Rabbit syndrome induced by the use of Risperidone: a case report

Context: Risperidone is a selective monoaminergic antagonist, its main action as an antipsychotic is attributed to its affinity to dopamine D2 receptors. However, intervention in dopaminergic transmission by this medication can affect the motor control performed by the striatum, generating the so-called extrapyramidal syndromes. Among these syndromes, we have the rabbit syndrome (SC), which is manifested by the chronic use of antipsychotics and causes involuntary movements of the muscles of the jaw and tongue. Case report: E. B. L., a 89- year-old woman undergoing neurological follow-up due to dementia. He started using risperidone 1mg at night to treat behavioral changes and aggressions. However, 4 months after the start of the medication, he started to have a tremor of the chin and stiffness in the upper limbs. These symptoms improved after switching from risperidone to olanzapine 5mg at night. Conclusions: The present study emphasizes the importance of recognizing Rabbit Syndrome and the clinical repercussions of symptomatic variants, such as tardive dyskinesia, nocturnal bruxism and altered tongue motricity, in the differential diagnosis of drug-induced movement disorders. In this sense, neurological assessment includes an elucidating clinical history and targeted physical examination.