Delirium

In medicine, delirium is a "disorder characterized by confusion; inattentiveness; disorientation; illusions; hallucinations; agitation; and in some instances autonomic nervous system overactivity )."

According to the Diagnostic and Statistical Manual of Mental Disorders, delirium is "reduced ability to think or concentrate, restlessness, anxiety, irritability, drowsiness, hypersensitivity to stimuli, nightmares."

Subsyndromal delirium
Subsyndromal delirium may cause morbidity among hospitalized individuals.