Subsyndromal Delirium.

The authors sought to determine whether subsyndromal delirium is a qualitatively distinct clinical entity or a spectrum of cognitive and behavioral abnormalities. They conducted a prospective, longitudinal study on 325 patients in an acute care hospital with 3- and 6-month follow-ups. Patients were classified into one of three groups: those meeting full DSM criteria for delirium, those with subsyndromal delirium, and those with no symptoms of delirium. There were no differences in risk factors between those developing DSM-defined delirium or subsyndromal delirium. Number of independent risk factors was a significant predictor of delirium. Patients with subsyndromal delirium fall on a continuum between those with DSM-defined delirium and those with no symptoms of delirium. These data suggest that delirium does represent a spectrum of neurobehavioral impairment. Patients with symptoms of subsyndromal delirium are at risk for considerable morbidity; therefore clinicians should attempt to reduce and treat the onset of occurrence of subsyndromal delirium.