Bulimia nervosa

Interoceptive

People with bulimia exhibit several interoceptive deficits, in which one experiences impairment in recognizing and discriminating between internal sensations, feelings, and emotions.^[21] People with bulimia may also react negatively to somatic and affective states.^[22] Regarding interoceptive sensation, hyposensitive individuals may not detect normal feelings of fullness at the appropriate time while eating, and are prone to eating more calories in a short period of time as a result of this decreased sensitivity.^[21]

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.^[23]

Related disorders

People with bulimia are at a higher risk 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.^[24] Another study in the Journal of Affective Disorders found that of the population of patients that were diagnosed with an eating disorder according to the DSM-V guidelines about 27% also suffered from bipolar disorder. Within this article, the majority of the patients were diagnosed with bulimia nervosa, the second most common condition reported was binge-eating disorder.^[25] Some individuals 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.^[26] There may be an increased risk for diabetes mellitus type 2.^[27] 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.

Research has shown that there is a relationship between bulimia and narcissism.^[28][29][30] According to a study by the Australian National University, eating disorders are more susceptible among vulnerable narcissists. This can be caused by a childhood in which inner feelings and thoughts were minimized by parents, leading to "a high focus on receiving validation from others to maintain a positive sense of self".^[31]

The medical journal Borderline Personality Disorder and Emotion Dysregulation notes that a "substantial rate of patients with bulimia nervosa" also have borderline personality disorder.^[32]

A study by the Psychopharmacology Research Program of the University of Cincinnati College of Medicine "leaves little doubt that bipolar and eating disorders—particularly bulimia nervosa and bipolar II disorder—are related." The research shows that most clinical studies indicate that patients with bipolar disorder have higher rates of eating disorders, and vice versa. There is overlap in phenomenology, course, comorbidity, family history, and pharmacologic treatment response of these disorders. This is especially true of "eating dysregulation, mood dysregulation, impulsivity and compulsivity, craving for activity and/or exercise."^[33]

Studies have shown a relationship between bulimia's effect on metabolic rate and caloric intake with thyroid dysfunction.^[34]

Scientific research has shown that people suffering from bulimia have decreased volumes of brain matter, and that the abnormalities are reversible after long-term recovery.^[35]

Biological

As with anorexia nervosa, there is evidence of genetic predispositions contributing to the onset of this eating disorder.^[36] 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.^[37][38]

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.^[39]

Bulimia has been compared to drug addiction, though the empirical support for this characterization is limited.^[40] However, people with bulimia nervosa may share dopamine D2 receptor-related vulnerabilities with those with substance use disorders.^[41]

Dieting, a common behaviour in bulimics, is associated with lower plasma tryptophan levels.^[42] Decreased tryptophan levels in the brain, and thus the synthesis of serotonin, such as via acute tryptophan depletion, increases bulimic urges in currently and formerly bulimic individuals within hours.^[43][44]

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.^[45]

In recent years, evolutionary psychiatry as an emerging scientific discipline has been studying mental disorders from an evolutionary perspective. If eating disorders, Bulimia nervosa in particular, have evolutionary functions or if they are new modern "lifestyle" problems is still debated.^[46][47][48]

Social

Media portrayals of an 'ideal' body shape are widely considered to be a contributing factor to bulimia.^[20] 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.^[49] 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.^[50] In addition, the suicide rate among people with bulimia nervosa is 7.5 times higher than in the general population.^[51]

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.^[52] 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.^[53]

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. Every one 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 culturally bound in that it may not be necessarily applicable to cultures outside of 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.^[54][55]

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.^[56]

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 women that read fashion magazines tend to have more bulimic symptoms than those women who do not. This further demonstrates the impact of media on the likelihood of developing the disorder.^[57] 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 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.^[58]

A study dedicated to investigating the thin ideal internalization as a factor of bulimia nervosa is Thompson's and Stice's research. Their study aimed 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, 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.^[59] 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.^[60]

Criteria

Bulimia Nervosa is diagnosed using the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). The diagnostic criteria includes the following:^[13][64]

• Recurrent episodes of binge eating
• Recurrent inappropriate compensatory behavior to prevent weight gain, like self-induced vomiting, misuse of laxatives or other medications, fasting, or excessive exercise.
• The binge eating and compensatory behaviors both occur at least once a week for three months
• Self-evaluation is influenced by body shape and weight.

Other methods are also used to narrow down the diagnosis, including:

• Physical exams: May include measuring your height and weight, checking vital signs, checking skin and nails, and listening to the heart and lungs.
• Lab tests: May include a complete blood count, tests to check electrolytes and protein, or a urinalysis might be performed.
• Psychological evaluations: A therapist or mental health provider will likely inquire about your thoughts, feelings, and eating habits, as well as asking you to complete a questionnaire.

Psychotherapy

Cognitive behavioral therapy (CBT) is considered the gold standard for the treatment of bulimia nervosa. This approach focuses on helping patients identify and change distorted thought patterns related to eating, body image, and self worth^[66][67]

CBT helps patients identify and challenge the distorted thinking individuals might have about food, weight and body image. It also helps by offering the chance to identify the unhelpful thoughts about food and body image.^[67]

By using CBT people record how much food they eat and periods of vomiting with the purpose of identifying and avoiding emotional fluctuations that bring on episodes of bulimia on a regular basis, as a component of this therapy is food journaling.^[68] CBT is necessarily good for those with bulimia as it targets the binge-purge cycle, which is the hallmark of bulimia.^[9][69][70] People undergoing CBT who exhibit early behavioral changes are most likely to achieve the best treatment outcomes in the long run.^[71]

Researchers have also reported some positive outcomes for interpersonal psychotherapy and dialectical behavior therapy.^[72][73] These therapies have good outcomes for treating bulimia, especially in patients with emotional regulation difficulties or interpersonal issues. While these therapies are not as extensively research as CBT, they can be beneficial when integrated into a comprehensive treatment plan.^[66]

For adolescents, Family-Based therapy (FBT) has been identified as an effective treatment. FBT involes the family in the treatment process, where parents are empowered to take an active role in helping their child recover from bulimia nervosa. This approach is particularly helpful in younger patients who are still living with their families^[66]

The use of CBT has been shown to be quite effective for treating bulimia nervosa (BN) in adults, but little research has been done on effective treatments of BN for adolescents.^[74] Although CBT is seen as more cost-efficient and helps individuals with BN in self-guided care, Family Based Treatment (FBT) might be more helpful to younger adolescents who need more support and guidance from their families.^[75] Adolescents are at the stage where their brains are still quite malleable and developing gradually.^[76] Therefore, young adolescents with BN are less likely to realize the detrimental consequences of becoming bulimic and have less motivation to change,^[77] which is why FBT would be useful to have families intervene and support the teens.^[74] Working with BN patients and their families in FBT can empower the families by having them involved in their adolescent's food choices and behaviors, taking more control of the situation in the beginning and gradually letting the adolescent become more autonomous when they have learned healthier eating habits.^[74]

Medication

Antidepressants, particularly selective serotonin reuptake inhibitors (SSRI), are often prescribed to treat bulimia nervosa, especially when comorbid depression or anxiety disorders are present. However, medications alone are generally not sufficient and are typically used in conjunction with psychotherapy^[13][66] Compared to placebo, the use of a single antidepressant has been shown to be effective.^[78] Combining medication with counseling can improve outcomes in some circumstances.^[79] Some positive outcomes of treatments can include: abstinence from binge eating, a decrease in obsessive behaviors to lose weight and in shape preoccupation, less severe psychiatric symptoms, a desire to counter the effects of binge eating, as well as an improvement in social functioning and reduced relapse rates.^[4]

A combination of psychotherapy, especially CBT and pharmacological treatments, such as SSRIs, often lead to better outcomes for individuals with bulimia. Combining both approaches is particularly beneficial in severe or chronic cases, where behavioral modification and mood stabilization are crucial.^[66]

Alternative medicine

Some researchers have also claimed positive outcomes in hypnotherapy.^[80] The first use of hypnotherapy in Bulimic patients was in 1981. When it comes to hypnotherapy, Bulimic patients are easier to hypnotize than Anorexia Nervosa patients. In Bulimic patients, hypnotherapy focuses on learning self-control when it comes to binging and vomiting, strengthening stimulus control techniques, enhancing ones ego, improving weight control, and helping overweight patients see their body differently (have a different image).^[81]

Risk factors

Being female and having bulimia nervosa takes a toll on mental health. Women frequently reported an onset of anxiety at the same time of the onset of bulimia nervosa.^[82] The approximate female-to-male ratio of diagnosis is 10:1.^[5] In addition to cognitive, genetic, and environmental factors, childhood gastrointestinal problems and early pubertal maturation also increase the likelihood of developing bulimia nervosa.^[83] Another concern with eating disorders is developing a coexisting substance use disorder.^[84]

Etymology

The term bulimia comes from Greek βουλιμία boulīmia, "ravenous hunger", a compound of βοῦς bous, "ox" and λιμός, līmos, "hunger".^[104] Literally, the scientific name of the disorder, bulimia nervosa, translates to "nervous ravenous hunger".

Before the 20th century

Although diagnostic criteria for bulimia nervosa did not appear until 1979, evidence suggests that binging and purging were popular in certain ancient cultures. The first documented account of behavior resembling bulimia nervosa was recorded in Xenophon's Anabasis around 370 B.C, in which Greek soldiers purged themselves in the mountains of Asia Minor. It is unclear whether this purging was preceded by binging.^[105] In ancient Egypt, physicians recommended purging once a month for three days to preserve health.^[106] This practice stemmed from the belief that human diseases were caused by the food itself. In ancient Rome, elite society members would vomit to "make room" in their stomachs for more food at all-day banquets.^[106] Emperors Claudius and Vitellius both were gluttonous and obese, and they often resorted to habitual purging.^[106]

Historical records also suggest that some saints who developed anorexia (as a result of a life of asceticism) may also have displayed bulimic behaviors.^[106] Saint Mary Magdalen de Pazzi (1566–1607) and Saint Veronica Giuliani (1660–1727) were both observed binge eating—giving in, as they believed, to the temptations of the devil.^[106] Saint Catherine of Siena (1347–1380) is known to have supplemented her strict abstinence from food by purging as reparation for her sins. Catherine died from starvation at age thirty-three.^[106]

While the psychological disorder "bulimia nervosa" is relatively new, the word "bulimia", signifying overeating, has been present for centuries.^[106] The Babylon Talmud referenced practices of "bulimia", yet scholars believe that this simply referred to overeating without the purging or the psychological implications bulimia nervosa.^[106] In fact, a search for evidence of bulimia nervosa from the 17th to late 19th century revealed that only a quarter of the overeating cases they examined actually vomited after the binges. There was no evidence of deliberate vomiting or an attempt to control weight.^[106]

20th century

Globally, bulimia was estimated to affect 3.6 million people in 2015.^[8] 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.^[3] The condition is less common in the developing world.^[4] Bulimia is about nine times more likely to occur in women than men.^[5] Among women, rates are highest in young adults.^[5] Bulimia was named and first described by the British psychiatrist Gerald Russell in 1979.^[107][108]

At the turn of the century, bulimia (overeating) was described as a clinical symptom, but rarely in the context of weight control.^[109] Purging, however, was seen in anorexic patients and attributed to gastric pain rather than another method of weight control.^[109]

In 1930, admissions of anorexia nervosa patients to the Mayo Clinic from 1917 to 1929 were compiled. Fifty-five to sixty-five percent of these patients were reported to be voluntarily vomiting to relieve weight anxiety.^[109] Records show that purging for weight control continued throughout the mid-1900s. Several case studies from this era reveal patients with the modern description of bulimia nervosa.^[109] In 1939, Rahman and Richardson reported that out of their six anorexic patients, one had periods of overeating, and another practiced self-induced vomiting.^[109] Wulff, in 1932, treated "Patient D", who would have periods of intense cravings for food and overeat for weeks, which often resulted in frequent vomiting.^[106] Patient D, who grew up with a tyrannical father, was repulsed by her weight and would fast for a few days, rapidly losing weight. Ellen West, a patient described by Ludwig Binswanger in 1958, was teased by friends for being fat and excessively took thyroid pills to lose weight, later using laxatives and vomiting.^[106] She reportedly consumed dozens of oranges and several pounds of tomatoes each day, yet would skip meals. After being admitted to a psychiatric facility for depression, Ellen ate ravenously yet lost weight, presumably due to self-induced vomiting.^[106] However, while these patients may have met modern criteria for bulimia nervosa, they cannot technically be diagnosed with the disorder, as it had not yet appeared in the Diagnostic and Statistical Manual of Mental Disorders at the time of their treatment.^[106]

An explanation for the increased instances of bulimic symptoms may be due to the 20th century's new ideals of thinness.^[109] The shame of being fat emerged in the 1940s when teasing remarks about weight became more common. The 1950s, however, truly introduced the trend of aspiration for thinness.^[109]

In 1979, Gerald Russell first published a description of bulimia nervosa, in which he studied patients with a "morbid fear of becoming fat" who overate and purged afterward.^[107] He specified treatment options and indicated the seriousness of the disease, which can be accompanied by depression and suicide.^[107] In 1980, bulimia nervosa first appeared in the DSM-III.^[107]

After its appearance in the DSM-III, there was a sudden rise in the documented incidents of bulimia nervosa.^[106] In the early 1980s, incidents of the disorder rose to about 40 in every 100,000 people.^[106] This decreased to about 27 in every 100,000 people at the end of the 1980s/early 1990s.^[106] However, bulimia nervosa's prevalence was still much higher than anorexia nervosa's, which at the time occurred in about 14 people per 100,000.^[106]

In 1991, Kendler et al. documented the cumulative risk for bulimia nervosa for those born before 1950, from 1950 to 1959, and after 1959.^[110] The risk for those born after 1959 is much higher than those in either of the other cohorts.^[110]