The Difference between Hallucinations and Delusions
People with hallucinations see, hear, smell, taste, or feel things that aren’t there and ultimately accept the fact that their perceptions are not reality. People with delusions — delirium — are convinced that what they see is real.
Older people recovering in the hospital or living in a long-term care facility are particularly at risk of delirium. Any condition that results in a hospital stay, especially in intensive care, increases the risk of delirium. Common causes include dehydration and infections, such as urinary tract infection, pneumonia, and skin and abdominal infections.
If you notice signs and symptoms of delirium in a person in a hospital or nursing home, report your concerns to the nursing staff or doctor rather than assuming that those problems have been observed. The sooner delirium is identified, the faster it can be treated. With quick treatment, delirium may clear within a few days.
The onset of delirium is usually sudden, often within hours or a few days. (Dementia usually begins with relatively minor symptoms that gradually worsen over time.) The symptoms of delirium often fluctuate throughout the day, so a person may have periods of no symptoms.
Primary Signs and Symptoms of Delirium
A reduced awareness of the environment that may result in:
- An inability to stay focused on a topic or to change topics
- Wandering attention
- Getting stuck on an idea rather than responding to questions or conversation
- Being easily distracted by unimportant things
- Being withdrawn, with little or no activity or little response to the environment
Poor thinking skills (cognitive impairment) that may appear as:
- Poor memory, particularly of recent events
- Disorientation, or not knowing where one is, who one is or what time of day it is
- Difficulty speaking or recalling words
- Rambling or nonsense speech
- Difficulty understanding speech
- Difficulty reading or writing
- Seeing things that don’t exist (hallucinations)
- Restlessness, agitation, irritability or combative behavior
- Disturbed sleep habits
- Extreme emotions, such as fear, anxiety, anger or depression
Mayo Clinic — Diseases and Conditions — Delirium
Delirium vs. Dementia by Leslie Kernisan, MD, in A Place for Mom, July 20, 2015. [excellent article]