Eating Disorders in Adults

1. Overview

Eating disorders are serious, potentially life-threatening mental health conditions characterised by persistent disturbances in eating behaviours, distorted cognitions about body weight and shape, and significant medical and psychological complications. The principal diagnoses include Anorexia Nervosa (AN), Bulimia Nervosa (BN), and Binge Eating Disorder (BED), alongside Other Specified Feeding or Eating Disorder (OSFED) and Avoidant/Restrictive Food Intake Disorder (ARFID).

Anorexia nervosa carries the highest mortality rate of any psychiatric disorder, with standardised mortality ratios ranging from 5.9 to 10.5 compared to the general population. [1,2] Mortality results primarily from medical complications (cardiac arrhythmias, electrolyte disturbances, infections) and suicide. The chronic nature of these conditions, combined with high rates of relapse and medical comorbidity, makes eating disorders a critical public health concern requiring early recognition and multidisciplinary intervention.

The medical complications are extensive and affect virtually every organ system. Refeeding syndrome, occurring during nutritional rehabilitation in severely malnourished patients, represents one of the most dangerous complications, with rapid shifts in electrolytes (particularly hypophosphataemia) leading to cardiac arrhythmias, respiratory failure, and death if not carefully managed. [3,4] Other serious medical sequelae include cardiovascular complications (bradycardia, hypotension, QTc prolongation), endocrine dysfunction (hypothalamic amenorrhoea, osteoporosis), gastrointestinal disorders (delayed gastric emptying, constipation), and haematological abnormalities.

Management requires integrated care combining evidence-based psychological therapies (CBT-ED, MANTRA, family-based therapy), nutritional rehabilitation, medical monitoring, and treatment of comorbid psychiatric conditions. Despite advances in understanding and treatment, recovery rates remain suboptimal, with approximately 50% of patients with anorexia nervosa achieving full recovery, 30% partial recovery, and 20% developing chronic illness or dying from complications. [5]

Key Clinical Messages

• Early intervention improves outcomes: Duration of untreated illness is a negative prognostic factor
• Medical stabilisation takes priority: Cardiac and metabolic complications require immediate attention
• Specialist eating disorder services: Evidence supports multidisciplinary teams over generic mental health services
• Avoid premature weight restoration: Refeeding syndrome risk necessitates careful nutritional rehabilitation protocols
• Address comorbidity: Depression, anxiety, OCD, and personality disorders commonly co-occur

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2. Epidemiology

Prevalence and Incidence

Eating disorders affect an estimated 8.4% of women and 2.2% of men at some point in their lifetime. [6] The prevalence varies significantly by disorder type:

Binge eating disorder is the most common eating disorder in population studies, though it remains underdiagnosed and undertreated. [7]

Age of Onset

• Peak onset: 14-19 years for anorexia nervosa and bulimia nervosa
• Bimodal distribution with secondary peak in mid-20s
• Increasing recognition of eating disorders in adults > 40 years (late-onset cases)
• Binge eating disorder has later average onset (early to mid-20s)

Demographic Trends

Increasing incidence in previously underrepresented groups:

• Males: Prevalence increasing, particularly for binge eating disorder and muscle dysmorphia presentations
• Ethnic minorities: Previously thought to be predominantly a Western/white disorder, but evidence shows comparable rates across ethnic groups when culturally adapted screening tools are used
• LGBTQ+ populations: Higher prevalence of eating disorders, particularly in transgender individuals and sexual minority men
• Older adults: Eating disorders can persist into later life or develop de novo in older adults

Risk Factors

Biological Factors

• Genetics: Heritability estimates 50-80% for anorexia nervosa; family history increases risk 7-12 fold [8]
• Neurobiology: Altered serotonin, dopamine, and opioid system function
• Puberty: Hormonal changes and body composition shifts
• Previous obesity: Risk factor for bulimia nervosa and binge eating disorder

Psychological Factors

• Personality traits: Perfectionism, obsessive-compulsive traits, harm avoidance, negative emotionality
• Low self-esteem: Poor self-worth and self-efficacy
• Body image disturbance: Internalisation of thin ideal
• Comorbid psychiatric disorders: Depression (50-75%), anxiety disorders (60%), OCD (25-35%)

Social and Environmental Factors

• Dieting: Most consistent precipitant; weight-loss dieting increases risk 18-fold
• Cultural pressures: Sociocultural emphasis on thinness, diet culture, social media exposure
• Trauma and abuse: Childhood sexual abuse associated particularly with bulimia nervosa (30-50% report abuse history)
• Life transitions: Moving away from home, relationship breakdown, bereavement
• Specific occupations/activities: Ballet, gymnastics, modelling, distance running, wrestling, jockeying

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3. Aetiology and Pathophysiology

Biopsychosocial Model

Eating disorders arise from complex interactions between genetic vulnerability, neurobiological factors, psychological traits, and environmental triggers. No single cause is sufficient; rather, multiple risk factors interact to precipitate and maintain illness.

Neurobiological Mechanisms

Neurotransmitter Systems

Serotonin (5-HT) Dysfunction:

• Reduced 5-HT activity associated with impulsivity, mood disturbance, and binge eating
• Increased 5-HT activity (in recovered AN) associated with anxiety, obsessionality, and behavioural inhibition
• Dietary restriction reduces tryptophan availability, leading to reduced 5-HT synthesis
• May explain temporary anxiety reduction seen with food restriction in AN

Dopamine Alterations:

• Altered reward processing in ventral striatum affects food motivation and pleasure
• Reduced dopamine response to food in AN (foods lose rewarding properties)
• Enhanced dopamine response to weight loss and exercise in AN (becomes self-reinforcing)

Endogenous Opioids:

• Starvation increases β-endorphin levels, potentially creating euphoric "starvation high"
• May contribute to difficulty in weight restoration and relapse risk

Neuroendocrine Changes

Hypothalamic-Pituitary-Gonadal (HPG) Axis:

• Functional hypothalamic amenorrhoea results from energy deficit and low leptin
• Hypogonadotropic hypogonadism: low LH, FSH, oestradiol
• Loss of pulsatile GnRH secretion
• Amenorrhoea contributes to osteoporosis risk

Hypothalamic-Pituitary-Adrenal (HPA) Axis:

• Hypercortisolaemia common in AN (cortisol resistance)
• Contributes to bone loss, muscle catabolism, mood disturbance

Thyroid Function:

• "Sick euthyroid syndrome": low T3, normal/low T4, normal TSH
• Represents adaptive response to starvation; thyroid supplementation not indicated

Growth Hormone and IGF-1:

• GH elevated, IGF-1 reduced (GH resistance)
• Contributes to impaired bone formation

Psychological Mechanisms

Cognitive Biases:

• Attentional bias toward body shape and food-related cues
• Interpretation bias: neutral comments perceived as fat-related criticism
• Memory bias: selective recall of perceived failures and weight-related events

Core Maintaining Factors (Cognitive-Behavioural Model):

1. Over-evaluation of weight and shape: Self-worth judged predominantly through control of eating, weight, and shape
2. Dietary restraint: Rigid food rules and caloric restriction
3. Binge eating: Breakdown of dietary restraint leads to loss of control eating
4. Compensatory behaviours: Purging, laxatives, excessive exercise to control weight
5. Starvation effects: Preoccupation with food, emotional lability, cognitive rigidity perpetuate disorder

Emotion Regulation Deficits:

• Difficulty identifying and expressing emotions (alexithymia)
• Use of eating disorder behaviours to manage negative affect
• Restriction reduces emotional awareness; binge eating temporarily reduces negative emotions

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4. Clinical Presentation

Anorexia Nervosa (AN)

DSM-5 Diagnostic Criteria

A. Restriction of Energy Intake

• Persistent restriction relative to requirements leading to significantly low body weight
• "Significantly low weight": weight less than minimally normal (adults) or expected (children/adolescents)
• Guideline: BMI less than 18.5 kg/m² in adults; typically less than 17.5 kg/m² in clinical practice

B. Intense Fear of Weight Gain

• Intense fear of gaining weight or becoming fat
• OR persistent behaviour that interferes with weight gain, even at significantly low weight

C. Disturbance in Body Experience

• Disturbance in the way body weight or shape is experienced
• Undue influence of weight/shape on self-evaluation
• OR persistent lack of recognition of the seriousness of current low body weight

Severity Specifiers (BMI for adults)

• Mild: BMI ≥17 kg/m²
• Moderate: BMI 16-16.99 kg/m²
• Severe: BMI 15-15.99 kg/m²
• Extreme: BMI less than 15 kg/m²

Subtypes

• Restricting type: Weight loss through dieting, fasting, excessive exercise; no regular binge eating or purging
• Binge-eating/purging type: Regular binge eating and/or purging behaviours (self-induced vomiting, laxative/diuretic misuse)

Cardinal Features

Behavioural:

• Extreme dietary restriction (severe caloric limitation, elimination of food groups)
• Ritualised eating patterns (cutting food into tiny pieces, eating very slowly, hiding food)
• Excessive exercise (compulsive, continues despite fatigue or injury)
• Social withdrawal (avoidance of social eating situations)
• Body checking behaviours (repeated weighing, mirror checking, body measuring)
• Wearing baggy clothes to hide body shape

Psychological:

• Intense fear and anxiety around food, eating, weight gain
• Distorted body image (feeling fat despite emaciation)
• Poor insight into illness severity
• Cognitive rigidity (black-and-white thinking, rule-bound)
• Preoccupation with food, calories, recipes (despite not eating)
• Depression, irritability, emotional lability

Physical Signs and Symptoms

General Appearance:

• Emaciation, muscle wasting
• Hypothermia (cold intolerance, poor peripheral perfusion)
• Lanugo hair (fine, downy hair on face, back, arms)
• Dry skin, brittle hair and nails
• Hair loss (telogen effluvium)
• Cyanosis of extremities, cold hands and feet
• Oedema (particularly with refeeding or when purging stops)

Cardiovascular:

• Bradycardia (less than 60 bpm common; less than 40 bpm indicates severe risk)
• Hypotension (less than 90/60 mmHg)
• Orthostatic hypotension (drop > 20 mmHg systolic or pulse rise > 20 bpm on standing)
• Mitral valve prolapse
• Pericardial effusion (in severe cases)
• Prolonged QTc interval on ECG (risk of sudden cardiac death)

Gastrointestinal:

• Constipation (delayed gastric emptying, reduced gut motility)
• Bloating and early satiety
• Abdominal pain

Reproductive:

• Amenorrhoea (loss of menstrual periods for ≥3 months)
• Loss of libido
• Infertility

Musculoskeletal:

• Muscle weakness, reduced muscle mass
• Osteopenia and osteoporosis (fracture risk increased)
• Pathological fractures (stress fractures common)

Neurological:

• Impaired concentration and memory
• Seizures (if severe hypoglycaemia or electrolyte disturbance)
• Peripheral neuropathy (thiamine deficiency)

Bulimia Nervosa (BN)

DSM-5 Diagnostic Criteria

A. Recurrent Binge Eating Episodes

Characterised by BOTH:

1. Eating, in a discrete period (e.g., 2 hours), an amount of food definitively larger than most people would eat in similar circumstances
2. Sense of lack of control over eating during the episode

B. Recurrent Inappropriate Compensatory Behaviours

• Self-induced vomiting
• Misuse of laxatives, diuretics, enemas, or other medications
• Fasting
• Excessive exercise

C. Frequency: Binge eating and compensatory behaviours occur, on average, at least once weekly for 3 months

D. Self-Evaluation Unduly Influenced by Body Shape and Weight

E. Does Not Occur Exclusively During Episodes of Anorexia Nervosa

Severity Specifiers

• Mild: 1-3 episodes/week
• Moderate: 4-7 episodes/week
• Severe: 8-13 episodes/week
• Extreme: ≥14 episodes/week

Cardinal Features

Behavioural:

• Recurrent episodes of binge eating (often in secret)
• Eating until uncomfortably full
• Eating large amounts when not physically hungry
• Eating much more rapidly than normal
• Purging behaviours after eating (vomiting, laxative abuse)
• Hoarding or stealing food
• Frequent trips to bathroom after meals (to vomit)

Psychological:

• Feeling disgusted, depressed, or guilty after binge eating
• Low self-esteem and shame
• Preoccupation with weight and shape
• Impulsivity in other areas (substance use, self-harm, risky sexual behaviour)

Physical Signs (Purging Type)

Orofacial:

• Russell's sign: Calluses, scarring, or abrasions on dorsum of hand (from inducing vomiting)
• Dental erosion: Loss of enamel, particularly on lingual surfaces of front teeth (from gastric acid exposure)
• Parotid/salivary gland enlargement ("chipmunk cheeks") - bilateral parotid hypertrophy
• Palatal trauma, pharyngeal erythema

Other Physical Findings:

• Usually normal weight or overweight (BMI 18.5-30 kg/m²)
• Facial puffiness
• Knuckle scars
• Subconjunctival haemorrhages (from vomiting-induced increased venous pressure)

Complications from Purging:

• Electrolyte abnormalities (hypokalaemia, hypochloraemia, metabolic alkalosis)
• Oesophageal tears (Mallory-Weiss), oesophagitis
• Gastric dilatation (rare but life-threatening)
• Cardiac arrhythmias (from hypokalaemia)
• Chronic constipation (laxative abuse)

Binge Eating Disorder (BED)

DSM-5 Diagnostic Criteria

A. Recurrent Binge Eating Episodes

Characterised by BOTH:

1. Eating, in discrete period, amount larger than most people would eat
2. Sense of lack of control

B. Binge Eating Episodes Associated with ≥3 of:

• Eating much more rapidly than normal
• Eating until feeling uncomfortably full
• Eating large amounts when not physically hungry
• Eating alone due to embarrassment
• Feeling disgusted, depressed, or guilty afterward

C. Marked Distress Regarding Binge Eating

D. Frequency: At least once weekly for 3 months

E. NO Regular Compensatory Behaviours (distinguishes from BN)

Severity Specifiers

• Mild: 1-3 episodes/week
• Moderate: 4-7 episodes/week
• Severe: 8-13 episodes/week
• Extreme: ≥14 episodes/week

Cardinal Features

Presentation:

• Often overweight or obese (BMI > 30 kg/m² in 60-70% of cases)
• Distress about binge eating (unlike obesity without BED)
• Associated metabolic complications (type 2 diabetes, hypertension, dyslipidaemia)
• Significant functional impairment and reduced quality of life
• High rates of comorbid depression and anxiety

Other Specified Feeding or Eating Disorder (OSFED)

Clinically significant eating disorders that do not meet full criteria for AN, BN, or BED.

Examples:

• Atypical anorexia nervosa: All AN criteria met except weight remains in/above normal range despite significant weight loss
• Bulimia nervosa (low frequency): All BN criteria except frequency less than 1/week or duration less than 3 months
• Binge eating disorder (low frequency): All BED criteria except frequency less than 1/week or duration less than 3 months
• Purging disorder: Recurrent purging without binge eating
• Night eating syndrome: Recurrent episodes of night eating (after evening meal or upon awakening)

Clinical Significance: OSFED is NOT a mild eating disorder; morbidity and mortality can be equivalent to full-threshold disorders. [9]

Avoidant/Restrictive Food Intake Disorder (ARFID)

Key Features:

• Avoidance or restriction of food intake leading to nutritional/energy deficiency
• NOT driven by weight/shape concerns (distinguishes from AN)
• NOT due to lack of available food or culturally sanctioned practice

Presentations:

1. Sensory-based avoidance: Sensitivity to appearance, colour, smell, texture, temperature, taste
2. Fear of aversive consequences: Choking, vomiting, abdominal pain
3. Lack of interest in food: Low appetite, forgetting to eat

Consequences:

• Significant weight loss or failure to gain expected weight
• Nutritional deficiency requiring supplementation
• Dependence on enteral feeding or oral supplements
• Psychosocial impairment

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5. Medical Complications

Eating disorders affect virtually every organ system, with severity correlating with degree of malnutrition, rapidity of weight loss, and purging behaviours.

Cardiovascular Complications

Most Common Cause of Death in Anorexia Nervosa

Refeeding-Related Cardiac Complications:

• Congestive heart failure (rapid fluid shifts)
• Arrhythmias from electrolyte shifts
• Increased risk if rapid caloric increase

Electrolyte and Metabolic Disturbances

Common in Purging Behaviours (Vomiting, Laxatives, Diuretics):

Metabolic Alkalosis (vomiting): Hypochloraemic, hypokalaemic metabolic alkalosis Metabolic Acidosis (laxative abuse): High anion gap or normal anion gap (bicarbonate loss)

Refeeding Syndrome

Definition: Potentially fatal metabolic disturbances occurring during nutritional rehabilitation of severely malnourished patients, characterised by severe shifts in fluids and electrolytes. [3,4]

Pathophysiology:

1. Prolonged starvation → cellular adaptation to fat/ketone metabolism
2. Reintroduction of carbohydrates → insulin secretion increases
3. Insulin drives glucose, phosphate, potassium, magnesium into cells
4. Severe hypophosphataemia (most critical), hypokalaemia, hypomagnesaemia
5. Thiamine depletion (required for carbohydrate metabolism)

Risk Factors (MARSIPAN Criteria for High Risk):

• BMI less than 16 kg/m² OR
• Unintentional weight loss > 15% in past 3-6 months OR
• Little/no nutritional intake for > 10 days OR
• Low baseline levels of K+, PO4²⁻, or Mg²⁺

Clinical Features:

• Onset: typically 2-5 days after starting refeeding
• Cardiovascular: Arrhythmias, heart failure, hypotension, sudden cardiac death
• Respiratory: Respiratory failure (diaphragmatic weakness)
• Neurological: Confusion, seizures, delirium, Wernicke's encephalopathy
• Haematological: Haemolytic anaemia, thrombocytopenia
• Neuromuscular: Muscle weakness, rhabdomyolysis, paraesthesias

Prevention:

• "Start Low, Go Slow" nutritional rehabilitation
• Initial caloric intake: 5-10 kcal/kg/day (very high risk); 10-20 kcal/kg/day (moderate risk)
• Gradual increase: 200-300 kcal every 2-3 days
• Thiamine supplementation: 200-300 mg/day oral (or IV if high risk) BEFORE refeeding
• Electrolyte monitoring: Daily PO4, K+, Mg²⁺ for first week
• Prophylactic supplementation: Phosphate, potassium, magnesium as needed
• Fluid restriction initially (1-1.5 L/day) to prevent fluid overload

Gastrointestinal Complications

Endocrine Complications

Reproductive:

• Hypothalamic amenorrhoea (functional hypogonadotropic hypogonadism)
• Low oestrogen → bone loss
• Low testosterone (males) → reduced libido, bone loss
• Infertility, pregnancy complications

Thyroid:

• Sick euthyroid syndrome (low T3, normal/low T4, normal TSH)
• Adaptation to starvation; thyroid replacement not indicated

Bone:

• Osteopenia and osteoporosis: Prevalence 40-90% in AN
• Mechanisms: Low oestrogen, hypercortisolaemia, low IGF-1, nutritional deficiency
• Fracture risk increased 2-7 fold [10]
• Bone density loss may be partially irreversible, especially if illness in adolescence (peak bone mass not achieved)

Glucose:

• Hypoglycaemia (AN, particularly with exercise)
• Insulin resistance (refeeding)

Haematological Complications

• Anaemia: Normocytic normochromic (chronic disease); iron, B12, folate deficiency
• Leucopenia: Mild neutropenia common in AN; rarely clinically significant
• Thrombocytopenia: Mild; rarely causes bleeding
• Mechanism: Bone marrow hypoplasia/gelatinous transformation (starvation)
• Generally benign and resolves with nutritional rehabilitation

Renal Complications

• Acute kidney injury: Dehydration, hypotension, rhabdomyolysis
• Chronic kidney disease: Laxative/diuretic abuse, chronic dehydration, hypokalaemic nephropathy
• Nephrolithiasis: Dehydration
• Oedema: Refeeding, laxative/diuretic cessation (rebound oedema)

Neurological Complications

• Cerebral atrophy: Grey and white matter volume loss; reversible with weight restoration [11]
• Cognitive impairment: Concentration, memory, decision-making
• Peripheral neuropathy: Thiamine, B12 deficiency
• Seizures: Hypoglycaemia, hyponatraemia, hypophosphataemia
• Wernicke's encephalopathy: Thiamine deficiency (during refeeding if not supplemented)

Dermatological Manifestations

• Lanugo hair (AN)
• Dry, scaly skin, xerosis
• Hair loss, brittle nails
• Carotenaemia (yellow-orange skin, palms/soles; from excessive carrot/vegetable intake)
• Acrocyanosis (cold, blue extremities)
• Russell's sign (BN)

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6. Investigations

Initial Assessment

Aims:

1. Confirm diagnosis and subtype
2. Assess medical stability and identify complications
3. Evaluate severity and need for admission
4. Screen for comorbid psychiatric conditions
5. Baseline for monitoring during treatment

Clinical Assessment

History:

• Detailed eating, weight, and exercise history
• Binge/purge behaviours (frequency, methods)
• Psychiatric history (mood, anxiety, self-harm, substance use)
• Psychosexual history (amenorrhoea onset)
• Medical review of systems (focus on cardiac, GI, neurological symptoms)
• Medication and supplement use
• Family history of eating disorders, psychiatric illness, obesity

Physical Examination:

Orthostatic Vital Signs:

• Measure BP and HR supine, then after 3 minutes standing
• Positive if: Systolic BP drop ≥20 mmHg OR HR increase ≥20 bpm
• Indicates volume depletion, autonomic dysfunction; high-risk feature

Laboratory Investigations

First-Line Blood Tests

Additional Tests (If Indicated)

Urinalysis

• Specific gravity (assess hydration)
• Glucose, ketones (if diabetic or suspected ketoacidosis)

Electrocardiogram (ECG)

Indications: ALL patients with anorexia nervosa or significant purging behaviours

Common Findings:

QTc Calculation: QTc = QT / √RR interval

• Normal: less than 440ms (males), less than 460ms (females)
• Prolonged: > 450ms (males), > 470ms (females)
• High risk: > 500ms

Bone Density Assessment (DEXA Scan)

Indications:

• Anorexia nervosa duration > 12 months
• Amenorrhoea > 6-12 months
• BMI less than 15 kg/m² for extended period
• History of fractures

Interpretation:

• T-score (comparison to young adult mean): Used in postmenopausal women
• Z-score (comparison to age-matched peers): Used in premenopausal women, men less than 50
• Z-score ≤-2.0 = "below expected range for age"

Management: Weight restoration is primary treatment; bisphosphonates not recommended in premenopausal women (teratogenic risk, unclear benefit)

Psychological Assessment

Structured Diagnostic Interviews

• SCID (Structured Clinical Interview for DSM-5)
• EDE (Eating Disorder Examination) - gold standard, semi-structured interview

Screening Tools

SCOFF Questionnaire (High sensitivity/specificity for EDs): [12]

1. Do you make yourself Sick because you feel uncomfortably full?
2. Do you worry you have lost Control over how much you eat?
3. Have you recently lost more than One stone (14 lbs/6.35 kg) in 3 months?
4. Do you believe yourself to be Fat when others say you are thin?
5. Would you say Food dominates your life?

Scoring: ≥2 "yes" answers → high likelihood of eating disorder (sensitivity 84-100%, specificity 73-90%)

EAT-26 (Eating Attitudes Test): 26-item questionnaire; score ≥20 suggests eating disorder EDI-3 (Eating Disorder Inventory): 91-item multidimensional assessment

Comorbidity Screening

• PHQ-9 (depression)
• GAD-7 (anxiety)
• OCI-R (obsessive-compulsive symptoms)
• AUDIT (alcohol use)

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7. Differential Diagnosis

Medical Conditions Causing Weight Loss

Key Differentiator: Eating disorders characterised by fear of weight gain and body image disturbance, absent in medical causes of weight loss.

Psychiatric Differential Diagnoses

Comorbidity is Common: 50-75% of individuals with eating disorders have comorbid mood/anxiety disorders. Careful assessment needed to distinguish primary from secondary diagnoses.

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8. Management

Management of eating disorders requires a multidisciplinary approach involving psychiatry, dietetics, medicine, and nursing. Treatment setting (outpatient, day programme, inpatient) depends on medical and psychiatric risk.

General Principles

1. Engagement and motivation: Build therapeutic alliance; acknowledge ambivalence about change
2. Medical stabilisation: Identify and treat life-threatening complications
3. Nutritional rehabilitation: Restore healthy weight and eating patterns
4. Psychological therapy: Address maintaining factors (cognitive, behavioural, emotional)
5. Treat comorbidity: Depression, anxiety, OCD, trauma
6. Family involvement: Particularly important for adolescents; supportive for adults
7. Relapse prevention: Long-term monitoring, early intervention for setbacks

Assessment of Medical Risk (MARSIPAN Guidelines)

MARSIPAN (Management of Really Sick Patients with Anorexia Nervosa) provides criteria for medical emergency admission. [13]

High-Risk Criteria (Require Urgent Medical Assessment ± Admission)

Moderate Risk: BMI 13-15, HR 40-50, electrolyte abnormalities (mild), medical complications requiring outpatient monitoring

Low Risk: BMI > 15, medically stable, engaging with treatment

Treatment Settings

Outpatient Treatment

Indications: Medically stable, motivated, adequate support

• Most patients treated as outpatients
• Regular appointments with psychiatrist/psychologist, dietitian
• Medical monitoring: Weekly initially (weight, vitals, bloods as needed)

Day Programme/Partial Hospitalisation

Indications: Moderate risk, failed outpatient treatment, need structured support

• Structured meals with supervision
• Intensive therapy (individual, group, family)
• Medical monitoring
• Return home evenings

Inpatient Admission

Indications:

1. Medical: MARSIPAN high-risk criteria
2. Psychiatric: Acute suicidal risk, severe comorbid disorder
3. Social: Lack of support, failed less intensive treatment

Settings:

• Medical/paediatric ward (if primarily medical instability)
• Specialist eating disorder unit (if available; best outcomes)
• Psychiatric ward (if primarily psychiatric risk)

Duration: Typically weeks to months for weight restoration and medical stabilisation

Psychological Therapies

Anorexia Nervosa (Adults)

NICE NG69 Recommendations (First-line therapies): [14]

1. Enhanced Cognitive Behavioural Therapy (CBT-ED)

• 40 sessions over 40 weeks (outpatient) or 20 sessions over 20 weeks (inpatient)
• Addresses maintaining factors: over-evaluation of weight/shape, dietary restraint, mood intolerance
• Focuses on normalising eating, weight restoration, cognitive restructuring
• Evidence: Moderate efficacy; 40-50% remission rates

2. Maudsley Anorexia Nervosa Treatment for Adults (MANTRA)

• 20-30 sessions over 6-12 months
• Addresses maintaining factors: rigidity, avoidance, pro-anorexia beliefs, emotional issues
• Uses motivational interviewing, cognitive remediation, emotion skills training
• Evidence: Non-inferior to CBT-ED in trials

3. Specialist Supportive Clinical Management (SSCM)

• 20+ sessions over 6-12 months
• Combines psychoeducation, care, support, pragmatic advice on nutrition
• Non-specific factors (therapeutic alliance, hope) as active ingredients
• Evidence: Comparable to CBT-ED/MANTRA in some trials

Second-Line (if first-line ineffective or declined):

• Focal psychodynamic therapy
• Cognitive Analytic Therapy (CAT)

NOT Recommended as Sole Treatment:

• Medication alone (no evidence for efficacy in underweight AN)
• Dietary counselling alone (without psychological component)

Anorexia Nervosa (Adolescents)

First-Line: Family-Based Therapy (FBT) [15]

• Also called "Maudsley Family Therapy"
• Parents take active role in weight restoration
• 3 phases: (1) Parental control of eating, (2) Return control to adolescent, (3) Establish healthy identity
• Evidence: Most effective for adolescent AN; 40-50% remission
• Duration: 12-20 sessions over 6-12 months

Bulimia Nervosa

First-Line: CBT-BN or CBT-ED [14]

• 16-20 sessions over 4-5 months
• Targets binge-purge cycle, dietary restraint, over-evaluation of weight/shape
• Evidence: Most effective treatment for BN; 40-50% abstinence from binge/purge at end of treatment
• Superior to medication alone, interpersonal therapy

Guided Self-Help (GSH-CBT):

• For those unwilling/unable to engage in full CBT
• Self-help manual with brief practitioner support (4-9 sessions)
• Evidence: Effective for motivated individuals; less intensive resource use

Interpersonal Psychotherapy (IPT):

• Second-line if CBT ineffective or patient preference
• Focuses on interpersonal difficulties maintaining disorder
• Evidence: Effective but slower onset than CBT

Binge Eating Disorder

First-Line Options:

1. CBT-BED:

• 16-20 sessions over 4-6 months
• Addresses binge eating, weight/shape concerns, mood regulation
• Evidence: 40-60% abstinence from binge eating; limited weight loss

2. Guided Self-Help (GSH-CBT):

• Often tried first (stepped-care model)
• Evidence: Effective; less resource-intensive

3. Interpersonal Psychotherapy (IPT):

• Evidence: Similar efficacy to CBT in long-term

Dialectical Behaviour Therapy (DBT):

• Adapted for BED; focuses on emotion regulation
• Evidence: Reduces binge eating; comparable to CBT

Nutritional Rehabilitation

Goals:

1. Restore weight to healthy range (BMI 18.5-25 kg/m²)
2. Normalise eating patterns (regular meals, variety)
3. Address nutritional deficiencies
4. Reduce eating disorder behaviours

Principles for Anorexia Nervosa

Weight Restoration Targets:

• Adults: BMI ≥18.5-20 kg/m² (individualised based on premorbid weight, menstrual recovery)
• Adolescents: Return to premorbid growth trajectory

Caloric Prescription:

Outpatient:

• Start: 1500-1800 kcal/day (balance refeeding risk vs. therapeutic progress)
• Increase: 200-300 kcal every 3-7 days
• Target: 2500-3500 kcal/day for weight gain (1.0-1.5 kg/week)

Inpatient (High Refeeding Risk):

• Start LOW: 5-10 kcal/kg/day if BMI less than 14 or severe risk factors
• Gradual increase: 200 kcal every 2-3 days
• Close monitoring for refeeding syndrome

Composition:

• Balanced diet: 50-55% carbohydrate, 15-20% protein, 25-30% fat
• Regular meals and snacks (3 meals, 2-3 snacks)
• Avoid tube feeding unless medical emergency (risks dependence, avoids psychological work)

Monitoring:

• Weight: 1-2 times weekly (more frequent can increase anxiety)
• Bloods: Electrolytes (daily initially if high refeeding risk, then weekly)
• Vitals: Daily if inpatient, weekly if outpatient

Refeeding Syndrome Prevention

Thiamine Supplementation (CRITICAL):

• 200-300 mg PO daily BEFORE refeeding (or 100 mg IV if very high risk)
• Continue for first 10 days of refeeding
• Prevents Wernicke's encephalopathy

Electrolyte Supplementation (As Needed):

• Phosphate: Oral replacement if PO4 less than 0.8 mmol/L; IV if less than 0.5 mmol/L
• Potassium: Oral replacement if K+ less than 3.5 mmol/L
• Magnesium: Oral replacement if Mg²⁺ less than 0.5 mmol/L

Monitoring Schedule (High Risk):

• Daily: Weight, vitals, U&Es, PO4, Mg²⁺, Ca²⁺, glucose (Days 1-7)
• Reduce frequency after first week if stable

Fluid Restriction:

• Limit to 1-1.5 L/day initially to prevent fluid overload/heart failure
• Monitor for oedema

Nutritional Approach for Bulimia Nervosa and Binge Eating Disorder

• Regular eating pattern: 3 meals + 2-3 snacks; avoid long gaps (prevents hunger-triggered binges)
• Reduce dietary restraint: Challenge food rules, introduce "forbidden" foods
• Meal planning: Structure reduces impulsive eating
• No compensatory behaviours: Discourage purging, fasting, excessive exercise
• Portion control training: Helps reduce binge size over time

Pharmacological Treatment

Medications have LIMITED role in eating disorders; psychological therapy is primary treatment.

Anorexia Nervosa

NO medication is first-line treatment for AN. [14]

Atypical Antipsychotics (Olanzapine):

• Limited evidence; may reduce pre-meal anxiety, obsessional thoughts about food
• Dose: 2.5-10 mg/day
• Use: Severe AN refractory to psychological treatment, co-occurring severe anxiety
• Side effects: Weight gain (may be helpful), sedation, metabolic syndrome

SSRIs:

• No evidence of efficacy in underweight AN
• May be helpful for comorbid depression/anxiety AFTER weight restoration
• Fluoxetine 20-60 mg for relapse prevention post-weight restoration (limited evidence)

What NOT to Use:

• Tricyclic antidepressants (arrhythmia risk in malnourished patients)
• Bupropion (seizure risk)

Bulimia Nervosa

SSRI - Fluoxetine (Evidence-based pharmacotherapy): [16]

• Dose: 60 mg daily (higher than for depression)
• Mechanism: Reduces binge-purge frequency, improves mood
• Evidence: RCTs show 50-60% reduction in binge/purge episodes
• Use: Adjunct to CBT (combination superior to either alone) OR if CBT unavailable/declined
• Duration: At least 6-12 months; relapse common on discontinuation

Other SSRIs (less evidence): Sertraline, citalopram, escitalopram (lower doses than fluoxetine)

Other Medications (Limited Evidence):

• Topiramate: Reduces binge/purge; off-label; side effects (cognitive dulling, paraesthesias)
• Lisdexamfetamine: Approved for BED in USA; NOT routinely used in UK/Europe

Binge Eating Disorder

First-Line: Psychological therapy (CBT)

Pharmacotherapy (Adjunct or if therapy unavailable):

Lisdexamfetamine (LDX):

• Approved for moderate-severe BED (USA; not UK-licensed)
• Dose: 30-70 mg/day
• Evidence: Reduces binge days by ~40% vs. placebo
• Side effects: Insomnia, dry mouth, increased HR/BP
• Caution: Stimulant; abuse potential

SSRIs (Fluoxetine, Sertraline):

• Modest reduction in binge frequency
• Dose: Fluoxetine 60 mg, Sertraline 150-200 mg
• Minimal weight loss

Topiramate (off-label):

• Reduces binge eating and promotes weight loss
• Dose: 100-250 mg/day (titrate slowly)
• Side effects: Cognitive impairment, paraesthesias, renal stones
• Limited use due to tolerability

Treating Comorbid Conditions

Depression/Anxiety:

• SSRIs (fluoxetine, sertraline, escitalopram)
• Consider after weight restoration in AN (more effective when not underweight)

OCD:

• High-dose SSRIs, CBT with exposure-response prevention

Substance Use:

• Integrated treatment; address eating disorder and substance use concurrently

Involuntary Treatment (Mental Health Act)

Indications:

• Severe AN with life-threatening medical risk
• Patient lacks capacity to consent to treatment
• Patient refuses necessary treatment despite capacity (in some jurisdictions, can use MHA if risk to life)

Ethical Considerations:

• Balance autonomy vs. preservation of life
• Compulsory treatment controversial; evidence suggests can save lives in extreme cases
• Use as last resort; prioritise voluntary engagement

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9. Complications and Prognosis

Mortality

Anorexia Nervosa: Highest mortality of psychiatric disorders [1,2]

• Standardised Mortality Ratio (SMR): 5.9-10.5 (6-10 times higher than general population)
• Crude Mortality Rate: 5-10% per decade of illness
• Causes of Death:
  • "Medical complications: 50% (cardiac arrhythmias, electrolyte disturbances, infections, multi-organ failure)"
  • "Suicide: 25-30%"
  • "Unknown/other: 20-25%"

Bulimia Nervosa:

• SMR: 1.5-2.0 (lower than AN but still elevated)
• Mortality primarily from suicide, medical complications (electrolyte disturbances, gastric rupture)

Binge Eating Disorder:

• Mortality primarily related to obesity-related complications (cardiovascular disease, diabetes)

Recovery and Outcome

Anorexia Nervosa (Long-term Follow-up Studies)

Predictors of POOR Prognosis:

• Longer duration of illness
• Very low BMI at presentation
• Older age at onset
• Purging behaviours
• Comorbid psychiatric disorder (depression, OCD, personality disorder)
• Poor family relationships
• Premorbid developmental/social difficulties

Predictors of GOOD Prognosis:

• Shorter duration (early intervention)
• Adolescent onset (vs. adult onset)
• Higher BMI at presentation
• Good family support
• Absence of binge/purge behaviours

Bulimia Nervosa

Better prognosis than AN: Earlier presentation, higher treatment-seeking, better response to CBT

Binge Eating Disorder

• Good response to treatment: 40-60% achieve abstinence from binge eating with CBT
• Weight outcomes variable: Most do not lose significant weight despite reduction in binge eating
• Long-term: Relapse common; ongoing monitoring beneficial

Physical Sequelae

Irreversible Complications:

• Osteoporosis (partially irreversible, especially if onset during adolescence)
• Dental damage (enamel erosion)
• Growth stunting (if onset before growth completion)

Reversible Complications (with recovery):

• Cardiac abnormalities (bradycardia, reduced cardiac mass)
• Cerebral atrophy
• Amenorrhoea (typically returns with BMI > 18.5-19 kg/m²)
• Haematological abnormalities
• Most electrolyte/metabolic disturbances

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10. Prevention and Screening

Primary Prevention

Aims: Prevent onset of eating disorders in at-risk populations

Strategies:

• School-based programmes promoting healthy body image, media literacy
• Reduce weight-based teasing and bullying
• Discourage dieting in adolescents
• Promote healthy attitudes to food and exercise in families

Evidence: Some programmes (e.g., Body Project, Media Smart) show small reductions in risk factors; limited evidence for preventing disorder onset

Secondary Prevention (Early Intervention)

Screening in High-Risk Groups:

• Adolescents and young adults (peak risk period)
• Athletes (particularly aesthetic/weight-class sports)
• Type 1 diabetes (higher eating disorder prevalence)
• Patients presenting with amenorrhoea, low weight, unexplained weight loss

Screening Tools:

• SCOFF questionnaire (quick, 5 questions; high sensitivity/specificity) [12]
• EAT-26 (more comprehensive; research settings)

Benefits of Early Intervention:

• Shorter duration of untreated illness → better prognosis
• Prevention of severe medical complications
• Reduced chronicity

Tertiary Prevention (Relapse Prevention)

High Relapse Rates: 30-50% relapse within first year after treatment

Strategies:

• Ongoing outpatient monitoring (monthly then less frequent)
• Booster sessions of psychological therapy
• Early re-intervention at first signs of relapse
• Address life stressors (transitions, relationship difficulties)
• Continued family involvement and support

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11. Special Populations

Pregnancy and Eating Disorders

Risks:

• Maternal: Relapse/worsening of ED, hyperemesis gravidarum, preterm delivery, gestational diabetes (BED), caesarean section
• Fetal: Intrauterine growth restriction, low birth weight, prematurity, congenital malformations (if severe malnutrition), perinatal mortality

Management:

• Preconception counselling: Optimise weight, stabilise ED
• Multidisciplinary care: Obstetrics, psychiatry, dietetics
• Nutritional support: Ensure adequate caloric intake, weight gain
• Monitor fetal growth: Serial ultrasounds
• Medication review: Avoid fluoxetine in first trimester if possible (though low risk); avoid topiramate (teratogenic)

Postpartum:

• High relapse risk postpartum
• Breastfeeding: Nutritional support for mother; safe on most SSRIs (sertraline preferred)
• Screen for postnatal depression

Men with Eating Disorders

Underdiagnosed and Undertreated: [17]

• Prevalence increasing (now ~10-25% of ED cases)
• Delayed presentation due to perception of EDs as "female" disorders
• Higher rates of muscle dysmorphia (drive for muscularity rather than thinness)

Presentation Differences:

• Often history of childhood obesity
• More likely driven by sport/athletic performance
• Muscle dysmorphia: preoccupation with being too small/not muscular enough; excessive weightlifting, protein supplements, anabolic steroid use

Treatment:

• Same evidence-based psychological therapies (CBT-ED, etc.)
• Consider gender-specific groups (reduce stigma, increase engagement)

Older Adults

Late-Onset Eating Disorders:

• Can develop de novo in older adults (often triggered by life stressors: bereavement, divorce, retirement)
• OR chronic EDs persisting from youth

Diagnostic Challenges:

• Weight loss may be attributed to medical illness, depression, or "normal ageing"
• Amenorrhoea criterion not applicable (postmenopausal)

Medical Risks:

• Higher baseline medical comorbidity (cardiovascular disease, osteoporosis)
• Increased frailty and risk of falls
• Poorer outcomes due to chronicity (if long-standing ED)

Athletes

High-Risk Sports:

• Aesthetic: Ballet, gymnastics, figure skating, diving
• Endurance: Distance running, cycling, swimming
• Weight-class: Wrestling, boxing, rowing, jockeying

"Relative Energy Deficiency in Sport (RED-S)":

• Syndrome in athletes with low energy availability (calories < expenditure)
• Consequences: Impaired bone health, menstrual dysfunction, cardiovascular risk, impaired performance
• May or may not meet full ED criteria

Management:

• Multidisciplinary: Sports medicine, nutrition, psychology
• Address energy deficit while maintaining performance goals
• Consider temporary reduction/cessation of training if severe

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12. Key Evidence and Guidelines

Major Guidelines

Landmark Studies and Evidence

Mortality and Epidemiology:

1. Arcelus et al. (2011): Meta-analysis of mortality in eating disorders; SMR for AN = 5.9 [1]
2. Fichter & Quadflieg (2016): 12-year outcomes in AN; 50% full recovery, 21% chronic [5]

Treatment Trials: 3. Fairburn et al. (2015): Transdiagnostic CBT-ED for eating disorders [18] 4. Schmidt et al. (2015): MANTRA vs. SSCM for adult AN (non-inferiority) [19] 5. Lock et al. (2010): Family-based therapy for adolescent AN [15] 6. Fluoxetine Bulimia Nervosa Collaborative Study Group (1992): 60mg fluoxetine reduces binge/purge in BN [20]

Medical Complications: 7. Mehler & Brown (2015): Medical complications of anorexia nervosa [21] 8. Crook et al. (2001): Refeeding syndrome in anorexia nervosa [3]

Screening: 9. Morgan et al. (1999): SCOFF questionnaire validation [12]

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13. Examination Scenarios and Viva Questions

Common OSCE/Clinical Scenarios

Scenario 1: Medical Assessment of Patient with Anorexia Nervosa

Stem: A 22-year-old woman presents to ED with dizziness and collapse. BMI 14 kg/m². How would you assess her?

Approach:

1. ABCDE assessment: Airway, breathing, circulation (check for shock)
2. Vital signs: HR (bradycardia?), BP (hypotension? postural drop?), temperature (hypothermia?), SpO2
3. Focused history: Eating/weight history, purging, exercise, duration of illness, previous treatment
4. Examination: General appearance (cachexia, muscle wasting), cardiovascular (bradycardia, murmurs), abdomen, neurology (proximal weakness)
5. Investigations:
   • Urgent: ECG (QTc, arrhythmias), capillary glucose, U&Es (K+, Na+, urea, creatinine), FBC
   • Lying/standing BP (orthostatic hypotension)
6. Risk assessment: Apply MARSIPAN criteria (high risk = BMI less than 13, HR less than 40, SBP less than 90, QTc > 450, K+ less than 3.0, temp less than 35.5)
7. Management: If high-risk → medical admission, IV fluids (cautious), electrolyte replacement, thiamine, avoid rapid refeeding

Key Points to Mention:

• Anorexia nervosa has highest psychiatric mortality
• Bradycardia less than 40, hypotension, and QTc prolongation = medical emergency
• Refeeding syndrome risk if BMI less than 16 or rapid weight loss

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Scenario 2: Bulimia Nervosa - Management Plan

Stem: A 28-year-old woman presents to GP with daily binge eating followed by vomiting for 2 years. What is your management approach?

Approach:

1. Confirm diagnosis: DSM-5 criteria for BN (binge eating + compensatory behaviours ≥1/week for 3 months; self-worth tied to weight/shape)
2. Assess severity: Frequency (daily = severe), medical complications, comorbidity
3. Medical assessment:
   • Vitals, BMI, examination (parotid enlargement, Russell's sign, dental erosion)
   • Bloods: U&Es (K+), ECG if hypokalaemia/high purging frequency
4. Psychosocial assessment: Mood, anxiety, suicide risk, substance use, psychosocial stressors
5. Treatment plan:
   • First-line: CBT-BN (16-20 sessions over 4-5 months) OR guided self-help CBT
   • Medication: Fluoxetine 60mg as adjunct to CBT or if CBT declined
   • Dietitian: Nutritional counselling, regular eating pattern
   • Monitoring: Weekly initially (weight, electrolytes if needed)
6. Referral: Specialist eating disorder service if available; consider day programme if severe/not responding

Key Points:

• CBT-BN is most effective treatment
• Fluoxetine 60mg (higher dose than for depression) reduces binge/purge
• Hypokalaemia risk from vomiting → cardiac arrhythmias; needs ECG if K+ less than 3.0

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Scenario 3: Refeeding Syndrome Prevention

Stem: You are admitting a patient with severe anorexia nervosa (BMI 13 kg/m²) for nutritional rehabilitation. How do you prevent refeeding syndrome?

Approach:

1. Identify high risk: BMI less than 14, little intake for > 10 days, rapid weight loss > 15% in 3-6 months, low baseline K+/PO4/Mg²⁺
2. Pre-refeeding:
   • Thiamine: 200-300mg PO (or 100mg IV) BEFORE starting feeding
   • Baseline bloods: U&Es, PO4, Mg²⁺, Ca²⁺, glucose
   • Baseline ECG: QTc
3. Start feeding LOW and SLOW:
   • Initial calories: 5-10 kcal/kg/day (e.g., 400-600 kcal/day for 60 kg patient) if very high risk
   • Gradual increase: 200 kcal every 2-3 days
   • Balanced macronutrients; avoid high carbohydrate load initially
4. Electrolyte replacement (prophylactic):
   • Phosphate, potassium, magnesium supplementation if low-normal or low
5. Fluid restriction: 1-1.5 L/day to prevent fluid overload
6. Monitoring:
   • Daily for first week: Weight, vitals (HR, BP), U&Es, PO4, Mg²⁺, Ca²⁺, glucose
   • Reduce frequency if stable after 1 week
7. Watch for symptoms: Confusion, weakness, arrhythmias, oedema, respiratory distress → check bloods urgently, slow/stop feeding if refeeding syndrome

Key Points:

• Thiamine BEFORE refeeding (prevents Wernicke's)
• Hypophosphataemia is hallmark of refeeding syndrome
• "Start low, go slow" caloric approach in high-risk patients

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Viva Questions and Model Answers

Q1: What is the mortality rate of anorexia nervosa and what are the main causes of death?

Model Answer: "Anorexia nervosa has the highest mortality rate of any psychiatric disorder, with a standardised mortality ratio of approximately 6 to 10 compared to the general population. [1,2] The crude mortality rate is around 5-10% per decade of illness.

The main causes of death are:

1. Medical complications (50%): Primarily cardiac arrhythmias secondary to electrolyte disturbances and QTc prolongation, also multi-organ failure, infections
2. Suicide (25-30%): Reflects the severe psychological distress and high comorbidity with depression
3. Other/unknown causes (20-25%)

This underscores the importance of early intervention, multidisciplinary medical and psychiatric monitoring, and aggressive treatment of severe cases."

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Q2: Describe the key features of refeeding syndrome and how to prevent it.

Model Answer: "Refeeding syndrome is a potentially fatal complication occurring during nutritional rehabilitation of severely malnourished patients. [3,4]

Pathophysiology: When feeding resumes after prolonged starvation, the shift from fat to carbohydrate metabolism causes insulin secretion, which drives phosphate, potassium, and magnesium into cells. This causes severe hypophosphataemia and other electrolyte deficiencies.

Risk factors include BMI less than 16, unintentional weight loss > 15% in 3-6 months, little nutritional intake for > 10 days, or low baseline electrolytes.

Clinical features: Cardiac arrhythmias and heart failure, respiratory failure from diaphragmatic weakness, seizures, delirium, rhabdomyolysis, and haemolytic anaemia. It typically occurs 2-5 days after starting refeeding.

Prevention strategies:

1. Thiamine 200-300mg daily BEFORE refeeding to prevent Wernicke's encephalopathy
2. Start feeding cautiously: 5-10 kcal/kg/day in very high-risk patients; increase by 200 kcal every 2-3 days
3. Monitor electrolytes daily: Phosphate, potassium, magnesium, calcium for the first week
4. Prophylactic supplementation of phosphate, potassium, and magnesium
5. Fluid restriction to 1-1.5 L/day initially

The mantra is 'start low, go slow' with close medical monitoring."

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Q3: What are the first-line psychological treatments for (a) anorexia nervosa in adults, (b) bulimia nervosa, (c) binge eating disorder?

Model Answer: "According to NICE guidelines [14]:

(a) Anorexia nervosa in adults: Three first-line options of equal recommendation:

• CBT-ED (enhanced cognitive behavioural therapy): 40 sessions over 40 weeks
• MANTRA (Maudsley Anorexia Nervosa Treatment for Adults): 20-30 sessions addressing rigidity, avoidance, and emotional factors
• SSCM (Specialist Supportive Clinical Management): Pragmatic support and psychoeducation

For adolescents, family-based therapy (FBT/Maudsley Family Therapy) is first-line. [15]

(b) Bulimia nervosa: CBT-BN or CBT-ED is first-line. [18]

• 16-20 sessions over 4-5 months
• Targets binge-purge cycle, dietary restraint, over-evaluation of weight/shape
• Evidence shows 40-50% abstinence from binge/purge
• Guided self-help CBT is an alternative for motivated patients

(c) Binge eating disorder: CBT-BED is first-line.

• 16-20 sessions over 4-6 months
• Guided self-help CBT often tried first (stepped-care approach)
• Interpersonal psychotherapy (IPT) and dialectical behaviour therapy (DBT) are alternatives"

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Q4: A patient with bulimia nervosa has potassium of 2.8 mmol/L and QTc of 480ms. What are your immediate actions?

Model Answer: "This patient has severe hypokalaemia and QTc prolongation, both of which increase risk of life-threatening cardiac arrhythmias (including torsades de pointes). Immediate actions:

1. Admit to medical ward with cardiac monitoring capability

2. Cardiac monitoring: Continuous ECG monitoring for arrhythmias

3. Repeat ECG: Serial ECGs to monitor QTc

4. Potassium replacement:

• Oral: If patient can tolerate, give oral potassium supplements (Sando-K 2-3 tablets TDS)
• IV: If K+ less than 2.5 or symptomatic, give IV potassium chloride (max rate 10-20 mmol/hour via central line or slower peripherally)
• Target: K+ > 3.5 mmol/L

5. Check other electrolytes: Magnesium (low Mg²⁺ impairs K+ repletion), calcium, phosphate

6. Stop QT-prolonging medications: Review medications; avoid drugs that further prolong QT

7. Assess for other complications: Volume status, renal function, consider other causes of hypokalaemia

8. Address underlying cause: Encourage cessation of purging behaviours; may need 1:1 nursing supervision to prevent vomiting

9. Psychiatric review: Assess engagement with treatment, commence/optimise psychological therapy and fluoxetine

10. Dietitian input: Nutritional rehabilitation, regular eating pattern

The patient should remain on medical ward until electrolytes stable and QTc less than 500ms, then transfer to psychiatric/eating disorder care."

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Q5: How do you differentiate anorexia nervosa from depression-related weight loss?

Model Answer: "The key differentiator is the presence of eating disorder-specific psychopathology in anorexia nervosa:

Anorexia Nervosa:

• Intense fear of weight gain, even at low weight
• Body image disturbance: Feels fat despite being underweight; overvaluation of weight/shape
• Deliberate dietary restriction: Active avoidance of food, calorie counting, food rituals
• Lack of insight: Does not recognise seriousness of low weight
• May have amenorrhoea (secondary to low weight)
• Often ego-syntonic (behaviours consistent with self-image)

Major Depressive Disorder:

• Weight loss is unintentional (due to loss of appetite, not deliberate restriction)
• No fear of weight gain; may want to regain weight
• No body image disturbance: Recognises underweight
• Ego-dystonic: Distressed by symptoms
• Appetite and weight often improve with treatment of depression

Comorbidity is common: 50-75% of individuals with AN also have depression. In such cases, the eating disorder psychopathology (fear of weight gain, body image distortion) distinguishes AN as the primary diagnosis.

Clinical assessment should include direct questions: 'Are you afraid of gaining weight? Do you feel fat? Do you want to lose more weight?' Positive responses suggest AN rather than depression alone."

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14. Patient and Family Education

For Patients

What is an eating disorder? An eating disorder is a mental health condition where your thoughts and feelings about food, eating, weight, and body shape cause you to develop harmful eating behaviours. The main types are anorexia (restricting food and being severely underweight), bulimia (binge eating followed by purging), and binge eating disorder (binge eating without purging).

Why is treatment important? Eating disorders can cause serious health problems affecting your heart, bones, kidneys, brain, and other organs. They can be life-threatening. Early treatment improves the chances of full recovery.

What does treatment involve?

• Talking therapy (such as CBT) to help change unhelpful thoughts and behaviours around food and weight
• Nutritional support from a dietitian to restore healthy eating patterns and weight
• Medical monitoring to check for and treat complications
• Sometimes medication (especially for bulimia)

Recovery is possible: Many people make a full recovery with the right treatment and support. Recovery takes time, but with help, you can get better.

Where to get help:

• GP: First point of contact; can refer to specialist services
• BEAT Eating Disorders (UK): Helpline, online support, resources (beateatingdisorders.org.uk)
• Emergency: If you feel suicidal or have severe medical symptoms (chest pain, collapse, severe weakness), go to A&E

For Families and Carers

How can I help?

• Be supportive, not controlling: Express concern and willingness to help, but avoid comments about weight, appearance, or food
• Educate yourself: Understand the illness; it is not about vanity or attention-seeking
• Encourage professional help: Gently encourage your loved one to see a doctor
• Mealtimes: Provide regular, structured meals; eating together can help
• Avoid food battles: Do not force eating or police behaviours; this often backfires
• Look after yourself: Caring for someone with an eating disorder is stressful; seek your own support

Family involvement in treatment:

• For adolescents, family-based therapy is often first-line; parents play an active role
• For adults, family support is helpful but the patient leads their own treatment

Signs of emergency (call 999 or go to A&E):

• Collapse, fainting, severe dizziness
• Chest pain, very slow or irregular heartbeat
• Confusion, seizures
• Suicidal thoughts with plan/intent

Support organisations:

• BEAT: Support for sufferers and families
• Anorexia & Bulimia Care (ABC): Christian-based support charity
• Carers UK: General carer support

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15. Red Flags and Safety Netting

Medical Red Flags (Require Urgent Assessment/Admission)

Safety Netting for Outpatients

Monitoring Frequency:

• High risk (BMI 13-15, moderate complications): Weekly reviews (weight, vitals, bloods)
• Moderate risk (BMI 15-17, stable): Fortnightly reviews initially, then monthly
• Low risk (BMI > 17, stable, engaging): Monthly reviews

Parameters to Monitor:

• Weight, BMI
• Vitals: HR, BP (lying/standing), temperature
• Bloods (as needed): U&Es, PO4, Mg²⁺, glucose, FBC, LFTs
• ECG if bradycardia, hypokalaemia, or QTc previously prolonged

When to Escalate:

• New medical red flags (above)
• Weight loss despite treatment
• Non-engagement with treatment
• Deteriorating mental state (depression, suicide risk)
• Pregnancy

Patient and Family Education:

• Explain warning signs
• Give clear instructions on when to seek help
• Provide emergency contact numbers (ED service, crisis team, GP)

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16. Summary: Key Exam Takeaways

Top 10 Facts for Exams:

1. Anorexia nervosa has the highest mortality of any psychiatric disorder (SMR 5.9-10.5). [1,2]

2. DSM-5 criteria for AN: Restriction → low weight (BMI less than 18.5); fear of weight gain; body image disturbance. Amenorrhoea NO LONGER required.

3. Refeeding syndrome: Severe hypophosphataemia during refeeding of malnourished patients; prevent with thiamine, "start low go slow" feeding, daily electrolyte monitoring. [3,4]

4. MARSIPAN high-risk criteria: BMI less than 13, HR less than 40, SBP less than 90, K+ less than 3.0, QTc > 450, temp less than 35.5 → medical admission. [13]

5. CBT-ED is first-line psychological treatment for BN and BED; for adult AN use CBT-ED, MANTRA, or SSCM; for adolescent AN use family-based therapy. [14,15]

6. Fluoxetine 60mg is evidence-based for bulimia nervosa (reduces binge/purge); NOT effective for underweight AN. [16,20]

7. Bulimia nervosa complications: Hypokalaemia (from vomiting/laxatives) → arrhythmias; Russell's sign, dental erosion, parotid enlargement.

8. Binge eating disorder: Most common eating disorder; associated with obesity, no compensatory behaviours (differentiates from BN).

9. Osteoporosis in AN: Due to low oestrogen, hypercortisolaemia, malnutrition; may be partially irreversible; weight restoration is primary treatment (NOT bisphosphonates in premenopausal women).

10. SCOFF questionnaire: 5 questions; ≥2 "yes" = high likelihood of eating disorder (sensitivity > 80%). [12]

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17. References

1. Arcelus J, Mitchell AJ, Wales J, Nielsen S. Mortality rates in patients with anorexia nervosa and other eating disorders. A meta-analysis of 36 studies. Arch Gen Psychiatry. 2011;68(7):724-731. doi:10.1001/archgenpsychiatry.2011.74

2. Smink FR, van Hoeken D, Hoek HW. Epidemiology of eating disorders: incidence, prevalence and mortality rates. Curr Psychiatry Rep. 2012;14(4):406-414. doi:10.1007/s11920-012-0282-y

3. Crook MA, Hally V, Panteli JV. The importance of the refeeding syndrome. Nutrition. 2001;17(7-8):632-637. doi:10.1016/s0899-9007(01)00542-1

4. Mehanna HM, Moledina J, Travis J. Refeeding syndrome: what it is, and how to prevent and treat it. BMJ. 2008;336(7659):1495-1498. doi:10.1136/bmj.a301

5. Fichter MM, Quadflieg N. Mortality in eating disorders - results of a large prospective clinical longitudinal study. Int J Eat Disord. 2016;49(4):391-401. doi:10.1002/eat.22501

6. Galmiche M, Déchelotte P, Lambert G, Tavolacci MP. Prevalence of eating disorders over the 2000-2018 period: a systematic literature review. Am J Clin Nutr. 2019;109(5):1402-1413. doi:10.1093/ajcn/nqy342

7. Kessler RC, Berglund PA, Chiu WT, et al. The prevalence and correlates of binge eating disorder in the World Health Organization World Mental Health Surveys. Biol Psychiatry. 2013;73(9):904-914. doi:10.1016/j.biopsych.2012.11.020

8. Bulik CM, Thornton LM, Root TL, et al. Understanding the relation between anorexia nervosa and bulimia nervosa in a Swedish national twin sample. Biol Psychiatry. 2010;67(1):71-77. doi:10.1016/j.biopsych.2009.08.010

9. Fairburn CG, Cooper Z, Bohn K, et al. The severity and status of eating disorder NOS: implications for DSM-V. Behav Res Ther. 2007;45(8):1705-1715. doi:10.1016/j.brat.2007.01.010

10. Miller KK, Grinspoon SK, Ciampa J, et al. Medical findings in outpatients with anorexia nervosa. Arch Intern Med. 2005;165(5):561-566. doi:10.1001/archinte.165.5.561

11. Seitz J, Bühren K, von Polier GG, et al. Morphological changes in the brain of acutely ill and weight-recovered patients with anorexia nervosa. A meta-analysis and qualitative review. Z Kinder Jugendpsychiatr Psychother. 2014;42(1):7-17. doi:10.1024/1422-4917/a000265

12. Morgan JF, Reid F, Lacey JH. The SCOFF questionnaire: assessment of a new screening tool for eating disorders. BMJ. 1999;319(7223):1467-1468. doi:10.1136/bmj.319.7223.1467

13. Royal College of Psychiatrists. MARSIPAN: Management of Really Sick Patients with Anorexia Nervosa (College Report CR233). 3rd ed. London: RCPsych Publications; 2022.

14. National Institute for Health and Care Excellence. Eating disorders: recognition and treatment (NG69). London: NICE; 2017 (updated 2020). Available from: https://www.nice.org.uk/guidance/ng69

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Last Reviewed: 2026-01-08 | MedVellum Editorial Team

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Medical Disclaimer: This content is for educational purposes and clinical reference. For patients experiencing eating disorder symptoms, please seek professional help from your GP or contact BEAT Eating Disorders (UK): 0808 801 0677.