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.
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.
Walter A. Brown, MD, is a clinical professor in the Department of Psychiatry and Human Behavior, Brown University, Providence, RI, and a practicing psychiatrist.
1. Dobie DJ. Depression, dementia, and pseudodementia. Semin Clin Neuropsychiatry. 2002;7:170-186.
2. Lamberty GJ, Bieliauskas LA. Distinguishing between depression and dementia in the elderly: a review of neuropsychological findings. Arch Clin Neuropsychol. 1993;8:149-170.
3. Weytingh MD, Bossuyt PM, van Crevel H. Reversible dementia: more than 10% or less than 1%? A quantitative review. J Neurol. 1995;242:466-471.
4. Clarfield AM. The reversible dementias: do they reverse? Ann Intern Med. 1988;109:476-486.
5. Clarfield AM. The decreasing prevalence of reversible dementias: an updated meta-analysis. Arch Intern Med. 2003;163:2219-2229.
6. Hejl A, Hogh P, Waldemar G. Potentially reversible conditions in 1000 consecutive memory clinic patients. J Neurol Neurosurg Psychiatry. 2002; 73:390-394.
7. Wells CE. Pseudodementia. Am J Psychiatry. 1979;136:895-900.
8. Rosenstein LD. Differential diagnosis of the major progressive dementias and depression in middle and late adulthood: a summary of the literature of the early 1990s. Neuropsychol Rev. 1998;8:109-167.
9. Tractenberg RE, Weiner MF, Patterson MB, et al. Comorbidity of psychopathological domains in community-dwelling persons with Alzheimer's disease. J Geriatr Psychiatry Neurol. 2003;16:94-99.
10. Cummings JL, Ross W, Absher J, et al. Depressive symptoms in Alzheimer disease: assessment and determinants. Alzheimer Dis Assoc Disord. 1995;9:87-93.
11. Snowden M, Sato K, Roy-Byrne P. Assessment and treatment of nursing home residents with depression or behavioral symptoms associated with dementia: a review of the literature. J Am Geriatr Soc. 2003;9:1305-1317.
12. Devanand DP, Sano M, Tang MX, et al. Depressed mood and the incidence of Alzheimer's disease in the elderly living in the community. Arch Gen Psychiatry. 1996;53:175-182.
13. Sweet RA, Hamilton RL, Butters MA, et al. Neuropathologic correlates of late-onset major depression. Neuropsychopharmacology. 2004;29:2242-2250.
14. Alexopoulos GS, Meyers BS, Young RC, et al. The course of geriatric depression with "reversible dementia": a controlled study. Am J Psychiatry. 1993;150:1693-1699.
15. Kiloh LG. Pseudo-dementia. Acta Psychiatr Scand. 1961;37:336-351.
16. Kaplan HI, Sadock BJ, eds. Comprehensive Textbook of Psychiatry/VI. Baltimore: Williams and Wilkins; 1995.
17. Beer MH, Berkow R, eds. The Merck Manual of Diagnosis and Therapy. 17th ed. Somerset, NJ: John Wiley and Sons; 2005.
18. Marx JA, Hockberger RS, Walls RM, eds. Rosen's Emergency Medicine: Concepts and Practice. 5th ed. St Louis: Mosby; 2002.