Psychiatry of Eating Disorders

Introduction

Eating disorders are complex mental health conditions that have a significant impact on both physical and psychological well-being. This guide aims to provide an overview of the psychiatry of eating disorders, focusing on key points that are relevant for the United States Medical Licensing Examination (USMLE).

Definition and Classification

• Eating disorders are characterized by disturbances in eating behaviors and attitudes towards food, weight, and body shape.
• The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) classifies eating disorders into several categories:
  • Anorexia nervosa (AN)
  • Bulimia nervosa (BN)
  • Binge eating disorder (BED)
  • Avoidant/restrictive food intake disorder (ARFID)
  • Other specified feeding or eating disorder (OSFED)
  • Unspecified feeding or eating disorder (UFED)

Anorexia Nervosa (AN)

• AN is characterized by:
  • Restriction of energy intake leading to significantly low body weight
  • Intense fear of gaining weight or becoming fat
  • Disturbance in perception of body weight or shape
• AN subtypes:
  • Restricting type: Weight loss achieved primarily through dieting, fasting, or excessive exercise.
  • Binge-eating/purging type: Recurrent episodes of binge eating or purging behaviors (e.g., self-induced vomiting or misuse of laxatives).

Bulimia Nervosa (BN)

• BN is characterized by:
  • Recurrent episodes of binge eating (eating an unusually large amount of food in a discrete period) combined with a sense of lack of control.
  • Recurrent inappropriate compensatory behaviors to prevent weight gain (e.g., self-induced vomiting, misuse of laxatives, excessive exercise).
  • Self-evaluation influenced by body shape and weight.
• BN subtypes:
  • Purging type: Regular use of self-induced vomiting or misuse of laxatives, diuretics, or enemas.
  • Non-purging type: Inappropriate compensatory behaviors other than vomiting or misuse of laxatives.

Binge Eating Disorder (BED)

• BED is characterized by:
  • Recurrent episodes of binge eating without inappropriate compensatory behaviors.
  • Eating more rapidly than normal, eating until uncomfortably full, eating large amounts when not physically hungry, eating alone due to embarrassment, or feeling disgusted, depressed, or guilty after overeating.
• BED is the most common eating disorder in the United States.

Assessment and Diagnosis

• Diagnosis of eating disorders involves a comprehensive assessment, including:
  • Detailed history of eating patterns, weight changes, and psychological symptoms.
  • Physical examination, including vital signs and assessment of nutritional status.
  • Laboratory investigations to assess electrolytes, liver function, and hormonal profiles.
  • Psychological evaluation, including assessment of body image dissatisfaction, self-esteem, and co-occurring mental health conditions.
• It is important to rule out any medical conditions that may mimic or contribute to eating disorder symptoms.

Management

• The management of eating disorders requires a multidisciplinary approach involving psychiatrists, psychologists, dieticians, and other healthcare professionals.
• Treatment modalities include:
  • Psychotherapy: Cognitive-behavioral therapy (CBT) is the most effective psychotherapy for eating disorders.
  • Medications: Selective serotonin reuptake inhibitors (SSRIs) may be used in BN and BED, but have limited efficacy in AN.
  • Nutritional rehabilitation: Restoration of normal eating patterns and weight regain under the supervision of a dietician.
• Hospitalization may be required for patients with severe AN, medical complications, or imminent danger to themselves.

Prognosis and Complications

• Eating disorders have a significant impact on physical health, leading to complications such as electrolyte imbalances, cardiac arrhythmias, osteoporosis, and gastrointestinal disturbances.
• Psychiatric comorbidities, including depression, anxiety disorders, and substance use disorders, are commonly associated with eating disorders.
• Early intervention and comprehensive treatment can significantly improve the prognosis, but relapse rates remain high.

Conclusion

Understanding the psychiatry of eating disorders is essential for healthcare professionals involved in the care of patients with these conditions. This guide provides a concise overview of the key aspects of eating disorders that are relevant for the USMLE.