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Differentiating depression from dementia in the elderly
Depression in the elderly is a common mental health problem. It may be difficult to distinguish it from dementia because the two diseases share many of the same symptoms. Untreated, depression shortens life, increases health care costs, adds to disability from medical illnesses and is the leading cause of suicide among older people. In this article, Drs Onalaja, Sikabofori and Jainer discuss the diagnosis of depression and dementia.
Depressive disorder is the most common mental health problem in the elderly1. A systematic review of a community based study of the prevalence of depression in later life yielded an average prevalence of approximately 15 per cent of clinically relevant depressive syndromes2.
The general practitioner (GP) is often the first point of contact for patients and as a consequence, most depression is treated entirely in primary care2. However, there is evidence of inadequate detection3,4 and hence treatment. Untreated, depression shortens life, increases health care costs, adds to disability from medical illnesses5 and it has been shown to be the leading cause of suicide among the elderly6. Quality of life improves when treated7.
In this article, two interesting cases are reported that were referred to our Old Age Psychiatric Service by their respective GPs who thought they had dementia or memory loss, but they both actually turned out to have depression.
Diagnosis
Depression could be easily misdiagnosed as dementia. Misdiagnosis occurs because depression and dementia share many of the same symptoms. These include:
It is extremely important that depression is appropriately diagnosed because of the suffering it causes to many who go undiagnosed and untreated6. In addition, it burdens families and institutions that provide care for the elderly by disabling those who might otherwise be able-bodied6. Early recognition and initiation of treatment presents opportunities for improvements in quality of life or premature death, and the maintenance of optimal levels of functioning and independence for the elderly6.
Screening tools
The Geriatric Depression Scale (GDS) measures depression in the elderly. It consists of 30 'yes' or 'no' questions designed for self-administration and takes five to 10 minutes to complete. A score of 0Ð10 indicates 'not depressed', 11Ð20 'mild depression' and 21Ð30 'severe depression'10.
The Mini-Mental State Examination (MMSE) is a 30Ðpoint scale divided into two sections. The first which requires vocal responses only covers orientation, memory, and attention; the maximum score is 21. The second part tests ability to name, follow verbal and written commands, write sentences spontaneously, and copy a complex polygon; the maximum score is nine. A cut-off of 24 indicates screening for dementia. It takes about 10 minutes to complete. Rating is done objectively by interview method. Training is helpful to elicit the responses from the subject, which will in turn increase the validity and reliability of the MMSE10.
Table 1 highlights the difference between depression and early manifestation of AlzheimerÕs disease11. It is worth noting that depression and dementia are fundamentally different entities, however a recent study has revealed the complexity of the relationship between them12. Both conditions are highly prevalent in the elderly13, they can coexist together12, and a history of depression seems to be elevated in dementia patients13 Ð a recent review of literature of prospective and case-control studies have found a two fold increase in risk of dementia13.
These findings may have the following explanations: depression may present as an early problem of dementia, it may advance the clinical manifestation of dementia or lead to damage of the hippocampus through glucocorticoid cascade.
Conclusion
References
2. Beekman AT, Copeland JR, Prince MJ. Review of community prevalence of depression in later life. British Journal of Psychiatry 1999; 174: 307Ð11
3. Marks JN, Goldberg DP, Hillier VF. Determinants of the ability of general practitioners to detect psychiatric illness. Psychological Medicine 1979; 9: 337Ð53
4. Iliffe S, Haines A, Gallivan S, et al. Assessment of elderly people in general practice. 1. Social circumstances and mental state. British Journal of General Practice 1991; 41: 9Ð12
5. Penninx BW, Deeg DJ, van Eijk JT, et al. Changes in depression and physical decline in older adults: a longitudinal perspective. Journal of Affective Disorders 2000; 61: 1Ð12
6. Lebowitz BD, Pearson Jl, Schneider LS, et al. Diagnosis and treatment of depression in later life. JAMA 1997; 278: 1186Ð90
7. Shmuely Y, Baumgarten M, Rovner B, Berlin J. Predictors of improvement in health-related quality of life among elderly patients with depression. International Psychogeriatrics 2001; 13: 63Ð73
8. Folstein MF, Folstein SE, McHugh PR. ÒMini-Mental StateÓ: a practical method for grading the cognitive state of patients for the clinicians. Journal of Psychiatric Research 1975; 12: 189Ð98
9. Yesavage JA, BrinkTL, Rose TL, et al. Development and validation of a geriatric depression screening scale: A preliminary report. Journal of Psychiatric Research 1983; 17: 37Ð49
10. Burns A, Lawlor B, Craig S. Assessment Scales in Old Age Psychiatry, Martin Dunitz Ltd, 1999, 2Ð3, 34Ð5
11. Gauthier S, Burns A, William P. Clinical diagnosis. AlzheimerÕs Disease in Primary Care, Martin Dunitz Ltd,1997; 8Ð13
12. Copeland JRM, Abou-Saleh MT, Blazer DG. Distinguishing depression from dementia. Principles and Practice of Geriatric Psychiatry 1996; 403Ð4
13. Janzing JGE. Depression and dementia: missing the link. Current Opinion in Psychiatry 2003 ;16: 13Ð16
Dr Demi Onalaja is a Consultant in Old Age Psychiatry, Dr Tonye Sikabofori is a Senior House Officer, Old Age Psychiatry and Dr Ashok Kumar Jainer is a Consultant in General Adult Psychiatry, Coventry Primary Care Trust, Clifford Bridge Road, Coventry
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