Therapieprozesse und Wirkmechanismen psychologischer Schmerztherapie

This dissertation project investigated treatment processes and mechanisms of graded in vivo exposure and cognitive-behavioral therapy during the treatment of individuals suffering from chronic low back pain and high levels of fear-avoidance. A randomized controlled trial design with individuals suffering from chronic low back pain and high levels of fear-avoidance (n=61) was applied to investigate unique and common treatment processes based on weekly session-by-session measures. We identified changes in fear-avoidance belief as a common treatment process. In addition, changes in relaxation, distraction, confrontation, activity and self-efficacy influenced the treatment success of exposure and cognitive-behavioral therapy. A subsequent single-case design with individuals suffering from chronic low back pain and high levels of fear-avoidance (n=12) was used to evaluate isolated treatment elements based on daily processes measurements. Moreover, effects on biological stress markers were explored. While exposure experience initiated several immediate changes, cognitive-behavioral interventions seemed to build their effect later in time. Furthermore, the exposure group showed relatively lower cortisol levels during a behavioral test immediately after treatment. Thus, treatment effects on biological stress markers appear to be a promising object of future investigation. An experimental design with healthy female students (n=112) was applied to evaluate therapist instructions during the conduction of exposure sessions. These instructions were justified by competing theories on mechanisms of change. Assumptions of the habituation model and the inhibitory learning model were compared. Both instructions improved cognitive pain coping. Only the instruction according to the inhibitory learning model increased pain tolerance. Similarly, only the instruction according to the inhibitory learning model lead to specific psychophysiological changes. These psychophysiological changes can be better explained by assumptions of the inhibitory learning model compared to assumptions of the habituation model. Overall, this dissertation project contributes to an improved understanding of treatment process-es and mechanisms within psychological pain treatments. At the same time, isolated treatment elements and therapist instructions were evaluated. Methodological considerations concerning respective research designs are discussed regarding future psychotherapy research.