The Fear of Pain Questionnaire: psychometric properties of a Brazilian version for adolescents and its relationship with brain-derived neurotrophic factor (BDNF).

Objectives: The primary aim was to assess the psychometric properties (including internal consistency, construct validity, criterion validity, criterion-group validity and responsiveness) of the Fear of Pain Questionnaire (FOPQ) for adolescents (FOPQ-A) and parents (FOPQ-P) translated to Brazilian Portuguese (BrP). The secondary aim was to analyze the factor structures and their ability to identify subjects with chronic pain conditions and identify the relationship of the BrP FOPQ-A with saliva brain-derived neurotrophic-factor (BDNF).

Methods: A cross-sectional study was conducted with 286 adolescents aged 11 to 18 (257 healthy adolescents [157 females] and 29 adolescents with chronic pain [16 females]).