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Other intracranial causes of cognitive impairment should be asertained
- Dr Abdulfatai Kunle Salawu MBBS,FMCP(Nig), Dr Ibrahim Kida, MBBS (8 September 2004)
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This could be loss of DHEA of old age...
- James M. Howard (15 October 2004)
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Depression in Dementia
- Ramneesh Puri (15 October 2004)
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Depression and cognitive impairment: multiple implications!
- Dr. Naseem A. Qureshi MD, IMAPA, LMIPS (17 October 2004)
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Depression accompanying cognitive decline
- Dietmar Fuchs, Christiana Winkler, Katharina Schroecksnadel (29 October 2004)
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Dr Abdulfatai Kunle Salawu MBBS,FMCP(Nig), Consultant neurologist Federal Medical Centre,Yola.Nigeria, Dr Ibrahim Kida, MBBS
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The article cited was very interesting indeed,we are only wondering how other causes of cognitive impairment in these elderly individuals were excluded.Multi-infarct dementia is a well recognized cause of cognitive impairment with patients presenting with or without subtle lateralizing signs.In such instances neuroradiological(Computerized Tomography or Magnetic Resonance Imaging of the brain) investigations would be of utmost importance. Competing interests: Computerized tomography of brain in elderly folks is very important indeed,albeit expensive |
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James M. Howard, independent biologist 1037 North Woolsey Avenue, Fayetteville, Arkansas 72701-2046, U.S.A.
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It is my hypothesis that increases in DHEA during evolution produced the mammals and their large brains ("Hormones in Mammalian Evolution," Rivista di Biologia / Biology Forum 2001; 94: 177-184). I suggest DHEA is especially important to growth and development and maintenance of the brain. DHEA naturally begins to decline around age twenty, reaching very low levels in old age. In 1985, I first suggested that low DHEA may result in depression and Alzheimer's disease. Loss of DHEA should adversely affect all tissues, including those of the brain. I suggest the findings of Vinkers, et al., represent the effects of loss of DHEA in their elderly subjects. Competing interests: None declared |
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Ramneesh Puri, SHO in Old age Psychiatry Brocerwin Centre, Haverford West, Pembrokeshire, UK. SA61 2PZ
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Vinkers et al have addressed an important day to day issue in old age psychiatry. A major depressive episode is found in approximately 10 per cent of patients, minor depressive episode in 25 per cent, some features of depression in 50 per cent, and an assessment of depression by a carer in up to 85 per cent. 8–10. (ref:Oxford textbook of psychiatry). Hence it becomes even more important to look out for treatable depressive symptoms as a cause of cognitive decline. Competing interests: None declared |
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Dr. Naseem A. Qureshi MD, IMAPA, LMIPS, Director, CME&R POBox.2292, Buraidah Ment. Halth. Hosp., Saudi Arabia.
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Sir, This prospective population based study by Vinkers and colleagues [1] is very interesting and it buries some of the controversies linked to depression and dementia. Most notably, mild cognitive impairment among elderly population, which is determined by multiple etiologies signifies and amplifies the occurrence of depression/depressed moods/depressive symptoms but not vice versa is a valid and very useful conclusion of this research. Indeed, dementia represented by mild/moderate/severe cognitive impairment is associated not only with depressive symptoms but also with delirium, delusions and other unspecified disorganized behaviors. Therefore, carers of patients with dementia should look for all the psychopathological symptoms. Further depression and dementia may enhance the mortality rate among patients with such co-morbid disorders. Elderly patients with depression when not responding to adequate doses of suitable antidepressants may indicate underlying cerebrovascular pathology as reflected in vascular depression that is coupled with cognitive impairment. Also elderly demented patients with co-morbid depression are at higher risk for suicide, which entails prompt treatment of depression and hence prevention of preventable deaths. Besides depression as a reaction to attention and memory deficits, other biopsychosocial factors such as CNS neurotransmitter perturbations, genetic mechanisms, adverse life events, and lack of social supports and networks could also explain the occurrence of depression among patients with cognitive impairment. Finally, depression can masquerade cognitive deficits in terms of pseudo-dementia, which needs careful assessment and treatment as this condition (depression) has overall good prognosis and outcome. Reference: David J Vinkers, Jacobijn Gussekloo, Max L Stek, Rudi G J Westendorp, and Roos C van der Mast . Temporal relation between depression and cognitive impairment in old age: prospective population based study BMJ 2004; 329: 881-0 Competing interests: None declared |
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Dietmar Fuchs, Innsbruck Medical University A-6020 Innsbruck, Austria, Christiana Winkler, Katharina Schroecksnadel
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With interest we read the article by Vinkers et al. on the association between cognitive impairment and development of depression in the elderly (1). The authors observed that depressive symptoms had increased more quickly in individuals with cognitive impairment and loss of memory, and they conclude that depression could represent a psychological reaction to the awareness of cognitive decline. Mood disturbances and cognitive impairment are probably linked to a disturbed metabolism of monoamine 5-hydroxytryptamine (serotonin) (2). Production of serotonin depends on the availability of its biosynthetic precursor, the essential amino acid tryptophan. During cellular immune response, Th1-type cytokine interferon-g stimulates tryptophan degradation by the enzyme indoleamine-(2,3)-dioxygenase in various cells including monocyte-derived macrophages and dendritic cells. Thereby, deprivation of tryptophan represents an important antimicrobial and antitumoural immune defence mechanism. In older aged healthy individuals, signs of immune activation are common. This is also reflected by increased concentrations of immune activation marker neopterin, and in parallel enhanced degradation of tryptophan is observed which goes along with significantly lowered tryptophan levels in the elderly (3). Several studies demonstrated a relationship between blood tryptophan concentrations and cognitive ability in patients with dementia (4), and also worse quality of life in cancer patients was found to be associated with immune activation and with lowered blood tryptophan concentrations (5). In contrast to the conclusion of the authors, there seems to exist a common aetiology which could explain the association between depression and cognitive impairment, namely impaired tryptophan availability. Reduced blood tryptophan concentrations, which are due to inflammation and immune stimulation in older age, will cause shortage in serotonin availability. It may depend, e.g., on genetically determined serotonin receptor affinity and distribution on cells, whether depression or cognitive impairment may precede each other. Thus, depression in elderly patients with memory loss is unlikely to solely represent a psychological reaction to the awareness of cognitive decline, rather it is another consequence of immune activation pathways which are involved in the pathogenesis of dementia. Christiana Winkler
1. Vinkers DJ, Gussekloo J, Stek ML, Westendorp RG, Van Der Mast RC. Temporal relation between depression and cognitive impairment in old age: prospective population based study. BMJ 2004;329:881. 2. Murr C, Widner B, Sperner-Unterweger B, Ledochowski M, Schubert C, Fuchs D. Immune reaction links disease progression in cancer patients with depression. Medical Hypotheses 2000:55;137-40. 3. Frick B, Schroecksnadel K, Neurauter G, Leblhuber F, Fuchs D. Increasing production of homocysteine and neopterin and degradation of tryptophan with older age. Clin Biochem 2004;37:684-7. 4. Widner B, Leblhuber F, Walli J, Tilz GP, Demel U, Fuchs D. Tryptophan degradation and immune activation in Alzheimer's disease. J Neural Transmission 2000;107:343-53. 5. Huang A, Fuchs D, Widner B, Glover C, Henderson DC, Allen-Mersh TG. Serum tryptophan decrease correlates with immune activation and impaired quality of life in colorectal cancer. Brit J Cancer 2002;86:1691- 6. Competing interests: None declared |
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