Which of the following is a benefit of a categorical classification over dimensional classification?
A. Categorical classifi cation refers to the current ICD-10 and DSM-IV approach of using mutually exclusive labels for diagnosis in an ‘all or none’ fashion. A diagnosis is either present or absent according to this system, very similar to the medical model – pneumonia is either present or absent. Relative advantages of a categorical system are:
A dimensional approach considers a continuum of diagnostic issues; it uses degrees of severity of a particular dimension (say mood, anxiety) rather than mutually exclusive ‘boxes’ of diagnosis. In this way various dimensions can be employed simultaneously to describe a patient’s diffi culties. Relative advantages of a dimensional system include:
Reference:
Which of the following disorders has the most evidence for existing as a continuum in the population, making a dimensional approach more rational?
B. It has been argued that personality disorders are better considered in a continuum with normalcy and so a dimensional approach is tipped for personality disorders in future DSM classifications. Note that contemporary cognitive psychologists consider delusions to exist in a continuum of normal beliefs and so a modular approach is criticized. But this does not imply that delusional disorders, as defined currently, exist in such a continuum.
By definition, the nature of delirium that differentiates it from dementia includes which of the following?
B. Delirium is an acute confusional state by definition. It may or may not be reversible depending on the aetiology. Most cases are reversible and have a non-deteriorating episodic course. Both dementia and delirium have an impact on global cognitive abilities, including memory.
Which of the following best describes the nature of cognitive impairment required to diagnose dementia?
C. Dementia is an organic syndrome wherein progressive, global cognitive disturbance is noted. Dementia is often irreversible. Cognitive disturbances include memory difficulties (amnesia), aphasia, agnosia, apraxia, impaired executive function, and personality changes. Significant psychosocial impairment must be present to warrant a diagnosis of dementia. Clouding of consciousness, impaired attention, wide diurnal fluctuation, presence of autonomic signs, and a high degree of reversibility on treating the potential cause are other differentiating features that point towards delirium.
The most common cause of presenile dementia is:
C. Alzheimer’s dementia is the most common dementia in both older and younger patients. Risk of Alzheimer’s increases with age. About 1% risk at age 60 years then doubles every 5 years becoming nearly 40% of those aged 85 years. Women are affected three times more often. Down’s syndrome, previous head injury, hypothyroidism, family history of dementia, and supposedly low educational attainment are other risk factors. Alzheimer’s is implicated in up to two-thirds of all senile dementia.
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