Delirium is a decline in attention and consciousness. This mental disorder also involves perceptual disturbances and problems with eye-hand coordination and the sleep cycle. Although life-threatening, delirium is treatable. Delirium is found in one to two percent of the general population and increases with age. In adults older than 85, around 14% have delirium. In the hospitalized elderly, around 20-60% develop delirium.

Last Updated: September 27, 2023

Delirium is caused by multiple factors but is commonly an illness, a result of a procedure or treatment course (i.e. surgery, ICU stay), and medications. Thus, patients who take several medications or who underwent multiple surgeries will more likely present with signs and symptoms of delirium. Additionally, those who have strokes, multiple illnesses, dementia, and alcoholics are predisposed to developing delirium. 

People who have delirium will usually present with a reduced ability to focus or sustain attention. They also present problems regarding memory, language, reasoning, and perception. They are usually disoriented. 

Doctors classify these symptoms as either hyperactive, hypoactive, or mixed. Hyperreactive symptoms commonly manifest as agitation, restlessness, refusal to cooperate with medical care, hallucinations, delusion, and exaggerations in feelings or emotions. On the other hand, hypoactive symptoms often present as the opposite. For example, sluggishness, lethargy that approaches stupor, and minimal speech. Hypoactive delirium patients are unusually quiet or behaved. Lastly, mixed delirium is when a patient exhibits the behavior of both hyperactive and hypoactive delirium.

Doctors use the Confusion Assessment Method (CAM) to diagnose if a person has delirium or not. A patient must have both features 1 and 2 plus either feature 3 or 4.

Feature 1- Acute change in mental status with a fluctuating course.

Feature 2. Inattention or reduced ability to sustain attention and follow conversations.

Feature 3- Disorganized thinking, or when a patient is asked about a topic but gives a completely unrelated answer. For example, a patient may keep on talking about flowers in a garden but was asked about the current day.

Feature 4- Altered level of consciousness, which can be assessed as alert (normal), vigilant (hyperactive), lethargic (drowsy/easily aroused), stupor (difficult to arouse), or comatose (unarousable).



There are several drugs to treat delirium, including:

  • Haloperidol;
  • Chlorpromazine;
  • Risperidone;
  • and Diazepam.

However, some drugs can indirectly cause delirium; thus, adhering to a physician’s order is necessary.

Prevention remains to be the most effective way in fighting against delirium.  This can be done by reducing the following:

  • sensory deficits;
  • immobility;
  • sleep disturbance;
  • dehydration;
  • cognitive impairment.

Other strategies that can be done to help patients with delirium are the following:

  • communicating clearly and concisely by repeated verbal reminders of the day, time, and location;
  • providing clear signposts denoting the patient’s location;
  • having familiar objects from the patient’s home in the room;
  • using a TV/radio for relaxation to help patients maintain contact with the outside world.


American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.).


Ramírez Echeverría MdL, Schoo C, Paul M. Delirium. [Updated 2022 Sep 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from:

Last Updated: September 27, 2023