Do patients with high-functioning autism have similar social cognitive deficits as patients with a chronic cause of schizophrenia?

OBJECTIVE: There is substantial evidence that both patients with schizophrenia and patients with autism spectrum disorders (ASD) have impaired social cognition including theory of mind (ToM) deficits. However, it remains unclear if both verbal (explicit) and non-verbal (implicit) ToM as well as social perception are similarly affected in both disorders.

METHODS: Twenty-one patients diagnosed with schizophrenia and 11 patients diagnosed with ASD were matched one-to-one to healthy controls based on gender, age, and educational level. Social functioning was measured by Personal and Social Performance (PSP) scale. Neurocognition was measured using Brief Assessment of Cognition in Schizophrenia (BACS-DK), and four subtests from Wechsler Adult Intelligence (WAIS-IV) scale were applied to estimate IQ. The Animated Triangles Task was used to measure implicit ToM, while explicit ToM and social perception were measured by The Awareness and Social Inference Test (TASIT).

RESULTS: Patients with schizophrenia had deficits in implicit ToM and complex social perception compared to their matched controls, but no problems with explicit ToM. Surprisingly, patients with ASD solely had deficits with regard to complex social perception compared to their matched controls. The two patient groups were similar regarding estimated IQ, social functioning and years of education, but differed in age and neurocognition. When adjusting the p-values for age and neurocognitive deficits, both patients groups had similar social cognitive deficits.

CONCLUSIONS: Results imply that we compared schizophrenia patients with substantial neurocognitive deficits to a group of high-functioning patients with ASD. However, these two subgroups may have the same level of social cognitive deficits.