Factor structure of the Schizophrenia Quality of Life Scale Revision 4 (SQLS-R4)

The Schizophrenia Quality of Life Scale Revision 4 (SQLS-R4) appears to offer excellent potential as an easily administered and patient acceptable assessment and monitoring measure of quality of life (QoL). However, a principle psychometric criterion crucial to the use and validity of the instrument concerns the underlying factor structure. The SQLS-R4 comprises two sub-scales, these being cognition and vitality QoL and psychosocial feelings QoL. However, the factor structure of the SQLS-R4 has yet to be established in a patient group in the UK. Confirmatory factor analysis was conducted on the SQLS-R4 to determine its psychometric properties in 100 patients with a primary ICD-10 diagnosis of schizophrenia. Internal reliability of the SQLS-R4 cognition and vitality QoL and psychosocial feelings QoL sub-scales was found to be excellent. Consistent with the original validation of the SQLS-R4, two correlated factors comprising cognition and vitality QoL and psychosocial feelings QoL were observed to offer the best fit to the data. In conclusion, the SQLS-R4 would appear to be suitable for use in patients with a primary diagnosis of schizophrenia in the UK. Potential clinical uses and the direction of future research with the SQLS-R4 are indicated.