Researchers examined medical records of all patients in Denmark, admitted to an ICU over a three year period. According to Dr. Derek Angus from UPMC, "there was an absolute new risk of new psychiatric diagnoses and new psycho-active medication use. Even though it was less than one percent it was 20 fold higher than the likelihood of getting a new psychiatric illness had you been a general population member with similar underlying characteristics."
However, the study also showed that the critically ill patients were already more likely to have a psychiatric illness or be on a psychiatric medication before being admitted to the ICU.
The risk for psychiatric illness in these patients was highest in the first three months after being discharged and it returned to normal between nine and 12 months. The study is in the current issue of the "Journal of the American Medical Association."