Subtyping chronic catatonia: Clinical and neuropsychological characteristics of progressive periodic catatonia and chronic system catatonias vs. non-catatonic schizophrenia

Catatonia has been defined by ICD-11 as a nosologically unspecific syndrome. Previous neuropsychiatric conceptions of catatonia such as Wernicke-Kleist-Leonhard's (WKL) one, have isolated chronic catatonic entities, such as progressive periodic catatonia (PPC) and chronic system catatonias (CSC). This study aimed at comparing the clinical and neuropsychological features of PPC, CSC and non-catatonic patients, all diagnosed with a schizophrenia spectrum disorder (SSD). The clinical and cognitive measures were compared among 53 SSD patients, first by separating catatonic (C-SSD, n = 27) and non-catatonic patients (NC-SSD, n = 26), and second, by separating PPC (n = 20), CSC (n = 6) and NC-SSD patients. Bayes factors were used to compare the model with 1 or 2 catatonic groups. We found that PPC had a more frequent schizo-affective presentation, higher levels of depression and less positive psychotic symptoms than both CSC and NC-SSD. CSC patients had an earlier illness onset, a poorer cognitive functioning, and higher antipsychotics doses than both PPC and NC-SSD. Most differences between C- and NC-SSD were accounted by characteristics of either PPC or CSC. The model with 2 catatonic groups clearly outperformed that with 1 catatonic group. Our results point to a substantial clinical heterogeneity of 'catatonia' within the SSD population and suggest that distinguishing (at least) 2 chronic catatonic phenotypes (PPC and CSC) may represent a relevant step to apprehend this heterogeneity. It is also a more parsimonious attempt than considering the around 32.000 distinct catatonic presentations resulting from the combinations of 3 out of 15 polythetic criteria for ICD-11 catatonia.