Cognitive Features of High-functioning Adults with Autism and Schizophrenia Spectrum Disorders

Abstract

Objective: Autism Spectrum Disorder (ASD) and schizophrenia share common features in terms of pathophysiology and clinical appearance. Cognitive deficits are also present in both disorders. However, ASD and schizophrenia are heterogeneous syndromes, and few studies have addressed patients with these disorders who have above average educational attainment. In this study, we assessed the cognitive functions of a group of adult ASD patients with adequate mental development and verbal communication skills (High Functioning Autism, HFA) and compared them with a group of Schizophrenia patients matched for level of education.

Method: Three groups of patients and controls [(HFA, n= 32), Schizophrenia (n= 17), Controls (n= 23)], all with at least a high school education, were assessed with the Wechsler Adult Intelligence Scale (WAIS), Wisconsin Card Sorting Test (WCST), and Rey Auditory Verbal Learning Test (RAVLT). For the assessment of HFA, scores on the Autism Spectrum Disorders in Adults Screening Questionnaire were taken into consideration. Clinical diagnoses were based on DSM-IV TR and DSM-5 criteria.

Results: High Functioning Autism and Schizophrenia groups performed similarly in all subtests except for WAIS Comprehension and Digit Symbol, WCST Perseveration, and RAVLT Learning.

Conclusion: Comprehension abilities of educated adults with HFA could be higher than average in situations that do not involve social interaction. Tendency to perseveration in the presence of adequate concept formation ability may reflect the clinical symptoms of rigidity and repetitive behavior. In patients with higher levels of functioning and education, their diagnosis appears to be weakly associated with cognitive functioning. The potential roles of other variables, such as environmental factors, during development deserve further exploration in future studies.