Bulimia nervosa

Bulimia nervosa is an eating disorder characterized by recurrent binge eating, followed by compensatory behaviors.^[1] The most common form is defensive vomiting, sometimes called purging; fasting, the use of laxatives, enemas, diuretics, and over exercising are also common.^[2]

The word bulimia derives from the Latin (būlīmia), which originally comes from the Greek βουλιμία (boulīmia; ravenous hunger), a compound of βους (bous), ox + λιμός (līmos), hunger.^[3] Bulimia nervosa was named and first described by the British psychiatrist Gerald Russell in 1979.^[4][5]

Signs and symptoms

These cycles often involve rapid and out-of-control eating, which may stop when the bulimic is interrupted by another person or the stomach hurts from overextension, 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,^[6] and may directly cause:

• Chronic gastric reflux after eating
• Dehydration and hypokalemia caused by frequent vomiting
• Electrolyte imbalance, which can lead to cardiac arrhythmia, cardiac arrest, and even death
• Esophagitis, or inflammation of the esophagus
• Oral trauma, in which repetitive insertion of fingers or other objects causes lacerations to the lining of the mouth or throat
• Gastroparesis or delayed emptying
• Constipation
• Infertility
• Enlarged glands in the neck, under the jaw line
• Peptic ulcers
• Calluses or scars on back of hands due to repeated trauma from incisors^[7][8]
• Constant weight fluctuations

The frequent contact between teeth and gastric acid, in particular, may cause:

• Severe dental caries
• Perimolysis, or the erosion of tooth enamel^[9]
• Swollen salivary glands^[9][10]

Related disorders

Bulimics are much more likely than non-bulimics to have an affective disorder, such as depression or general anxiety disorder: A 1985 Columbia University study on female bulimics at New York State Psychiatric Institute found 70% had suffered depression some time in their lives (as opposed to 25.8% for adult females in a control sample from the general population), rising to 88% for all affective disorders combined.^[11] Another study by the Royal Children's Hospital in Melbourne on a cohort of 2000 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 doubling of risk for substance dependency.^[12] Bulimia also has negative effects on the sufferer's dental health due to the acid passed through the mouth from frequent vomiting causing acid erosion, mainly on the posterior dental surface.

Diagnosis

The onset of bulimia nervosa is often during adolescence, between 13 and 20 years of age, and many cases have previously suffered obesity, with many sufferers relapsing in adulthood into episodic binging and purging even after initially successful treatment and remission.^[13]

Bulimia nervosa can be difficult to detect, compared to anorexia nervosa, because bulimics tend to be of average or slightly above or below average weight. Many bulimics may also engage in significantly disordered eating and exercising patterns without meeting the full diagnostic criteria for bulimia nervosa.^[14] The diagnostic criteria utilized by the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV TR) published by the American Psychiatric Association 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.^[15] 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.

There are two sub-types of bulimia nervosa:

• Purging type bulimics self-induce vomiting (usually by triggering the gag reflex or ingesting emetics such as syrup of ipecac) to rapidly remove food from the body before it can be digested, or use laxatives, diuretics, or enemas.
• Non-purging type bulimics (approximately 6%–8% of cases) exercise or fast excessively after a binge to offset the caloric intake after eating. Purging-type bulimics may also exercise or fast, but as a secondary form of weight control.^[16]

Management

Pharmacological

Some researchers have hypothesized a relationship to mood disorders and clinical trials have been conducted with tricyclic antidepressants,^[17] MAO inhibitors, mianserin, fluoxetine,^[18] lithium carbonate, nomifensine, trazodone, and bupropion. Research groups who have seen a relationship to seizure disorders have attempted treatment with phenytoin, carbamazepine, and valproic acid. Opiate antagonists naloxone and naltrexone, which block cravings for gambling, have also been used.^[19]

There has also been some research characterizing bulimia nervosa as an addiction disorder, and limited clinical use of topiramate, which blocks cravings for opiates, cocaine, alcohol and food.^[20] Researchers have also report positive outcomes when bulimics are treated in an addiction-disorders inpatient unit.^[21]

Psychotherapy

There are several empirically-supported psychosocial treatments for bulimia nervosa. Cognitive behavioral therapy (CBT), which involves teaching clients to challenge automatic thoughts and engage in behavioral experiments (e.g., in session eating of "forbidden foods") has demonstrated efficacy both with and without concurrent antidepressant medication.^[22][23] Researchers have also reported some positive outcomes for interpersonal psychotherapy and dialectical behavior therapy.^[24][25]

Maudsley Family Therapy or "Family Based Treatment" (FBT), developed at the Maudsley Hospital in London for the treatment of anorexia nervosa (AN) has been shown to have positive results for the treatment of bulimia nervosa. FBT has been shown through empirical research to be the most efficacious treatment of AN for patients under the age of eighteen and within three years of onset of illness. The studies to date using FBT to treat BN have been promising.^[26]

Some researchers have also claimed positive outcomes in hypnotherapy treatment.^[27][28][29]

Other

Brain-derived neurotrophic factor (BDNF) is under investigation as a possible cause.^[30][31]

Epidemiology

There are little data on the prevalence of bulimia nervosa in-the-large, on general populations. Most studies conducted thus far have been on convenience samples from hospital patients, high school or university students. These have yielded a wide range of results: between 0.1% and 1.4% of males, and between 0.3% and 9.4% of females.^[32] Studies on time trends in the prevalence of bulimia nervosa have also yielded inconsistent results.^[33]

There are higher rates of eating disorders in groups involved in activities which idealize a slim physique, such as dance,^[37] gymnastics, modeling, cheerleading, running, acting, rowing and figure skating. Bulimia is more prevalent among Caucasians.^[44] Exposure to mass media also appears to have an effect: a survey of 15–18 year-old high schoolgirls 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.^[45]

Notes