A 74-year-old man is referred for suspected dementia after his family notices he can no longer manage his bills or recall recent conversations. On assessment he is profoundly low in mood and tearfully aware of and distressed by his own decline. After eight weeks of antidepressant treatment, his cognitive performance returns almost entirely to baseline. What is this presentation?
This is depressive pseudodementia: severe memory and concentration difficulty, striking enough to resemble true dementia, that tracks closely with the severity of a depressive episode and improves substantially once the depression is treated — exactly what a genuine degenerative dementia would not do. It is not true dementia, since the cognitive picture reversed with mood treatment; not an amnestic state, which is a more circumscribed, organic new-learning deficit unrelated to mood; and not delirium, since there is no clouding of consciousness described.
References
- Casey, P. & Kelly, B. (2019). Fish's Clinical Psychopathology, 4th ed. Ch. 5, 'Disorders of Memory'.