Commentary on Kim et al., Effects of therapeutic relationship, expectancy, and credibility in breathing therapies for anxiety.

Kim and colleagues (2015) explored influences on clinical outcomes related to nonspecific therapeutic factors, addressing the importance of client expectancy and development of the therapeutic alliance. In the process, however, the authors carry forward conclusions from their prior research on treatment of panic that two opposing breathing retraining protocols are equally effective. Neither the experimental design nor the sample size of the current or previous study warrants reaching those conclusions. This commentary examines the findings of the current and previous studies and points to consistent trends that suggest that breathing retraining of panic patients may be enhanced by protocols aimed at raising exhaled CO2.