Overlapping but distinct: delirium and catatonia-related features in critically ill patients

To characterize patient-level and patient-day-level overlap between delirium and catatonia-related features in critically ill patients during intensive care unit (ICU) stay.

In this prospective observational study conducted in a cardiovascular ICU, adult patients underwent daily paired neuropsychiatric assessments throughout ICU stay. Delirium was screened using the Intensive Care Delirium Screening Checklist (ICDSC) and catatonia-related features using the Bush-Francis Catatonia Screening Instrument (BFCSI). Assessments were performed once daily when patients were sufficiently arousable (Richmond Agitation-Sedation Scale ≥ -3). Overlap was summarized at patient and patient-day levels using descriptive statistics and Cohen's κ.

Among 44 patients, delirium and catatonia-related features occurred both independently and concurrently. At the patient level, 6 patients (13.6%) were delirium only, 4 (9.1%) were catatonia only, and 6 (13.6%) experienced both. Concordance was fair (κ =0.40; 95% CI, 0.09-0.70). Across 247 ICU days, 17 (6.9%) were delirium only, 18 (7.3%) were catatonia only, and 13 (5.3%) were both, with fair concordance (κ =0.35; 95% CI, 0.18-0.52). Delirium-positive days increased across Sequential Organ Failure Assessment (SOFA) categories, whereas catatonia-related features were observed across severity strata without a consistent severity-dependent gradient.

Delirium and catatonia-related features demonstrate partial and dynamic overlap during critical illness. The differential associations with illness severity suggest that these represent related but distinguishable neuropsychiatric phenomena in the ICU.

This study is a prospective observational study and not a clinical trial; therefore, trial registration was not required.