Lydia Poole

The puzzle of depression and acute coronary syndrome: Reviewing the role of acute inflammation

The relationship between depression and coronary heart disease is well-established, but causal mechanisms are poorly understood. The aim of this review is to stimulate different ways of viewing the relationship between depression and adverse outcomes following acute coronary syndrome (ACS) and coronary artery bypass graft (CABG) surgery patients. We present an argument for depression in ACS and CABG patients being a qualitatively distinct form from that observed in psychiatric populations. This is based on three features: (1) depression developing after cardiac events has been linked in many studies to poorer outcomes than recurrent depression; (2) somatic symptoms of depression following cardiac events are particularly cardiotoxic; (3) depression following an ACS does not respond well to antidepressant treatments. We propose that inflammation is a common causal process responsible in part both for the development of depressive symptoms and for adverse cardiac outcomes, and we draw parallels with inflammation-induced sickness behaviour. Clinical implications of our observations are discussed along with suggestions for further work to advance the field.

Physical activity, stress reduction, and mood: insight into immunological mechanisms.

Psychosocial factors, such as chronic mental stress and mood, are recognized as an important predictor of longevity and wellbeing. In particular, depression is independently associated with cardiovascular disease and all-cause mortality, and is often comorbid with chronic diseases that can worsen their associated health outcomes. Regular exercise is thought to be associated with stress reduction and better mood, which may partly mediate associations between depression, stress, and health outcomes. The underlying mechanisms for the positive effects of exercise on wellbeing remain poorly understood. In this overview we examine epidemiological evidence for an association between physical activity and mental health. We then describe the exercise withdrawal paradigm as an experimental protocol to study mechanisms linking exercise, mood, and stress. In particular we will discuss the potential role of the inflammatory response as a central mechanism.

Associations of objectively measured physical activity with daily mood ratings and psychophysiological stress responses in women

The aim of this study was to examine associations of objectively measured physical activity with daily mood ratings and psychophysiological stress responses. We recruited 40 healthy females (aged 28.7 ± 6.1 yrs) who completed a once-a-day mood rating scale for 7 days, along with a 7-day assessment of physical activity using accelerometers and psychophysiological stress testing. The findings suggest that levels of physical activity as measured using an accelerometer are associated with both depressive symptoms over the past 2 weeks (CES-D) (r = - .33, p = .038) and with daily positive emotional style (r = .49, p = .001). The relationship between physical activity and positive emotional style remained after controlling for age, body mass index, and negative emotional style (t = 3.31, p = .002). Physical activity was not related to any psychophysiological stress responses.

Psychophysiological Bases of Disease

Psychological and social factors are thought to influence risk for a range of physical illnesses including coronary heart disease, high blood pressure, type 2 diabetes, infectious illness, bronchial asthma, and musculoskeletal pain. These associations are underpinned by the impact of psychological stress and other biobehavioral stimuli on the systemic biological responses implicated in disease risk. Several systems are involved, with cardiovascular, neuroendocrine, immune, inflammatory, metabolic, and musculoskeletal responses all being relevant. The nature and extent of influence on health outcome vary across diseases, and different types of study design are needed to evaluate these processes in different health conditions.

Television viewing, C-reactive protein, and depressive symptoms in older adults.

There is emerging evidence for a link between sedentary behavior and mental health, although the mechanisms remain unknown. We tested if an underlying inflammatory process explains the association between sedentary behavior and depressive symptoms. We conducted a two year follow-up of 4964 (aged 64.5±8.9 years) men and women from the English Longitudinal Study of Ageing, a cohort of community dwelling older adults. Self-reported TV viewing time was assessed at baseline as a marker of leisure time sedentary behavior. The eight-item Centre of Epidemiological Studies Depression (CES-D) scale was administered to measure depressive symptoms at follow-up. At baseline, TV time was associated with C-reactive protein (CRP), adjusted geometric mean CRP values were 2.94 mg/L (<2 h/d TV); 3.04 mg/L (2-4 h/d TV); 3.29 mg/L (4-6 h/d TV); 3.23 mg/L (>6 h/d TV). We observed both a direct association of TV time on CES-D score at follow-up (B=0.08, 95% CI, 0.05, 0.10) and indirect effects (B=0.07, 95% CI, 0.05, 0.08). The indirect effects were largely explained through lack of physical activity, smoking, and alcohol, but not by CRP or body mass index.

Morningness-eveningness interferes with perceived health, physical activity, diet and stress levels in working women: A cross-sectional study

Sleep and health are closely interrelated and sleep quality is a well-known contributor to perceived health. However, effects of sleep-timing preference i.e. morningness–eveningness on health has yet to be revealed. In this study, we explored the relationship between morningness–eveningness and perceived health in a sample of female working professionals (N = 202). Sleep-timing preference was measured using the Composite Scale of Morningness. Perceived health was characterized by Center for Epidemiologic Studies Depression Scale, WHO Well-Being Scale-5 and Patient Health Questionnaire-15 scores. We also investigated possible mechanisms, including stress and health-impairing behaviours. In accordance with previous data, we found more depressive mood, lower well-being and poorer perceived health among evening types. To assess health-impairing behaviours we collected data on smoking habits, alcohol consumption, physical activity and diet. Among the possible mechanism variables, greater stress, less frequent physical activity and less healthy diet were associated with eveningness. Furthermore, stress diminished the strength of the association between morningness–eveningness and depressed mood. Physical activity attenuated the strength of the association between morningness–eveningness and well-being. No effects of alcohol consumption could be identified. Our data show that evening preference behaves as a health risk in terms of associating with poor perceived health. Our findings also suggest that this effect might be mediated by health behaviours and stress.

The effects of exercise withdrawal on mood and inflammatory cytokine responses in humans

Mechanisms underlying the relationship between exercise and mood are not well understood. This study sought to investigate the role of pro- and anti-inflammatory cytokines and autonomic balance in determining the impact of exercise withdrawal on negative mood. Healthy men and women who regularly exercised (N = 26, mean age = 25.5 years, SD = 4.5 years) were randomised to exercise withdrawal or exercise maintenance for 2 weeks. Protocol adherence was monitored using accelerometers. Inflammatory markers from plasma (interleukin-6, IL-6; tumour necrosis factor-alpha; interleukin-10; and interleukin-1 receptor antagonist), heart-rate variability (HRV) and measures of mood (General Health Questionnaire-28 (GHQ) and the Profile of Mood States (POMS)) were assessed at study entry and at 2-week follow-up. Exercise withdrawal resulted in significant increases in negative mood over time on both the GHQ (p = 0.028) and the POMS (p = 0.005). Following the intervention, IL-6 concentration was lower in the exercise withdrawal than exercise maintenance condition (p = 0.05). No intervention effects were observed for other cytokines or HRV. The mood changes were significantly related to changes in IL-6 concentration (β = − 0.50, p = 0.011), indicating that reduction in IL-6 was related to increased negative mood. Our results are consistent with positive effects of exercise on mental health, but further research on inflammatory pathways is warranted.

Optimism and recovery after acute coronary syndrome: a clinical cohort study.

Objective Optimism is associated with reduced cardiovascular mortality, but its impact on recovery after acute coronary syndrome (ACS) is poorly understood. We hypothesized that greater optimism would lead to more effective physical and emotional adaptation after ACS and would buffer the impact of persistent depressive symptoms on clinical outcomes. Methods This prospective observational clinical study took place in an urban general hospital and involved 369 patients admitted with a documented ACS. Optimism was assessed with a standardized questionnaire. The main outcomes were physical health status, depressive symptoms, smoking, physical activity, and fruit and vegetable consumption measured 12 months after ACS, and composite major adverse cardiac events (cardiovascular death, readmission with reinfarction or unstable angina, and coronary artery bypass graft surgery) assessed over an average of 45.7 months. Results We found that optimism predicted better physical health status 12 months after ACS independently of baseline physical health, age, sex, ethnicity, social deprivation, and clinical risk factors (B = 0.65, 95% confidence interval [CI] = 0.10–1.20). Greater optimism also predicted reduced risk of depressive symptoms (odds ratio = 0.82, 95% CI = 0.74–0.90), more smoking cessation, and more fruit and vegetable consumption at 12 months. Persistent depressive symptoms 12 months after ACS predicted major adverse cardiac events over subsequent years (odds ratio = 2.56, 95% CI = 1.16–5.67), but only among individuals low in optimism (optimism × depression interaction; p = .014). Conclusions Optimism predicts better physical and emotional health after ACS. Measuring optimism may help identify individuals at risk. Pessimistic outlooks can be modified, potentially leading to improved recovery after major cardiac events.

The combined association of depression and socioeconomic status with length of post-operative hospital stay following coronary artery bypass graft surgery: Data from a prospective cohort study

Objective To understand the association between pre-operative depression symptoms, including cognitive and somatic symptom subtypes, and length of post-operative stay in patients undergoing coronary artery bypass graft (CABG) surgery, and the role of socioeconomic status (SES). Methods We measured depression symptoms using the Beck Depression Inventory (BDI) and household income in the month prior to surgery in 310 participants undergoing elective, first-time, CABG. Participants were followed-up post-operatively to assess the length of their hospital stay. Results We showed that greater pre-operative depression symptoms on the BDI were associated with a longer hospital stay (hazard ratio = 0.978, 95% CI 0.957–0.999, p = .043) even after controlling for covariates, with the effect being observed for cognitive symptoms of depression but not somatic symptoms. Lower SES augmented the negative effect of depression on length of stay. Conclusions Depression symptoms interact with socioeconomic position to affect recovery following cardiac surgery and further work is needed in order to understand the pathways of this association.

Depression, C-reactive protein and length of post-operative hospital stay in coronary artery bypass graft surgery patients

Highlight • Elevated depression symptoms prior to CABG were associated with increased odds of extended hospital stays and post-operative CRP responses mediated this association.