Theory of Mind and social functioning among neuropsychiatric disorders: A transdiagnostic study.

Social dysfunction is commonly present in neuropsychiatric disorders of schizophrenia (SZ) and Alzheimer's disease (AD). Theory of Mind (ToM) deficits have been linked to social dysfunction in disease-specific studies. Nevertheless, it remains unclear how ToM is related to social functioning across these disorders, and which factors contribute to this relationship. We investigated transdiagnostic associations between ToM and social functioning among SZ/AD patients and healthy controls, and explored to what extent these associations relate to information processing speed or facial emotion recognition capacity. A total of 163 participants were included (SZ: n=56, AD: n=50 and age-matched controls: n=57). Social functioning was assessed with the Social Functioning Scale (SFS) and the De Jong-Gierveld Loneliness Scale (LON). ToM was measured with the Hinting Task. Information processing speed was measured by the Digit Symbol Substitution Test (DSST) and facial emotion recognition capacity by the facial emotion recognition task (FERT). Case-control deficits in Hinting Task performance were larger in AD (r _rb  = -0.57) compared to SZ (r _rb  = -0.35). Poorer Hinting Task performance was transdiagnostically associated with the SFS (β _Hinting-Task  = 1.20, p<0.01) and LON (β _Hinting-Task  = -0.27, p<0.05). DSST, but not FERT, reduced the association between the SFS and Hinting Task performance, however the association remained significant (β _Hinting-Task  = 0.95, p<0.05). DSST and FERT performances did not change the association between LON and Hinting Task performance. Taken together, ToM deficits are transdiagnostically associated with social dysfunction and this is partly related to reduced information processing speed.
Competing Interests: Conflicts of Interest G.R. Dawson is co-owner and employee of P1vital LTD who provide the FERT and the digital version of the DSST for this study. A. Bilderbeck is an employee of P1vital LTD who provide the FERT and the digital version of the DSST for this study. Dr. Arango has been a consultant to or has received honoraria or grants from Acadia, Angelini, Biogen, Boehringer, Gedeon Richter, Janssen Cilag, Lundbeck, Medscape, Minerva, Otsuka, Pfizer, Roche, Sage, Servier, Shire, Schering Plough, Sumitomo Dainippon Pharma, Sunovion and Takeda. Dr van der Wee was on advisory boards for Pfizer, Servier and Eli Lilly and received grants from the EU and the Netherlands Organisation for Health Research and Development. All other authors declare that they have no conflicts of interest.
(Copyright © 2022. Published by Elsevier B.V.)