Differential Effects of Autistic Traits and Psychotic‐Like Experiences on the Interpretation and Inference of Social Intentions

OBJECTIVE: Theory of mind (ToM), the ability of mental state attribution, is an important aspect of social cognition. The autism-psychosis diametrical model suggests that there is an opposite impact of autistic traits and psychotic-like experiences (PLE) upon ToM, with autistic traits associated with under-mentalizing and PLE linked to over-mentalizing. This exploratory study aimed to examine the diametrical model at both subclinical and clinical levels. METHOD: We recruited 240 college students (Study 1), 28 patients with chronic schizophrenia and their demographically-matched controls (Study 2). The animated shapes task was used to assess ToM ability. This task was a non-verbal task involving the interpretation of geometric figure interactions in random and ToM conditions. All participants completed the Community Assessment of Psychic Experiences (CAPE) and the Autism-Spectrum Quotient (AQ) to measure PLE and autistic traits. The positive symptom subscale (PANSS-P) and the dimensional autism severity score (PAUSS) of the PANSS were additionally used to assess the severity of positive symptoms and autistic phenotypes in clinical populations. RESULTS: Patients with chronic schizophrenia demonstrated a mixed pattern of ToM impairment, combining over-mentalizing for random movements and under-mentalizing for movements involving mental state. Correlational analysis preliminarily suggested that regardless of diagnostic status, PLE was associated with over-mentalizing, that is, more intentionality attribution to random movement. Autistic-like symptoms among patients were related to less intentionality with less appropriate answers in ToM condition. However, the interaction of the two symptoms, or the co-occurrence of PLE and autistic traits had no significant beneficial effect on ToM performances. DISCUSSION: Autistic traits and positive psychotic symptoms may have differential effects on mentalizing, but there is no support that ToM impairments would be attenuated in individuals with mixed symptom expressions.