Which condition is acute and fluctuates, requiring differentiation from depression in older adults?

• A. Delirium
• B. Dementia
• C. Parkinson's disease
• D. Anxiety disorder

Answer: (A)

Delirium is an acute, fluctuating disturbance in attention and awareness, usually arising from an underlying medical issue, infection, or substances. In older adults, this rapid onset with waxing and waning cognitive function is what distinguishes delirium from depression, which tends to be a chronic mood state with persistent symptoms rather than sudden, hour-to-hour fluctuations in consciousness. Dementia involves a gradual, progressive decline rather than an abrupt change in cognition; Parkinson’s disease adds motor symptoms to the mix and isn’t defined by an acute, fluctuating mental status. Anxiety can cause distress but does not produce the acute, fluctuating attention deficit and altered consciousness seen in delirium.