Portuguese adaptation of the Behavioral Inhibition Questionnaire (BIQ)

Behavioral inhibition (BI) is a temperamental trait characterized by a consistent pattern of behavioral and emotional responses to unfamiliar people and novel situations. BI exhibits moderate stability across development and is considered a risk factor for the emergence of emotional disorders in adolescence and adulthood, making early assessment crucial for understanding this behavioral pattern. In the Portuguese context, there is a paucity of measures specifically designed to assess BI in childhood. To address this gap, we aimed to adapt and examine the psychometric properties of the Behavioral Inhibition Questionnaire (BIQ) in Portuguese children. We obtained BIQ ratings from both parents and teachers of 435 children (average age = 57.1 months; SD = 13.8). Confirmatory factor analysis supported a six-factor measurement model, each factor loading onto a higher-order BI factor. Additionally, we included a method factor to account for reversed items. Full scalar measurement invariance across gender and age groups was supported. Parents and teachers showed good agreement in their ratings of BIQ scores. Comparisons with other instruments revealed good convergent validity. The BIQ scores showed acceptable reliability, although the subscales exhibited limited sensitivity in discriminating between different contexts where BI may manifest. This study suggests that the BIQ is a reliable and valid tool for assessing BI in Portuguese children.