The use of the Italian version of the Parental Bonding Instrument (PBI) in a clinical sample and in a student group: an exploratory and confirmatory factor analysis study

Abstract

The aim of this study was to verify the construct validity of the Italian version of Parental Bonding Instrument (PBI) a questionnaire which estimates the parental style as reported by the son or daughter. The questionnaire was administered to a group of 102 students (62 males and 40 females) attending University of L'Aquila and to a sample of 128 patients (76 males and 52 females) consecutively admitted to a psychiatric unit for an index episode. We compared the means of the two factors (care, protection) separately for each parent in the two groups using a t-test for independent samples. After having estimated the internal consistency of items of each scale by calculating Cronbach's coefficient alpha, a factor analysis was performed for students and patients to find the structural factors of the questionnaire; then, we conducted a confirmatory factor analysis of the PBI items, for the students only, to evaluate the fit of the real items to models proposed in the literature. The Italian version of the Parental Bonding Instrument, demonstrated the ability to discriminate between patients and controls; it showed an high internal consistency. The factor analysis identified a two factors solution which accounted for 44.6% and 44.3% of the variance of the mother's and father's PBI scores respectively for the group of students and it identified two factors which accounted for 49.3% and 46.6% of the variance in the group of patients. The psychiatric patients showed a low "care"-high "protection" confirming an association between the "affectionless control" pattern and psychiatric disorders.