Response: Can Epileptic Seizures Explain Hyperactive Catatonia in Patients with Autism and Intellectual Disability?

To the Editor:

We appreciate the recent letter by Dr. Marques discussing our brief report outlining the use of intramuscular ketamine to obtain intravenous access for electroconvulsive therapy in patients with autism spectrum disorder, intellectual disability, and hyperactive catatonia (Srinivasan et al., 2025). Given the high rates of catatonia and epilepsy in this population (Capal and Jeste, 2024; Smith et al., 2025), as well as the complex interplay between epilepsy and catatonia more broadly (Rogers et al., 2024), Dr. Marques specifically raises the question of epilepsy as a contributing factor for catatonia in this patient population.

While catatonia may occur in the setting of neurodevelopmental disorders without an underlying medical or psychiatric cause, we agree with Dr. Marques that all underlying medical or psychiatric etiologies of catatonia must be ruled out before determining that catatonia is due to autism or another neurodevelopmental disorder. This is especially important for patient populations with communication difficulties, such as pediatrics and neurodivergent individuals. This diagnostic step in the care of individuals experiencing catatonia is critical, as addressing the underlying condition while also treating catatonia directly is likely to lead to the best longitudinal outcome. To address this, we have developed a clinical roadmap at Vanderbilt University Medical Center to ensure adequate medical workup has been undertaken in cases of pediatric catatonia (Smith et al., 2024). While this roadmap is specific to pediatric catatonia, our institution also follows other international guidelines when assessing catatonia in adult patients (Rogers et al., 2023).

Regarding this specific brief report, we did not include diagnostic information, as we felt it was beyond the scope of the article. Our intention was to specifically highlight the safe and successful use of ketamine for autistic patients with hyperactive catatonia who were also prescribed high-dose benzodiazepines. However, we want to assure Dr. Marques that all patients included in this sample underwent extensive medical workups as part of their ongoing medical care and that no other identifiable causes of catatonia were identified in this process. We again thank Dr. Marques for the important points made in their recent letter to the editor.