Social Cognitive Performance in Schizophrenia Spectrum Disorders Compared With Autism Spectrum Disorder: A Systematic Review, Meta-analysis, and Meta-regression

Abstract

Importance: Schizophrenia spectrum disorders (SSDs) and autism spectrum disorder (ASD) both feature social cognitive deficits; however, these disorders historically have been examined separately using a range of tests and subdomain focus and at different time points in the life span. Moving beyond diagnostic categories and characterizing social cognitive deficits can enhance understanding of shared pathways across these disorders.

Objective: To investigate how deficits in social cognitive domains diverge or overlap between SSDs and ASD based on the extant literature.

Data sources: Literature searches were conducted in MEDLINE, PsycInfo, Embase, and Web of Science from database inception until July 26, 2020.

Study selection: Original research articles were selected that reported performance-based measures of social cognition in both SSDs and ASD samples. Selected articles also had to be published in English and use International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, DSM-IV, or more recent diagnostic criteria.

Data extraction and synthesis: This systematic review and meta-analysis was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-analyses and Meta-analysis of Observational Studies in Epidemiology reporting guidelines, including data extraction and quality assessment using a modified version of the Newcastle-Ottawa Scale. Data were pooled using a random-effects model.

Main outcomes and measures: Effect sizes were calculated as Hedges g (SSDs vs ASD). The primary outcomes were performance on emotion processing tasks, theory of mind (ToM) tasks, and the Reading the Mind in the Eyes Test (RMET) in SSDs compared with ASD. Meta-regressions were performed for age difference, publication year, quality assessment scores, and antipsychotic medication use.

Results: Of the 4175 screened articles, 36 studies directly comparing social cognitive performance in individuals with SSDs vs ASD were included in the qualitative analysis (n = 1212 for SSDs groups and n = 1109 for ASD groups), and 33 studies were included in the quantitative analyses (n = 1113 for SSDs groups and n = 1015 for ASD groups). Most study participants were male (number of studies [k] = 36, 72% [878 of 1212] in SSDs groups and 82% [907 of 1109] in ASD groups), and age (k = 35) was older in SSDs groups (mean [SD], 28.4 [9.5] years) than in ASD groups (mean [SD], 23.3 [7.6] years). Included studies highlighted the prevalence of small, male-predominant samples and a paucity of cross-disorder clinical measures. The meta-analyses revealed no statistically significant differences between SSDs and ASD on emotion processing measures (k = 15; g = 0.12 [95% CI, -0.07 to 0.30]; P = .21; I2 = 51.0%; 1 outlier excluded), ToM measures (k = 17; g = -0.01 [95% CI, -0.21 to 0.19]; P = .92; I2 = 56.5%; 1 outlier excluded), or the RMET (k = 13; g = 0.25 [95% CI, -0.04 to 0.53]; P = .10; I2 = 75.3%). However, SSDs vs ASD performance differences between studies were statistically significantly heterogeneous, which was only minimally explained by potential moderators.

Conclusions and relevance: In this analysis, similar levels of social cognitive impairment were present, on average, in individuals with SSDs and ASD. Cross-disorder studies of social cognition, including larger samples, consensus batteries, and consistent reporting of measures, as well as data across multiple levels of analysis, are needed to help identify subgroups within and across disorders that may be more homogeneous in etiology and treatment response.

Figure 1.. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Flow Diagram Showing Study Selection

Literature searches were conducted from database inception until July 26, 2020. ASD indicates autism spectrum disorder; ICD-10, International Statistical Classification of Diseases and Related Health Problems, Tenth Revision; SSDs, schizophrenia spectrum disorders.

Figure 2.. Graphical Display of Study Heterogeneity (GOSH) Plots for Visualizing Between-Study Heterogeneity

GOSH plots were generated by performing separate meta-analyses on all possible subsets of included studies (combinatorial meta-analyses) for emotion processing (A), theory of mind (B), and the Reading the Mind in the Eyes Test (C). Each plot shows overall standardized mean difference (Hedges g) and between-study heterogeneity (I² statistic) for each of the meta-analyses performed to enable visualization of patterns between effect sizes and heterogeneity. The data points for meta-analyses that included studies detected as outliers are shown in red (with larger effect sizes and higher heterogeneity), and all others are shown in blue. Hedges g values exceeding 0 indicate that SSDs groups outperformed ASD groups. Greater I² statistics represent higher between-study heterogeneity.

Figure 3.. Forest Plots of Effect Sizes for Each Meta-analysis

After outlier removal (where detected), forest plots for meta-analyses show standardized mean difference (Hedges g) and 95% CIs for emotion processing (A),^{,,,,,,,,,,,,,,} theory of mind (B),^{,,,,,,,,,,,,,,} and the Reading the Mind in the Eyes Test (C).^,,,,,,,,,,,, Hedges g values exceeding 0 indicate that SSDs groups outperformed ASD groups. Square size is proportional to study weight in the model. The diamond signifies the overall effect size and its 95% CI.