What causes bulimia nervosa?

Biological factors of bulimia nervosa

The idea that a person’s genes may impact their odds of developing an eating disorder is still relatively new. Yet, advances in technology have allowed scientists to take a closer look at this concept.

Many eating disorders, including bulimia nervosa, are now considered at least “moderately heritable,” meaning they can be passed down through families. (1) In fact, one ground-breaking study on the subject found genetic similarities in 57% of the study’s participants. (1)

Scientists are increasingly finding the inherited traits that can make a person more susceptible to bulimia can manifest in a number of ways, from the types of genes and hormones triggered, to the way their brain interprets signals from the body.

Library sections you should visit

• An overview on the eating disorder bulimia
• Treating bulimia nervosa
• The cause of an eating disorder
  

Hormonal triggers

Research has found a link between female puberty and the development of eating disorders. (2)

One study found that, up to age eleven, there were no genetic influences on the development of eating disorders in girls. But by age 17, at least 50% of recorded cases were caused by biology. (2) 

A follow-up to this finding discovered that a type of estrogen called estradiol plays a role. Primarily responsible for the development and growth of reproductive organs, the hormone goes into overdrive during puberty. This second study concluded this excess estradiol was also “switching on” certain genes that could lead to the development of eating disorders in affected girls. (3)

Brain activity

 Another study connected the disorder to the neurological pathways in the brain responsible for motivation and reinforcement. (4) Typically, these systems are used to ensure a person seeks out enough nutrition for the body, and stops eating once they’re satiated. 

But disruption of these pathways was found in people struggling with bulimia. 

Multiple studies have found that these neurological delivery systems can be affected by the repeated behavior of binge eating. Continuing to deprive the body of food for extended periods of time, then overloading the body on carbohydrates, fats, and, especially, sucrose, can trigger a flood of the “feel-good” chemical dopamine and other opioids operated by the brain’s reward center. (4) The rush of happy hormones also overrides those sent out to signal to the brain that the body is satiated, leading to binge eating. Eventually, this cycle can become self-sustaining.

Research has also found the purging behaviors of bulimia nervosa may be linked to biology, but scientists are continuing to explore the subject. At least one finding suggested that the neurotransmitter acetylcholine, which helps transmit the feeling of satiety, may be overwhelmed by the feel-good hormones involved in binge eating but brought back to more normal levels by the action of purging. (4)

Environmental factors of bulimia nervosa

Most studies on causes of bulimia and other eating disorders have focused on sociocultural influences. In fact, many scientists have long attributed the development of these disorders almost exclusively to environmental factors. 

While the examination of biological causes of bulimia continues to expand and round out scientific knowledge on the issue, there are also a number of outside factors that play a big role in developing BN.

Psychological/emotional/identity

Like eating disorders, personality traits were once thought to be primarily environmentally driven. Now they are increasingly being found to have hereditary links. But how these traits manifest in a person—and impact their life choices, including those that encourage eating disorders—is often very much tied to the person’s environment.

Bulimia nervosa has been connected to a number of comorbid conditions, which are conditions that occur at the same time and often play off each other. Some of the most closely linked conditions include obsessive-compulsive disorder, perfectionism, and a behavior called trait urgency, which is the tendency to react recklessly in response to stress. (1,5)

What causes bulimia in people with these risk factors depends on a number of things. But individuals often use eating as a coping mechanism to deal with the stress of these disorders and cultural pressure that thinness leads to life improvements. (5) 

This idea is supported by other research, which has also shown that parental role modeling can have a significant influence on a person’s feelings about both food and body image. (6) In fact, the study found a significant number of daughters mimicked their mothers’ purging behaviors, which are the hallmark signs of bulimia nervosa. (6)

Even more evidence points to especially stressful experiences in the lives of people struggling with BN. A disproportionate amount of people participating in eating disorder studies have reported traumatic pasts, including instances of sexual assault, physical and emotional abuse, teasing and bullying, and the loss of a parent. (7) And one study found up to 25% of participants with bulimia showed signs of post-traumatic stress disorder. (7)

Social/peer pressure/competition

Social and cultural pressure to remain thin have classically been considered the main causes of bulimia—and there is still plenty of research that points to their role in developing the disorder today.

A huge number of studies have been conducted on the subject, with one overview summarizing that more than 25 different reports had successfully linked body dissatisfaction and signs of bulimia to both peer and family influence. (8)

Other studies have worked to piece together more specific aspects of peer pressure on the development of bulimia and other eating disorders. What they found were three major “domains” of influence. (9)

The first, called message pressure, consisted mainly of weight-related bullying, which was found to have strong correlations to the development of bulimia, especially in adolescents. The second domain was an interaction between peers, in which certain peer groups would share concerns about eating and body weight, which could either trigger or perpetuate bulimic behavior or signs of other eating disorders. Likeability pressure is the third domain, which connects the perception of being more well liked with “thinness”. (9)

This third domain has also been connected to the images perpetuated on social media and in popular culture, which favorthin women and muscular men. One recent study found that more than 70% of models were found to be underweight, and more than 75% were less than 85% of their ideal body weight. (10)

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Treatment of bulimia nervosa

Bulimia nervosa is a dangerous and potentially deadly disease. But it is entirely treatable. In fact, nearly 74% of people struggling with bulimia fully recover after seeking treatment for the disorder. (11) 

Several types of therapy have been found to be especially effective against BN, making it easier for people to find the type of treatment that will help them the most.

Cognitive behavioral therapy (CBT) may be the most widely-used therapeutic option for treating bulimia nervosa. CBT helps patients recognize the underlying emotional and environmental factors in play, then teaches them healthier coping mechanisms to deal with those issues, while also working on reprogramming their ideas around body image.

Self-help has also been found to be a useful treatment for bulimia nervosa. Mostly mirroring the concepts of CBT, self-help allows a patient to practice these techniques at their own pace, by working through a notebook, with little or no interaction with a therapist.

Art therapy, family therapy, and a number of other forms of treatment have also been found beneficial in treating BN. But the common denominator among all these therapies is ensuring the person gets the treatment they need.

If you or someone you know is showing signs of suffering from bulimia, it’s important to find them treatment as soon as possible.