The Schizophrenia Caregiver Quality of Life questionnaire (S-CGQoL): Development and validation of an instrument to measure quality of life of caregivers of individuals with schizophrenia

Abstract

Objective

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

Methods

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.

Results

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.

Conclusion

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.

Introduction

Schizophrenia is a disabling and severe psychiatric disorder with either episodic or continuous evolution that can result in physical, psychological and social problems related to both the disease and the potential side effects of its treatment (Green et al., 2000, Kasckow et al., 2001, Kurtz et al., 2008, Lehman, 1983, Reine et al., 2005). Schizophrenia also affects the functioning of family caregivers, especially because the caregivers have assumed functions that were performed in the past by psychiatric institutions (Caqueo-Urizar et al., 2009, Ochoa et al., 2008, Reine et al., 2003b). The impact of caregiving on caregivers' quality of life (QoL) is important (Caqueo-Urizar et al., 2009, Martens and Addington, 2001). Caregivers of individuals with schizophrenia have reported reduced QoL, especially when experiencing a significant burden (Glozman, 2004, Li et al., 2007), restricted roles and activities, and increased psychosomatic, anxious, or depressive symptoms (Awad and Voruganti, 2008, Schulz and Beach, 1999). Caregivers' negative experience may affect their ability to care for the patients. This is an important concern because involvement of family caregivers is essential for optimal treatment of patients by ensuring treatment compliance, continuity of care, and social support (Reine et al., 2003b, Velligan et al., 2009). Several studies have shown that a lack of family involvement in treatment planning is associated with problems in treatment adherence (Ahn et al., 2008, Cooper et al., 2007, Valenstein et al., 2004). Therefore, assessing and preserving caregivers' QoL is a noteworthy issue both for the caregivers themselves and indirectly for patients' health.

Caregivers of individuals with schizophrenia have received significant attention in the past few years. Most of the research is focused on caregivers' burden (Levene et al., 1996, Provencher and Mueser, 1997, Schene et al., 1994), caregiving (Joyce et al., 2000, Szmukler et al., 1996), coping strategies (Magliano et al., 1996, Roncone et al., 2007, Rosen et al., 1989, Rosen et al., 2001) and opinions on the causes and consequences of mental disorders (Kallert and Nitsche, 2008, Magliano et al., 1999). Although studies have been conducted on specific issues in caregiving, little has been done to explore QoL among caregivers of individuals with schizophrenia, and no QoL measurement scale has been specifically developed for use with this population (Caqueo-Urizar et al., 2009, Li et al., 2007, Martens and Addington, 2001). A self-administered instrument based on the caregivers' point of view and anchored in an explicit conceptual approach (McKenna, 1997) could constitute an innovative area of research in schizophrenia. An exploration and evaluation of the caregivers' QoL could be useful in improving patients' health and QoL, preserving caregivers' health and their ability to care, and developing new care strategies.

We present the results of the development and the validation of a self-administered, multidimensional QoL instrument based on the point of view of caregivers of individuals with schizophrenia: the Schizophrenia Caregiver Quality of Life questionnaire (S-CGQoL).