Bulimia nervosa (BN), also known simply as bulimia, is an eating disorder characterized by binge eating (eating large quantities of food in a short period of time, often feeling out of control) followed by compensatory behaviors, such as self-induced vomiting or fasting, to prevent weight gain.
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 commercializes or glamorizes dieting, and having parental figures who fixate on 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.
==Signs and symptoms==
Bulimia typically involves rapid and out-of-control eating, which is 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: Dehydration Electrolyte imbalance can lead to abnormal heart rhythms, cardiac arrest, and even death Oral trauma, lacerations to the lining of the mouth or throat due to forced throwing up movements. Russell's sign: calluses on knuckles and back of hands due to repeated trauma from incisors Swollen salivary glands (in the neck, under the jawline) Gastrointestinal problems, like constipation and acid reflux Constipation or diarrhea Hypotension Infertility and/or irregular menstrual cycles Weight Fluctuations
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 an extreme consciousness of one's weight Low self-esteem and/or self-harm 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 the 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, side effects such as 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. 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.
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 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. 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. 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.Carlson, N.R., et al. (2007). Psychology: The Science of Behaviour – 4th Canadian ed. Toronto, ON: Pearson Education Canada. 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.
Research has shown that there is a relationship between bulimia and narcissism. 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".
The medical journal Borderline Personality Disorder and Emotion Dysregulation notes that a "substantial rate of patients with bulimia nervosa" also have borderline personality disorder.
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."
Studies have shown a relationship between bulimia's effect on metabolic rate and caloric intake with thyroid dysfunction.
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.
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. 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 use 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, such as via acute tryptophan depletion, 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.
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.
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.Nolen-Hoeksema, Susan (2014). "Bulimia Nervosa" Abnormal Psychology. 6e. pg 344.
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. 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.
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.