Abnormal Psychology

Cognitive Disorders 691

the elderly more vulnerable to develop delirium. Table 15.3 provides additional in-

formation about delirium.

Symptoms of delirium can also occur with other disorders, which may make

it diffi cult to provide a defi nitive—or even a tentative—diagnosis. The following

symptoms may seem similar to those of delirium:

• Psychotic symptoms. In schizophrenia or a mood disorder with psychotic features,

the psychotic elements (i.e., delusions and hallucinations) are often integral to the

symptoms of the disorder. In contrast, in delirium, the aspects of symptoms that

appear psychotic are not as systematic.

• Mood, anxiety, or dissociative symptoms. With mood, anxiety, or dissociative dis-

orders, the symptoms of fear, anxiety, or dissociation are relatively stable and tend

not to vary with cognitive symptoms. In contrast, with delirium, symptoms of

fear, anxiety, or dissociation tend to fl uctuate along with the cognitive symptoms,

and attentional problems are prominent.

If the clinician has reason to suspect that the symptoms arise because of a medi-

cal condition, as in the case of Ms. Richardson, or substance use, delirium is a

tentative diagnosis, pending physical or laboratory tests. In addition, the clinician

Prevalence

• Older adults are more likely than others to develop delirium.


• At any given time, 0.4% of adults over the age of 18 may be delirious; among those 55 years of
  age or older, the prevalence almost triples, to 1.1%.


• Among elderly patients in hospitals, 10–15% are delirious when admitted and 10–40% may be
  diagnosed with delirium during their stay.


• Among residents in nursing homes who are age 75 and older, up to 60% may be delirious at
  any point in time.


• Up to 80% of terminally ill patients will become delirious, particularly when they are close to
  death (Brown & Boyle, 2002).
  Comorbidity


• Delirium may occur along with another cognitive disorder or a substance-related disorder.
  Onset


• When delirium is caused by certain drugs, such as cocaine or hallucinogens (see Chapter 9),
  symptoms usually emerge within minutes to hours. When delirium arises from other sub-
  stances, such as benzodiazepines, symptoms may take longer to emerge.


• Delirium can arise after head trauma, in which case symptoms often develop immediately.
  Course


• Symptoms of delirium typically fl uctuate over the course of the day.


• For most people, symptoms completely subside within a few hours or days; for others, espe-
  cially the elderly, symptoms may persist for months or longer.


• A shorter course occurs when the cause of delirium is contained and brief, as with substance
  intoxication.


• People who had relatively good health and cognitive functioning before their delirium began
  are likely to make a better recovery.


• People with previous episodes of delirium are more vulnerable to subsequent episodes.
  Gender Differences


• Among the elderly, men are more likely than women to become delirious.
  Cultural Differences


• Countries have different guidelines for diagnosing delirium, which can prohibit making mean-
  ingful comparisons across countries (Leentjens & Diefenbacher, 2006).
  Source: Unless otherwise noted, the source for information is American Psychiatric Association, 2000.

Table 15.3 • Delirium Facts at a Glance