Neuropsychiatric factors in the illusion of visitors among geriatric patients: a case series.

The 'illusion of visitors' is a common phenomenon among geriatric patients presenting for psychiatric or neurologic evaluation and treatment. Although these illusory beliefs are etiologically diverse, patients may commonly have visual impairment and functional and/or structural disruption of frontal and right-hemisphere-mediated cognitive functioning. This article outlines eight cases of illusory beliefs among elderly patients, presenting psychiatric, neurologic, neuroimaging, and neuropsychological findings among these patients. Commonalities and differences among these cases are discussed, and a framework is provided for multidisciplinary assessment and treatment of patients presenting with illusory beliefs.