Learning Objective 1: The learner will be able to describe the cardiovascular reactivity (CVR) to laboratory-induced mental stress in patients with major depressive disorder(MDD).
Learning Objective 2: The learner will be able to compare the difference in CVR between MDD patients with high depressive levels and those with low depressive levels.
Cardiovascular reactivity (CVR) is defined as the degree of an individual’s hemodynamic responses to mental stress and provides an index of the sympathetic activation. Autonomic nervous system dysregulation is one of the most plausible biological mechanisms that account for the increased CV risk in depression. This study examined the differences in CVR between major depressive disorder (MDD) patients with high depressive levels and those with low depressive levels.
All participants underwent a stress testing protocol including the Stroop Color and Word Test (SCWT) and the Mirror Star Tracing Task (MSTT). The Beck Depression Inventory (BDI) was used to assess the depressive level of participants. Individuals with a BDI less than or equal to 10 were designated as the low BDI group whereas those with a BDI greater than 10 were designated as the high BDI group.
A total of 89 MDD patients were included in the study. Even there was a trend showing that the high BDI group had less hemodynamic reactivity than the low BDI group, there were no differences between the groups in all of the hemodynamic reactivity with the exception in SV reactivity (p=.02). However, after using a regression analysis to make additional adjustment for anxiety level, the difference in SV reactivity between two groups became non-significant (p=.08). Depressive level was negatively correlated to degree of SV reactivity (p=.05).
Our results revealed that there were no statistical significant differences in CVR between two groups. Given that individuals with a score of BDI-II less than 10 are identified as having no depression, our results raise a tentative speculation that in MDD patients, a stress-induced pattern of CVR may be sustained even in those who are responded to treatment and currently without depression.