Question 16#

Which one of the following is NOT a risk factor for developing dementia?

A. Smoking

E. Smoking is a risk factor for dementia especially of the vascular type, though controversies exist as to whether smoking could prevent Alzheimer’s disease. A large survey of UK male doctors followed up from 1951 has demonstrated that smoking in fact increases the risk of Alzheimer’s. Also in a prospective, population-based cohort study of 6868 participants >55 years followed up for an average of 7 years, smoking was associated with increased risk of any dementia in general, and Alzheimer’s in particular. Ageing increases the risk of dementia. Boxing is associated with dementia pugilistica wherein neurofibrillary tangles are observed. Alcoholic dementia occurs in excessive drinkers. Living alone does not increase the risk of dementia.

Reference:

1. Reitz C et al. Relation between smoking and risk of dementia and Alzheimer disease: the Rotterdam Study. Neurology 2007; 69: 998–1005.

Question 17#

The best option for preventing dementia available currently is:

A. Regular NSAIDs

E. Evidence for dementia preventive strategies has emerged recently though this is largely concerned with delaying the onset rather than abolishing the risk. Sustained use of NSAIDs is associated with a reduced risk of developing AD. Some NSAIDs appear to modulate the amyloid load in the brain. But NSAIDs have significant adverse effects that might limit their potential as primary preventive agents in AD. Oestrogens and HRT cannot be recommended and the potential of statins remains to be fully assessed. Evidence for using antioxidant supplements such as vitamin E and vitamin C is far from clear cut and there are safety concerns about higher doses of vitamin E. Strategies to target mid-life vascular risk factors are likely to have an important effect on the age of presentation of AD, though as of now none of the given options are recommended to prevent dementia.

Reference:

1. Jones RW. Primary prevention of dementia. Psychiatry 2007; 6: 511–513.

Question 18#

Which one of the following genetic factor is associated with senile dementia of Alzheimer’s type?

A. Presenilin 1 only

D. Of patients with Alzheimer’s, 40% have a positive family history of Alzheimer’s. This is especially true if the patient is younger (<55). Among various genes implicated, Chromosome 21 carries the gene for amyloid precursor protein (APP) which when mutant increases amyloid deposition even before senility, so it is associated with younger-onset dementia. Trisomy 21 acts via the same mechanism in Down’s. The APO gene on chromosome 19 codes for apolipoprotein (apo). People with one copy of the APOE4 allele have Alzheimer’s three times more frequently than do those with no APOE4 allele, and people with two APOE4 alleles have the disease eight times more frequently. Diagnostic testing for APOE4 is not recommended because it is seen in more patients without Alzheimer’s than those with the disease and so accounts only for 50% of genetic variance. E3 is the most common APOE allele and E2 may be protective. It is possible that apoE4 mediates Alzheimer’s risk via lipid metabolism as the presence of apoE4 increases cholesterol levels in blood. Chromosome 14 (presenilin 1) and chromosome 1 (presenilin 2) are also implicated in early-onset Alzheimer’s via increased beta amyloid deposition.

Reference:

1. Gelder MG et al., eds. New Oxford Textbook of Psychiatry. Oxford University Press, 2000, p. 392.

Question 19#

With respect to the major classificatory systems ICD and DSM, the term ‘operational definition’ refers to which of the following?

A. Definition arrived at by a consensus

B. The term operational definition refers to a definition that is specified by a series of precise, unambiguous inclusion and exclusion criteria. In other words, an operational definition is arrived at by using a checklist. This improves the reliability of a classificatory system tremendously. Before the popular use of ICD and DSM systems, the cross-national agreement for psychiatric diagnosis was very poor, as exemplified by the US–UK diagnostic study. In the UK, the rate of manic depression was ten times higher and the rate of schizophrenia was two times lower than the prevalence in the US (Cooper, 1972). Operational definitions paved the way for the wider use of standardized diagnostic instruments, increasing the reliability of classification.

References:

1. Gelder MG et al., ed. Shorter Oxford Textbook of Psychiatry, 5th edn. Oxford University Press, 2006, p. 30.
2. Cooper JE. et al. Psychiatric Diagnosis in New York and London. Maudsley Monograph 20. Oxford: Oxford University Press, 1972.

Question 20#

Dementia secondary to which of the following is not reversible?

A. Nutritional deficiencies

C. Reversible causes constitute nearly 15% of initial diagnoses of dementia. The proportion is higher in younger patients. The reversible causes are commonly subdural haematoma, normal pressure hydrocephalus (NPH), vitamin B₁₂ deficiency, metabolic causes, and hypothyroidism. Stroke causes vascular dementia which is irreversible.

Reference:

1. Semple DM et al., eds. Oxford Handbook of Psychiatry, 1st edn. Oxford University Press, 2005, p. 132.