Bulimia nervosa

 

Bulimia nervosa

Bulimia nervosa, also known as simply bulimia, is an eating disorder characterized by binge eating followed by purging, and excessive concern with body shape and weight. The aim of this activity is to expel the body of calories eaten from the binging phase of the process. 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, breakdown of the teeth and effects on metabolic rate and caloric intake which cause thyroid dysfunction. Bulimia is frequently associated with other mental disorders such as depression, anxiety, borderline personality disorder, bipolar disorder and problems with drugs or alcohol. There is also a higher risk of suicide and self-harm. Clinical studies show a relationship between bulimia and vulnerable narcissism as caused by childhood 'parental invalidation' leading to a later need for social validation.

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 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 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.

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.

Causes

Biological

As with anorexia nervosa, there is evidence of genetic predispositions contributing to the onset of this eating disorder.[38] 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.[42] 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.