About Delirium

The word “delirium” hints at the state of feverish ecstasy that fuels artistic creation and spiritual awakening. But delirium is actually a clearly defined medical condition — and it’s frightening, not exciting.

Delirium is a decline in attention, awareness and mental clarity often triggered by serious illness. The signs of delirium may include restlessness, agitation and combativeness. Often, though, delirium looks like drowsiness and indifference to your surroundings.

Delirium occurs in about one-third of hospitalized people over age 65, and in more than 70 percent of older people in intensive care units. In spite of its frequency, delirium often goes unrecognized, especially in people with dementia.


The most successful approach to preventing delirium is to target risk factors that might trigger an episode. Hospital environments present a special challenge — frequent room changes, use of restraints, loud noise, poor lighting and lack of natural light can worsen confusion.

Strategies that have been proved to help prevent delirium in hospitalized older people include:

  • Simple communication about current place and time
  • Stimulating activities
  • Mobility and range-of-motion exercises
  • Minimal use of psychoactive drugs
  • Uninterrupted sleep
  • Nondrug treatment for sleep problems or anxiety
  • Adequate fluids and nutrition
  • Use of eyeglasses, hearing aids and other adaptive equipment for vision or hearing impairment
  • Pain management

Delirium is one of the top causes of preventable injury in people over age 65. If your parent or another older person in your life enters the hospital, be aware of any subtle changes in behavior. Seek support from hospital staff if you have concerns.

Symptoms of delirium

Delirium is divided into three subtypes, based on differences in behavior.

  • Hyperactive delirium, marked by agitation, irritability, combativeness, rapid or loud speech, and hallucinations
  • Hypoactive delirium, sometimes called “quiet” delirium, marked by drowsiness, apathy, and little to no speech or movement
  • Mixed delirium, alternating between quiet and restless states

Signs and symptoms of delirium can come and go throughout the day, often becoming more severe in the evening and at night. They may include:

  • Constantly shifting attention
  • Confusion
  • Rambling, disorganized or incoherent speech
  • Inability to name objects or learn new information
  • Disorientation, or not knowing where you are
  • Hallucinations (visual or hearing)
  • Emotional disturbances, such as fear, anger, anxiety or irritability
  • Disruptive vocalization, such as screaming, cursing or muttering
  • Increased or decreased activity — constant hand movements (pulling at clothes or bedding), or, conversely, not moving
  • Disrupted sleeping and waking

Although dementia, including Alzheimer’s disease, has many of the same symptoms, it develops more slowly and is permanent. The hallmark of dementia is an alert state with decreased memory.

Causes of delirium

Researchers haven’t pinpointed an exact cause of delirium. Usually, many factors play a role. In someone who’s vulnerable — such as a frail older person — a combination of changes or stresses can intersect to trigger an episode of delirium. For example, a new medication, sleep deprivation or a change in environment may cause delirium when the body is already acutely stressed by blood loss, dehydration, infection or heart attack.

Medications are among the most common triggers for delirium. Medications that can cause delirium include:

  • Antihistamines (Benadryl, Hydroxyzine HCL, others)
  • Pain medications (Demerol, long-acting OxyContin, others)
  • Muscle relaxants (Soma, Flexeril)
  • Benzodiazepines (Ativan, Valium)
  • Sleep medications (Ambien, Sonata)
  • H-2 blockers (Zantac)
  • Anti-emetics (Compazine, prochlorperazine)
  • Antipsychotics (Haloperidol)
  • Antidepressants (nortriptyline, Paxil)
  • Urinary medications (Detrol, Ditropan)

Other possible reasons for delirium include:

  • Sleep deprivation
  • Infection
  • Alcohol withdrawal
  • Metabolic changes due to blood loss, dehydration, heart disease or other changes in body chemistry
  • Dementia, along with a change in environment
  • Low oxygen level
  • Constipation or fecal impaction

Delirium and dementia often overlap. Two-thirds of people who develop delirium have dementia, and the two conditions may share common roots.


Diagnosing delirium can be challenging. Lethargy, behavior changes and thinking problems may be attributed to old age, illness, loss of sleep, fatigue or depression. Delirium is often mistaken for dementia, because many of the signs and symptoms are similar and the two conditions frequently occur in the same person. In diagnosing delirium, a doctor will look first for possible causes of delirium.

The evaluation of delirium relies mainly on a clinical evaluation, which includes:

  • Mental status assessment. A doctor starts by assessing awareness, attention and thinking. This can be done informally through conversation, or more formally with tests or screening checklists that assess mental state, confusion, perception and memory.
  • Medical history. The doctor will try to understand what might have triggered the episode of delirium. Family members and caregivers can provide information about the medical history, since the delirious person likely will not be able to do so. The doctor may ask about the person’s normal behavior patterns, including eating and drinking; any recent illnesses; use of alcohol, sedatives and other drugs; and recent depression, falls or head injuries. He or she will also consider possible infection, breathing problems and cardiovascular symptoms.
  • Medication review. A critical part of diagnosing delirium is to know every medication the person has taken. If possible, a family member should bring in all medications, including over-the-counter drugs, supplements and any other drugs the person may have taken.
  • Physical and neurological exam. The doctor will perform a physical exam, checking for signs of dehydration, infection, alcohol withdrawal and other problems. The physical exam can also help detect underlying disease. Delirium may be the first or only sign of a serious condition such as respiratory failure or heart attack. A neurological exam — checking vision, balance, coordination and reflexes — can help determine if a stroke or another neurological disease is causing the delirium.

Other possible tests
If the cause or trigger of delirium can’t be determined from the medical history or exam, the doctor may order blood, urine and other diagnostic tests such as chest X-ray or electrocardiogram tests. If it’s impossible to determine a cause of delirium, the doctor may consider special neurological studies, such as a CT (computerized tomography) scan, which uses special X-ray equipment to show cross-sectional images of the brain and skull, or an electroencephalogram (EEG), which records the brain’s electrical activity.

Treatment for delirium

The first goal of treatment for delirium is to address any underlying causes or triggering factors — by stopping use of a particular medication, for example, or treating an infection. No medications have been proved effective to treat delirium itself. Instead, treatment focuses on creating an optimal environment for healing the body and calming the brain.

Supportive care
Supportive care aims to prevent complications by protecting the airway, providing fluids and nutrition, assisting with movement, treating pain, addressing incontinence and keeping people with delirium oriented to their surroundings.

A number of simple, nondrug approaches have been found to help.

  • A calm, comfortable environment that includes clocks, calendars and familiar objects
  • Regular verbal reminders of location and what’s happening
  • Involvement of family members
  • Avoidance of change in surroundings and caregivers
  • Uninterrupted periods of sleep at night, with low levels of noise and light
  • Open blinds during the day
  • Avoidance of physical restraints and bladder tubes
  • Use of music, massage and relaxation techniques to ease agitation
  • Opportunities to get out of bed, walk and perform self-care activities
  • Provision of glasses, hearing aids and interpreters as needed

Drug treatment is generally reserved only for people who are very agitated and pose a risk to themselves, to ensure they’re calm enough to be cared for safely. The usual drug of choice is an antipsychotic medication, which is believed to be helpful in treating the disorganized thinking that accompanies delirium.