What is the treatment for anorexia nervosa?

Treatment of Anorexia Nervosa

Anorexia nervosa requires intensive multidisciplinary treatment centered on eating disorder-focused psychotherapy (minimum weekly, preferably biweekly sessions), structured nutritional rehabilitation targeting 0.5-1 kg weekly weight gain to achieve BMI >18.5 kg/m², medical monitoring with weekly vital signs and weight checks initially, and consideration of SSRI therapy for comorbid psychiatric symptoms. 1

Initial Assessment Requirements

Before initiating treatment, conduct a comprehensive psychiatric evaluation that includes:

• Current weight and BMI calculation to establish baseline severity 1, 2
• Quantification of all restrictive eating behaviors and compensatory behaviors (vomiting, laxative use, excessive exercise) with frequency documentation 3, 1
• Vital signs assessment including orthostatic measurements, as cardiovascular instability is common and life-threatening 4
• Laboratory evaluation including complete blood count, comprehensive metabolic panel, and electrolytes to identify hypokalemia, hypochloremic alkalosis from purging, or hyponatremia from fluid manipulation 3, 2
• Electrocardiogram to evaluate for QTc prolongation and arrhythmias 2
• Screening for psychiatric comorbidities including depression, anxiety, obsessive-compulsive disorder, and substance abuse 3, 1
• Assessment of suicidal ideation and history of physical or sexual abuse 3

Psychotherapy Framework

Individual eating disorder-focused psychotherapy is the cornerstone of treatment and must be implemented at minimum weekly frequency, with biweekly sessions preferred during active treatment phases. 1 The therapy should utilize cognitive behavioral techniques specifically adapted for anorexia nervosa, focusing on normalizing eating behaviors, addressing distorted cognitions about weight and body image, and treating the psychological aspects driving the disorder. 2

Family therapy is crucial when treating younger patients, as parental involvement significantly impacts long-term prognosis. 3 Evaluate parents' understanding of the illness and their approach to treatment, as denial or conflicting treatment philosophies can exacerbate the condition. 3

Nutritional Rehabilitation Protocol

Set individualized weekly weight gain targets of 0.5-1 kg per week for outpatient treatment, with higher goals of 1-1.5 kg weekly appropriate for inpatient settings. 1 These targets should be adjusted based on age, height, pubertal stage, premorbid weight, and previous growth charts. 3

Calculate target weight range based on multiple physiological markers: restoration of menses in females, achievement of BMI >18.5 kg/m², and return of normal physiological functioning including normalized vital signs and electrolytes. 1, 4

A critical pitfall is refeeding syndrome in severely malnourished patients—avoid replenishing nutrients too quickly and consider phosphorus supplementation during initial refeeding. 3 This complication can be fatal if not anticipated and prevented through slow, monitored nutritional rehabilitation.

Medical Monitoring Schedule

During the first 3 months of treatment, conduct weekly weight checks and vital sign assessments to monitor cardiovascular stability and weight restoration progress. 1 Orthostatic vital signs are particularly important as they indicate volume status and cardiovascular adaptation. 4

Laboratory reassessment should occur every 2-4 weeks initially, then transition to monthly intervals as medical stability improves. 1 Focus on electrolytes (potassium, chloride, sodium), as abnormalities are common despite often being initially normal. 3

For patients with amenorrhea, monitor for long-term complications of osteopenia and osteoporosis, which develop from hypogonadotropic hypogonadism and require long-term management. 3

Pharmacological Considerations

Consider SSRI therapy specifically for comorbid anxiety, depression, or obsessive-compulsive symptoms that commonly present as neuropsychiatric features in anorexia nervosa. 1 Note that SSRIs are not effective for treating the core symptoms of anorexia nervosa itself, but address frequently co-occurring conditions that impact recovery. 1

Symptomatic treatment for gastrointestinal distress and constipation is often necessary as these are common complications of malnutrition and restrictive eating. 3

Hospitalization Criteria

Categorical restriction from all activities and immediate hospitalization is required for:

• BMI <16 kg/m² in patients with diagnosed anorexia nervosa 3, 4
• Severe orthostatic hypotension (e.g., systolic BP drop >20 mmHg with heart rate increase >30 bpm) indicating cardiovascular instability 4
• Rapid weight loss exceeding 15-20% over 3 months 4
• Moderate-to-severe bulimia nervosa with purging >4 times per week 3
• Concurrent stimulant abuse (e.g., Adderall), which must be discontinued immediately due to risk of sudden cardiac death 4

Discharge from hospitalization requires: BMI >18.5 kg/m², normalized orthostatic vital signs, normal electrolytes maintained on oral intake, and an established outpatient multidisciplinary treatment plan. 4

Technology-Augmented Support

Online self-monitoring tools or mobile applications for daily food intake, weight tracking, and mood logging can enhance treatment adherence between sessions. 1 Email or secure messaging support between scheduled appointments improves outcomes and patient satisfaction. 1

Prognostic Indicators

Positive prognostic factors include: higher baseline BMI at treatment initiation and shorter total illness duration. 1

Poor prognostic indicators requiring treatment intensification include: longer illness duration (>10 years), BMI <16 kg/m², alcohol or substance abuse comorbidity, and poor social adjustment. 3, 1 These patients have higher premature mortality rates and require more aggressive intervention. 3

Treatment Escalation for Severe and Enduring Cases

For patients with several years of unsuccessful treatment, consider escalating interventions including highly intensive outpatient programs, eating disorder daycare, residential treatment, or inpatient specialized eating disorder services. 5 After prolonged futile treatment, deep brain stimulation should be considered to prevent chronic disease course. 5

Nutritional interventions can be escalated from counseling to nasogastric tube feeding when oral intake is insufficient. 5 Patients who rely on nasogastric feeding long-term may benefit from percutaneous endoscopic gastrostomy (PEG), and those who vomit despite nasogastric tubes may require nasojejunal tube feeding. 5

Critical Clinical Pitfall

Most medical complications of anorexia nervosa are reversible with optimal medical care, but the disorder has the highest mortality rate of any psychiatric disorder. 6 The key to preventing mortality is early recognition, aggressive treatment, and avoiding premature discharge or inadequate treatment intensity. 3, 6 Normal laboratory results do not exclude serious illness or medical instability—clinical assessment of weight status, vital signs, and eating behaviors is paramount. 3