2.5.1 Anorexia Nervosa and Bulimia Nervosa

Anorexia Nervosa and Bulimia Nervosa

Anorexia Nervosa and Bulimia Nervosa are common eating disorders that affect a significant portion of the adult population. These disorders are characterized by severe disturbances in eating behaviour, such as restrictive eating, binge eating, and purging. This educational piece aims to provide a comprehensive overview of the prevalence, aetiology, gender, onset, presentation, treatment, and outcome of these disorders in adulthood.

Prevalence and Incidence:

Eating disorders are more common in women than men, with a female-to-male ratio of around 10:1. According to recent estimates, the prevalence of anorexia nervosa and bulimia nervosa in adults is around 0.4% and 1-1.5%, respectively (Hudson, Hiripi, Pope Jr, & Kessler, 2007). However, these estimates may be conservative, and the actual prevalence of these disorders could be higher due to underreporting and misdiagnosis.

Aetiology:

The aetiology of anorexia nervosa and bulimia nervosa is complex and multifactorial. Biological, psychological, and environmental factors all play a role in the development and maintenance of these disorders. Genetic predisposition, altered brain chemistry, and hormonal imbalances are thought to contribute to the development of these disorders. Psychological factors such as low self-esteem, perfectionism, and anxiety may also increase the risk of developing these disorders. Environmental factors, such as cultural pressures to conform to ideal body images, can also contribute to the development of these disorders.

Gender:

As mentioned earlier, eating disorders are more common in women than men. The reasons for this gender difference are not entirely clear, but it may be due to a combination of genetic, hormonal, and environmental factors. Women may be more susceptible to cultural pressures to conform to ideal body images, which can contribute to the development of these disorders.

Onset and Presentation:

Anorexia nervosa and bulimia nervosa typically onset in adolescence or early adulthood. Individuals with anorexia nervosa tend to be excessively preoccupied with their weight and body shape, leading to restrictive eating behaviour and severe weight loss. They may also engage in compulsive exercise and other purging behaviours. Individuals with bulimia nervosa, on the other hand, tend to engage in binge eating followed by purging behaviours such as self-induced vomiting, laxative abuse, or excessive exercise. Both disorders can have serious medical consequences, including electrolyte imbalances, dehydration, and gastrointestinal problems.

Treatment:

The treatment of anorexia nervosa and bulimia nervosa typically involves a combination of medical, psychological, and nutritional interventions. Inpatient treatment may be necessary for those with severe medical complications, while outpatient treatment may be appropriate for those with less severe symptoms. Nutritional counselling and weight restoration are important components of treatment for anorexia nervosa, while cognitive-behavioural therapy (CBT) is a common form of psychological treatment for both disorders. Family-based therapy may also be effective, particularly for adolescents with anorexia nervosa. In some cases, medication may be used to treat comorbid psychiatric conditions, such as depression or anxiety.

Outcome:

The long-term outcome of anorexia nervosa and bulimia nervosa is highly variable and depends on several factors, including the severity and duration of the illness, the presence of comorbid psychiatric conditions, and the effectiveness of treatment. Some individuals may recover completely from these disorders, while others may struggle with persistent symptoms and relapses.

The majority of patients with AN and BN can recover fully or partially, although the treatment may be prolonged and relapses are common. It is important to address the physical and psychological aspects of these disorders to achieve successful outcomes. Early intervention and diagnosis are key in improving prognosis and preventing long-term complications.

Comparison of Anorexia Nervosa and Bulimia Nervosa

Characteristics	Anorexia Nervosa	Bulimia Nervosa
Prevalence/incidence	0.3-0.9%	1-1.5%
Aetiology	Genetic Environmental Psychological	Genetic Environmental Psychological
Gender	More common in females	More common in females
Age of onset	Adolescence	Late adolescence
Presentation	Severe weight loss Body image distortion Fear of gaining weight	Recurrent episodes of binger eating followed by compensatory behaviours such as purging
Treatment	Nutritional rehabilitation Psychotherapy Pharmacotherapy Support	Nutritional rehabilitation Psychotherapy Pharmacotherapy Support
Outcome	Early diagnosis improves recovery	Early diagnosis improves recovery

Reference:

1. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Arlington, VA: Author.
2. Arcelus, J., Mitchell, A. J., Wales, J., & Nielsen, S. (2011). Mortality rates in patients with anorexia nervosa and other eating disorders: A meta-analysis of 36 studies. Archives of General Psychiatry, 68(7), 724-731.
3. Crow, S. J., & Peterson, C. B. (2020). The economic and social burden of eating disorders. Current Psychiatry Reports, 22(6), 1-8.
4. National Institute for Health and Care Excellence. (2017). Eating disorders: recognition and treatment (NICE guideline NG69). Retrieved from https://www.nice.org.uk/guidance/ng69
5. Treasure, J., & Zipfel, S. (2014). Anorexia nervosa. The Lancet, 383(9912), 1052-1067.