Catatonia. I. Rating scale and standardized examination

To facilitate the systematic description of catatonic signs, we developed a catatonia rating examination, rating scale and screening instrument. We constructed a 23‐item rating scale and a truncated 14‐item screening instrument using operationalized definitions of signs ascribed to catatonia in published sources. Inter‐rater reliability was tested in 44 simultaneous ratings of 28 cases defined by the presence of ≥2 signs on the 14‐item screen. Inter‐rater reliability for total score on the rating scale was 0.93, and mean agreement of items was 88.2% (SD 9.9). Inter‐rater reliability for total score on the screening instrument was 0.95, and mean agreement of items was 92.7% (SD 4.9). Diagnostic agreement was high based on criteria for catatonia put forth by other authors. Seven per cent (15/215) of consecutively admitted patients to an academic psychiatric in‐patient facility met criteria for catatonia. It is concluded that catatonia is a distinct, moderately prevalent neuropsychiatric syndrome. The rating scale and screening instrument are reliable and valid. Their use facilitates diagnosis, treatment protocols, and cross‐study comparisons.