The model of the relationships among the predictors of quality of life in chronic stage of schizophrenia.

We attempted to formulate a model of quality of life (QoL) in chronic stage of schizophrenia with 72 patients by including key variables, i.e., psychopathology, insight, executive functioning, and side effects, proposed to be its significant predictors in previous studies. We applied the structural equation modelling (SEM) method to simultaneously test a number of possible hypotheses concerning the inter-relations among the predictors of QoL in schizophrenia patients by formulating possible models and examining their levels of fitness. Our most fit model (X(2)=2.106, df=4, P=0.716; CFI=1.000; TLI=1.213; RMSEA=0.000, LO=0.000, HI=0.132) showed that the severity of psychopathology not only directly causes poor QoL, but also by adversely affecting insight. On the other hand, executive function may not be affected significantly by psychopathology, but executive function still plays an important role in determining the QoL not only directly, but also indirectly by influencing self-evaluation of side-effects. Impaired insight and executive function caused by severe level of psychopathology contribute to an increased reporting of side-effects, resulting in cumulative dysfunction in daily life for patients with chronic schizophrenia. Our study illustrates that the complexity of the relationships among the predictors of QoL in chronic patients of schizophrenia should be considered when designing studies on QoL of this group.