The essential feature of the DSM-5 diagnosis of delirium is a disturbance in at- tension/awareness and in cognition that develops over a short period of time, represents a change from baseline, and tends to fluctuate in severity during the course of a day. Which of the following additional conditions must apply? A. There must be laboratory evidence of an evolving dementia. B. The disturbance must be associated with a disruption of the sleep-wake cycle. C. The disturbance must not occur in t...