A usually brief state of excitement and mental confusion often accompanied by hallucinations WordNet 3.0 & Open English WordNet

Delirium is a specific state of acute confusion attributable to the direct physiological consequence of a medical condition, effects of a psychoactive substance, or multiple causes, which usually develops over the course of hours to days. Wikipedia

Common and severe neuropsychiatric syndrome. Wikipedia Disambiguation

Severe confusion that develops quickly, and often fluctuates in intensity, neurocognitive disorder Wikidata

A temporary mental state with a sudden onset, usually reversible, including symptoms of confusion, inability to concentrate, disorientation, anxiety, and sometimes hallucinations. Causes can include dehydration, drug intoxication, and severe infection. Wiktionary

Mental state of confusion. Wiktionary (translation)