We appreciate the opportunity to respond to the criticism of our recent study on the impact of depression and antidepressant treatment on heart rate variability (HRV). The commentary by Licht et al. raised two key issues: 1) we should have included, not excluded, studies on patients with comorbid cardiovascular disease (CVD), and 2) we cannot dismiss a detrimental effect of antidepressant medication, particularly selective serotonin reuptake inhibitors (SSRIs), on HRV. While we strongly reject the argument that we should have included patients with CVD in our meta-analysis, we agree, in part, with the second issue raised. While our article concluded that antidepressant medication (except for tricyclic medication) has minimal impact on HRV, we stated explicitly that future studies are needed to confirm the impact of treatment using a longer posttreatment period. Licht et al. also present new data in their commentary, reporting that “antidepressant use but not major depression per se reduces HRV.” Although they had offered us these data to include in our meta-analysis, we decided not to incorporate their data into analyses for a number of reasons, including methodological concerns, which we elaborate on below, and the unpublished nature of the dataset. Therefore, in addition to responding to the two criticisms that were raised over our meta-analysis, we would also like to make a few comments on their own data and their interpretations and provide some recommendations for future research.
Kemp, A.H., Quintana, D.S., Gray, M. (2011). Is heart rate variability reduced in depression without cardiovascular disease? Biological Psychiatry, 69; e3-e4.