Anxiety reduces baroreflex cardiac control in older adults with major depression

Objective: Although depression and anxiety predict risk of cardiac mortalit y, the contributions of depression and anxiety to vagal cardiac control hav e not been systematically evaluated. The goal of this study was to examine the relationship between state anxiety and vagal control of heart rate in o lder adults with major depressive disorder (MDD). Older adults (50-70 years old) were selected for this study because of the greater cardiac risk asso ciated with low vagal cardiac control across this age range. Methods: Fifty -six men and women with MDD were evaluated. MDD was diagnosed using the Dia gnostic Interview Schedule, and severity of depression was measured using t he Beck Depression Inventory and the Hamilton Rating Scale for depression. State anxiety was measured using the Spielberger State Anxiety Inventory. P ower spectral analysis was used to measure two indices of vagal control: ba roreflex control of heart rate (BRCSPEC) and respiratory sinus arrhythmia ( RSA). Results: State anxiety was negatively correlated with levels of BRCSP EC (r = -0.32, p < .05), whereas depression severity was not related to eit her RSA or BRCSPEC. Furthermore, BRCSPEC was reduced by approximately 33% i n MDD patients with state anxiety scores (ST-ANX) in the highest quartile ( ST-ANX > 41, N = 13), compared with patients with ST-ANX scores in the lowe st quartile (ST-ANX < 25, N = 14; p < .05). Conclusions: Anxiety, but not d epression severity, is associated with reduced BRCSPEC in older men and wom en. Future studies are needed to determine whether comorbid anxiety contrib utes to the increased cardiovascular risk associated with MDD.