Metaphor Processing Dysfunctions in Schizophrenia Patients With and Without Substance Use Disorders

Ewa Karabanowicz; Ernest Tyburski; Karol Karasiewicz; Andrzej Sokołowski; Monika Mak; Monika Folkierska-Żukowska; Wioletta Radziwiłłowicz

doi:10.3389/fpsyt.2020.00331

Metaphor Processing Dysfunctions in Schizophrenia Patients With and Without Substance Use Disorders

Front Psychiatry. 2020 Apr 24:11:331. doi: 10.3389/fpsyt.2020.00331. eCollection 2020.

Authors

Ewa Karabanowicz¹, Ernest Tyburski², Karol Karasiewicz¹, Andrzej Sokołowski³, Monika Mak⁴, Monika Folkierska-Żukowska⁵, Wioletta Radziwiłłowicz⁶

Affiliations

¹ Institute of Psychology, University of Szczecin, Szczecin, Poland.
² Institute of Psychology, SWPS University of Social Sciences and Humanities, Poznan, Poland.
³ Department of Neurology, Memory and Aging Center, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, United States.
⁴ Independent Clinical Psychology Unit, Pomeranian Medical University, Szczecin, Poland.
⁵ Interdisciplinary Centre for Behavioural Genetics Research, Faculty of Psychology, University of Warsaw, Warsaw, Poland.
⁶ Institute of Psychology, University of Gdansk, Gdansk, Poland.

Abstract

Background: Patients with schizophrenia have difficulties comprehending metaphors, which significantly impedes communication. However, this topic has not been thoroughly studied in people with a dual diagnosis. On this basis, we formulated two research aims: a) to compare the ability to comprehend metaphors in schizophrenia patients without (SZ) and with substance use disorder (SZ-SUD) and b) to determine the relationship between the processing of metaphorical content and the severity of psychopathological symptoms in both clinical groups.

Methods: A total of 40 individuals with SZ and 40 individuals with SZ-SUD took part in the study. The control group was composed of 40 individuals without a psychiatric or neurological diagnosis. Four subtests from the Right Hemisphere Language Battery (Picture Metaphor Test, Written Metaphor Test, Picture Metaphor Explanation Test, Written Metaphor Explanation Test) were used to measure the ability to understand and explain metaphors.

Results: Both groups of individuals with schizophrenia (SZ and SZ-SUD) scored lower than individuals from the control group on all tests of metaphor processing. However, no differences were observed between the two clinical groups. SZ-SUD patients had better results for Picture Metaphor Explanation than for Written Metaphor Explanation. Negative symptoms were found to be significant predictors of difficulties with understanding and explaining metaphors.

Conclusion: Individuals with schizophrenia, regardless of their substance use disorder (SUD) status, exhibit impaired metaphorical content processing. SUD in schizophrenia is not associated with significant impairments in understanding and explaining metaphorical content. Moreover, impairments in processing metaphorical content are associated with more severe negative symptoms of schizophrenia.

Keywords: cognitive functions; dual diagnosis; metaphor processing; schizophrenia; substance use disorder.