Can delirium be caused by fasting and lack of sleep? My 25-year-old daughter is delirious. She does not know who she is, thinks she was in a coma, etc. Hospital ran blood and urine test and a cat scan, all were normal. No new medications. I thought it has to be something physical because it came on so quick, but nothing was found. How do we help her return to herself? Hospital advised Benedryl to help sleep and to encourage food and drink.