Eating Disorder History Taking OSCE — Anorexia, Bulimia, SCOFF & Safeguarding

Why Eating Disorder History Is Tested in OSCEs

Eating disorders have the highest mortality of any psychiatric condition, making early identification and management critical. OSCE stations test whether candidates can ask sensitively about a stigmatised topic, apply validated screening tools, identify physical complications, assess risk, and know the referral pathway. The station simultaneously assesses communication skills, psychiatric history-taking, and clinical medicine (electrolytes, ECG changes, refeeding syndrome).

Setting Up for a Sensitive Consultation

Acknowledge the difficulty of the topic before beginning: "I appreciate these questions can feel quite personal — please know that everything you share stays confidential (with limits I can explain if needed). I'm asking because I want to understand what you've been going through and how I can best help you." Maintain a non-judgmental, unhurried tone throughout.

SCOFF Questionnaire — Validated Screening Tool

The SCOFF is a five-question validated screening tool for eating disorders. Two or more positive answers suggest probable anorexia or bulimia (sensitivity ~78–100%, specificity ~90%).

Characterising the Eating Disorder

Anorexia Nervosa

• Restriction of caloric intake relative to requirements, leading to low body weight
• Intense fear of gaining weight or becoming fat (even when already underweight)
• Disturbed body image (body dysmorphia) — "I feel fat even though people say I'm not"
• Restriction may be with or without purging/compensatory behaviours (specify subtype)
• BMI <17.5 kg/m² is the diagnostic threshold for severe weight loss in DSM-5/ICD-11

Bulimia Nervosa

• Recurrent episodes of binge eating (large quantities in a discrete time period, sense of loss of control)
• Recurrent compensatory behaviours: self-induced vomiting, laxative misuse, diuretics, excessive exercise, fasting
• Self-evaluation unduly influenced by body shape and weight
• Must be distinguished from binge-eating disorder (no compensatory behaviours)

ARFID (Avoidant/Restrictive Food Intake Disorder)

• Avoidance of food based on sensory characteristics (texture, colour, smell) rather than body image concerns
• No fear of weight gain; often associated with autism spectrum disorder, anxiety disorders
• Leads to significant nutritional deficiency and psychosocial impairment

Detailed Symptom History

Ask about:

• Dietary intake: typical day's food and drink, restriction patterns, "safe" and "fear" foods
• Bingeing: frequency, triggers, typical binge content, feelings during and after (shame, guilt, disgust)
• Compensatory behaviours: vomiting (ask directly: "Some people make themselves sick after eating — has that happened to you?"), laxatives, diuretics, excessive exercise, fasting
• Calorie counting, food rituals, food rules: rigid rules about what/when/how much to eat
• Body image: perception of weight/shape, clothes size awareness, mirror checking, body checking behaviours
• Weight history: current weight, lowest adult weight, highest adult weight, target weight

Physical Complications Screen

Psychiatric and Psychosocial History

• Mood: depression (comorbid in ~70% of eating disorder patients), anxiety
• OCD features: intrusive thoughts, rituals around food
• Self-harm and suicidality: eating disorders have a high suicide rate; always ask
• Trauma history: childhood abuse, bullying, family dysfunction
• Triggers: onset of eating disorder (life event, comment about appearance, transition)
• Social impact: school/work attendance, social isolation, relationship difficulties

Safeguarding and Risk Assessment

Eating disorders require mandatory consideration of safeguarding if the patient is a child or young person, or if there is severe physical compromise. Assess:

• Physical risk: BMI <15 requires urgent medical assessment; BMI <13 may require inpatient admission under the Mental Health Act
• Suicide and self-harm risk (see suicide risk assessment framework)
• Capacity to consent to treatment (especially in severe anorexia)
• Parental/carer awareness and involvement if patient is under 18

Investigations to Mention

ECG (QTc prolongation, arrhythmia from hypokalaemia), U&Es (hypokalaemia, hyponatraemia), glucose, FBC (pancytopenia in bone marrow suppression), LFTs (liver impairment from starvation), magnesium, phosphate (refeeding risk), calcium, albumin, TFTs (low in starvation), bone density (DXA scan in prolonged anorexia).

Referral Pathway

NICE CG9 / NG69: refer to community EATING DISORDER SERVICE (CEDS). Urgent psychiatric review if high suicide risk or severe medical compromise. Inpatient medical admission if: BMI <13, severe electrolyte disturbance, ECG abnormality, haemodynamic compromise, or rapid weight loss.

Frequently Asked Questions

"How do I ask about purging behaviours without making the patient feel judged?"

Normalise the question before asking it: "Some people, when they feel very full or anxious after eating, find themselves doing certain things to feel more in control — like making themselves sick, using laxatives, or exercising a lot. Has anything like that happened to you?" This phrasing avoids the accusatory "do you make yourself sick?" and frames it as a common, understandable response. If the patient confirms purging, explore: method (vomiting, laxatives, diuretics, exercise), frequency (times per day/week), duration, and feelings before and after. Do not show surprise or alarm, as this may cause the patient to withdraw. Thank them for sharing: "Thank you for telling me — I know that wasn't easy, and it really helps me understand what's going on."

"What are the diagnostic criteria for anorexia nervosa that I need to know for an OSCE?"

DSM-5 criteria for anorexia nervosa require three components: (1) Restriction of energy intake relative to requirements, leading to significantly low body weight in the context of age, sex, developmental trajectory, and physical health (BMI <17.5 is used as a practical threshold); (2) Intense fear of gaining weight or of becoming fat, or persistent behaviour that interferes with weight gain, even though the patient is significantly underweight; and (3) Disturbance in the way body weight or shape is experienced, undue influence of body weight or shape on self-evaluation, or persistent lack of recognition of the seriousness of the current low body weight. The two subtypes are: restrictive type (no bingeing or purging) and binge-eating/purging type. ICD-11 uses similar criteria. In the OSCE, being able to articulate these three criteria concisely scores consistently well.

"What is refeeding syndrome and when should I be concerned about it?"

Refeeding syndrome is a potentially fatal metabolic disturbance that occurs when nutrition is reintroduced after a period of starvation. During starvation, intracellular electrolytes (especially phosphate, potassium, and magnesium) are depleted, although serum levels may appear normal. When carbohydrate is reintroduced, insulin secretion surges, driving these electrolytes into cells — serum phosphate drops dramatically (hypophosphataemia). This causes: cardiac arrhythmias, respiratory failure, muscle weakness, seizures, and haemolytic anaemia. It can occur within 72 hours of refeeding. Risk factors: BMI <16, weight loss >15% in 3–6 months, little/no nutritional intake for >5 days. Management: start nutrition slowly (10 kcal/kg/day), supplement phosphate, potassium, magnesium and thiamine (Pabrinex) before and during refeeding, daily electrolyte monitoring. NICE guidelines (CG32) provide specific refeeding protocols.

"How do I approach risk assessment for a patient with an eating disorder?"

Risk assessment in eating disorders has two parallel domains: medical risk and psychiatric risk. Medical risk: assess BMI and rate of weight loss, screen for dangerous electrolyte disturbances (U&Es, ECG — QTc prolongation), haemodynamic stability (HR, BP, orthostatic hypotension), and degree of physical compromise. Psychiatric risk: screen for suicidal ideation — eating disorders have one of the highest mortality rates of any psychiatric condition, with approximately 5% of deaths from suicide. Use the same risk assessment framework as any suicide screen: ideation, plan, intent, access to means, protective factors. Ask directly: "Have you had any thoughts of harming yourself or of not wanting to be alive?" Safeguarding must be considered for under-18s — does the school, parent, or local authority need to be informed? Capacity assessment may be required in severe anorexia where the patient refuses treatment.

"What physical signs should I look for when examining a patient with a suspected eating disorder?"

Key examination findings: general — cachexia, pallor, lanugo hair (fine downy hair on trunk and face due to thermoregulation in starvation), peripheral oedema (hypoalbuminaemia), peripheral cyanosis and cold extremities (poor peripheral perfusion); vital signs — bradycardia (HR <50 in severe anorexia), hypotension, postural hypotension (intravascular depletion); skin and hands — Russell's sign (dorsal hand calluses from induced vomiting), dry skin, hair loss, yellow discolouration (hypercarotenaemia), Raynaud's phenomenon; oral — dental erosion (perimylolysis from acid vomiting), parotid gland hypertrophy (bilateral swelling giving "chipmunk facies"), mouth ulcers; musculoskeletal — proximal muscle weakness (hypokalaemia, hypophosphataemia). Documenting these findings is essential for monitoring and medicolegal records.

"What is the SCOFF questionnaire and how do I use it in an OSCE consultation?"

The SCOFF is a validated five-question screening questionnaire for eating disorders, originally developed at St George's Hospital London. The five questions screen for: induced vomiting (Sick), loss of control over eating (Control), significant weight loss (One stone), body dysmorphia (Fat), and food preoccupation (Food). Two or more positive responses indicate probable anorexia or bulimia with a sensitivity of 78–100% depending on the population. In the OSCE, introduce it naturally: "I'd like to ask five standard questions about eating that help us understand whether there are any difficulties we should explore further." Score each answer and state the result: "You've answered yes to three of those questions, which is something I'd like to talk more about." The SCOFF is not diagnostic — it triggers a detailed clinical assessment and referral to an eating disorder service. Mentioning it by name and being able to recall the questions scores specific marks in psychiatric history stations.

Related guides: Psychiatric History OSCE · Mental State Examination OSCE · Depression and Anxiety History OSCE · Safeguarding OSCE Guide · Breaking Bad News OSCE Guide