40. Exploration not Perseveration: Computational Modeling of Probabilistic Reversal Learning Impairments in Psychosis

Abstract

Background: Theory of mind (ToM) is an aspect of social cognition which refers in part to the capacity to perceive and understand other people's mental state. Deficits in these mentalizing processes are commonly observed in both schizophrenia and Autism Spectrum Disorder (ASD), and are thus evident in disorders with very different symptoms and clinical presentations. The aim of this study was to conduct a meta-analysis of all published data examining ToM deficits in schizophrenia and autism in order to determine whether these two disorders have distinct deficit profiles across multiple domains of ToM. We additionally aimed to explore the relationship between clinical symptoms and phase of illness on ToM deficits in schizophrenia. Methods: A literature search identified 74 eligible studies in schizophrenia involving 3555 cases and 22 studies in ASD involving 810 cases, as of August 2016. Meta-analyses were conducted to calculate the pooled effect size of deficits for each patient group in each ToM domain. Results: As expected, significant theory of mind deficits were observed in both schizophrenia and ASD. Strikingly, the most significantly impaired ToM domain in schizophrenia was understanding verbal intention (g = −1.33) followed by indirect speech (g = −1.09), second-order false belief (g = −0.89), faux-pas −0.88), emotional ToM (g = −0.76) and firstorder false belief (g = −0.61). Understanding visual intention was not significantly impaired. In ASD, the most impaired domain was understanding indirect speech (g = −1.40), followed by faux-pas (g = −1.27), emotional ToM (g = −0.75), and understanding false belief (g = −0.467). Intention inferencing was not significantly impaired in ASD (g = −0.01). Planned meta-regression analyses revealed that positive symptoms significantly modulated the magnitude of deficit across several ToM domains in schizophrenia. Conclusion: Common symptoms of schizophrenia, such as paranoia and persecutory ideas, chime with the greatest observed ToM deficit observed here, which was understanding verbal intention, which was not impaired in ASD. Conversely, understanding meaning in speech was most impaired in ASD, but this was less impaired in schizophrenia. This study reveals that schizophrenia and ASD populations have distinct ToM deficit profiles. Understanding differences in ToM deficit profiles can help differentiate the clinical phenotypes of these disorders in a way that might enhance the identification of disorder-specific behavioral markers and the development of explanatory models and new treatments. Background: The mechanism of auditory hallucinations has been avidly pursued for decades although its formation remains largely cryptic. Another domain of clinical symptoms in schizophrenia is reduced working memory, for which the "phonological loop" is the elementary component. The phonological loop is a subvocal rehearsal of verbal information to support working memory for holding information while other information is manipulated. We hypothesize that auditory hallucinations and w...