Mental health, blood pressure and the development of hypertension

Hypertension (HTN) has been associated with a greater risk of affective disorders. Paradoxically, several studies have shown the opposite effect in which high blood pressure relates to less depressive symptoms and greater well-being. Here we dissolve this paradox and clarify the relationship between mental health, blood pressure and the development of HTN using the UK Biobank. In adjusted multiple linear regression models, we found that the presence of a HTN diagnosis was associated with impaired mental health (i.e. more depressive symptoms (N = 303,771; {beta} = 0.043; 95% CI [0.039, 0.047]; p<0.001) and lower well-being scores (N = 129,876; {beta} = -0.057; 95% CI [-0.064, - 0.050]; p<0.001)) at baseline, whereas higher systolic blood pressure (SBP) was associated with fewer depressive symptoms (N = 303,771; {beta} = -0.063; 95% CI [-0.067, -0.060]; p<0.001) and higher well-being scores (N = 129,876; {beta} = 0.057; 95% CI [0.051, 0.063]; p<0.001). These effects persisted until follow-up ([~]10 years later). To explore a potential link between the mental health-blood pressure association and the development of HTN, we compared participants who were normotensive at baseline and developed HTN until follow-up with those who stayed normotensive. Notably, the adjusted model showed impaired mental health already at baseline in HTN developers (i.e., before HTN diagnosis; depressive symptoms: {beta} = 0.060; 95% CI [0.045, 0.076]; p<0.001; well-being: {beta} = -0.043; 95% CI [-0.068, -0.017]; p<0.001), indicating that people who develop HTN might require higher blood pressure levels for the same mental health outcomes as normotensives. In addition, the negative association between SBP and depressive symptoms at baseline was moderated by HTN development ({beta} = -0.014; 95% CI [-0.026, -0.003]; p=0.015), suggesting that the negative relationship between mental health and blood pressure was accentuated in people developing HTN several years before receiving their HTN diagnosis. We further observed that higher SBP was associated with lower emotion-related brain activity from functional magnetic resonance imaging (fMRI; {beta} = -0.032 95% CI [-0.045, -0.019]; p<0.001). This effect was also moderated by HTN diagnosis, suggesting an impact of SBP and HTN on the central nervous processing of emotions. Possible mechanisms are discussed, including regulatory baroreceptor circuits linking arterial blood pressure to neural processing of emotions. Overall, our results show an interrelation between mental health and blood pressure that may be involved in the development of HTN. In people who develop HTN, this relationship seems to be altered, such that higher blood pressure is required to sustain mental health, potentially offering a novel perspective for developing preventive and therapeutic measures.