16 DELIRIUM
General Discussion
Delirium is often initially misdiagnosed as depression or dementia. In distinguishing delirium from depression, an evaluation of the onset and timeline of depressive and cognitive symptoms is important. The degree of cognitive impairment in delirium is much more severe and pervasive than in depression, with a more abrupt temporal onset. In addition, delirium manifests a disturbance in arousal or consciousness, while it is usually not a feature of depression. When considering dementia, it is important to remember that the patient with dementia is alert and does not have the disturbance of consciousness or arousal that is characteristic of delirium. Dementia is characterized by a more gradual onset of symptoms and is chronically progressive, with less impairment of the sleep–wake cycle.
