Is the association between depression and blunted cardiovascular stress reactions mediated by perceptions of stress?

Symptoms of depression are related to blunted cardiovascular reactions to acute stress tasks. However, it is unclear what factors might mediate this association and whether blunted responses are specific to mental stress tasks or are also evident with other forms of stress. The present study assessed cardiovascular reactivity to both mental and postural stress and the role of background stress exposure and stress perception. Undergraduate students (N=119, 81 females) were screened for depressive symptoms using the Beck Depression Inventory. Twenty-six participants with probable depression and 26 non-depressed controls underwent cardiovascular stress testing. Heart rate (HR), systolic (SBP) and diastolic (DBP) blood pressure were measured at rest and in response to a 5min orthostatic challenge and an 8min mental arithmetic task. Stress exposure was measured using the Undergraduate Stress Questionnaire. Perceptions of general life stress were assessed using the Perceived Stress Scale (PSS) and perceptions of the stress task impact were measured using Threat Appraisal (TA). Symptoms of depression were associated with blunted HR, F(2,98)=5.26, p=.010, η(2)=.097, and SBP, F(2,98)=6.47, p=.008, η(2)=.117, reactions to the mental stress but not to postural challenge. HR reactions were mediated by PSS score, while both PSS score and TA emerged independently as mediators of SBP reactions. These results confirm a negative relationship between depressive symptoms and cardiovascular reactions to acute stress, suggest that this association may be stress task-specific, and may be mediated by perceptions of stress.