According to the Aging and Disability Services Administration, 30 to 50 percent of all those suffering from dementia also have clinical depression--yet many of these individuals go unnoticed because the symptoms of depression and dementia are so similar. Left untreated, depression worsens the symptoms of dementia; it becomes harder to remember things, and the individual becomes more confused, anxious, and withdrawn.
Assessing individuals with dementia for depression is a tremendous challenge. However, in 1988 a team of researchers led by Dr. George Alexopoulos developed the Cornell Scale for Depression in Dementia, the first tool of its kind. It has proven to be highly effective in identifying individuals with dementia in need of help for depression.
Design
The Cornell scale consists of 19 items representing symptoms of depression, such as anxiety, loss of interest, and lack of energy. For each individual being assessed, the scale is administered to two people: the individual himself, and a caregiver. Each is asked whether the various symptoms of depression have been present during the week preceding the test; responses are recorded as "absent," "mild or intermittent," or "severe." A score of zero is given each response of "absent," a score of one is given "mild or intermittent," and a score of two is given "severe." A total score of eight or above suggests significant depressive symptoms are present.
Population
Although the Cornell scale was designed primarily to detect depression among the elderly suffering from dementia, it has been found to be equally effective in identifying individuals who have mistakenly been diagnosed as having depression, but who are not, in fact, depressed. A team of researchers led by Dr. Ann Gruber-Baldini of the University of Maryland School of Medicine found that 33 percent of nursing home residents who had been prescribed antidepressants did not actually suffer from depression. Conversely, they found that just 42 percent of individuals with depression had been appropriately identified prior to administration of the Cornell scale. The Cornell scale has also been found to be effective when used with individuals not suffering from dementia.
Validity
In a comparison with the Geriatric Depression Scale, researchers in Denmark found that the Cornell scale had significantly higher sensitivity and specificity; that is, it appropriately identified depressed individuals without mistakenly identifying individuals who were not depressed. Furthermore, the Cornell scale alone was effective in assessing depression in individuals with dementia. The Alzheimer Research Forum recommends the Cornell scale as being sensitive, reliable, and valid for testing for depression in Alzheimer patients. The American Geriatrics Society and the American Association for Geriatric Psychiatry have both advocated for the use of the Cornell scale.
Weaknesses
The Cornell Scale for Depression in Dementia takes longer than many other depression assessment tools, requiring approximately 20 minutes to interview the caregiver and 10 minutes to interview the individual. In comparison, the Geriatric Depression Scale can be completed in less than 10 minutes. The Cornell scale also requires that a caregiver who has carefully observed the individual during the preceding week be available; staffing in long-term care facilities does not always allow one caregiver to follow an individual's status throughout the week.
Strengths
The very aspects that can be considered weaknesses of the Cornell scale can also be considered strengths. The increased time spent on the interview process elicits more meaningful data. And incorporating a caregiver's perspective helps to overcome the inherent deficiencies of a sole interview with the individual with dementia. The scale is easy to administer, the questions are unambiguous, and the results straightforward to interpret. The Cornell scale has had a great impact on the delivery of mental health services for the elderly.
References
- Aging and Disability Services Administration: Dementia
- "Biological Psychiatry"; Cornell Scale for Depression in Dementia; George Alexopoulos, Robert Abrams, Robert Young, & Charles Shamoian; February 1988
- "The Gerontologist"; Characteristics Associated With Depression in Long-Term Care Residents With Dementia; Ann Gruber-Baldini, Sheryl Zimmerman, Malaz Boustani, Lea Watson, Christianna Williams, and Peter Reed; 2005
- Alzheimer Research Forum: Neuropsychological Testing
- "Nordic Journal of Psychiatry"; The Geriatric Depression Scale and the Cornell Scale for Depression in Dementia: A validity study; Alex Kørner, Lise Lauritzen, Kirsten Abelskov, Nils Gulmann, Anne Marie Brodersen, Torben Wedervang-Jensen, and Karen Marie Kjeldgaard; 2006
