A 70-year-old man is brought to the clinic by his son due to memory issues that began 2 months ago, shortly after the sudden death of his wife. The patient frequently complains about his memory, stating, "My brain is just broken; I can't remember anything." During cognitive testing, he puts forth poor effort and frequently answers "I don't know" to questions, though he can often provide the correct answers when gently prompted. He also reports early morning awakenings, decreased appetite, and a 4-kg (8.8-lb) weight loss over this period. His physical and neurological examinations are unremarkable. Which of the following is the most likely diagnosis?
- Major depressive disorderAnswer
- BAlzheimer disease
- CVascular dementia
- DBrief psychotic disorder
- ENormal pressure hydrocephalus
Answer
Major depressive disorder
The correct answer is major depressive disorder. In elderly patients, severe depression can present with significant cognitive impairment, a condition historically termed 'pseudodementia'. Key distinguishing features from true neurocognitive disorders (like Alzheimer disease) include a rapid onset (often following a stressor), prominent complaints about memory loss (insight is intact), poor effort on testing (giving 'I don't know' answers rather than confabulating), and the presence of vegetative depressive symptoms like insomnia and weight loss.
Step-by-Step Solution
Key Concept
Major depressive disorder in the elderly can present with prominent cognitive deficits (pseudodementia), distinguished from true dementia by acute onset, prominent complaints of memory loss, 'I don't know' answers, and associated vegetative symptoms.