Validation of the Pediatric Catatonia Rating Scale (PCRS).

INTRODUCTION Despite the increased recognition of catatonia in children and adolescents, no specific assessment instrument has been validated in this population. METHOD Within the context of a prospective study on catatonia, we developed the Pediatric Catatonia Rating Scale (PCRS, maximum score=60), adapted from the Bush and Francis Catatonia Rating Scale for its use in child and adolescent inpatients. We assessed the psychometric properties of the PCRS by measuring its internal consistency, construct validity, and factor structure. Bivariate analyses were performed to compare the different diagnostic patient groups across the extracted factors. RESULTS Internal consistency was moderate (Cronbach's α for total score=0.67) suggesting multidimensionality. Multiple factors underlie the PCRS items, as revealed by factor analysis. Four distinct dimensions of catatonic symptoms were identified and accounted for 44% of total variance: a "negative withdrawal" factor (with mutism, negativism, and social withdrawal), a "catalepsy" factor (with posturing and waxy flexibility), an "abnormal movements" factor (with mannerisms and stereotypes) and an "echo phenomenon" factor (with echolalia and echopraxia). Receiver operating characteristic (ROC) analysis showed that the PCRS performance in discriminating individuals with catatonia vs. those without catatonia was excellent for a threshold≥9 (Area Under the Curve=0.983) in this sample. DISCUSSION These results support the validity of the PCRS among children and adolescent inpatients. With regard to such analyses, the internal structure of catatonic syndrome in children and adolescents is roughly comparable with the adult form, except the lack of a "hyperactive/excitement" dimension.