What is the likely cause of a 13-year-old patient with a history of depression and anxiety on Wellbutrin XR (bupropion) experiencing an episode of transient paralysis, aphasia, and staring, followed by recovery with emotional release?

Likely Diagnosis: Psychogenic Non-Epileptic Seizure (PNES) or Conversion Disorder

This clinical presentation is most consistent with a psychogenic non-epileptic seizure (PNES) or conversion disorder, particularly given the transient paralysis, aphasia, staring spell with full recovery in 20 minutes, emotional release, and intact memory of the event. 1

Key Diagnostic Features Supporting PNES/Conversion Disorder

The constellation of symptoms strongly suggests a functional neurological disorder rather than an organic neurological event:

• Intact memory during the episode: True epileptic seizures with impaired consciousness typically result in amnesia for the event, whereas this patient could remember what occurred 1
• Rapid complete recovery (20 minutes): Organic neurological events causing paralysis and aphasia (stroke, Todd's paralysis) typically have longer recovery periods 1
• Emotional release associated with recovery: This is characteristic of conversion/dissociative episodes rather than neurological pathology 1
• Combination of motor and speech symptoms: The simultaneous presentation of limb paralysis and aphasia with staring in an adolescent with psychiatric history is classic for PNES 1

Bupropion Considerations

While bupropion (Wellbutrin XR) can lower seizure threshold and cause neurological adverse effects, several factors argue against a medication-induced seizure:

• Seizure characteristics: Bupropion-induced seizures are typically generalized tonic-clonic with loss of consciousness and postictal confusion, not focal deficits with preserved awareness 2, 3
• Dose-dependent risk: At therapeutic doses ≤450 mg/day in divided schedules, bupropion's seizure rate is comparable to other antidepressants 3
• Neurological manifestations: Bupropion overdose causes seizures, encephalopathy, and cardiovascular effects—not isolated transient paralysis with aphasia 2, 4

Critical Differential Considerations

Rule out organic causes first despite the presentation suggesting functional etiology:

• Seizure disorder: Obtain EEG to exclude focal seizures, particularly temporal lobe epilepsy which can present with staring and postictal aphasia (though memory would typically be impaired) 1
• Transient ischemic attack (TIA): Extremely rare in adolescents but must be excluded given the aphasia and paralysis; however, TIAs don't typically present with staring or emotional release 1
• Hemiplegic migraine: Can cause transient paralysis and aphasia but usually includes headache 1
• Medication toxicity: Check bupropion levels if overdose suspected, though clinical picture doesn't fit 2, 4

Recommended Evaluation Algorithm

1. Immediate neurological assessment: Examine for any persistent focal deficits or new neurological findings that would warrant urgent neuroimaging 1

2. EEG monitoring: Obtain routine or video-EEG to capture episodes and differentiate epileptic from non-epileptic events 1

3. Medication review: Verify bupropion dosing is within therapeutic range (≤450 mg/day) and assess for drug interactions, particularly with other serotonergic agents that could cause serotonin syndrome 5

4. Psychiatric evaluation: Given the history of depression/anxiety and the clinical presentation, comprehensive psychiatric assessment is essential to evaluate for conversion disorder, dissociative episodes, or worsening underlying psychiatric condition 1

5. Neuroimaging if indicated: MRI brain only if focal neurological findings persist, concern for structural lesion, or EEG shows focal abnormalities 1

Management Approach

If PNES/conversion disorder is confirmed:

• Avoid reinforcing illness behavior: Present diagnosis in a supportive, non-judgmental manner explaining that symptoms are real but not due to neurological disease 1
• Psychiatric referral: Essential for cognitive behavioral therapy and management of underlying depression/anxiety 1
• Continue bupropion: Unless there's evidence of toxicity or adverse effects, as depression/anxiety are likely contributing to functional symptoms 1
• Monitor for suicidality: Bupropion carries a black box warning for suicidal thinking in patients under age 24; close monitoring is required 1

Important Caveats

Do not dismiss as "just psychiatric" without proper workup: Functional neurological disorders are diagnoses of inclusion based on positive clinical features, not exclusion diagnoses 1. The combination of psychiatric history and functional symptoms doesn't eliminate the need to rule out organic pathology, particularly in a first episode 1.

Bupropion-related concerns: While this presentation is atypical for bupropion toxicity, be aware that bupropion can cause extrapyramidal symptoms (rare), lower seizure threshold, and when combined with SSRIs can precipitate serotonin syndrome 6, 5. However, serotonin syndrome presents with autonomic instability, hyperthermia, and neuromuscular hyperactivity—not isolated paralysis and aphasia 1, 5.