Clonidine for ADHD with Comorbid Oppositional Defiant Disorder in a Patient with Congenital Long QT Syndrome

Background: Oppositional defiant disorder (ODD) and attention-deficit/hyperactivity disorder (ADHD) co-occur in roughly half of children with ADHD. Pharmacological management for both disorders typically involves stimulants or antipsychotics. However, in patients with congenital Long QT syndrome (LQTS), the use of stimulants might present an additional clinical risk for ventricular arrhythmias. Alternatives must be sought as the impact of these untreated psychiatric conditions can be significantly limiting to these patients.

Case Presentation: A 14-year-old male with ODD and comorbid ADHD was started on risperidone 0.25 mg daily for severe behavioral dysregulation following incidents of serious aggression towards an infant sibling. Electrocardiography demonstrated marked QT prolongation (QTc = 508 ms) and subsequently confirmed a diagnosis of congenital LQTS with a maternal family history over 3 generations. Risperidone was discontinued and nadolol 20 mg daily was initiated by a pediatric cardiologist. After a second psychiatric opinion for persistent ADHD, oppositionality, aggression, and suicide risk, he was started on clonidine, a possible alternative to avoind the use of stimulants or antipsychotics. At the one-month follow-up, parents reported a lessening of impulsivity, physical aggression, and improved emotional self-regulation. He is continuing with psychological and cardiac monitoring.

Discussion: This case demonstrated a different approach to treating patients with congenital LQTS and neurodevelopmental disorders when first-line pharmacotherapies present a risk to the patient. Clonidine offered clinical benefits without the risk of arrhythmia that comes with stimulants or antipsychotics. Given the lack of studies done on this population, more controlled studies are needed to study the effects of clonidine on patients with congenital LQTS and ODD with comorbid ADHD.

Conclusion: Clonidine may be a promising alternative for treating ADHD and ODD in patients with congenital Long QT syndrome, although further research is needed to confirm its safety and effectiveness.