Executive Functions and Psychopathology Dimensions in Deficit and Non-Deficit Schizophrenia

This study: (a) compared executive functions between deficit (DS) and non-deficit schizophrenia (NDS) patients and healthy controls (HC), controlling premorbid IQ and level of education; (b) compared executive functions in DS and NDS patients, controlling premorbid IQ and psychopathological symptoms; and (c) estimated relationships between clinical factors, psychopathological symptoms, and executive functions using structural equation modelling. Participants were 29 DS patients, 44 NDS patients, and 39 HC. Executive functions were measured with the Mazes Subtest, Spatial Span Subtest, Letter Number Span Test, Color Trail Test, and Berg Card Sorting Test. Psychopathological symptoms were evaluated with the Positive and Negative Syndrome Scale, Brief Negative Symptom Scale, and Self-evaluation of Negative Symptoms. Compared to HC, both clinical groups performed poorer on cognitive flexibility, DS patients on verbal working memory, and NDS patients on planning. DS and NDS patients did not differ in executive functions, except planning, after controlling premorbid IQ and negative psychopathological symptoms. In DS patients, exacerbation had an effect on verbal working memory and cognitive planning; in NDS patients, positive symptoms had an effect on cognitive flexibility. Both DS and NDS patients presented deficits, affecting the former to a greater extent. Nonetheless, clinical variables appeared to significantly affect these deficits.

Automated summary

This study compared executive functions between deficit and non-deficit schizophrenia patients and healthy controls, while controlling for IQ and level of education. It also compared executive functions within the two patient groups, while controlling for IQ and psychopathological symptoms. Relationships between clinical factors, psychopathological symptoms, and executive functions were estimated using structural equation modeling. Results showed that both patient groups performed poorer on cognitive flexibility compared to healthy controls, with deficit schizophrenia patients performing worse on verbal working memory and non-deficit schizophrenia patients performing worse on planning. After controlling for IQ and negative symptoms, there were no differences in executive functions between deficit and non-deficit schizophrenia patients, except for planning. Clinical variables appeared to significantly impact these deficits.