Theory of mind in schizophrenia: correlation with clinical symptomatology, emotional recognition and ward behavior

Disentangling the Relationships Between the Clinical Symptoms of Schizophrenia Spectrum Disorders and Theory of Mind: A Meta-analysis

BACKGROUND AND HYPOTHESIS

Previous studies have suggested links between clinical symptoms and theory of mind (ToM) impairments in schizophrenia spectrum disorders (SSD), but it remains unclear whether some symptoms are more strongly linked to ToM than others.

STUDY DESIGN

A meta-analysis (Prospero; CRD42021259723) was conducted to quantify and compare the strength of the associations between ToM and the clinical symptoms of SSD (Positive, Negative, Cognitive/Disorganization, Depression/Anxiety, Excitability/Hostility). Studies (N = 130, 137 samples) including people with SSD and reporting a correlation between clinical symptoms and ToM were retrieved from Pubmed, PsycNet, Embase, Cochrane Library, Science Direct, Proquest, WorldCat, and Open Gray. Correlations for each dimension and each symptom were entered into a random-effect model using a Fisher's r-to-z transformation and were compared using focused-tests. Publication bias was assessed with the Rosenthal failsafe and by inspecting the funnel plot and the standardized residual histogram.

STUDY RESULTS

The Cognitive/Disorganization (Zr = 0.28) and Negative (Zr = 0.24) dimensions revealed a small to moderate association with ToM, which was significantly stronger than the other dimensions. Within the Cognitive/Disorganization dimension, Difficulty in abstract thinking (Zr = 0.36) and Conceptual disorganization (Zr = 0.39) showed the strongest associations with ToM. The association with the Positive dimension (Zr = 0.16) was small and significantly stronger than the relationship with Depression/Anxiety (Zr = 0.09). Stronger associations were observed between ToM and clinical symptoms in younger patients, those with an earlier age at onset of illness and for tasks assessing a combination of different mental states.

CONCLUSIONS

The relationships between Cognitive/Disorganization, Negative symptoms, and ToM should be considered in treating individuals with SSD.

Functional Impairments and Theory of Mind Deficits in Schizophrenia: A Meta-analysis of the Associations

Schizophrenia is associated with major functioning difficulties. Theory of mind (ToM), the ability to infer the mental states of others, is an important determinant of functioning. However, the contribution of ToM to each specific domain of functioning remains to be better understood. The objectives of this meta-analysis were to document and compare the magnitude of the associations between ToM and (1) different domains of functioning (social functioning, productive activities, and instrumental activities of daily living), each assessed separately for functional performance and functional outcome and (2) different aspects of functioning (functional performance and functional outcome) in schizophrenia. Fifty-nine studies (N = 4369) published between 1980 and May 2019 targeting patients with schizophrenia or schizoaffective disorder aged between 18 and 65 years old were included. Studies were retrieved from seven databases. Correlations were extracted from the articles, transformed into effect sizes Zr and combined as weighted and unweighted means. The strength of the associations between the domains and aspects of functioning were compared using focused tests. A moderate association was observed between ToM and all domains of functioning, with a stronger association between ToM and productive activities compared with social functioning (only for functional outcome [χ2(2) = 6.43, P = 0.040]). Regarding the different aspects of functioning, a stronger association was observed between ToM and functional performance, compared with functional outcome, for overall functioning (χ2(1) = 13.77, P < 0.001) and social functioning (χ2(1) = 18.21, P < 0.001). The results highlight a stronger association of ToM with productive activities and with functional performance, which should be considered in future studies to improve functional recovery in schizophrenia.