Psychometric evaluation of the illness perception questionnaire for schizophrenia in a Chinese population

Illness perceptions have been associated with patients' reactions to health threats and further health outcomes. The Illness Perception Questionnaire for Schizophrenia (IPQS)¹ has been applied in different contexts. However, the validity and reliability of IPQS remain unknown in mainland China.

To test the psychometric properties of the Chinese version of IPQS in mainland China.

A cross-sectional survey.

A total of 200 community-dwelling patients with schizophrenia were surveyed in Beijing, China. The validity and reliability of the instrument were tested. As well as demographic data, the IPQS and the Knowledge About Schizophrenia Test (KAST)² were also administered.

Factor analysis was utilised to refine the factor structure of the IPQS. The difference between IPQS and KAST denoted the discriminant validity. The subscale scores among patients of different illness duration, educational attainment, and medication adherence in the past two years were significantly different (P＜0.05), indicating the known-group validity of the IPQS. Except for 'personal control' and 'burdensome effect', other subscales were internally consistent. Most of the subscales proved stable over a four-week period.

The Chinese version of IPQS can be used, with some refinements, to assess illness perceptions about schizophrenia for patients in future studies. This will provide empirical evidence for its generalizability and clinical utility and provide deeper insight into Chinese patients' illness perceptions about schizophrenia.