Thought Disorder on Object Sorting Test Is Associated with Executive Dysfunction in Schizophrenia

Background: Thought disorder is considered to be central to the core disturbances in schizophrenia and was described by Goldstein as aberrant “concept formation.” Executive dysfunction is another core deficit in schizophrenia. With a greater emphasis on psychopathology in nosological systems, the classical thought disorder receives less prominence. The present study aimed to understand the association between classical thought disorder (aberrant concept formation and concrete abstraction) and executive dysfunction. Methods: Thirty patients with schizophrenia and thirty healthy subjects, matched on age, gender, education, and socioeconomic status, were screened using MINI 5.0, following which they were assessed on object sorting test (OST) and selected tests for executive functions (EFs). Results: Individuals with schizophrenia were found to have significantly decreased performance on all domains of EFs and OST. Total peculiar scores on OST were significantly associated with mental speed, focused attention, and divided attention. Total impoverished scores on OST was significantly associated with focused attention, sustained attention, planning, set shifting, perseveration, and concept formation. Conclusion: Several correlations, among performance on OST and neuropsychological tests, suggest that patterns of responses on OST can point to underlying executive dysfunction. Both thought disorder and executive dysfunction mirror similar constructs. This similarity represents a conceptual bridge between the classical and contemporary descriptions of the core deficits in schizophrenia.