Interview-based assessment of cognition is a strong predictor of quality of life in patients with schizophrenia and severe negative symptoms

OBJECTIVE: To analyze the correlation between quality of life, symptoms, and cognition assessed by the interview-based Schizophrenia Cognition Rating Scale (SCoRS). METHODS: Seventy-nine outpatients diagnosed with schizophrenia were evaluated with the Quality of Life Scale – Brazilian version (QLS-BR), the SCoRS, and symptoms scales (Positive and Negative Syndrome Scale [PANSS]). After determining the potential explanatory variables using Spearman’s correlation and Student’s t test results, we ran simple, multivariate, and decision-tree regression analyses to assess the impact of SCoRS and PANSS ratings on mean overall quality of life. RESULTS: Cognitive deficits and negative symptoms were the best predictors of quality of life. A low degree of negative symptoms (PANSS negative < 11) was a strong predictor of better quality of life (QLS ∼ 75), regardless of SCoRS rating. Among participants with more severe negative symptoms, elevated cognitive impairment (interviewer SCoRS ∼ 44) was a predictor of worse quality of life (QLS ∼ 44). CONCLUSIONS: Cognitive impairment determined by interview-based assessment seems to be a strong predictor of quality of life in subjects with severe negative symptoms. These results support the usefulness of SCoRS for cognitive assessment that is relevant to the everyday life of patients with schizophrenia.