A comparative study of cognitive functions between schizophrenia and obsessive-compulsive disorder

BACKGROUND: Schizophrenia (SZ) and obsessive-compulsive disorder (OCD) are closely linked, have a high comorbidity rate, and their differential diagnosis is challenging in clinic. Some studies have found common cognitive deficits in some domains between them. The goal of this research was to compare the cognitive functions of SZ and OCD in order to offer a clinical foundation for differential diagnosis and treatment of the two disorders. METHODS: A control design was used in this study, which comprised 61 patients with SZ, 60 individuals with OCD, and 51 healthy controls (HC). We assessed patients' cognitive functions by testing six domains, including visual learning, reasoning and problem solving, verbal learning, attention/vigilance, speed of processing and working memory. RESULTS: The results showed that patients with SZ had cognitive impairments in all areas except attention/vigilance, while patients with OCD only had cognitive impairment in reasoning and problem-solving. Overall, patients with SZ did not perform as well as patients with OCD in all domains. CONCLUSIONS: In terms of neurocognition, both of SZ and OCD patients have defects in reasoning and problem solving. In addition to this, SZ patients also performed worse than HC in other areas such as speed of processing, working memory, verbal learning and visual learning. On the overall level, cognitive performance is better in OCD patients than in SZ patients. The field of reasoning and problem solving can be used as a new goal to study the relationship and treatment strategies between them in the future.