Hypoactive delirium is typified by which of the following?

• A. Hyperactivity and aggression
• B. Rapid, anxious motor activity
• C. Fluctuating attention with agitation
• D. Slow response to verbal stimuli and psychomotor slowing

Answer: (D)

Hypoactive delirium presents with reduced activity and responsiveness rather than overt agitation. The key feature is slow response to verbal stimuli and psychomotor slowing, meaning the patient moves slowly, speaks slowly or less than usual, and appears lethargic or withdrawn. Delirium overall involves an acute change in attention and cognition with fluctuations, but the hypoactive subtype specifically shows decreased activity and reactivity.

The other descriptions point to hyperactive delirium—characterized by increased motor activity and agitation—or a mixed presentation with agitation and fluctuating attention. Hence, slow verbal responses and slowed movements best fit hypoactive delirium. This form can be easy to miss, so regular screening and attention to baseline function are important.