Treatment of ADHD in Patients with Comorbid Bulimia Nervosa
For patients with comorbid ADHD and bulimia nervosa, the recommended first-line treatment approach is eating disorder-focused cognitive-behavioral therapy (CBT) combined with a serotonin reuptake inhibitor (e.g., fluoxetine 60mg daily), while carefully considering atomoxetine as the preferred ADHD medication instead of stimulants. 1, 2
Assessment Considerations
- Comprehensive evaluation should include:
- Assessment of vital signs, including orthostatic measurements
- Physical examination for signs of malnutrition or purging
- Laboratory assessment (CBC, comprehensive metabolic panel)
- ECG (especially important due to risk of QTc prolongation with some medications)
- Screening for substance use disorders (relevant for stimulant consideration)
- Assessment of comorbid psychiatric conditions 1
Treatment Algorithm
Step 1: Address the Eating Disorder First
- Begin with eating disorder-focused CBT as the foundation of treatment 1
- Add fluoxetine 60mg daily either initially or if minimal response to psychotherapy alone by 6 weeks 1
- For adolescents with involved caregivers, consider eating disorder-focused family-based treatment 1
Step 2: ADHD Treatment Selection
For patients with bulimia nervosa and ADHD, consider atomoxetine as first-line ADHD treatment 2
- Starting dose: 0.5 mg/kg/day
- Target dose: 1.2 mg/kg/day
- Advantages: Non-stimulant with less risk of abuse potential and may help with impulse control
Avoid stimulants as first-line treatment due to:
- Risk of exacerbating eating disorder symptoms
- Appetite suppression that could complicate eating disorder treatment
- Abuse potential in a vulnerable population 2
Step 3: Monitoring and Follow-up
- Regular monitoring of:
- Eating disorder symptoms (binge/purge frequency)
- ADHD symptoms
- Vital signs (blood pressure, heart rate)
- Weight and BMI
- Medication side effects
- For atomoxetine: liver function and suicidal ideation 2
Special Considerations
When to Consider Stimulants
Despite general caution, stimulants may be considered in specific circumstances:
- When atomoxetine has failed to adequately control ADHD symptoms
- When bulimia symptoms are stable or in remission
- When there is no history of substance abuse
- With close monitoring by a multidisciplinary team 3, 4
Some case reports suggest stimulants may reduce binge eating and purging in patients with comorbid ADHD and bulimia nervosa 3, 5. However, the evidence is limited to case reports and small studies, and the high rate of adverse effects (including weight loss, decreased appetite, cardiovascular effects) makes this approach risky 4.
Comorbidity Patterns
- Up to 31-37% of patients with bulimia nervosa may have ADHD symptoms 6
- Binge eating/purging behaviors are strongly associated with ADHD symptoms 6, 7
- Recovery from bulimia is associated with decreased ADHD symptoms, suggesting a bidirectional relationship 7
Treatment Pitfalls to Avoid
- Do not initiate stimulant medication before stabilizing the eating disorder - this could worsen the eating disorder through appetite suppression
- Do not overlook the need for regular ECG monitoring - both eating disorders and some ADHD medications can affect cardiac function
- Do not treat ADHD in isolation - the comprehensive treatment plan must address both conditions simultaneously
- Do not assume ADHD symptoms are stable - they may improve with successful eating disorder treatment 7
Evidence Limitations
Current evidence for treating this comorbidity is limited:
- Most studies are case reports or small case series 3, 4, 5
- There are insufficient controlled trials examining stimulant use in patients with both conditions 4
- Guidelines do not specifically address this comorbidity in detail
When treating this challenging comorbidity, prioritize eating disorder treatment while carefully selecting ADHD medications that minimize risks to eating disorder recovery.