Rabbit Syndrome Likely Induced by Escitalopram

Abstract

Objective: As reports of rabbit syndrome (RS) unrelated to antipsychotic medications have appeared, antidepressants, especially serotonin reuptake inhibitors (SSRIs), have been pointed as offenders producing RS. The induction of RS by SSRIs has been thought to be a consequence of serotonergically mediated inhibition of the dopaminergic system. We present a case of escitalopram-induced RS to increase awareness of this problem. Case Summary: A 35-year-old male, diagnosed with moderate depressive disorder, was started on escitalopram 10 mg/day along with clonazepam 0.5 mg at night on an outpatient basis. Personal and family history was not significant for any medical or psychiatric disorder, including movement disorders. Results: Three months after the initiation of escitalopram, the patient started complaining of abnormal trembling perioral movements, which increased on tasks involving focusing. A computed tomography scan of the brain revealed normal findings. With a diagnosis of drug-induced RS, escitalopram was stopped and 2 mg/day trihexyphenidyl was started. The patient reported complete improvement in 20 days. Trihexyphenidyl was stopped and sodium valproate 400 mg was started for irritability. Conclusions: Escitalopram can induce RS. This effect suggests that, for some patients, escitalopram has neuropsychiatric effects similar to those of a dopamine-blocking antipsychotic drug. Besides stopping medication, some patients may require medications temporarily to relieve symptoms.