[Measurement of pain-related experiential avoidance: analysis of the Acceptance and Action Questionnaire-II-Pain in patients with chronic pain]. / Messung von schmerzbezogener Erlebensvermeidung: Analyse des Acceptance and Action Questionnaire-II-Pain bei Patienten mit chronischem Schmerz.

INTRODUCTION AND OBJECTIVE: Experiential avoidance is a core process variable in the concept of Acceptance and Commitment Theory (ACT) and has been connected to various disorders. A widely used instrument for the measurement of experiential avoidance is the Acceptance and Action Questionnaire II (AAQ-II). Recently, a pain-specific version for chronic pain patients was introduced in the Netherlands (AAQ-II­P). High scores indicate strong pain-related experiential avoidance. The aim of the current study was to measure pain-related experiential avoidance in a sample of chronic pain patients using the German translation of the AAQ-II­P and to analyze its psychometric qualities. METHODS: After a forward-backward translation procedure of the AAQ-II and adaptation to the pain context, a sample of N = 168 patients from a multidisciplinary pain center answered the German version of the AAQ-II­P. Additional questionnaires were administered to measure specific constructs of interest: chronic pain grade (CPG), pain catastrophizing (PCS), health-related quality of life (SF-12), psychopathology (HADS-D), personality (BFI­K) and mindfulness (KIMS-S). Reliability, factorial validity and construct validity of the AAQ-II­P were identified. RESULTS: The AAQ-II­P had high internal consistency (α = 0.89) and the one-factor solution explained 61% of the total variance. Correlations to personality and mindfulness subscales were low (maxima: r = 0.44 with neuroticism and r = -0.43 with acceptance). High correlations were shown for catastrophizing (r = 0.75), depression (r = 0.73) and anxiety (r = 0.66). Also, there was a substantial correlation to health-related quality of life, specifically the psychological total scale (r = -0.58). DISCUSSION AND CONCLUSION: The German AAQ-II­P has good reliability. Regarding factorial structure and construct validity, it is highly comparable to the original version. Direction and magnitude of the relationship to adjacent constructs mostly measure up to our expectations. Chronic pain patients inclined to pain-related experiential avoidance tend to indicate more pain catastrophizing and show restricted quality of life regarding psychological variables. Apparently, pain-related experiential avoidance can be relevant for popular target variables in psychotherapy.