This study aims to validate a self-administered, multidimensional QoL instrument based on the point of view of caregivers of individuals with schizophrenia.

Data were collected through the departments of six psychiatric hospitals in France (n = 246). The item reduction and validation processes were based on both item response theory and classical test theory.

The S-CGQoL contains 25 items describing seven dimensions (Psychological and Physical Well-Being; Psychological Burden and Daily Life; Relationships with Spouse; Relationships with Psychiatric Team; Relationships with Family; Relationships with Friends; and Material Burden). The seven-factor structure accounted for 74.4% of the total variance. Internal consistency was satisfactory; Cronbach's alpha coefficients ranged from 0.79 to 0.92 in the whole sample. The scalability was satisfactory, with INFIT statistics falling within an acceptable range. In addition, the results confirmed the absence of DIF and supported the invariance of the item calibrations.

The S-CGQoL is a self-administered QoL instrument that presents satisfactory psychometric properties and can be completed in 5 min, thereby fulfilling the goal of brevity sought in research and clinical practice.