Clinical Features

The main symptom is an acute (hours to days) alteration in the level of awareness and attention.

Other features may include:

• Disorganized thinking

• Illusions

• Hallucinations (mostly visual)

• Cognitive deficits (e.g., memory)

• Reversal of the sleep-wake cycle

• Emotional lability

• Agitation, combativeness

• Alterations in psychomotor activity may occur.

The severity of symptoms fluctuates throughout the day and worsens in the evening (termed sundowning).

Symptoms are reversible; their duration and severity depend on the underlying illness.