Delirium is caused by an interplay between predisposing (risk) factors and precipitating (causative) factors. The more risk factors an individual has the more vulnerable the brain is to an insult that can precipitate a delirium. Relevant insults may appear minor, such as a new drug or constipation.
In principle, anyone can experience a delirium, just as anyone’s brain can have a seizure - the less vulnerable the person, the higher the insult required.
The most common risk factor for delirium is dementia. Others include advanced age, visual impairment and depression.
