The relationship between experiential deficits of negative symptoms and subjective quality of life in schizophrenia

Understanding the link between quality of life and symptoms in schizophrenia is important in enhancing the prospect of patient recovery. Only weak associations have been found between subjective quality of life (SQOL) and negative symptoms. However, this may be because many existing symptom assessment scales inadequately assess the experiential deficits of negative symptoms. This study aimed to re-evaluate these findings using the Clinical Assessment Interview for Negative Symptoms (CAINS), which as been designed to capture both the expressive and experiential subdomains of negative symptoms as separate constructs. In this observational study 275 participants with at least moderate negative symptoms were assessed three times over nine months using the CAINS, the Positive and Negative Syndrome Scale (PANSS), and the Manchester Short Assessment of Quality of Life (MANSA). A significant negative association between SQOL and the CAINS experiential subscale was found in the cross-sectional analysis (adj. B = -0.28, 95% CI = -0.44 to -0.12, P = 0.001), and in the change scores (adj. B = -0.13, 95% CI = -0.26 to -0.01, P = 0.032). No associations between SQOL and expressive symptoms, or negative symptoms measured using the PANSS were detected in the multivariable models. These findings suggest that the association between negative symptoms and SQOL is related primarily to experiential deficits, and highlights the importance of measuring the separate subdomains of negative symptoms as distinct constructs. The findings also highlight the impact of negative symptoms and experiential deficits in particular on social outcomes, further emphasising the need to develop new treatments for these symptoms.