How does thyroid dysfunction impact Attention Deficit Hyperactivity Disorder (ADHD) symptoms in teenagers taking Wellbutrin (bupropion)?

How Thyroid Dysfunction Impacts ADHD Symptoms in Teenagers on Wellbutrin

Thyroid dysfunction worsens ADHD symptoms and occurs at significantly higher rates in adolescents with ADHD (5.4% vs <1% in the general population), but neither the thyroid abnormalities nor bupropion treatment directly cause each other—instead, they represent independent comorbidities that must be screened for and managed separately. 1, 2

The Bidirectional Relationship

Prevalence of Thyroid Dysfunction in ADHD

• Adolescents with ADHD have 1.72 times higher risk of hyperthyroidism and 2.23 times higher risk of hypothyroidism compared to peers without ADHD 2
• Approximately 5.4% of children and adolescents with ADHD have thyroid function abnormalities, compared to less than 1% in the general population 1
• In two-thirds of cases, ADHD is diagnosed before hyperthyroidism becomes apparent, and in half of cases, ADHD precedes hypothyroidism diagnosis 2

Impact on ADHD Symptom Presentation

• Thyroid dysfunction exacerbates the executive function deficits already present in ADHD, including visuospatial and verbal working memory, inhibitory control, vigilance, planning, and reward regulation 3, 4
• Hypothyroidism specifically worsens inattention, cognitive slowing, and the "brain fog" complaints common in ADHD 3
• Hyperthyroidism amplifies hyperactivity, impulsivity, and emotional dysregulation symptoms 2

Critical Clinical Implications for Teenagers on Bupropion

Bupropion Does Not Cause Thyroid Dysfunction

• ADHD pharmacotherapy, including stimulants and bupropion, has no significant influence on the risk of developing hyperthyroidism (aHR: 1.09, P=0.363) or hypothyroidism (aHR: 0.95, P=0.719) 2
• Bupropion remains a safe nonstimulant option for adolescents with ADHD, with efficacy comparable to methylphenidate 5
• Bupropion is particularly valuable when comorbid depression, anxiety, or substance use disorders are present 5

Mandatory Screening Protocol

• The American Academy of Pediatrics mandates screening all adolescents with newly diagnosed ADHD for multiple comorbidities, and thyroid dysfunction should be added to this assessment given the 5.4% prevalence 6, 1
• Obtain baseline thyroid function tests (TSH, free T4, total T4) in all adolescents presenting with ADHD symptoms 1
• Repeat thyroid screening if ADHD symptoms worsen despite adequate treatment, or if new symptoms suggesting thyroid dysfunction emerge 1, 2

Treatment Algorithm for Adolescents with Both Conditions

When Thyroid Dysfunction is Detected

1. Treat the thyroid dysfunction first to physiologic normalization before expecting full ADHD symptom control 1
2. Continue bupropion during thyroid treatment—no medication adjustment is needed based solely on thyroid status 2
3. Re-evaluate ADHD symptom severity after achieving euthyroid state, as some symptoms may improve with thyroid normalization alone 1

Optimizing Bupropion in This Population

• Bupropion demonstrates efficacy in improving ADHD symptoms in adolescents, with effect sizes smaller than methylphenidate but with better tolerability profile (fewer headaches) 5
• Bupropion is particularly advantageous when comorbid depression or anxiety is present, as these internalizing conditions are more common in adolescents with ADHD and may be amplified by thyroid dysfunction 3, 5
• The dopamine and norepinephrine reuptake inhibition mechanism of bupropion addresses ADHD symptoms without cardiac side effects seen with some stimulants 7, 5

Common Pitfalls to Avoid

Do Not Assume Thyroid Dysfunction Explains All ADHD Symptoms

• While thyroid abnormalities are more common in ADHD, generalized resistance to thyroid hormone (GRTH) is extremely rare (prevalence <1:2500) and should not be routinely suspected 1, 8
• Mild laboratory thyroid abnormalities may not differ significantly from rates in normal children and may not require treatment 8

Do Not Discontinue ADHD Treatment While Addressing Thyroid Issues

• Untreated ADHD increases risk for early death, suicide, psychiatric comorbidity, lower educational achievement, motor vehicle crashes, criminality, and substance use disorders 6, 3
• Continue bupropion while initiating thyroid hormone replacement or antithyroid medication 2
• The American Academy of Pediatrics recommends managing ADHD as a chronic condition following medical home principles with ongoing monitoring 6, 3

Screen for Additional Comorbidities

• Adolescents with ADHD require screening for substance use, depression, anxiety, and learning disabilities, as these fundamentally alter treatment approach 6, 3
• Girls with ADHD are more likely to have internalizing conditions such as anxiety or depression, which can be worsened by thyroid dysfunction 4

Monitoring Strategy

• Establish bidirectional communication with school personnel to monitor functioning across settings, as both thyroid dysfunction and ADHD affect academic performance 6, 3
• Reassess thyroid function every 6-12 months in adolescents with ADHD, particularly if symptom control deteriorates 1, 2
• Monitor for emergence of new psychiatric comorbidities throughout treatment, as the majority of adolescents with ADHD meet criteria for another mental health disorder 6, 4