On Seizures and Knives: Perampanel-Induced Psychosis: A Case Report and Literature Review

Managing epilepsy in the context of intellectual disability can be complicated as this population is known to have higher rates of drug resistance and sensitivity to side effects of antiseizure medications (ASMs). Perampanel is a novel ASM recently approved as an adjunctive treatment for drug resistant focal seizures. It carries a black-box warning for serious psychiatric and behavioral adverse reactions of aggression, irritability, et cetera. However, psychosis is a seldom reported side effect of perampanel. We herein describe a case of a 15-year-old girl with moderate intellectual disability who presented with refractory seizures managed successfully after using perampanel. Around 2 months later, she developed psychosis and aggression. The patient's history lacked any significant family or personal history of mental illness. Managing psychotic symptoms was difficult in this case; as perampanel was needed for proper seizure control, and both psychosis and seizures were severe and significantly endangering the patient and people around her. Thus, symptoms were addressed by adding a low-dose risperidone, an atypical antipsychotic. This paper highlights the importance of pre-treatment counselling and monitoring for the emergence of psychiatric side effects including the rarely occurring psychosis while using perampanel, particularly in highly sensitive patients, e.g., those with intellectual disability. We also emphasize on the importance of accurate weighing of risks and benefits while managing psychosis as an adverse event to ASMs in the background of drug-resistant epilepsy.