Concept and validation of the German version of the Cognitive Fusion Questionnaire (CFQ-D)

Within the ACT model of psychological flexibility, cognitive fusion (CF) refers to individuals' attitudes towards their own thoughts and beliefs, more specifically, the extent to which they identify with and are behaviorally regulated by the form and content of their own thoughts and beliefs. This concept is of growing interest for those treating chronic conditions. Evidence supports the relevance of CF in the context of pathological conditions such as chronic pain. Recently developed measures of CF are available in English but so far, have been lacking in German. This study aims to explore the reliability and validity of the German translation of the Cognitive Fusion Questionnaire (CFQ) within a clinical sample (n = 216) of patients suffering from chronic pain at a rehabilitation clinic and a non-clinical sample (n = 166). Participants also completed a set of standard clinical measures as well as the German translation of the Psychological Inflexibility in Pain Scale (PIPS) to assess concurrent and convergent validity. Confirmatory factor analysis (CFA) confirmed a one-factor solution, referred to as CF, which had been identified previously. The scale had good psychometric properties. Furthermore, the CFQ-D total sum score was correlated with measures of psychological inflexibility in pain, pain intensity, self-reported state of health and limitation of physical functioning, functional ability, quality of life, pain related self-instructions and depression. Further analyses indicate that CFQ-D is a reliable and valid instrument for assessing CF in a German-speaking population.