Type D personality and stress responsivity: Moderating and mediating mechanisms

Introduction: Type D personality has been consistently associated with adverse cardiovascular health, with atypical cardiovascular reactions to psychological stress one potential underlying mechanism. Despite this, studies examining the association between Type D personality and cardiovascular reactions to acute stress have yielded mixed findings. Thus, the current thesis examined if, and under what conditions, Type D personality is associated with cardiovascular reactivity to stress.

Methods: This thesis reports on the findings from two systematic reviews, two quasi-experimental laboratory studies, and one cross-sectional survey study. Study 1 sought to synthesise existing studies examining the association between Type D personality and cardiovascular reactivity to acute stress in the literature via a systematic review and meta-analysis. Study 2, also using a systematic review, aimed to summarise the range of outcomes predicted by blunted cardiovascular reactivity to psychological stress in the  literature, and to identify a range of blunted cardiovascular reaction levels that predicted these outcomes. Study 3, using a quasi-experimental laboratory study, examined if the association between Type D personality and cardiovascular reactivity was mediated via self-reported social relationships (social support and perceptions of negative social  relationships). Study 4, using a cross-sectional survey design, examined if Type D personality was associated with a greater number and perception of stressful life events, and if self-reported social relationships mediated these associations. Finally, Study 5 employed a quasi-experimental laboratory protocol to examine if Type D personality had predictive utility for cardiovascular reactivity above anxiety and depressive symptoms,  as well as its individual subcomponents (negative affect; NA, social inhibition; SI). Across studies, Type D personality was assessed using the 14-item Type D scale (Denollet, 2005). A Finometer Pro and Dinamap were used to assess cardiovascular parameters, such as systolic blood pressure (SBP), diastolic blood pressure (DBP), and  heart rate (HR). 

Results: The meta-analyses reported in Study 1 revealed that Type D personality was associated with lower cardiovascular reactivity to stress, particularly amongst females and in response to stressors of lower social salience. The systematic review reported in  Study 2 revealed that atypically low or “blunted” cardiovascular reactivity to stress predicts adverse cardiovascular health, primarily in cardiac samples and outcomes associated with motivational and behavioural dysregulation in healthy samples. The cardiovascular reactivity threshold levels that were predictive of adverse health outcomes  ranged between −3.00–12.59 bpm (14.41% to 136.59% lower than the sample mean) and  −2.4–5.00 mmHg (65.99% to 133.80% lower than sample mean), for HR and DBP respectively. Study 3 revealed that the association between Type D personality and lower cardiovascular reactivity was mediated via lower social support and increased perceptions of negative social relationships. Study 4 revealed that Type D personality was associated with a greater perception of life events stress, and that this association was mediated via self-reported social relationships. Finally, Study 5 indicated that Type D personality had  predictive utility for cardiovascular reactivity above its individual subcomponents (NA  and SI), as well as depressive symptoms and anxiety. 

Conclusion: Type D personality is primarily associated with lower cardiovascular reactivity, particularly amongst females and in response to stressors of lower social salience. This lower response may be indicative of blunted cardiovascular reactivity and constitute a physiological mechanism leading to adverse health outcomes for individuals  scoring high on Type D personality. While Type D personality does have predictive utility  for stress responsivity above the effects of NA and SI, this is somewhat limited, and was likely overestimated in prior studies.