DSM Diagnostic Criteria and Treatment for Bulimia Nervosa and OCD
Bulimia Nervosa
DSM-5 Diagnostic Criteria
Bulimia nervosa requires recurrent episodes of binge eating followed by inappropriate compensatory behaviors to prevent weight gain, occurring at least once weekly for 3 months, with self-worth overly influenced by body shape and weight. 1
The core diagnostic features include:
- Recurrent binge eating episodes: Consuming a larger amount of food within a discrete 2-hour period compared to what most people would eat, with a perceived lack of control during the episode 2
- Inappropriate compensatory behaviors: Self-induced vomiting, laxative abuse, periods of starvation, or excessive exercise 1
- Frequency threshold: Behaviors must occur at least once weekly for 3 months (reduced from twice weekly in DSM-IV) 1
- Body image disturbance: Self-evaluation is unduly influenced by body shape and weight 1
Key Differential Diagnosis
The primary distinction between anorexia nervosa binge-eating/purging subtype and bulimia nervosa is weight status—individuals with bulimia nervosa do not maintain significantly low body weight. 1, 3
Treatment Recommendations
For adults with bulimia nervosa, the recommended first-line treatment is eating disorder-focused cognitive-behavioral therapy (CBT) combined with fluoxetine 60 mg daily. 1
- Pharmacotherapy: Fluoxetine (Prozac) 60 mg/day is FDA-approved for bulimia nervosa and indicated for treatment of binge-eating and vomiting behaviors in patients with moderate to severe bulimia nervosa 4
- Psychotherapy for adults: Eating disorder-focused CBT addresses both psychological aspects (fear of weight gain, body image disturbance) and behavioral components (normalizing eating patterns, eliminating compensatory behaviors) 1
- Treatment for adolescents: For adolescents and emerging adults with involved caregivers, eating disorder-focused family-based treatment is the preferred approach 1
Clinical Assessment Essentials
Comprehensive assessment should include:
- Vital signs and anthropometrics: Height, weight, BMI, and physical examination for signs of malnutrition or purging behaviors (e.g., Russell's sign, dental erosion, parotid enlargement) 1
- Laboratory evaluation: Complete blood count, comprehensive metabolic panel with particular attention to electrolytes (hypokalemia, hypochloremia), liver enzymes, and renal function 1
- Cardiac assessment: Electrocardiogram is recommended for patients with severe purging behaviors due to potential cardiac complications including QTc prolongation 1
Obsessive-Compulsive Disorder (OCD)
DSM-5 Diagnostic Criteria
OCD is characterized by the presence of obsessions and/or compulsions that are time-consuming (>1 hour daily) and cause clinically significant distress or functional impairment. 5
Core diagnostic features include:
- Obsessions: Recurrent, persistent, intrusive thoughts, impulses, or images that are ego-dystonic and cause marked anxiety or distress 5
- Compulsions: Repetitive, purposeful, intentional behaviors or mental acts performed in response to obsessions or according to rigid rules, recognized as excessive or unreasonable 5
- Clinical significance criterion: Obsessions and compulsions must be time-consuming (taking up >1 hour daily) and cause substantial distress or functional impairment 5
- Diagnostic hierarchy: Symptoms are not attributable to substance effects, another medical condition, or better explained by another mental disorder 5
DSM-5 Specifiers
Three insight specifiers are critical for treatment planning: good/fair insight, poor insight, and absent insight/delusional beliefs. 5
- Insight specifiers: Individuals with absent insight or delusional beliefs are convinced their OCD beliefs are true and must be recognized to avoid misdiagnosis as a psychotic disorder 5
- Tic specifier: Denotes individuals with current or past tic disorder; males are more likely to have early-onset OCD with comorbid tics 5
Treatment Recommendations
For adult OCD, first-line treatment is a selective serotonin reuptake inhibitor (SSRI) or clomipramine combined with exposure and response prevention (ERP) therapy. 4, 6
Pharmacotherapy Options:
- Fluoxetine (Prozac): FDA-approved for OCD in adults and children/adolescents; effective for treatment of obsessions and compulsions when they cause marked distress, are time-consuming, or significantly interfere with functioning 4
- Clomipramine: FDA-approved for OCD; demonstrated effectiveness in multicenter placebo-controlled trials with mean YBOCS reduction of approximately 10 points (35-42% improvement in adults, 37% in children/adolescents); maximum dose 250 mg/day for adults, 3 mg/kg/day (up to 200 mg) for children/adolescents 6
Key Treatment Considerations:
- Symptom dimensions: Obsessions and compulsions fall into stable symptom dimensions (contamination/cleaning, symmetry/ordering, forbidden thoughts/checking, hoarding) that tend to remain stable within individuals over time 5
- Duration of treatment: Long-term effectiveness beyond 13 weeks requires periodic reevaluation of treatment utility 4, 6
Differential Diagnosis Pitfalls
OCD must be distinguished from normal intrusive thoughts, which are common in the general population but do not consume >1 hour daily or cause substantial impairment. 5
Critical distinctions:
- Versus generalized anxiety disorder/depression: Worries and ruminations in GAD/depression are about real-life concerns and less irrational/ego-dystonic than OCD; compulsions are typically absent 5
- Versus other OCRDs: Body dysmorphic disorder, hoarding disorder, trichotillomania, and excoriation disorder have distinct foci of apprehension and forms of repetitive behaviors 5
- Versus psychotic disorders: OCD with absent insight/delusional beliefs should not be misdiagnosed as psychosis; OCD beliefs are specifically related to obsessional content without additional psychotic features 5
Clinical Assessment Essentials
Comprehensive psychiatric assessment should evaluate symptom dimensions, degree of insight, presence of tics, and functional impairment across multiple domains. 5