Assessing health-related quality of life in patients suffering from schizophrenia: a comparison of instruments.

OBJECTIVE: To compare three different kinds of health-related quality of life (HRQL) questionnaires available for use in patients suffering from schizophrenia: the SF-36 (a generic instrument), the QoLI (an instrument designed to a broad range of mental illnesses), the S-QoL (a questionnaire specific to schizophrenic patients), in terms of external validity and sensitivity to change.
METHODS: Two hundred and five patients were included at D0 and one-third retested at D30. Socio-demographic data and clinical history were recorded, clinical evaluation comprised psychotic symptoms (PANSS), depression (Calgary depression scale for schizophrenia), global functioning (GAF), clinical severity (CGI), and extrapyramidal symptoms (ESRS). HRQL was assessed using the SF-36, the QoLI and the S-QoL.
RESULTS: A better agreement is observed between the SF-36 and the S-QoL than between the QoLI and the two other instruments. S-QoL and SF-36 are more strongly correlated with clinical status than QoLI. Compared to the SF-36 and the QoLI, the S-QoL better discriminates patients with comorbidity from others. The S-QoL shows better responsiveness than the QoLI and the SF-36.
CONCLUSION: For descriptive purpose, either generic tools like SF-36 or specific ones should be used, whereas when aiming at evaluating health treatment and care for schizophrenic patients, specific instruments like the S-QoL should be favoured.