The second generation antipsychotic risperidone is generally considered to have low cardiac adverse events, with an increased risk of ventricular arrhythmias being reported only rarely in literature. We report here the case of a patient with a significant history of alcohol dependence, yet with no previous cardiac history, who had previously tolerated risperidone well, but had experienced isolated sinus tachycardia in the post detox period, following the reinitiation of risperidone therapy. The Naranjo Adverse Drug Reaction (ADR) probability scale rating for this being a medication adverse event (AE) was 4, thus indicating that this patient's AE was associated with risperidone therapy. This case report will contribute to the limited evidence of adverse cardiac events associated with risperidone therapy, with particular emphasis on the susceptibility of patients in a state of autonomic hypersensitivity.