Personality traits and cardiovascular diseases: is it about ‘don’t worry, be happy’, or is this a deeper underlying problem?

Abstract

This editorial refers to ‘Neuroticism personality traits are linked to adverse cardiovascular phenotypes in the UK Biobank’, by A. Mahmood et al., https://doi.org/10.1093/ehjci/jead166. Imbalanced brain–heart interactions may occur acutely such as in Takotsubo syndrome (‘broken heart syndrome’), which is triggered by emotional and psychological stressors, and during cerebral haemorrhage which may cause cardiac damage by various neural and humoral mechanisms. 1 On the other side of the spectrum, there are chronic mental diseases and variants of normal mental health, which are associated with cardiovascular (CV) risk. 2 Mechanisms whereby mental status exerts its influence on the heart still are incompletely elucidated. 3 However, there are clues that shed some light on this relationship. 4 First, mental health may affect health-related behaviour such as diet, smoking, alcohol consumption, or physical activity. Secondly, psychosocial factors may induce acute or chronic pathophysiological changes such as physiological hyper-reactivity (blood pressure, stress hormones) and pro-inflammatory cytokines. 5 Thirdly, psychosocial factors may interfere with access to and content of medical care. It is well established that personality traits, reflecting an individual’s relatively constant pattern of thinking, feeling, and behaving across different circumstances and over time, 6 are a solid predictor of mental health outcomes, including CV outcomes. For instance, neuroticism has been linked to an increased likelihood of anxiety and depressive disorders. In daily life, neuroticism may express as irritability, anger, sadness, anxiety, worry, hostility, self-consciousness, tendency to react out of proportion to the circumstances, often being self-critical, sensitive to the criticism of others, and feel personally inadequate. 7 Decades ago, a lot of work had been done on the Type A/hostility behaviour pattern, which has diagnostic but no prognostic information in patients with CV disease (CVD). 5 This led to deceased interest in this type of research. Interest in personality traits was renewed with the seminal work of the late Johan K. Denollet on Type D distressed personality (the tendency to suppress emotional distress). 5 The taxonomy of Type D is based on two broad and stable traits, those of negative affectivity and social inhibition. The interaction between social inhibition and negative emotions, rather than negative emotions per se predict poor clinical outcome. 8 Type D is an established determinant of psychological stress. Since the landmark study on 10-year mortality after myocardial infarction, 9 Type D personality has been linked to outcome in several cardiac patient populations. Type D patients are also at increased risk for impaired quality of life and seem to benefit less from medical and invasive treatment. 5 Both negative affectivity and social inhibition (defining Type D personality) are correlated with neuroticism. 10 Neuroticism has been similarly associated with poor health, CV risk factors, and coronary heart disease (CHD). Extensive overlapping polygenic architecture between genes associated with neuroticism and genes associated with CHD and CVD risk factors suggest that genetic factors may partly cause the association between neuroticism and CV dysfunction. 11 But, unlike Type D and similarly as Type A/hostility, firm prognostic information of neuroticism is limited. Mahmood et al. 12 describe an association between neuroticism and objective measures of adverse cardiac and arterial remodelling. The sample included individuals with available CV magnetic resonance (CMR) data and neuroticism scores, excluding those with pre-existing CVD. Neuroticism was evaluated using the Eysenck Personality Questionnaire-Revised Short Form. CV magnetic resonance metrics analysed various parameters of cardiac and vascular structure and function. In total, the study included 36 309 participants from the UK biobank and found significant associations between neuroticism and CV morphology and function. Specifically, higher neuroticism scores were associated with smaller and apparently poorly functioning ventricles, lower left ventricular (LV) mass, greater LV remodelling, higher myocardial fibrosis, and increased arterial stiffness. These associations were more pronounced in men. The results suggest that higher neuroticism scores are linked with pre-clinical, adverse cardiac remodelling indicative of greater cardiac aging. A strength of the study is the large patient population and the use of CMR as an accurate method to quantify CV structure and function. Importantly, this was an observational study with potential unmeasured confounders and therefore did not allow to conclude about a causal relationship between neuroticism and LV remodelling. The findings underline the importance of considering personality traits like neuroticism as part of a comprehensive CV risk assessment, contributing to the personalization of healthcare. The authors concluded that neuroticism is associated with unhealthy CV remodelling patterns, independent of traditional CV risk factors. An association between neuroticism and decreased arterial distensibility is consistent with a previous study, which related parameters of anger and anger suppression to carotid distensibility. 13 The study is limited by having a cross-sectional and not a prospective design and by lack of hard endpoints such as death and heart failure of myocardial infarction. The reader will badly miss absolute values and absolute differences of the measurements across the spectrum of neuroticism. We would very much have liked to see the quantitative importance of changes as well as overlap between groups. This would have helped to situate the findings in cardiological practice. The only parameter of cardiac function associated with neuroticism was lower stroke volume. Left ventricular ejection fraction was not included. Index of cardiac performance and longitudinal strain were not associated. However, a smaller stroke volume (accordingly in a smaller ventricle) can be distinct from a poorer function and might be related to body size, haematocrit, or heart rate. We feel that repeated references to poorer cardiac function in the presence of neuroticism are more than the data show and should be interpreted with much care. The study by Mahmood et al. 12 focuses on stable psychological trait of neuroticism. It emphasizes the link between mental health and CV health. The next step will be to demonstrate the relationship between neuroticism and CV outcome. Only then will it be possible to investigate, similarly as with Type A behavioural pattern and with Type D personality, if psychological interventions targeted at reducing the expression of psychological traits could be successful in reducing CV risk. This could lead to interventions targeted at emotional distress, depression, anger/hostility, and social support. But, it still will remain a risky endeavour to separate the effects of psychological interventions from other strategies that decrease CV risk. It however has been for decades a reasonable option to include psychological counselling as an inherent part of multi-disciplinary cardiac rehabilitation.