Examining relationships between state and trait psychotic symptoms and quality of life in schizophrenia spectrum disorders.

Positive and negative symptoms are core aspects of schizophrenia and have been shown to influence patient quality of life (QOL). Previous studies have largely focused on current or state symptoms, with limited work on the contributions of trait symptoms to QOL. This study sought to examine the relationship between both state and trait symptoms and objective and subjective QOL. Fifty-three schizophrenia spectrum disorder patients and 47 healthy controls were recruited. State symptomatology was assessed using the Positive and Negative Syndrome Scale in the patients only. In all participants, trait symptoms were assessed using the Oxford-Liverpool Inventory of Feelings and Experiences, and QOL using Lehman's QOL Interview. Hierarchical linear regression analyses, controlling for depression and neurocognition, revealed that negative state symptoms were related to objective QOL within the patients, while negative trait symptoms were associated with both objective and subjective QOL in patients and healthy controls. No relationships were observed with positive state or trait symptoms and either QOL measure. The findings suggest a degree of complexity in the associations between symptoms and QOL, with primacy for negative symptoms at both state and trait levels. A greater appreciation of trait symptoms may help explain non-complementary QOL changes following symptom remission.