Background: Caregiving experiences in dementia may have adverse effects on the caregiver's own physical and mental health. The Zarit Burden Interview (ZBI) is the most widely used instrument for assessing family carer burden and the purpose of the present study was to evaluate the psychometric properties of the Italian version of the ZBI (I-ZBI).
Methods: I-ZBI was administered to a non-randomized sample of 273 caregivers related to consecutively attending outpatients with a previously established primary diagnosis of dementia, according to DSM-IV criteria. Measurements used for the construct validity of the instrument were the General Health Questionnaire (GHQ-12), Hospital Anxiety and Depression Scale (HADS) and the Symptom Checklist-90-Revised (SCL-90-R). Validity and reliability were evaluated, as well as the factor structure of the instrument.
Results: Most caregivers were children (65%), female (72%) and living with the patient (53%), with quite a high level of burden. The I-ZBI demonstrates good reliability with high internal consistency (α = 0.90) and split-half correlation of 0.78, and good concurrent validity with other assessment tools. A five-factor solution was obtained for the I-ZBI and the original bi-factorial structure of the ZBI was not confirmed.
Conclusions: The Italian version of the Zarit Burden Interview is valid, reliable and useful for use in clinical contexts and in future studies that could lead to a better understanding of carer burden in dementia. Clarifying the factorial structure of the ZBI would help to further the understanding of the large body of research using it and would also help to advance the understanding of subjective burden.