Attention in patients with chronic schizophrenia: Deficit in inhibitory control and positive symptoms

Background and Objectives: Attention is a central mechanism controlling information processing, activating and inhibiting processes, and forming a complex system including diferent networks in specific areas of the brain1. To correctly assess the role of attention in schizophrenia it is necessary to discriminate its different attentional components, which may by selectively altered. Attention span, focused attention, selective attention, sustained attention and inhibitory response, were assessed in patients with chronic schizophrenia and healthy matched controls. Methods: The study included 32 patients diagnosed with chronic schizophrenia and 32 healthy subjects. The groups were matched in age, sex, and level of education. Symptom severity (positive symptoms, negative symptoms, and general psychopathology) was assessed with the Scale for the Assessment of Positive and Negative Symptoms (SAPS and SANS). Attentional components were measured by Forward Digit Span, Symbol Search, Digit Symbol Coding, Stroop Test and Picture Completion. Results: Schizophrenic patients exhibited lower attentional scores in all tests compared to the control group. Inhibitory control and sustained attention were the most affected traits in schizophrenic patients. An inverse correlation was observed between inhibitory control and delusions and disorganized thinking. No significant correlations were observed between negative symptoms and attentional performance. Conclusions: The pattern of results obtained in this paper evidences the role of an inhibitory control deficit in patients with chronic schizophrenia that could also be involved in other attentional and cognitive failures, and also be connected to positive symptoms.