Listening to the heart: A meta-analysis of cognitive behavior therapy impact on the heart rate of patients with anxiety disorders

Abstract Introduction The future of psychotherapy relies on the dialog with the basic science, being the identification of psychotherapeutifc biomarkers of efficacy a core necessity. Heart rate (HR) is one of the most studied psychophysiological parameters in anxiety disorders. Methods To investigate the impact of cognitive behavior therapy (CBT) on the HR of patients with anxiety disorders, we conducted a meta-analysis and systematic review. Electronic searches were conducted in the ISI/Web of Knowledge, PsychINFO and PubMed/MEDLINE for studies which evaluated HR at least once before and after CBT. Keywords related to anxiety disorders, HR and CBT were used in the search. Results 474 studies, of which 47 were selected for the systematic review and 8 for the meta-analysis, were identified. The results provide evidence that CBT significantly decreases the HR of posttraumatic stress disorder patients. In social phobia, obsessive–compulsive disorder and acute stress disorder, the results point in the same direction, although it is still early to attribute the decrease in HR to CBT. In specific phobias, traditional exposure therapy showed greater effect size than exposure with distractors or without psycho-education. Limitations Most of the randomized trials have not been conducted in accordance with rigorous methodological quality criteria. Conclusions Standardization in the methods used and in treatment protocols, as well as investigations in groups of patients with low physiological reactivity, are necessary in order to reach better conclusions. Notwithstanding these limitations, HR is beginning to emerge as a potential biomarker of efficacy in anxiety disorders.