Delirium 601
ium. Delirium may progress to stupor, coma, seizures, or death, particularly if the under-
lying cause remains untreated. Mortality amon g hospitalized individuals with delirium is
high, and as many as 40% of individuals with  delirium, particularly those with malignan-
cies and other significant underlying medical illness, die within a year after diagnosis. 
Risk and Prognostic Factors 
Environmental. Delirium may be increased in the cont ext of functional impairment, im-
mobility, a history of falls, low levels of activity, and use of drugs and medications with
psychoactive properties (particularly alcohol and anticholinergics).
Genetic and physiological. Both major and mild NCDs can increase the risk for delir-
ium and complicate the course. Older individu als are especially susceptible to delirium
compared with younger adults. Susceptibilit y to delirium in infancy and through child-
hood may be greater than in early and mi ddle adulthood. In ch ildhood, delirium may be
related to febrile illnesses and certain medications (e.g., anticholinergics).
Diagnostic Markers
In addition to laboratory find ings characteristic of underlying medical conditions (or in-
toxication or withdrawal states), there is often generalized slowing on electroencephalog-
raphy, and fast activity is oc casionally found (e.g., in some cases of alcohol withdrawal
delirium). However, electroence phalography is insufficiently sensitive and specific for di-
agnostic use.
Functional Consequences of Delirium 
Delirium itself is associated with increased functional decline and risk of institutional
placement. Hospitalized individuals 65 years or older with delirium have three times the