The Three Ds: Dementia, Delirium, and Depression

by Anthony J. Caprio, MD
November 2008

Everyone forgets names or misplacing an item from time to time. However, more serious memory problems can be observed in older adults. Forgetting names of close acquaintances, repeatedly mixing-up medications, or getting lost in familiar places are not typical lapses in memory and should prompt a more thorough evaluation. Although dementia is the most frequently discussed cognitive (thinking and memory) disorder in older adults, delirium and depression are important diagnoses which must be considered when evaluating patients for problems with memory and cognition.

Dementia is a general term used to describe a gradual loss in cognitive ability due to a variety of causes. In addition to a loss of memory, persons with dementia exhibit problems in other areas of thinking. This may include problems with orientation, language, judgment, or remembering how to perform simple, routine tasks. Progressive memory loss associated with dementia tends to involve short-term (recent) memory initially, but eventually involves long-term memory. Alzheimer’s Disease is the most common cause of dementia. Another common cause of dementia is "vascular" disease, or diseases associated with abnormal blood flow resulting in damage to the brain, such as the damage caused by a stroke. Many people with dementia probably have a mixture of Alzheimer’s Disease and vascular dementia.

Dementia is usually diagnosed after a clinical evaluation by a physician or other health care professional. There is no single test to diagnose dementia but the presence of memory symptoms and an abnormal performance on standardized cognitive tests can help support the diagnosis. Certain blood tests can identify underlying treatable medical problems which can interfere with memory, such as an underactive thyroid gland or vitamin B12 deficiency. Often, a CT scan or MRI is used to evaluate for evidence of strokes or other abnormalities which could interfere with memory. In rare cases, when the diagnosis is still uncertain, a Positron Emission Tomography (PET) scan is used to look for abnormal activity in certain areas of the brain associated with Alzheimer’s disease. A referral to a geriatric evaluation clinic, neurologist, or psychiatrist may also be helpful for sorting-out the causes of memory problems and for developing strategies to help slow cognitive decline and maximize a person’s daily functioning.

In general, dementia is associated with abnormally low levels of a neurotransmitter in the brain called acetylcholine. Most medications used to treat dementia help to increase levels of acetylcholine in the brain. Although these treatments are not a cure, they can help reduce the symptoms associated with dementia and enable people to function better in their daily lives. For patients with evidence of vascular dementia, controlling stroke risk factors, such as high blood pressure, high cholesterol, and diabetes, are important ways to prevent further strokes and declines in memory. Remaining physically and mentally active also helps persons with dementia maintain independence and slow decline.

Unfortunately, dementia is a progressive disease and the symptoms of memory loss and cognition tend to slowly worsen over time. In addition to memory problems, patients with dementia may eventually develop problems with eating, drinking, walking, and speaking. Support from groups like the Alzheimer’s Association can help address some of the complications associated with dementia including behavioral problems, safety concerns, and caregiver burn-out.

In contrast to dementia, delirium is a problem with memory and cognition which tends to develop very quickly and can fluctuate dramatically. A delirious person may appear confused, very sleepy, or very agitated. Their ability to focus and organize their thoughts can vary from hour-to-hour or day-to-day.

Patients with dementia are at higher risk of developing delirium, but patients with delirium do not necessarily have dementia. Unlike dementia, delirium is considered a temporary and reversible condition. It is usually caused by an underlying medical illness, such as an infection, metabolic problem, or medication side effect. Delirium is treated by treating the underlying cause. Sometimes, the exact cause of delirium can not be easily identified. Regardless of its cause, it is important to avoid and quickly identify medications or conditions which might make the delirium worse.

Delirium is a common condition experienced by acutely ill, hospitalized older adults. Simple interventions, like making sure that an older adult is using their hearing aids and eyeglasses in the hospital, have been shown to help prevent delirium. Unfortunately, when delirium does occur, the symptoms can linger for days, weeks, and even months. Patients developing delirium are at higher risk of a variety of complications, including repeated hospitalizations, falls, nursing home placement, and even death.

Depression is characterized by a gradual onset of depressed mood, a loss of interest in pleasurable activities, changes in sleep/appetite, poor energy, poor concentration, and feelings of despair or guilt. Unfortunately, depression can also cause problems with memory, and it can be difficult to distinguish from dementia. The loss of interest in pleasurable activities or an inability to experience pleasure is an important feature of depression. This is called anhedonia and it can sometimes be confused with apathy associated with dementia. Apathy is a loss of interest in activities or difficulty initiating an activity, but usually the person is still is capable of deriving pleasure. Despite the differences in dementia and depression, it is not unusual for both conditions to exist together. Since the treatments for dementia and depression are different, it is important to consider both conditions when evaluating a person with memory and cognitive problems.

Depression is associated with abnormally low levels of a brain neurotransmitter called serotonin. Many of the commonly used antidepressant medications help to raise levels of serotonin in the brain. Counseling and psychotherapy are also important treatments for depression and can be combined with medication therapy. Many older adults with depression have a very good prognosis, if appropriately diagnosed and treated.

The Three Ds: Dementia, Delirium, and Depression are important conditions which can cause memory and cognitive problems in older adults. It is important to understand the differences and similarities between these conditions in order to accurately diagnose and treatment these conditions. When one or more of the 3 Ds is identified, a comprehensive treatment plan can be devised to promote and enhance a person’s memory and cognition. Although dementia is an irreversible condition, there are treatments to help treat symptoms and improve a person’s overall function. Delirium can be prevented and reversed. Depression can be diagnosed and treated.

Memory Tips: Five Ss

1. Stress — Reduce stress; allow your brain to focus
2. Sleep — Rested brains work better and remember more
3. Structure — Use calendars, routines, and reminders
4. Stimulation — Exercise your brain
5. Slowing down — Our brains were not designed to multi-task

Glossary Of Terms

• Anhedonia — loss of interest in activities that previously brought pleasure; an inability to experience pleasure
• Apathy — a loss of interest in activities, lack of motivation; an apathetic person either can’t or won’t initiate a new activity. It is often reported by caregiver, rather than reported by a patient.
• Cognition — a term which refers to the ability to think and process information. It includes memory, but also includes other domains such as judgment, reasoning, and language abilities.
• Delirium — an acute change in a person’s ability to focus, think or maintain a normal level of alertness. It is characterized by fluctuations in the severity of these changes and is caused by an underlying medical illness. It is considered a reversible disorder.
• Dementia — a gradual loss of cognitive (thinking) ability, including memory, and associated with difficulties in language, judgment, or the loss of skills used to perform normal daily activities. It is a progressive and fatal degenerative disease of the nervous system.
• Depression — a common mental disorder that presents with depressed mood, loss of interest or pleasure, feelings of guilt or low self-worth, disturbed sleep or appetite, low energy, and poor concentration. These problems can become chronic or recurrent and lead to substantial impairments in an individual’s ability to take care of his or her everyday responsibilities.

Resources:

• Alzheimer’s Association
• National Institute of Neurological Disorders and Stroke (NINDS)
• WebMD: Is Your Memory Normal?
• Administration on Aging (HHS): Alzheimer’s Resource Room

Anthony J. Caprio, MD is Assistant Professor of Medicine, Division of Geriatric Medicine, in the Center for Aging and Health at the University of North Carolina at Chapel Hill.