Causes of Bulimia Nervosa
What are the causes of bulimia? Why is bulimia so common in North America?
In the United States about 1 million men and 7 million women suffer from an eating disorder, and the lifetime prevalence of bulimia in women is 1% - 3%. (See bulimia statistics) Many causes of bulimia are suspected but it is clear that eating disorders are linked to a cultural obsession with thinness and beauty. The causes of bulimia nervosa include factors that are biological, genetic, cultural, environmental and psychological.
Biological Causes of Bulimia
There are several parts of the body thought to contribute to eating behaviors including the hypothalamic-pituitary-adrenal axis (HPA). This system originates in several areas of the brain and is responsible for releasing neurotransmitters (chemical messengers) that regulate stress, mood and appetite. Of particular importance to eating disorders is the chemical messenger serotonin which is thought to be related to well-being, anxiety and appetite. A deficiency in serotonin is thought to be one of the causes of bulimia development1 and may be why selective serotonin reuptake inhibitors (SSRIs) are sometimes used for bulimia treatment.
No specific gene has been linked to bulimia, but it is known that a family history of eating disorders increases the child's risk of developing an eating disorder 2 - 20 times that of the general population. Studies also show that twins have a tendency to share specific eating disorders, including bulimia. At this time, areas on two chromosomes appear to be one of the causes of bulimia nervosa and anorexia but scientists are doubtful that a single gene will ever be found. Instead, it is likely that a number of genes contribute to an overall susceptibility to bulimia.2
The risk factors for bulimia center on physical, behavioral and psychological traits. Bulimia nervosa appears almost entirely in women with only 2% - 8% of cases being male. Bulimia has a median onset of age 18. Bulimic women tend to be of normal weight or slightly overweight. Bulimia is also common among people with type I diabetes.
It is thought that five personality traits put a person at the highest risk for bulimia or anorexia:
Dieting and Stress
It is thought that those already vulnerable to the causes of bulimia as listed above may have bulimia triggered by dieting. While dieting is not thought to be one of the direct causes of bulimia, bulimia is most frequently preceded by one or more incidences of dieting. (read about dangers of dieting)
Likewise, life stressors may be one of the causes of bulimia and tend to directly precede the development of an eating disorder. These stressors include incidences as common as breaking up with a boyfriend, to life transitions like moving to a new country or the death of a parent.
Environmental Causes of Bulimia
Genetic and environmental factors are difficult to separate as most family members tend to share similar environments. Bulimics tend to grow up in families that place stress and the desire to be perfect on the bulimic. Often families are controlling and so the bulimic learns to control their food intake as a coping mechanism to stress.
Other environmental factors are:
- Dieting of other family members, specifically the mother
- A coach or other authority figure focusing on weight
- Being praised for losing weight
- An overly critical family, particularly criticism of the bulimic's appearance
- A disturbed family relationship
While race is not a risk factor, a culture's beliefs can be one of the causes of bulimia. Cultures, where beauty and thinness are prized, create an environment where women are more likely to concentrate on being thinner and become less satisfied with their own body. These women are more likely to diet, control food intake, obsess about body image and do other things known to contribute to bulimia.
Psychological Issues Linked to Bulimia
Those diagnosed with an eating disorder share certain psychological traits and issues. In addition to sharing personality traits like perfectionism and anxiousness, bulimics also show a higher incidence of mood and personality disorders like depression, obsessive-compulsive disorder and borderline personality disorder. While no single psychological issue is a known cause of bulimia, other contributing issues include:
- Substance abuse
- History of physical or sexual abuse
- History of anorexia
Body Dysmorphic Disorder
The main body image disorder known as one of the causes of bulimia is known as body dysmorphic disorder (BDD). This disorder falls within the spectrum of obsessive-compulsive disorders and affects about 1 in 50 people. A person with BDD is obsessed with a perceived fault in her or his body and is only able to focus on this fault. The person with BDD is hypercritical of their own body and can engage in extreme behavior, like bulimia, to correct it. However, the person with BDD never feels the fault goes away and this can increase the severity of an eating disorder. People with BDD are also at higher risk for suicidal thinking and suicide attempts.3
Last Updated: 14 May 2016
Reviewed by Harry Croft, MD