Unilateral rubral tremor following treatment with risperidone.

Rubral tremor is a rare movement disorder that occurs typically with midbrain damage. The main features of this tremor are its low frequency, irregular rhythm, presence at rest, and acceleration during posture and active movement. Antipsychotic agent-induced tremors are usually bilateral parkinsonian tremors. We found no previous reports of unilateral rubral tremor in the literature. A 23-year-old man had unilateral rubral tremors as a result of a midbrain lesion plus risperidone exposure for treatment of manic symptoms. After we stopped the use of risperidone, the tremor became less apparent and then disappeared. This case highlights the importance of being aware of this rare complication in susceptible patients receiving risperidone treatment.