Critically ill patients receiving mechanical ventilation had a higher prevalence of prior psychiatric diagnoses and an increased risk of a new psychiatric diagnosis and medication use after hospital discharge, according to a study in the March 19 issue of JAMA.

With recent advances in medical care, more patients are surviving critical illness. Critically ill patients are exposed to stress, including pain, respiratory distress, and delirium, all of which may impact subsequent mental health. The extent of psychiatric illness prior to critical illness, as well as the magnitude of increased risk of psychiatric illness following critical illness, is unclear, according to background information in the article.

Hannah Wunsch, M.D., M.Sc., of Columbia University, New York, and colleagues assessed psychiatric diagnoses and medication prescriptions before and after critical illness. The study included critically ill patients in Denmark from 2006-2008 with follow-up through 2009, and matched comparison groups of hospitalized patients and the general population. Critical illness was defined as intensive care unit (ICU) admission with mechanical ventilation.

Among 24,179 critically ill patients included in the study, 6.2 percent had 1 or more psychiatric diagnoses in the 5 years prior to critical illness vs 5.4 percent for hospitalized patients and 2.4 percent for the general population. The proportion of 5-year preadmission prescriptions for psychoactive drugs (those that affect mental functioning such as mood, behavior, or thinking processes) were similar to those for hospitalized patients (48.7 percent vs 48.8 percent) but higher than those for the general population (33.2 percent).

Among the 9,921 critical illness survivors with no psychiatric history, the absolute risk of new psychiatric diagnoses was low but higher than that for hospitalized patients (0.5 percent vs 0.2 percent over the first 3 months) and the general population group (0.02 percent). The proportion of patients given new psychoactive medication prescriptions was also increased in the first 3 months (12.7 percent vs 5.0 percent for the hospital group) and 0.7 percent for the general population, but the these differences had largely resolved by the end of the first year of follow-up.

"… Our study provides important data on the burden of psychiatric illness among patients who experience critical illness requiring mechanical ventilation, as well as on the risks of psychiatric diagnoses and treatment with psychoactive medications in the year following ICU discharge. Discharge planning for these patients may require more comprehensive discussion of follow-up psychiatric assessment and provision of information to caregivers and other family members regarding potential psychiatric needs," the authors write.

"Although the absolute risks were low, given the strong association between psychiatric diagnoses, such as depression, and poor outcomes after acute medical events, such as myocardial infarction and surgery, our data suggest that prompt evaluation and management of psychiatric symptoms may be an important focus for future interventions in this high-risk group."