Factor analysis of the Communication Disturbances Index

The present study utilized factor analysis to investigate possible underlying processes in schizophrenic thought disorder. Using the Communication Disturbances Index [CDI; Arch. Gen. Psychiatry, 53, (1996) 358], a measure of disruption in the communication of meaning from speaker to listener, we examined the speech of 58 stable schizophrenia outpatients for six different types of referential communication disturbances. We calculated instances of disturbance per 100 words and then factor-analyzed our data using the SAS statistical package. Principal components analysis with an oblique rotation produced both a two- and a three-factor solution, depending on factor inclusion criteria. In the three-factor solution, the first two factors reflected weaknesses in language structural organization and in concept-boundary definition, respectively. The third factor appeared to reflect weaknesses in specific facets of memory functioning. In the two-factor solution, the aforementioned structural organization and concept-boundary definition factors were combined into a single executive functioning factor. Results from the study may be heuristic in the development of models of language disturbance in schizophrenia patients.