Bulimia Nervosa

More common than anorexia nervosa (prevalence 0.5–1%), with an even distribution across social class.

Diagnosis

• Regular episodes of binge eating — uncontrolled overeating of large amounts of food.
• Extreme compensatory weight-control behaviours to counteract the perceived effects of overeating: self-induced vomiting, purging (laxative/diuretic abuse), driven exercise, and/or fasting.
• Weight in the normal or overweight/obese range.
• Both the bingeing and the compensatory behaviour occur, on average, at least weekly for 3 months.
• Self-evaluation is unduly influenced by body shape and weight.

Management

Psychological therapy

CBT is effective, improving both the eating disorder and associated psychological features (e.g. depression). A typical program includes:

• Education about nutrition, shape/weight issues, and eating-disorder complications (e.g. hypokalaemia).
• Daily self-monitoring of relevant thoughts and behaviours.
• Prescribing a normal eating pattern and prohibiting restrictive dieting.
• Gradual reintroduction of avoided foods.
• Cognitive restructuring to identify and challenge problematic thoughts/attitudes.
• Problem-solving and relapse-prevention strategies.

For some patients standard CBT is more intensive than needed; conversely, patients with severe personality disturbance or a trauma history (e.g. following sexual abuse) may need longer-term or different therapy, such as DBT. CBT-enhanced (CBT-E) extends the standard approach to also address mood intolerance, low self-esteem, clinical perfectionism, and interpersonal difficulties.

Pharmacotherapy

Antidepressants can be used short-term specifically to reduce binge frequency, and/or as an adjunct to psychotherapy.

• Fluoxetine is the first-choice antidepressant — higher doses than used for depression are more effective in trials (60 mg), though starting lower and titrating up limits adverse effects. Typical dose: 20–60 mg each morning.
• Other SSRIs (citalopram 10–40 mg, fluvoxamine 50–300 mg, sertraline 50–200 mg daily) have only very limited trial evidence, uncertain long-term effectiveness, and high trial attrition — less well established than fluoxetine or psychotherapy.
• Topiramate (250 mg daily) has RCT evidence for reducing bingeing/purging and improving quality of life, but isn’t widely used given its significant adverse- effect burden.