Which feature best describes dementia?

• A. Onset is acute and reversible
• B. Consciousness is always impaired
• C. Onset is gradual, consciousness is typically intact, and progression is irreversible
• D. It is primarily a mood disorder

Answer: (C)

Dementia is a chronic, progressive decline in cognitive function that develops gradually, with consciousness typically preserved in the early stages, and progresses irreversibly. This pattern—slow onset, maintained awareness, and a steady, irreversible decline—is what sets dementia apart from other conditions. Delirium, for example, comes on suddenly and involves fluctuating consciousness and attention, not the steady, progressive change seen in dementia. While mood disorders can cause cognitive complaints, they do not produce the characteristic long-term, progressive neurocognitive decline of dementia.