There may be more than one possible cause of delirium. Some causes may be:
- medicine: prescription and over-the-counter (especially if more than 5 types of medicine are taken)
 - dehydration or not drinking enough fluids
 - constipation or diarrhea
 - infection, fever, pain, or an illness that’s getting worse
 - a recent fall
 - not eating well
 - a recent surgery or procedure
 - problems with their blood sugars if they have diabetes
 - a recent change in where they live or where they’re staying
 - withdrawing from alcohol
 - blood levels (e.g., potassium, vitamin B12) that aren’t in the normal range