What is Anorexia Nervosa?

What is Anorexia Nervosa?

Anorexia nervosa is a potentially life-threatening eating disorder characterised by a chronic restriction of energy intake leading to dangerously low body weight, in addition to severe body image distortions¹Fairburn CG, Shafran R, Cooper Z. A cognitive behavioural theory of anorexia nervosa. Behaviour Research and Therapy. 1999;37(1):1-13..

The criteria put forth by the latest Diagnostic and Statistical Manual of Mental Disorders are as follows:

• Persistent restriction of energy intake leading to significantly low body weight (in the context of what is minimally expected for age, sex, developmental trajectory, and physical health).
• Either an intense fear of gaining weight or of becoming fat, or persistent behaviour that interferes with weight gain (even though at a significantly low weight).
• Disturbance in the way one’s body weight or shape is experienced, undue influence of body shape and weight on self-evaluation, or persistent lack of recognition of the seriousness of the current low body weight.

When dealing with someone who may have anorexia nervosa, it is important to distinguish between two main “subtypes”

1. Binge-purge subtype: this occurs when a person, despite restricting their food intake, periodically and sometimes engages in binge eating or some form of compensatory behaviour, such as self-induced vomiting, laxative misuse, or diuretic misuse.
2. Restricting subtype: the restricting subtype is the more common anorexia nervosa subtype. This is where a person severely restricts their food via methods including maintaining very low calorie count, restricting the types of food eaten, or eating only one meal a day.

Anorexia Signs and Symptoms

There are a whole host of other signs and symptoms of anorexia nervosa that aren’t outlined in the DSM-V diagnostic criteria. Some of the more profound signs and symptoms are:

• Perfectionistic tendencies
• Rigid or black-and-white thinking styles
• Obsessive weight or shape checking
• Preoccupations around food, eating, weight, or shape
• Social withdrawal
• Absence of menstruation
• Frequently skipping meals or refusing to eat
• Denial of hunger or making excuses for not eating
• Lying about how much food has been eaten
• Refusal to eating in public settings

Read more on the symptoms of anorexia nervosa.

What about “Atypical” Anorexia Nervosa?

There are a number of people all over the world who exhibit many of the symptoms of anorexia nervosa but do not meet the specific diagnostic criteria for the disorder.

For example, a person can present with the restrictive behaviours and all of the features of anorexia nervosa without meeting the diagnostic criteria for low weight.

In most cases, these people meet criteria for what we call “atypical” anorexia nervosa.

People with atypical anorexia nervosa are still impaired, both physically, psychologically and socially.

In fact, there is evidence to suggest that there are no differences in levels of eating disorder and general psychiatric symptoms between typical and atypical cases, although atypical cases do tend to respond much better to psychological treatment²Silén Y, Raevuori A, Jüriloo E, et al. Typical Versus Atypical Anorexia Nervosa Among Adolescents: Clinical Characteristics and Implications for ICD‐11. European eating disorders review. 2015;23(5):345-351..

Causes of Anorexia Nervosa

As with all psychiatric disorders, we cannot pinpoint a single cause of anorexia nervosa. Rather, anorexia nervosa is caused by the complex interaction of various genetic and psychosocial factors³Striegel-Moore RH, Bulik CM. Risk factors for eating disorders. American Psychologist. 2007;62(3):181..

Genetic Factors

Genetics no doubt play an influential role in the development of anorexia nervosa.

For example, twin studies have reported heritability estimates to be as high as 76%, which means that only 24% of risk variation was accounted for by environmental factors⁴Klump KL, Miller K, Keel P, et al. Genetic and environmental influences on anorexia nervosa syndromes in a population–based twin sample. Psychological medicine. 2001;31(4):737-740..

Given the known involvement of both mood and appetite in anorexia nervosa onset, abnormalities of genes in the serotonergic system (e.g., serotonin receptor 2A, 2C) and the dopaminergic system (D3, D4 receptor) have been implicated as possible factors placing people at risk for the disorder⁵Klump KL, Gobrogge KL. A review and primer of molecular genetic studies of anorexia nervosa. International Journal of Eating Disorders. 2005;37(S1):S43-S48..

Further evidence for genes comes from studies showing that first-degree relatives of individuals with AN are 10 times more likely to develop the illness than relatives of unaffected individual⁶Lilenfeld LR, Kaye WH, Greeno CG, et al. A controlled family study of anorexia nervosa and bulimia nervosa: psychiatric disorders in first-degree relatives and effects of proband comorbidity. Archives of general psychiatry. 1998;55(7):603-610..

Other evidence shows the restricting behaviours associated with anorexia nervosa may stem from an imbalance between inhibitory and reward systems within the brain, which can lead to a shift in compulsive behaviour⁷Striegel-Moore RH, Bulik CM. Risk factors for eating disorders. American Psychologist. 2007;62(3):181..

Psychosocial Factors

• Obsessive-compulsive traits: OCD traits including cognitive rigidity, need for order, preoccupation with detail, and perfectionism all contribute to the risk of anorexia nervosa onset. These traits are said to influence body image distortions and restrictive eating patterns that characterise this disorder 7 PMID: 17147101.
• Cognitive deficits: cognitive deficits including weakness in set-shifting (i.e., ability to shift attention between tasks), central coherence, and learning are known risk factors of anorexia nervosa via their connection with the OCD-related traits mentioned above⁸Schmidt U, Treasure J. Anorexia nervosa: Valued and visible. A cognitive‐interpersonal maintenance model and its implications for research and practice. British Journal of Clinical Psychology. 2006;45(3):343-366..
• Thin-ideal internalisation: The extent to which a person prescribes to socially defined ideals of beauty (i.e., thin = beautiful), known as the “thin ideal internalisation” is a risk factor for anorexia nervosa. This thin-ideal internalisation places women at risk of the disorder because of its role in promoting body dissatisfaction and dieting behaviours⁹Stice E. Risk and maintenance factors for eating pathology: a meta-analytic review. Psychological Bulletin. 2002;128:825-848..
• Attachment difficulties: the bond you had with your parent in childhood may increase your risk of developing anorexia nervosa. An insecure attachment – a bond characterised by fear of rejection or abandonment – has been particularly associated with anorexia nervosa onset. This attachment form may place people at risk for developing personality traits (e.g., perfectionism, need for approval) that are characteristic of anorexia nervosa¹⁰Zachrisson HD, Kulbotten G. Attachment in anorexia nervosa: an exploration of associations with eating disorder psychopathology and psychiatric symptoms. Eating and Weight Disorders-Studies on Anorexia, Bulimia and Obesity. 2006;11(4):163-170..
• Negative self-evaluations: a general negative view of the self is also a risk factor for anorexia nervosa. Negative self-evaluations influence a person’s tendency to strive to achieve in domains related to shape, weight and eating. This can, therefore, encourage body image concerns and restrictive eating patterns¹¹Fairburn CG, Shafran R, Cooper Z. A cognitive behavioural theory of anorexia nervosa. Behaviour Research and Therapy. 1999;37(1):1-13..

Other important psychosocial risk factors of anorexia nervosa include:

• Stress
• Sexual abuse
• Social isolation
• Poor emotion regulation strategies
• General psychiatric comorbidities
• Parent-perceived childhood overweight

Consequences of Anorexia Nervosa

There are a whole host of negative medical, psychological, and social consequences of anorexia nervosa.

Medical Consequences

• Amenorrhea
• Infertility
• Osteoporosis
• Hypoglycemia
• Sudden death – arrhythmia
• Refeeding syndrome
• Bradycardia and hypotension
• Dry skin
• Dysphagia
• Respiratory failure
• Emphysema

Psychosocial Consequences

• Dysphoria
• Anxiety
• Social isolation
• Irritability
• Aggression
• Sexual promiscuity
• Substance use

Treatments for Anorexia Nervosa

There are a variety of treatments that are currently available for anorexia nervosa.

Various treatment approaches have produced large and relatively lasting improvements in weight gain and in the core symptoms of anorexia nervosa (e.g., body image distortions, restrictive eating etc.).

However, based on the available evidence, there is currently no “stand-out” treatment for anorexia nervosa. That is, studies comparing different treatment approaches for this disorder have consistently reported no differences in level of symptom improvement or weight gain, suggesting that available treatments for anorexia nervosa may be equally effective.

Some of the more widely used treatments for anorexia are:

Enhanced Cognitive Behaviour Therapy

CBT-E is manualized treatment that addresses the key factors that maintain anorexia nervosa. These maintaining factors are:

• Overvaluation of weight and shape
• Dietary restraint and dietary restriction
• Sudden changes in mood or affect

For underweight patients with anorexia nervosa, CBT-E typically lasts 40 weeks.

Patients can receive CBT in an inpatient, day patient, and outpatient setting – all forms of CBT-E are effective.

Evidence for CBT-E?

• Based on randomized controlled trial findings, CBT-E is equally effective to other common treatment approaches, such as the Maudsley based approach and to Specialist Supportive Clinical Management¹²Byrne S, Wade T, Hay P, et al. A randomised controlled trial of three psychological treatments for anorexia nervosa. Psychological Medicine. 2017:1-11..
• After CBT-E, 59% of patients have been shown to achieve a BMI of ≥ 18.5 and 48% have been shown to exhibit “normal” levels of eating disorder attitudes¹³Byrne S, Wade T, Hay P, et al. A randomised controlled trial of three psychological treatments for anorexia nervosa. Psychological Medicine. 2017:1-11..
• CBT-E can also effectively reduce comorbid symptoms of depression, anxiety and stress 12 months after treatment ends¹⁴Byrne S, Wade T, Hay P, et al. A randomised controlled trial of three psychological treatments for anorexia nervosa. Psychological Medicine. 2017:1-11..
• These positive effects of CBT-E occur for both adults and adolescents, making CBT-E a suitable treatment approach for all ages¹⁵Dalle Grave R, Calugi S, Doll HA, et al. Enhanced cognitive behaviour therapy for adolescents with anorexia nervosa: An alternative to family therapy? Behaviour Research and Therapy. 2013;51:R9-R12..

Maudsley Model Anorexia Nervosa Treatment for Adults (MANTRA)

MANTRA is a formulation-based treatment that is accompanied by a client workbook.

It is designed to be individually tailored to the clients presenting symptoms, personality traits, and neuropsychological profile.

MANTRA primarily focuses on targeting 4 core maintaining factors of anorexia nervosa:

1. A clients thinking style
2. A clients emotional/relational style
3. A loved ones’ responses to the person with anorexia nervosa
4. Core beliefs about the utility of anorexia nervosa in the person’s life.

Evidence for MANTRA?

• MANTRA was equally effective to specialist supportive clinical management and CBT-E in improving eating disorder features and weight gain in multiple randomized controlled trials.
• After MANTRA, 44% of patients have been shown to achieve a BMI of ≥ 18.5 and 51% have been shown to exhibit “normal” levels of eating disorder attitudes¹⁶Byrne S, Wade T, Hay P, et al. A randomised controlled trial of three psychological treatments for anorexia nervosa. Psychological Medicine. 2017:1-11..

Family Therapy

Family therapy is typically used for younger people with anorexia nervosa.

Family therapy includes the entire family within treatment sessions because it assumes that structural changes within the family system could have a positive impact on the eating disorder.

Treatment generally lasts around 12-15 sessions and can be broken up into three phases¹⁷Le Grange D, Hughes EK, Court A, et al. Randomized clinical trial of parent-focused treatment and family-based treatment for adolescent anorexia nervosa. Journal of the American Academy of Child & Adolescent Psychiatry. 2016;55(8):683-692..

1. Phase one focuses on supporting the parents and their efforts to assist their offspring in weight gain
2. Phase two aims to transition control over eating to the child.
3. Phase 3 is brief and introduces adolescent developmental tasks once the symptoms have largely subsided.

Evidence for family therapy?

• Recovery rates from family therapy have been shown to be as high as 43%¹⁸Le Grange D, Hughes EK, Court A, et al. Randomized clinical trial of parent-focused treatment and family-based treatment for adolescent anorexia nervosa. Journal of the American Academy of Child & Adolescent Psychiatry. 2016;55(8):683-692..
• Family therapy consistently results in weight gain and symptom improvement that are sustained one year after treatment ends¹⁹Lock J, Le Grange D, Agras WS, et al. Randomized clinical trial comparing family-based treatment with adolescent-focused individual therapy for adolescents with anorexia nervosa. Archives of general psychiatry. 2010;67(10):1025-1032..
• A shorter version of family therapy (10 sessions) appears to be equally effective to a longer form of family therapy (20 sessions).²⁰Lock J, Agras WS, Bryson S, et al. A Comparison of Short- and Long-Term Family Therapy for Adolescent Anorexia Nervosa. Journal of the American Academy of Child & Adolescent Psychiatry. 2005;44(7):632-639..