Theory of mind in schizophrenia: a comparison of subgroups with low and high IQ

Abstract

Background

Social cognitive impairment is common in schizophrenia, but it is unclear if it is present in individuals with high IQ. This study compared theory of mind (ToM) in schizophrenia participants with low or high IQ to healthy controls.

Methods

One hundred and nineteen participants (71 healthy controls, 17 high IQ (IQ ≥115), and 31 low IQ (IQ ≤95) schizophrenia participants) were assessed with the Movie for the Assessment of Social Cognition, providing scores for total, cognitive, and affective ToM, along with overmentalizing, undermentalizing, and no-mentalizing errors. IQ was measured with Wechsler Abbreviated Scale of Intelligence; clinical symptoms with the Positive and Negative Syndrome Scale.

Results

Healthy controls performed better than the low IQ schizophrenia group for all ToM scores, and better than the high IQ schizophrenia group for the total score and under- and no-mentalizing errors. The high IQ group made fewer overmentalizing errors and had better total and cognitive ToM than the low IQ group. Their number of overmentalizing errors was indistinguishable from healthy controls.

Conclusion

Global ToM impairment was present in the low IQ schizophrenia group. Overmentalizing was not present in the high IQ group and appears related to lower IQ. Intact higher-level reasoning may prevent the high IQ group from making overmentalizing errors, through self-monitoring or inhibition. We propose that high IQ patients are chiefly impaired in lower-level ToM, whereas low IQ patients also have impaired higher-level ToM. Conceivably, this specific impairment could help explain the lower functioning reported in persons with intact IQ.

Keywords:

• Social cognition
• mentalizing
• cognitive heterogeneity
• intelligence

Acknowledgements

We are grateful for the effort and time provided by our research participants. We would also like to extend our thanks to our colleagues and involved research personnel at the NORMENT center.

Disclosure statement

Anja Vaskinn has received honorarium from VeraSci Inc. Ole A. Andreassen is a consultant to HealthLytics and has received speaker’s honorarium from Lundbeck and Sunovion. No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the South-Eastern Norway Regional Health Authority (grants # 2010007 and # 2017069 to AV) and the Research Council of Norway (grant #271560 student research in psychology to ACS and HFR, and grant # 223273). The funding sources were not involved in study design, data collection, data analyses, drafting the manuscript or the decision to publish.

Notes on contributors

André C. Sahl

André Sahl, PsyD from the Department of Psychology, University of Oslo. He currently works as a clinical psychologist at CRUX in Stavanger, Norway.

Henning F. Rognlien

Henning Fleischer Rognlien, PsyD from the Department of Psychology, University of Oslo. He is currently working as a clinical psychologist at Drammen District Psychiatric Centre, Vestre Viken Hospital Trust, Norway.

Ole A. Andreassen

Ole Andreassen, MD PhD, Professor in psychiatry at University of Oslo. Director of the Norwegian Centre for Mental Disorders Research (NORMENT). His research activities has involved clinical, neurocognitive, brain imaging and molecular genetics tools to identify causes and underlying pathophysiology of psychotic disorder, and develop precision medicine tools in psychiatry.

Ingrid Melle

Ingrid Melle, MD PhD, Professor of adult psychiatry, Institute of Clinical Medicine, University of Oslo. She is co-director of the Norwegian Centre for Mental Disorders Research (NORMENT). Her research focuses on the course and outcome of psychotic disorders including schizophrenia and bipolar disorders.

Torill Ueland

Torill Ueland, PhD & specialist in clinical neuropsychology. Senior Scientist at the Norwegian Centre for Mental Disorders Research, Oslo University Hospital, Norway and Associate Professor in neuropsychology at the Department of Psychology, University of Oslo, Norway. Her research focuses on cognition in schizophrenia and bipolar disorder.

Anja Vaskinn

Anja Vaskinn, PhD & specialist in clinical adult psychology. She is currently a senior researcher at the Centre for Research and Education in Forensic Psychiatry at Oslo University Hospital, Gaustad, Norway, and has been affiliated with the TOP study since its beginning in 2002 (now called the Norwegian Centre for Mental Disorders Research). Her research has primarily focused on social and nonsocial cognition in different clinical populations, notably schizophrenia and bipolar disorder.