Assessing the impact on caregivers of patients with schizophrenia: psychometric validation of the Schizophrenia Caregiver Questionnaire (SCQ)

The final questionnaire comprised a ‘Humanistic impact’ supra-domain composed of a global score and four subdomain scores (‘Physical’; ‘Emotional’; ‘Social’; ‘Daily life’), and eight other domain scores related to the caregiving role (‘Exhaustion with caregiving’; ‘Feeling alone’; ‘Patient Dependence’; ‘Worries for the patient’; ‘Perception of caregiving’; ‘Financial dependence of the patient’; ‘Financial impact of caregiving’; ‘Overall difficulty of caregiving’). Two items from the SCQ were deleted. SCQ scores showed very good construct validity: Item convergent/discriminant validity were satisfactory; SCQ scores of caregivers of patients with more severe symptoms were higher indicating more impact (p < 0.05 for all scores); SCQ scores were meaningfully associated with measures of schizophrenia severity (PANSS and PSP) and caregivers’ Health-Related Quality of Life (Medical Outcome Survey Short Form 36 items). The SCQ Humanistic impact supra-domain scores demonstrated very good internal consistency reliability (Cronbach’s alphas between 0.80 and 0.96) and test-retest reliability (Intraclass Coefficient correlations ranging from 0.75 and 0.87); Other SCQ domain scores showed lower but still acceptable reliability coefficients. SCQ scores clearly increased for caregivers of patients whose schizophrenia worsened.