Bulimia nervosa, also known as simply bulimia, is an eating disorder characterized by binge eating followed by purging. Binge eating refers to eating a large amount of food in a short amount of time. Purging refers to the attempts to get rid of the food consumed. This may be done by vomiting or taking laxatives. Other efforts to lose weight may include the use of diuretics, stimulants, water fasting, or excessive exercise. Most people with bulimia are at a normal weight. The forcing of vomiting may result in thickened skin on the knuckles and breakdown of the teeth. Bulimia is frequently associated with other mental disorders such as depression, anxiety, and problems with drugs or alcohol. There is also a higher risk of suicide and self-harm.

Bulimia is more common among those who have a close relative with the condition. The percentage risk that is estimated to be due to genetics is between 30% and 80%. Other risk factors for the disease include psychological stress, cultural pressure to attain a certain body type, poor self-esteem, and obesity. Living in a culture that promotes dieting and having parents that worry about weight are also risks. Diagnosis is based on a person’s medical history; however, this is difficult, as people are usually secretive about their binge eating and purging habits. Further, the diagnosis of anorexia nervosa takes precedence over that of bulimia. Other similar disorders include binge eating disorder, Kleine-Levin syndrome, and borderline personality disorder.

Cognitive behavioral therapy is the primary treatment for bulimia. Antidepressants of the selective serotonin reuptake inhibitor (SSRI) or tricyclic antidepressant classes may have a modest benefit. While outcomes with bulimia are typically better than in those with anorexia, the risk of death among those affected is higher than that of the general population. At 10 years after receiving treatment about 50% of people are fully recovered.

Globally, bulimia was estimated to affect 3.6 million people in 2015. About 1% of young women have bulimia at a given point in time and about 2% to 3% of women have the condition at some point in their lives. The condition is less common in the developing world. Bulimia is about nine times more likely to occur in women than men. Among women, rates are highest in young adults. Bulimia was named and first described by the British psychiatrist Gerald Russell in 1979

Signs and symptoms

Bulimia typically involves rapid and out-of-control eating, which may stop when the person is interrupted by another person or the stomach hurts from over-extension, followed by self-induced vomiting or other forms of purging. This cycle may be repeated several times a week or, in more serious cases, several times a day and may directly cause:

• Chronic gastric reflux after eating, secondary to vomiting
• Dehydration and hypokalemia due to renal potassium loss in the presence of alkalosis and frequent vomiting
• Electrolyte imbalance, which can lead to abnormal heart rhythms, cardiac arrest, and even death
• Esophagitis, or inflammation of the esophagus
• Mallory-Weiss tears
• Boerhaave syndrome, a rupture in the esophageal wall due to vomiting
• Oral trauma, in which repetitive insertion of fingers or other objects causes lacerations to the lining of the mouth or throat
• Russell’s sign: calluses on knuckles and back of hands due to repeated trauma from incisors
• Perimolysis, or severe dental erosion of tooth enamel
• Swollen salivary glands (for example, in the neck, under the jaw line)
• Gastroparesis, or delayed gastric emptying
• Constipation or diarrhea
• Tachycardia or palpitations
• Hypotension
• Peptic ulcers
• Infertility
• Constant weight fluctuations are common
• Elevated blood sugar, cholesterol, and amylase levels may occur
• Hypoglycemia may occur after vomiting

These are some of the many signs that may indicate whether someone has bulimia nervosa

• A fixation on the number of calories consumed
• A fixation on and extreme consciousness of one’s weight
• Low self-esteem and/or self-harming
• Suicidal tendencies
• An irregular menstrual cycle in women
• Regular trips to the bathroom, especially soon after eating
• Depression, anxiety disorders and sleep disorders
• Frequent occurrences involving consumption of abnormally large portions of food
• The use of laxatives, diuretics, and diet pills
• Compulsive or excessive exercise
• Unhealthy/dry skin, hair, nails and lips
• Fatigue, or exhaustion

As with many psychiatric illnesses, delusions can occur, in conjunction with other signs and symptoms, leaving the person with a false belief that is not ordinarily accepted by others.

People with bulimia nervosa may also exercise to a point that excludes other activities.

Interoceptive

People with bulimia exhibit several interoceptive deficits, in which one experiences impairment in recognizing and discriminating between internal sensations, feelings, and emotions. People with bulimia may also react negatively to somatic and affective states. In relation to interoceptive sensitivity, hyposensitive individuals may not detect feelings of fullness in a normal and timely fashion, and therefore are prone to eating more calories.

Examining from a neural basis also connects elements of interoception and emotion; notable overlaps occur in the medial prefrontal cortex, anterior and posterior cingulate, and anterior insula cortices, which are linked to both interoception and emotional eating.

Related disorders

People with bulimia are more likely than people without bulimia to have an affective disorder, such as depression or general anxiety disorder. One study found 70% had depression at some time in their lives (as opposed to 26% for adult females in the general population), rising to 88% for all affective disorders combined.Another study by the Royal Children’s Hospital in Melbourne on a cohort of 2,000 adolescents similarly found that those meeting at least two of the DSM-IV criteria for bulimia nervosa or anorexia nervosa had a sixfold increase in risk of anxiety and a doubled risk for substance dependency. Some with anorexia nervosa exhibit episodes of bulimic tendencies through purging (either through self-induced vomiting or laxatives) as a way to quickly remove food in their system. There may be an increased risk for diabetes mellitus type 2. Bulimia also has negative effects on a person’s teeth due to the acid passed through the mouth from frequent vomiting causing acid erosion, mainly on the posterior dental surface.

Causes

Biological

As with anorexia nervosa, there is evidence of genetic predispositions contributing to the onset of this eating disorder. Abnormal levels of many hormones, notably serotonin, have been shown to be responsible for some disordered eating behaviors. Brain-derived neurotrophic factor (BDNF) is under investigation as a possible mechanism.

There is evidence that sex hormones may influence appetite and eating in women, and the onset of bulimia nervosa. Studies have shown that women with hyperandrogenism and polycystic ovary syndrome have a dysregulation of appetite, along with carbohydrates and fats. This dysregulation of appetite is also seen in women with bulimia nervosa. In addition, gene knockout studies in mice have shown that mice that have the gene encoding estrogen receptors have decreased fertility due to ovarian dysfunction and dysregulation of androgen receptors. In humans, there is evidence that there is an association between polymorphisms in the ERβ (estrogen receptor β) and bulimia, suggesting there is a correlation between sex hormones and bulimia nervosa.

Bulimia has been compared to drug addiction, though the empirical support for this characterization is limited. However, people with bulimia nervosa may share dopamine D2 receptor-related vulnerabilities with those with substance abuse disorders.

Dieting, a common behaviour in bulimics, is associated with lower plasma tryptophan levels. Decreased tryptophan levels in the brain, and thus the synthesis of serotonin, increases bulimic urges in currently and formerly bulimic individuals within hours.

Abnormal blood levels of peptides important for the regulation of appetite and energy balance are observed in individuals with bulimia nervosa, but it remains unknown if this is a state or trait.

Social

Media portrayals of an ‘ideal’ body shape are widely considered to be a contributing factor to bulimia. In a 1991 study by Weltzin, Hsu, Pollicle, and Kaye, it was stated that 19% of bulimics undereat, 37% of bulimics eat an average or normal amount of food, and 44% of bulimics overeat. A survey of 15- to 18-year-old high school girls in Nadroga, Fiji, found the self-reported incidence of purging rose from 0% in 1995 (a few weeks after the introduction of television in the province) to 11.3% in 1998. In addition, the suicide rate among people with bulimia nervosa is 7.5 times higher than in the general population.

When attempting to decipher the origin of bulimia nervosa in a cognitive context, Christopher Fairburn et al.‘s cognitive behavioral model is often considered the golden standard. Fairburn et al.’s model discusses the process in which an individual falls into the binge-purge cycle and thus develops bulimia. Fairburn et al. argue that extreme concern with weight and shape coupled with low self-esteem will result in strict, rigid, and inflexible dietary rules. Accordingly, this would lead to unrealistically restricted eating, which may consequently induce an eventual “slip” where the individual commits a minor infraction of the strict and inflexible dietary rules. Moreover, the cognitive distortion due to dichotomous thinking leads the individual to binge. The binge subsequently should trigger a perceived loss of control, promoting the individual to purge in hope of counteracting the binge. However, Fairburn et al. assert the cycle repeats itself, and thus consider the binge-purge cycle to be self-perpetuating.

In contrast, Byrne and Mclean’s findings differed slightly from Fairburn et al.‘s cognitive behavioral model of bulimia nervosa in that the drive for thinness was the major cause of purging as a way of controlling weight. In turn, Byrne and Mclean argued that this makes the individual vulnerable to binging, indicating that it is not a binge-purge cycle but rather a purge-binge cycle in that purging comes before bingeing. Similarly, Fairburn et al.‘s cognitive behavioral model of bulimia nervosa is not necessarily applicable to every individual and is certainly reductionist. Everyone differs from another, and taking such a complex behavior like bulimia and applying the same one theory to everyone would certainly be invalid. In addition, the cognitive behavioral model of bulimia nervosa is very cultural bound in that it may not be necessarily applicable to cultures outside of the Western society. To evaluate, Fairburn et al..’s model and more generally the cognitive explanation of bulimia nervosa is more descriptive than explanatory, as it does not necessarily explain how bulimia arises. Furthermore, it is difficult to ascertain cause and effect, because it may be that distorted eating leads to distorted cognition rather than vice versa.

A considerable amount of literature has identified a correlation between sexual abuse and the development of bulimia nervosa. The reported incident rate of unwanted sexual contact is higher among those with bulimia nervosa than anorexia nervosa.

When exploring the etiology of bulimia through a socio-cultural perspective, the “thin ideal internalization” is significantly responsible. The thin ideal internalization is the extent to which individuals adapt to the societal ideals of attractiveness. Studies have shown that young females that read fashion magazines tend to have more bulimic symptoms than those females who do not. This further demonstrates the impact of media on the likelihood of developing the disorder. Individuals first accept and “buy into” the ideals, and then attempt to transform themselves in order to reflect the societal ideals of attractiveness. J. Kevin Thompson and Eric Stice claim that family, peers, and most evidently media reinforce the thin ideal, which may lead to an individual accepting and “buying into” the thin ideal. In turn, Thompson and Stice assert that if the thin ideal is accepted, one could begin to feel uncomfortable with their body shape or size since it may not necessarily reflect the thin ideal set out by society. Thus, people feeling uncomfortable with their bodies may result in suffering from body dissatisfaction and may develop a certain drive for thinness. Consequently, body dissatisfaction coupled with a drive for thinness is thought to promote dieting and negative effects, which could eventually lead to bulimic symptoms such as purging or bingeing. Binges lead to self-disgust which causes purging to prevent weight gain.

A study dedicated to investigating the thin ideal internalization as a factor of bulimia nervosa is Thompson’s and Stice’s research. The aim of their study was to investigate how and to what degree media affects the thin ideal internalization. Thompson and Stice used randomized experiments (more specifically programs) dedicated to teaching young women how to be more critical when it comes to media, in order to reduce thin ideal internalization. The results showed that by creating more awareness of the media’s control of the societal ideal of attractiveness, the thin ideal internalization significantly dropped. In other words, less thin ideal images portrayed by the media resulted in less thin ideal internalization. Therefore, Thompson and Stice concluded that media greatly affected the thin ideal internalization. Papies showed that it is not the thin ideal itself, but rather the self-association with other persons of a certain weight that decide how someone with bulimia nervosa feels. People that associate themselves with thin models get in a positive attitude when they see thin models and people that associate with overweight get in a negative attitude when they see thin models. Moreover, it can be taught to associate with thinner people.

Diagnosis

The onset of bulimia nervosa is often during adolescence, between 13 and 20 years of age, and many cases have previously suffered from obesity, with many sufferers relapsing in adulthood into episodic bingeing and purging even after initially successful treatment and remission. A lifetime prevalence of 0.5 percent and 0.9 percent for adult and adolescent sufferers, respectively, is estimated among the United States population. Bulimia nervosa may affect up to 1% of young women and, after 10 years of diagnosis, half will recover fully, a third will recover partially, and 10–20% will still have symptoms.

Adolescents with bulimia nervosa are more likely to have self-imposed perfectionism and compulsivity issues in eating compared to their peers. This means that the high expectations and unrealistic goals that these individuals set for themselves are internally motivated rather than by social views or expectations.

Criteria

Bulimia nervosa can be difficult to detect, compared to anorexia nervosa, because bulimics tend to be of average or slightly above average weight. Many bulimics may also engage in significantly disordered eating and exercise patterns without meeting the full diagnostic criteria for bulimia nervosa. Recently, the Diagnostic and Statistical Manual of Mental Disorders was revised, which resulted in the loosening of criteria regarding the diagnoses of bulimia nervosa and anorexia nervosa. The diagnostic criteria utilized by the DSM-5 includes repetitive episodes of binge eating (a discrete episode of overeating during which the individual feels out of control of consumption) compensated for by excessive or inappropriate measures taken to avoid gaining weight. The diagnosis also requires the episodes of compensatory behaviors and binge eating to happen a minimum of once a week for a consistent time period of 3 months. The diagnosis is made only when the behavior is not a part of the symptom complex of anorexia nervosa and when the behavior reflects an overemphasis on physical mass or appearance. Purging often is a common characteristic of a more severe case of bulimia nervosa.