Pathological Gambling Disorder Associated With Modafinil Therapy in a Patient With Type 1 Narcolepsy

We report the case of a 22-year-old man with type 1 narcolepsy who experienced pathological gambling after modafinil therapy. The patient was administered with modafinil, which improved excessive daytime sleepiness (EDS). However, he experienced heart palpitations and nervousness, eventually developing gambling addiction. After six months of modafinil therapy, he engaged in various online gambling activities, leading to significant financial loss and stress. Consequently, modafinil was replaced with pitolisant, which is a potent and selective antagonist/inverse agonist of histamine H3 receptor. One month after modafinil discontinuation, EDS symptoms were well controlled with pitolisant and gambling urge was resolved. Modafinil is prescribed as a first-line therapy for treating EDS symptoms in patients with narcolepsy. However, it may cause psychiatric side effects via the dopaminergic system. Alternatively, pitolisant could be used to avoid modafinil’s psychiatric side effects in patients with narcolepsy.