Verbal fluency in chronic schizophrenia and severity of psychotic symptoms. Consideration of their relationship with errors in the tasks

Background and Objectives: There are many associations between psychotic symptoms and performance in Verbal Fluency (VF) tasks. However, most of these are found are with negative symptoms. In this study we examined the relationship between the performance in four VF tasks and the severity of both positive and negative symptoms. Methods: To compare performance in different VF tasks, two groups of participants were matched for age, sex and educational level, a Healthy Control Group (N = 83) and a Chronic Schizophrenia Group (N = 83). We examined the correlation between cognitive performance in these verbal tests and the severity of psychotic symptoms in the group of patients. Results: The results show that the performance of patients with chronic schizophrenia in VF tests is significantly lower than for healthy individuals. The analysis of correlations between tasks showed a significant correlation between the severity of negative symptoms and poor performance in VF tasks. Another interesting result was the association between the severity of formal thought disorder and poor performance in semantic VF. A particularly striking result was the correlation between the severity of positive symptoms and the number of errors in VF tasks in the patient group. Conclusions: These results have provided evidence for some of the proposed hypotheses and are in accordance with previous investigations. The correlations between the positive symptoms and the number of errors in the different VF tasks have not been previously reported. It is important to note that most of these correlations are between the severity of positive symptoms and intrusion errors.