T.D., Bulik, CM., Neale, M. & Kendler, KS. (2000). Anorexia nervosa and major depression: shared genetic and environmental risk factors. American Journal of Psychiatry, 157(3), 469-71.