The complexity of theory of mind deficit in schizophrenia: A cross-sectional analysis of baseline data from a longitudinal schizophrenia study.

A large number of trials have supported the functional significance of Theory of Mind (ToM) impairment in schizophrenia. However, the nature and the extent of the impairment are still unclear. Reviews on the topic suggest that, in many cases, studies use only one tool to assess the levels of difficulty in the field, limiting the validity of the measurement to one aspect of ToM. On the other hand, the divergence of the used assessment tools makes it hard to compare the result of these studies. Thus, we decided to use additional assessment tools to evaluate the extent of ToM in order to describe several aspects of the phenomenon. A hierarchical cluster analysis of variables was used on a sample of 68 participants with schizophrenia or schizoaffective disorder, to determine the similarity between variances of the assessed ToM subcomponents. Further cross-sectional correlational analysis was then performed to investigate the association between the identified clusters and other used measures (e.g.: neurocognition). The statistical analysis supported a five-cluster model. Identified clusters illustrate the difference between Hypo and HyperToM as well as the degree of ToM task complexity, allowing for a more accurate description of the nature of ToM deficit in schizophrenia.