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Difficulty: EasyNeurocognitive Disorders

A 75-year-old man is brought to the clinic by his daughter for a cognitive evaluation. Over the past 5 months, he has stopped managing his finances, spends most of the day sitting in a recliner, and frequently complains that his memory is 'completely gone.' When the physician asks him to perform serial sevens and recall three objects, he sighs loudly, states 'I just cannot do this anymore,' and refuses to try. Five months ago, he was forced to surrender his driver's license due to worsening macular degeneration. His daughter notes that he has lost 4.5 kg (10 lb) during this period. Neurologic examination is nonfocal. Which of the following is the most likely diagnosis?

  1. A
    Major neurocognitive disorder due to Alzheimer disease
  2. B
    Adjustment disorder
  3. Major depressive disorderAnswer
  4. D
    Vascular dementia
  5. E
    Normal age-related cognitive decline

Answer

Major depressive disorder
This patient is presenting with cognitive impairment secondary to major depressive disorder, a clinical picture often referred to as 'pseudodementia.' In the elderly, depression frequently manifests with prominent memory complaints. Key features that differentiate pseudodementia from genuine major neurocognitive disorder (like Alzheimer disease) include a more rapid onset (often following a stressor, such as losing driving privileges), intense distress or complaints about memory loss, and a characteristic lack of effort on cognitive testing. Instead of attempting to answer and making mistakes, depressed patients typically sigh, give up easily, or answer 'I do not know.' Furthermore, the patient's pervasive inactivity and significant weight loss are classic neurovegetative symptoms that confirm a major depressive episode.

Step-by-Step Solution

1
Identify the psychosocial stressor and timeline.
The patient lost his driver's license 5 months ago, correlating with the subacute onset of his symptoms.
A clear precipitating event with a subacute onset of cognitive complaints strongly suggests a psychiatric etiology rather than an insidious neurodegenerative disease.
2
Evaluate the patient's attitude toward his cognitive deficits.
He complains that his memory is 'completely gone' and refuses to try during the cognitive assessment.
Patients with depression-related cognitive impairment (pseudodementia) typically emphasize their deficits and show poor effort, unlike patients with genuine dementia who often lack insight and attempt to cover up their mistakes.
3
Look for neurovegetative symptoms of depression.
The patient exhibits severe anhedonia (sitting in a recliner all day) and a 10-lb weight loss.
These somatic symptoms confirm the presence of a major depressive episode.

Key Concept

Major depressive disorder in the elderly can present with prominent cognitive complaints (pseudodementia). It is differentiated from genuine major neurocognitive disorder by a subacute onset, exaggerated complaints about memory loss, poor effort on cognitive testing, and concurrent vegetative symptoms of depression.
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Topics

Neurocognitive Disorders

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