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Pseudodementia: Issues in Diagnosis: Page 2 of 2

Pseudodementia: Issues in Diagnosis: Page 2 of 2

The usual suggestion from the "dump-pseudodementia" camp is that what has been called pseudodementia should be renamed something such as the "dementia syndrome of depression." That certainly would get rid of connotations suggesting unrealness and fakery about the illness, but it is not a happy term.

Given all the good reasons for disposing of the term "pseudodementia," it is noteworthy that it has been retained in most textbooks that grapple with the differential diagnosis of dementia. Clinicians use it and seem to feel that it means something. It is also noteworthy that at least some textbooks display an exquisite ambivalence about the term. In a widely read and respected psychiatric textbook, for example, pseudodementia crops up in several chapters.16 In one chapter, it is derided as an inaccurate and anachronistic diagnosis; in another, it is carefully defined and included in the differential diagnosis of dementia.

So why is pseudodementia hanging in there? Is it time to drop the whole concept? I think not. The fact that it is on the list of differential diagnoses keeps alive in the clinician's consciousness the possibility that a patient complaining of memory loss does not necessarily have AD or vascular dementia. It reminds clinicians to look for depression in such patients and to treat it when they find it.

In fact, patients-usually but not always elderly-do turn up complaining of terrible memory loss. They give a lot of "I don't know" and "I can't do it" answers to formal mental status questions (in contrast to patients with AD and other dementing disorders, who try hard to come up with approximate answers), but when engaged in formal cognitive tasks, they show minimal impairment. (See Table for distinction between dementia and pseudodementia.) Such patients have the vegetative and psychological symptoms of depression. With successful treatment of depression, their complaints of memory loss diminish and their scores on formal mental status tests improve.

Conclusion

What we have learned recently is that the long-term prognosis for this condition is not as benign as we originally thought or as the term suggests. Elderly patients with depression and cognitive impairment, even when the impairment improves somewhat as the depression lifts, are at a substantially greater risk for dementia than their nondepressed counterparts.14 Pseudodementia may be an early sign of "true" dementia.

Most important, the concept of pseudodementia is useful in guiding the approach to the patient. Largely because no curative treatments are yet available for the common dementias-AD and vascular-there is no rush to detect one of these diagnoses. If the history and physical examination do not suggest the presence of normal-pressure hydrocephalus or another of the rare treatable dementias, and if there is even a small possibility that a patient's cognitive impairment is caused by depression, the best course may be to delay an extensive dementia workup and treat the depression. Tell patients and their family members that depression sometimes causes thinking problems and that the first step is to treat the depression.

Pages

Disclosures

Walter A. Brown, MD, is a clinical professor in the Department of Psychiatry and Human Behavior, Brown University, Providence, RI, and a practicing psychiatrist.

References

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