What are the key differences between dementia, delirium and depression?

In The News, Outcomes & Aging

Delirium and dementia can exist concurrently, but they are not the same. Dementia comes on gradually and is a permanent condition. Delirium usually occurs within hours or days, with fluctuations occurring during the day, and it typically goes away in days to weeks if treated properly. It is important to note that people who have dementia are at an increased risk of developing delirium.

Delays in care for delirium occur when the interprofessional care team does not recognize the cognitive changes in their patients or they inappropriately diagnose the changes as dementia or depression.  A patient’s family or caregiver is essential to identify if an acute change in cognition and behavior occurred (a sign of delirium) or if the observed changes occurred over a longer period (a sign of dementia). 

Three common signs of delirium are:

  • difficulty concentrating
  • changes in behavior, personality, or temperament
  • change in level of consciousness (e.g., being either super alert or drowsy)

One of the most common causes of delirium is medications, especially a reaction to a new medication.  Narcotics, benzodiazepines, anti-cholinergic medications, anti-Parkinsonian drugs, and some anti-epileptic medications are among the most common medications that cause delirium. Acute infection, surgery, or a new illness are other common causes.

Delirium Assessment Tool

There are various delirium assessment tools available for different care settings.  The Confusion Assessment Method for the ICU (CAM-ICU) is a widely used, evidence-based tool.  The 3D-CAM is a newer, brief diagnostic assessment for CAM-defined delirium used in the general medicine and surgical settings; it can be completed in three minutes. 

Within the 3D-CAM, two items were identified that can serve as an ultra-brief screener to rule out delirium in less than 40 seconds (Fick et al., 2018).  The 2-item Ultrabrief (UB) Delirium Screen© includes the following questions:

  • Please tell me the day of the week
  • Please tell me the months of the year backward, say December as your first month

The ultra-brief screener followed by the 3D-CAM is a promising and innovative approach to improve delirium identification by clinicians.

Connection to Hendrich II Fall Risk Model®

Confusion, disorientation and impulsivity are collectively one of the strongest fall risk factors. Delirium and dementia are two underlying causes that could cause these behaviors.  It is recommended that the care team discuss the patient’s history and the onset of these behaviors with their family and caregivers.  Additionally, it is recommended that a care team member conduct the 2-item Ultrabrief (UB) Delirium Screen© to assess for delirium and take action based on the results. 


Fick D., Inouye S., McDermott C., Zhou W., Ngo L., Gallagher J., McDowell J., Penrod J., Siuta J., Covaleski T., Marcantonio E., 2018. Pilot Study of a Two-Step Delirium Detection Protocol Administered by Certified Nursing Assistants, Physicians, and Registered Nurses. J Gerontol Nurs. 44(5) 18-24. doi: 10.3928/00989134-20180302-01

Guthrie P., Rayborn S., Butcher H., 2018. Evidence-Based Practice Guideline: Delirium. J Gerontol Nurs. 44(2) 14-24. doi: 10.3928/00989134-20180110-04

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