In our clinical practice, we encountered a patient with autism spectrum disorder (ASD) and comorbid narcolepsy who developed dyskinesia following the administration of modafinil for excessive daytime sleepiness. Modafinil is widely prescribed as a wakefulness-promoting agent for the treatment of narcolepsy. Although dyskinesia has been reported as a potential adverse effect of modafinil, to our knowledge, no cases have been described in individuals with ASD. We hypothesized that modafinil contributed to the development of dyskinesia in this patient and conducted a literature review to explore the possible underlying mechanisms. A 24-year-old Japanese woman with ASD was diagnosed with narcolepsy type 2. She had previously been treated with aripiprazole for ASD-related symptoms, but it had been discontinued more than two weeks before the sleep study. Modafinil was initiated at 100 mg/day and increased to 200 mg/day after three weeks because of insufficient efficacy. Two weeks after the dose increase, dyskinesia developed. A literature review was performed to identify potential mechanisms. Dyskinesia may have resulted from dysregulated striatal dopamine release associated with ASD and residual dopamine D2 receptor blockade from prior aripiprazole use, triggered by modafinil. Dopaminergic agents in individuals with ASD may induce dyskinesia, particularly following dose escalation, underscoring the need for clinical vigilance.
Niijima et al. (Mon,) studied this question.