placement. Hospitalized individuals 65 years or older with delirium have three times the
risk of nursing home placemen t and about three times the func tional decline as hospital-
ized patients without delirium at both discharge and 3 months postdischarge. 
Differential Diagnosis 
Psychotic disorders and bipolar and depre ssive disorders with psychotic features.
Delirium that is characterized by vivid hallucinations, delusions, language disturbances,
and agitation must be distinguished from br ief psychotic disorder, schizophrenia, schizo-
phreniform disorder, and other psychotic disord ers, as well as from bipolar and depres-
sive disorders with psychotic features.
Acute stress disorder. Delirium associated with fear, an xiety, and dissociative symptoms,
such as depersonalization, must be distingu ished from acute stress disorder, which is pre-
cipitated by exposure to a severely traumatic event.
Malingering and factitious disorder. Delirium can be distinguished from these disor-
ders on the basis of the often atypical presen tation in malingering and factitious disorder
and the absence of another medical condition or substance that is etiologically related to
the apparent cognitive disturbance.
Other neurocognitive disorders. The most common differential diagnostic issue when
evaluating confusion in older adults is dise ntangling symptoms of delirium and dementia.
The clinician must determine whether the in dividual has delirium; a delirium superim-
posed on a preexisting NCD, such as that due to Alzheimer’s disease; or an NCD without
delirium. The traditional distinction between delirium and dementia according to acute-
ness of onset and temporal course is particularly difficult in those elderly individuals who
had a prior NCD that may not have been reco gnized, or who develop persistent cognitive