Specific serotonin reuptake inhibition in major depressive disorder adversely affects novel markers of cardiac risk

Causal association between major depressive disorder and coronary heart disease: a two-sample bidirectional mendelian randomization study

BACKGROUND

Major depressive disorder (MDD) is a highly heterogeneous mental illness and a major public health problem worldwide. A large number of observational studies have demonstrated a clear association between MDD and coronary heart disease (CHD), and some studies have even suggested that the relationship is bidirectional. However, it was unknown whether any causal relationship existed between them and whether causality was bidirectional in such an instance. Thus, we aimed to determine whether there is a bidirectional causal relationship between major depressive disorders and coronary heart disease.

METHODS

Our two-sample Bidirectional Mendelian Randomization Study consisted of two parts: forward MR analysis regarded MDD as exposure and CHD as the outcome, and reverse MR analysis considered CHD as exposure and MDD as the outcome. Summary data on MDD and CHD were obtained from the IEU Open GWAS database. After screening criteria(P < [Formula: see text]), 47 MDD-associated SNPs and 39 CHD-associated SNPs were identified. The inverse-variance weighted (IVW) method, ME-Egger regression, and weighted median method were used to estimate causality. In addition, sensitivity methods, including the heterogeneity test, horizontal pleiotropy test, and leave-one-out method, were applied to ensure the robustness of causal estimation.

RESULTS

Based on the MR-Egger regression intercept test results, there did not appear to be any horizontal pleiotropy in this study (MDD: intercept = -0.0000376, P = 0.9996; CHD: intercept = -0.0002698, P = 0.920). Accordingly, IVW results suggested consistent estimates of causal effect values. The results showed that people with MDD increased the risk of CHD by 14.7% compared with those without MDD (OR = 1.147, 95%CI: 1.045-1.249, P = 0.009). But there was no direct evidence that CHD would increase the risk of MDD(OR = 1.008, 95%CI: 0.985-1.031, P = 0.490). The heterogeneity test and funnel plot showed no heterogeneity in 47 SNPs of MDD (Q = 42.28, [Formula: see text]=0, P = 0.629), but there was heterogeneity in 39 SNPs of CHD (Q = 62.48, [Formula: see text]=39.18%, P = 0.007). The leave-one-out method failed to identify instances where a single SNP was either biased toward or dependent on the causation.

CONCLUSION

Our study supports a one-way causal relationship between MDD and CHD, but there is no bidirectional causal relationship. MDD increases the risk of CHD, but there is no evidence that CHD increases the risk of MDD. Therefore, the influence of psychological factors should also be considered in the prevention and treatment of CHD. For MDD patients, it is necessary to prevent cardiovascular diseases.

Impact of antidepressant use on the autonomic nervous system: A meta-analysis and systematic review

Changes in cardiac autonomic nervous system (ANS) regulation observed in psychiatric disorders may be mitigated by antidepressants. We meta-analyzed and systematically reviewed studies examining antidepressants' effects on ANS outcomes, including heart rate variability (HRV). We conducted a PRISMA/MOOSE-compliant search of PubMed and Scopus until March 28th, 2022. We included randomized placebo-controlled trials (RCTs) and pre-post studies, regardless of diagnosis. We pooled results in random-effects meta-analyses, pooling homogeneous study designs and outcomes. We conducted sensitivity analyses and assessed quality of included studies. Thirty studies could be meta-analyzed. Selective serotonin reuptake inhibitors (SSRIs) were significantly associated with a reduction in the square root of the mean-squared difference between successive R-R intervals (RMSSD) (SMD= -0.48) and skin conductance response (SMD= -0.55) in RCTs and with a significant increase in RMSSD in pre-post studies (SMD=0.27). In pre-post studies, tricyclic antidepressants (TCAs) were associated with a significant decrease in several HRV outcomes while agomelatine was associated with a significant increase in high frequency power (SMD= 0.14). In conclusion, SSRIs reduce skin conductance response but have no or inconclusive effects on other ANS outcomes, depending on study design. TCAs reduce markers of parasympathetic function while agomelatine might have the opposite effect. Studies are needed to investigate the impact of SSRIs on the recovery of cardiac ANS regulation after acute myocardial infarction, and the effects of newer antidepressants.

Psychiatric symptoms are not associated with circulating CRP concentrations after controlling for medical, social, and demographic factors

Elevated serum concentrations (>3 mg/L) of the acute-phase protein, C-reactive protein (CRP), is used as a clinical marker of inflammation and is reported to be a strong risk factor for cardiovascular disease. In psychiatric populations, CRP concentration is reported to be higher in depressed versus healthy individuals. Positive associations between CRP and depression have been established in both clinical and community samples, but effect sizes are attenuated after controlling for confounding variables. Similarly, emerging research has begun to draw a link between inflammation, symptoms of anxiety, and substance abuse. Given the high level of comorbid anxiety and substance use disorders in many depressed populations, this study examined whether depression (Patient Health Questionnaire 9 [PHQ-9]) and substance use-related (Drug Abuse Screening Test [DAST]) symptoms were associated with CRP concentrations in the blood after adjusting for relevant medical, social, and demographic covariates in a large sample undergoing screening for several transdiagnostic psychiatric research studies. A total of 1,724 participants were analyzed for association of CRP with variables using multivariate linear regression. An unadjusted model with no covariates showed that PHQ-9 was significantly associated with CRP in All (β = 0.125), Female (β = 0.091), and Male (β = 0.154) participants, but DAST was significantly associated with CRP in males only (β = 0.120). For the adjusted model, in both males and females, mood-stabilizer treatment (β = 0.630), opioid medication (β = 0.360), body mass index (β = 0.244), percent body fat (β = 0.289), nicotine use (β = 0.063), and self-reported sleep disturbance (β = 0.061) were significantly associated with increased CRP concentrations. In females, oral contraceptive use (β = 0.576), and waist-to-hip ratio (β = 0.086), and in males, non-steroidal anti-inflammatory drug use (β = 0.367) were also associated with increased CRP concentrations. There was no significant association between CRP and individual depressive, anxiety, or substance use-related symptoms when covariates were included in the regression models. These results suggest that associations between circulating CRP and the severity of psychiatric symptoms are dependent on the type of covariates controlled for in statistical analyses.

Fluoxetine Treatment Decreases Cardiac Vagal Input and Alters the Serotonergic Modulation of the Parasympathetic Outflow in Diabetic Rats

Comorbid diabetes and depression constitutes a major health problem, worsening associated cardiovascular diseases. Fluoxetine's (antidepressant) role on cardiac diabetic complications remains unknown. We determined whether fluoxetine modifies cardiac vagal input and its serotonergic modulation in male Wistar diabetic rats. Diabetes was induced by alloxan and maintained for 28 days. Fluoxetine was administered the last 14 days (10 mg/kg/day; p.o). Bradycardia was obtained by vagal stimulation (3, 6 and 9 Hz) or i.v. acetylcholine administrations (1, 5 and 10 μg/kg). Fluoxetine treatment diminished vagally-induced bradycardia. Administration of 5-HT originated a dual action on the bradycardia, augmenting it at low doses and diminishing it at high doses, reproduced by 5-CT (5-HT_1/7 agonist). 5-CT did not alter the bradycardia induced by exogenous acetylcholine. Decrease of the vagally-induced bradycardia evoked by high doses of 5-HT and 5-CT was reproduced by L-694,247 (5-HT_1D agonist) and blocked by prior administration of LY310762 (5-HT_1D antagonist). Enhancement of the electrical-induced bradycardia by 5-CT (10 μg/kg) was abolished by pretreatment with SB269970 (5-HT₇ receptor antagonist). Thus, oral fluoxetine treatment originates a decrease in cardiac cholinergic activity and changes 5-HT modulation of bradycardic responses in diabetes: prejunctional 5-HT₇ receptors augment cholinergic-evoked bradycardic responses, whereas prejunctional 5-HT_1D receptors inhibit vagally-induced bradycardia.

Oral fluoxetine treatment changes serotonergic sympatho-regulation in experimental type 1 diabetes

AIMS

This study investigated whether fluoxetine treatment changes the 5-HT regulation on vascular sympathetic neurotransmission in type 1 diabetes.

MAIN METHODS

Four-week diabetes was obtained by a single alloxan s.c. administration in male Wistar rats, administering fluoxetine for 14 days (10 mg/kg/day; p.o.). Systolic blood pressure, heart rate, glycaemia, body weight (BW) evolution, creatinine, and blood urea nitrogen (BUN) were monitored. Afterward, rats were pithed to perform the vascular sympathetic stimulation. 5-HT_1A/1D/2A receptors expression was analysed by Western blot in thoracic aorta. Both i.v. norepinephrine and the electrical stimulation of the spinal sympathetic drive evoked vasoconstrictor responses.

KEY FINDINGS

Fluoxetine treatment significantly reduced the BW gain, hyperglycaemia, creatinine, and BUN in diabetic rats. The electrical-produced vasopressor responses were greater in untreated than in fluoxetine-treated diabetic rats. 5-HT decreased the sympathetic-produced vasopressor responses. While 5-CT, 8-OH-DPAT and L-694,247 (5-HT_1/7, 5-HT_1A and 5-HT_1D agonists, respectively) reproduced 5-HT-evoked inhibition, the 5-HT₂ activation by α-methyl-5-HT augmented the vasoconstrictions. The 5-CT sympatho-inhibition was reversed by 5-HT_1A plus 5-HT_1D antagonists (WAY-100,635 and LY310762, respectively), whereas ritanserin (5-HT_2A antagonist) blocked the α-methyl-5-HT potentiating effect. Norepinephrine-generated vasoconstrictions were increased or diminished by α-methyl-5-HT or 5-CT, respectively. 5-HT_1A/1D/2A receptors were expressed at vascular level, being 5-HT_1A expression increased by fluoxetine in diabetic rats.

SIGNIFICANCE

Our findings suggest that fluoxetine improves metabolic and renal profiles, changes the vasopressor responses, and 5-HT receptors modulating sympathetic activity in diabetic rats: 5-HT_1A/1D are involved in the sympatho-inhibition, while 5-HT_2A is implicated in the sympatho-potentiation, being both effects pre and/or postjunctional in nature.

Neighborhood environment perceptions associate with depression levels and cardiovascular risk among middle-aged and older adults: Data from the Washington, DC cardiovascular health and needs assessment

OBJECTIVES

Little is understood about associations between neighborhood characteristics and depression, a cardiovascular disease (CVD) risk factor, in diverse populations. We examined relationships between perceived/objective neighborhood characteristics, depression, and CVD markers within the Washington, DC CV Health/Needs Assessment, an evaluation among predominantly African-American (AA) adults in resource-limited DC communities.

METHOD

Factor analysis of overall neighborhood environment perception (NEP) identified three NEP sub-scores:1) violence; 2) physical/social environment; 3) social cohesion (higher score = more favorable perception). Objective neighborhood characteristics were measured by geospatially-derived scores of walkability, transportation, and crime. Depression was defined by the revised Center for Epidemiologic Studies Depression Scale (CESD-R). We used linear-regression modeling to examine neighborhood measures and CESD-R associations. To investigate a subsequent connection with CVD risk, we examined relationships between CESD-R and CVD-associated cytokines in a population subset.

RESULTS

Participants (N = 99; mean age = 59.06; 99% AA) had a mean CESD-R score = 5.8(SD = 8.88). In adjusted models, CESD-R scores decreased by 0.20 units (p = 0.01) for every overall NEP unit-increase. Perceived physical/social environment (β = -0.34, p = 0.04) and social cohesion (β = -0.82, p = 0.01) were related to CESD-R while perceived violence was not (β = -0.28, p = 0.1). Of objective neighborhood environment measures (i.e. walk, transit, bike, personal crime, and property crime scores), only property crime score was associated with depression (β = 4.99, p < 0.03). In population subset (n = 42), higher CESD-R associated with higher IL-1β (β = 21.25, p < 0.01) and IL-18 (β = 0.006, p = 0.01).

CONCLUSION

Favorable neighborhood perceptions are related to lower depressive symptoms in a predominantly AA cohort from Washington, DC resource-limited communities. Neighborhood perceptions appear to be strongly associated with depressive symptoms compared to objective characteristics. Increasing CESD-R scores were related to higher pro-inflammatory markers. Improving neighborhood perceptions may be beneficial to psychological well-being and CV health for urban minority residents.

Vascular sympathetic neurotransmission and its serotonergic regulation are modified by chronic fluoxetine treatment

Given the interconnection between depressive and cardiovascular disorders, we investigated whether antidepressant treatment (fluoxetine) modifies the serotonergic influence on rat vascular noradrenergic outflow. Twelve-week-old male Wistar rats received fluoxetine treatment (10 mg/kg/day; p.o.) for 14 days; then, they were pithed and prepared for sympathetic stimulation. Vasopressor responses were obtained by electrical stimulation of the sympathetic outflow (0.1, 0.5, 1, and 5 Hz) or i.v. noradrenaline (NA; 0.01, 0.05, 0.1, and 0.5 μg/kg). In fluoxetine-treated group, the electrical-induced vasoconstrictions were lower compared to non-treated rats. Intravenous infusion of 5-HT (10 μg/kg/min) inhibited the sympathetically-induced vasoconstrictions. Only 5-CT, 8-OH-DPAT and L-694,247 (5-HT1/7, 5-HT1A and 5-HT1D agonists, respectively) mimicked 5-HT-induced inhibition, while α-methyl-5-HT (5-HT2 agonist) increased the vasopressor responses. The inhibitory effect of 5-HT was: a) no modified by SB269970 (5-HT7 antagonist); b) abolished by WAY-100,635 (5-HT1A antagonist) plus LY310762 (5-HT1D antagonist); and c) potentiated by ritanserin (5-HT2A receptor antagonist). The vasoconstrictions induced by exogenous NA were not modified by 5-CT but were increased by α-methyl-5-HT. Our results suggest that fluoxetine treatment decreases NA release at vascular level and changes 5-HT modulation on rat vascular noradrenergic neurotransmission, inducing sympatho-inhibition via prejunctional 5-HT1A/1D receptors, and sympatho-potentiation via pre and/or postjunctional 5-HT2A receptors.

Pain assessment of the adult sedated and ventilated patients in the intensive care setting: A scoping review

BACKGROUND

Pain is frequently encountered in the intensive care setting. Given the impact of pain assessment on patient outcomes and length of hospital stay, studies have been conducted to validate tools, establish guidelines and cast light on practices relating to pain assessment.

OBJECTIVE

To examine the extent, range and nature of the evidence around pain assessment practices in adult patients who cannot self-report pain in the intensive care setting and summarise the findings from a heterogenous body of evidence to aid in the planning and the conduct of future research and management of patient care. The specific patient cohort studied was the sedated/ ventilated patient within the intensive care setting.

DESIGN

A scoping review protocol utilised the Preferred Reporting Items for Systematic Reviews and Meta-Analysis extension for Scoping review checklist (PRISMA-ScR).

METHODS

The review comprised of five phases: identifying the research question, identifying relevant studies, study selection, charting the data and collating, summarizing, and reporting the results. Databases were systematically searched from January to April 2020. Databases included were Scopus, Web of Science, Medline via Ovid, CINAHL COMPLETE via EBSCO host, Health Source and PUBMED. Limits were applied on dates (2000 to current), language (English), subject (human) and age (adult). Key words used were "pain", "assessment", "measurement", "tools", "instruments", "practices", "sedated", "ventilated", "adult". A hand search technique was used to search citations within articles. Database alerts were set to apprise the availability of research articles pertaining to pain assessment practices in the intensive care setting.

RESULTS

The review uncovered literature categorised under five general themes: behaviour pain assessment tools, pain assessment guidelines, position statements and quality improvement projects, enablers and barriers to pain assessment, and evidence appertaining to actual practices. Behaviour pain assessment tools are the benchmark for pain assessment of sedated and ventilated patients. The reliability and validity of physiologic parameters to assess pain is yet to be determined. Issues of compliance with pain assessment guidelines and tools exist and impact on practices. In some countries like Australia, there is a dearth of information regarding the prevalence and characteristics of patients receiving analgesia, type of analgesia used, pain assessment practices and the process of recording pain management. In general, pain assessment varies across different intensive care settings and lacks consistency.

CONCLUSION

Research on pain assessment practices requires further investigation to explore the causative mechanisms that contribute to poor compliance with established pain management guidelines. The protocol of this review was registered with Open Science Framework (https://osf.io/25a6) Tweetable abstract: Pain assessment in intensive care settings lacks consistency. New information is needed to understand the causative mechanisms underpinning poor compliance with guidelines.

Heart Rate Variability Changes in Patients With Major Depressive Disorder: Related to Confounding Factors, Not to Symptom Severity?

Background

The aim of this study was to assess the electrophysiological and other influencing factors correlating with symptom severity in patients with major depressive disorder (MDD) under three different conditions: baseline, stress exposure, and relaxation following stress exposure.

Methods

Symptom severity was assessed using the Beck Depression Inventory (BDI-II) in 89 inpatients (37 women; mean age 51 years) with MDD. Resting heart rate (RHR), heart rate variability (HRV), respiration rate (RR), skin conductance (SC), and skin temperature (ST) were recorded at baseline for 300 s, under stress exposure for 60 s, and under self-induced relaxation for 300 s. Age, nicotine consumption, body mass index, and blood pressure were evaluated as influencing factors.

Results

The BDI-II mean score was 29.7 points. Disease severity correlated positively with SC elevation under stress exposure and with a higher RR in the relaxed state, but no association was found between HRV and symptom severity. Age and higher blood pressure were both associated with lower HRV and higher RHR.

Conclusion

The results indicate that, in patients with MDD, changes in the autonomic nervous system (ANS) are complex; and the assessment of ANS reactivity to stressors is useful. Elevated blood pressure might be underdiagnosed, although it is already relevant in patients with MDD in their early 50s.

Repeated use of SSRIs potentially associated with an increase on serum CK and CK-MB in patients with major depressive disorder: a retrospective study

There is a large amount of evidence that selective serotonin reuptake inhibitors (SSRIs) are related to cardiovascular toxicity, which has aroused concern regarding their safety. However, few studies have evaluated the effects of SSRIs on cardiac injury biomarkers, such as creatine kinase (CK) and creatine kinase isoenzyme (CK-MB). The purpose of our study was to determine whether SSRIs elevated CK and CK-MB levels of prior medicated depressive patients (PMDP) compared to first-episode drug-naïve depressive patients (FDDPs). We performed an observational and retrospective study involving 128 patients with major depressive disorder. Patients who had never used any type of antidepressant were designated FDDP; patients who had used only one type of SSRI but were not treated after a recent relapse were designated PMDP. Serum CK and CK-MB levels were measured before and after using SSRIs for a period of time. The duration of current treatment in the FDDP and PMDP groups was 16.200 ± 16.726 weeks and 15.618 ± 16.902 weeks, respectively. After SSRI treatment, levels of serum CK in the PMDP group were significantly higher than in the FDDP group. Univariate ANCOVA results revealed that PMDP was 22.313 times more likely to elevate CK (OR 22.313, 95% CI 9.605-35.022) and 2.615 times more likely to elevate CK-MB (OR 2.615, 95% CI 1.287-3.943) than FDDP. Multivariate ANCOVA revealed an interaction between the group and sex of CK and CK-MB. Further pairwise analysis of the interaction results showed that in female patients, the mean difference (MD) of CK and CK-MB in PMDP was significantly greater than that in FDDP (MD = 33.410, P = 0.000, 95% CI 15.935-50.886; MD = 4.613, P = 0.000, 95% CI 2.846-6.381). Our findings suggest that patients, especially females, who had previously used SSRI antidepressants were more likely to have elevated CK and CK-MB, indicators of myocardial muscle injury. Use of SSRIs should not be assumed to be completely safe and without any cardiovascular risks.

Understanding loneliness in the twenty-first century: an update on correlates, risk factors, and potential solutions

PURPOSE

Loneliness is increasingly recognised as the next critical public health issue. A plausible reason for this concern may be related to emerging societal trends affecting the way we relate, communicate, and function in our social environment. In 2006, a prominent review of the clinical significance of loneliness was published. However, there has not been a comprehensive update on known and emerging risk factors and correlates of loneliness since then. Furthermore, there is no conceptual model that has been developed to better account for the complexity of loneliness and to inform the development of evidence-based solutions as we challenge the issues of the twenty-first century.

METHODS

We reviewed the current literature to identify either known or emerging risk factors and correlates of loneliness since 2006. This includes new or known evidence on: (1) demography; (2) health, including physical health; mental health; cognitive health; brain, biology, and genetics; and (3) socio-environmental factors including digital communication and the workplace.

RESULTS

We synthesized the literature according to a new proposed conceptual model of loneliness which showed the interplay between known and emerging correlates and risk factors from demography, health, to socio-environmental factors. In the conceptual model of loneliness, we illustrated how solutions can be delivered and tailored to an individual based on their life circumstances and preferences.

CONCLUSION

We concluded by making specific recommendations in advancing our scientific understanding of loneliness. Our knowledge can only be deepened if we increase scientific rigour via accounting for confounding variables and using longitudinal, multi-disciplinary, and multiple methodologies in research. We also call for the rigorous evaluation of programs targeting loneliness.

Österreichischer Blutdruckkonsens 2019

Erhöhter Blutdruck bleibt eine Hauptursache von kardiovaskulären Erkrankungen, Behinderung und frühzeitiger Sterblichkeit in Österreich, wobei die Raten an Diagnose, Behandlung und Kontrolle auch in rezenten Studien suboptimal sind. Das Management von Bluthochdruck ist eine häufige Herausforderung für Ärztinnen und Ärzte vieler Fachrichtungen. In einem Versuch, diagnostische und therapeutische Strategien zu standardisieren und letztendlich die Rate an gut kontrollierten Hypertoniker/innen zu erhöhen und dadurch kardiovaskuläre Erkrankungen zu verhindern, haben 13 österreichische medizinische Fachgesellschaften die vorhandene Evidenz zur Prävention, Diagnose, Abklärung, Therapie und Konsequenzen erhöhten Blutdrucks gesichtet. Das hier vorgestellte Ergebnis ist der erste Österreichische Blutdruckkonsens. Die Autoren und die beteiligten Fachgesellschaften sind davon überzeugt, daß es einer gemeinsamen nationalen Anstrengung bedarf, die Blutdruck-assoziierte Morbidität und Mortalität in unserem Land zu verringern.

Effects of SSRIs on peripheral inflammatory cytokines in patients with Generalized Anxiety Disorder

BACKGROUND

Extensive research into psychoneuroimmunology has led to substantial advances in our understanding of the reciprocal interactions between the central nervous system and the immune system in neuropsychiatric disorders. To date, inflammation has been implicated in the pathogenesis of depression and anxiety. The immunomodulating effects of antidepressants on depression have been reported, however, there is no evidence of the similar effects of antidepressants on anxiety. The aim of the study was to investigate the effects of selective serotonin reuptake inhibitors (SSRIs) on peripheral inflammatory cytokines in patients with first episode generalized anxiety disorder (GAD).

METHODS

A prospective cohort design was employed: 42 patients with first episode GAD were treated with either escitalopram or sertraline for 12 weeks. Anxiety was measured by the Generalized Anxiety Disorder Scale and the State Trait Anxiety Inventory, serum pro-inflammatory cytokine levels were measured by the enzyme-linked immunosorbent assay (ELISA), and CRP determined by an immunoturbidimetric method before and after SSRIs treatment RESULTS: Baseline levels of anxiety and pro-inflammatory cytokines including IL-1α, IL-6, IL-8, IL-12, IFN-γ, and CRP were significantly reduced after treatment of SSRIs (p < 0.05 in all cases). In addition, the change of anxiety measures co-vary with the change of peripheral cytokine levels (p < 0.05 in all cases). The regression model revealed that log transformed baseline levels of CRP and IL-6 predicted treatment response (p < 0.05 in both cases).

CONCLUSIONS

This study is the first to investigate the effects of SSRIs on pro-inflammatory cytokines in patients with first episode GAD. The findings indicate moderate acute anti-inflammatory effects of SSRIs in GAD, and suggest that these anti-inflammatory effects may underlie anxiolytic effects of SSRIs. The study also indicates that serum levels of CRP and IL-6 may predict treatment response. However, data from randomized controlled trials is warranted to confirm these findings.

A meta-analysis of heart rate variability in major depression

BACKGROUND

Major depression (MD) is a risk factor for cardiovascular disease. Reduced heart rate variability (HRV) has been observed in MD. Given the predictive value of HRV for cardiovascular health, reduced HRV might be one physiological factor that mediates this association.

METHODS

The purpose of this study was to provide up-to-date random-effects meta-analyses of studies which compare resting-state measures of HRV between unmedicated adults with MD and controls. Database search considered English and German literature to July 2018.

RESULTS

A total of 21 studies including 2250 patients and 1982 controls were extracted. Significant differences between patients and controls were found for (i) frequency domains such as HF-HRV [Hedges' g = -0.318; 95% CI (-0.388 to -0.247)], LF-HRV (Hedges' g = -0.195; 95% CI (-0.332 to -0.059)], LF/HF-HRV (Hedges' g = 0.195; 95% CI (0.086-0.303)] and VLF-HRV (Hedges' g = -0.096; 95% CI (-0.179 to -0.013)), and for (ii) time-domains such as IBI (Hedges' g = -0.163; 95% CI (-0.304 to -0.022)], RMSSD (Hedges' g = -0.462; 95% CI (-0.612 to -0.312)] and SDNN (Hedges' g = -0.266; 95% CI (-0.431 to -0.100)].

CONCLUSIONS

Our findings demonstrate that all HRV-measures were lower in MD than in healthy controls and thus strengthens evidence for lower HRV as a potential cardiovascular risk factor in these patients.

Fluoxetine oral treatment discloses 5-HT1D receptor as vagoinhibitor of the cardiac cholinergic neurotransmission in rat

Although depression and cardiovascular diseases are related, the role of antidepressants such as fluoxetine (increasing serotonin levels) within cardiac regulation remains unclear. We aimed to determine whether fluoxetine modifies the pharmacological profile of serotonergic influence on vagal cardiac outflow. Rats were treated with fluoxetine (10 mg/kg per day; p.o.) for 14 days or equivalent volumes of drinking water (control group); then, they were pithed and prepared for vagal stimulation. Bradycardic responses were obtained by electrical stimulation of the vagal fibers (3, 6, and 9 Hz) or i.v. acetylcholine (ACh; 1, 5, and 10 μg/kg). The i.v. administration of 5-hydroxytryptamine (5-HT; 10 and 50 μg/kg) inhibited the vagally induced bradycardia. 5-CT (5-HT1/7 agonist) and L-694,247 (5-HT1D agonist) mimicked the serotonin inhibitory effect while α-methyl-5-HT (5-HT2 agonist) was devoid of any action. SB269970 (5-HT7 antagonist) did not abolish 5-CT inhibitory action on the electrically induced bradycardia. Pretreatment with LY310762 (5-HT1D antagonist) blocked the effects induced by L-694,247 and 5-CT. 5-HT and 5-CT failed to modify the bradycardia induced by exogenous ACh. Our outcomes suggest that fluoxetine treatment modifies 5-HT modulation on heart parasympathetic neurotransmission in rats, evoking inhibition of the bradycardia via prejunctional 5-HT1D in pithed rats.

Replication and reproducibility issues in the relationship between C-reactive protein and depression: A systematic review and focused meta-analysis

One of the most common inflammatory markers examined in depression is C-reactive protein (CRP). However, the magnitude of the association between CRP and depression when controlling for potentially confounding factors such as age, sex, socio-economic status, body mass index, medication and other substance use, and medical illness, is unclear. Inconsistencies in other methodological practices, such as sample collection, assaying, and data cleaning and transformation, may contribute to variations in results. We aggregate studies that examined the association between CRP and depression in two ways. First, a systematic review summarizes how studies of CRP and depression have reported on methodological issues. Second, a tiered meta-analysis aggregates studies that have adhered to various levels of methodological rigor. Findings from the systematic review indicate a lack of protocol detail provided. The effect between depression and CRP was small, but highly significant across all stages of the meta-analysis (p < 0.01). The effect size in the most methodologically rigorous stage of the meta-analysis, which included studies controlling for age, sex, obesity, medical conditions and substance, medication, or psychosocial factors, was small (r = 0.05). There were also only 26 articles in this stage (13% of studies from the systematic review), suggesting that more studies that consistently account for these confounding factors are needed. Additionally, an a priori quality score of methodological rigor was a significant moderator in this stage of the meta-analysis. The effect size was strikingly attenuated (r = 0.005) and non-significant in studies with higher quality scores. We describe a set of recommended guidelines for future research to consider, including sample collection and assaying procedures, data cleaning and statistical methods, and control variables to assess.

Treatment with escitalopram modulates cardiovascular function in rats

Considering depression is three times more common in cardiac patients compared to the normal population and selective serotonin reuptake inhibitors (SSRI) as drug of choice for treating patients with cardiovascular disease and depression, our work aims to evaluate the cardiovascular effects of treatment for 21 days with escitalopram (5 mg/kg/day, ip) in rats. The treatment caused an increase in mean arterial pressure concomitant with a decrease in heart rate. Concerning heart rate variability, there was a significant reduction in the sympathetic component and an elevation of the parasympathetic component, indicating that escitalopram caused an autonomic imbalance with parasympathetic predominance. In addition, we observed a decrease in both low and very low frequency power in blood pressure variability. The cardiac autonomic blockade indicated an increase in parasympathetic modulation to the heart with escitalopram chronic treatment. However, no change was observed on baroreflex activity. On the other hand, there was a decrease in pressure response during acute restraint stress with no changes in the tachycardia response. These findings showed that despite the escitalopram be a relatively safe drug it can cause tonic effects on cardiovascular function as well as during aversive situations.

The relationships of current suicidal ideation with inflammatory markers and heart rate variability in unmedicated patients with major depressive disorder

Studies investigating inflammatory status and autonomic functioning simultaneously in depressed patients with current suicidal ideation (SI) are lacking. We recruited 58 unmedicated depressed patients with current SI but without lifetime history of suicidal behavior, as well as 61 equally depressed patients without lifetime history of SI or suicidal behavior. We measured serum cortisol, high-sensitivity C-reactive protein (hs-CRP), erythrocyte sedimentation rate (ESR), and autonomic functioning evaluated by frequency-domain measures of heart rate variability (HRV). The intensity of current SI was rated with the Columbia Suicide Severity Rating Scale. Chronic psychological stress was assessed using the Chinese version of the Perceived Stress Scale (PSS). Patients with current SI showed higher hs-CRP and ESR but lower variance (total HRV), low frequency (LF), and high frequency (HF) HRV than those without lifetime history of SI. We found no differences in cortisol levels and PSS scores. The intensity of current SI was negatively correlated with variance, LF, and HF but positively correlated with hs-CRP. Our results help improve the understanding of the relationships among current SI, inflammation, and autonomic functioning in depressed patients. The combined use of inflammatory markers and HRV indices may one day be applied in predicting and monitoring patients' suicide risk.

Consensus paper of the WFSBP Task Force on Genetics: Genetics, epigenetics and gene expression markers of major depressive disorder and antidepressant response

Major depressive disorder (MDD) is a heritable disease with a heavy personal and socio-economic burden. Antidepressants of different classes are prescribed to treat MDD, but reliable and reproducible markers of efficacy are not available for clinical use. Further complicating treatment, the diagnosis of MDD is not guided by objective criteria, resulting in the risk of under- or overtreatment. A number of markers of MDD and antidepressant response have been investigated at the genetic, epigenetic, gene expression and protein levels. Polymorphisms in genes involved in antidepressant metabolism (cytochrome P450 isoenzymes), antidepressant transport (ABCB1), glucocorticoid signalling (FKBP5) and serotonin neurotransmission (SLC6A4 and HTR2A) were among those included in the first pharmacogenetic assays that have been tested for clinical applicability. The results of these investigations were encouraging when examining patient-outcome improvement. Furthermore, a nine-serum biomarker panel (including BDNF, cortisol and soluble TNF-α receptor type II) showed good sensitivity and specificity in differentiating between MDD and healthy controls. These first diagnostic and response-predictive tests for MDD provided a source of optimism for future clinical applications. However, such findings should be considered very carefully because their benefit/cost ratio and clinical indications were not clearly demonstrated. Future tests may include combinations of different types of biomarkers and be specific for MDD subtypes or pathological dimensions.

Lack of association between depression and C-reactive protein level in the baseline of Longitudinal Study of Adult Health (ELSA-Brasil)

BACKGROUND

Depression has been linked to increased levels of inflammatory markers in clinical studies, but results from general population samples are inconsistent. We aimed to investigate whether depression was associated with serum CRP levels in a cross-sectional analysis of a large cohort from a middle-income country.

METHODS

We analyzed baseline data from 14,821 participants (35-74 years) of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). Current depression (last 7 days) was assessed by the Clinical Interview Schedule-Revised (CIS-R). Because individuals on antidepressants could be negative on CIS-R due to their therapeutic effect, the explanatory variable had three categories: (1) negative on CIS-R and not using antidepressant (reference); (2) negative on CIS-R but using antidepressant; (3) positive on CIS-R with/without antidepressant use. Associations with CRP were investigated by general linear model (GLM).

RESULTS

After adjustments for confounders, neither current depression, nor antidepressant use was statistically associated with elevated CRP levels. Additionally, analyzes stratified by gender, type and severity of depression did not change the results.

LIMITATIONS

The reference group in our analysis might include participants with a lifetime history of depression. Additionally, the exclusion of questions on weight fluctuation and appetite from the CIS-R applied in ELSA-Brasil may have slightly underestimated the prevalence of depression, as well as limited our ability to assess the presence of somatic symptoms.

CONCLUSION

This study found no association between current depression, use of antidepressants, and serum CRP levels.

Association of anxiety and depression with hypertension control: a US multidisciplinary group practice observational study

OBJECTIVE

The presence of a mental health disorder with hypertension is associated with higher cardiovascular disease mortality than hypertension alone. Although earlier detection of hypertension has been demonstrated in patients with anxiety and depression, the relationship of mental health disorders to hypertension control is unknown. Our objective was to evaluate rates and predictors of incident hypertension control among patients with anxiety and/or depression compared with patients without either mental health diagnosis.

METHODS

A 4-year retrospective analysis included 4362 patients, at least 18 years old, who received primary care in a large academic group practice from 2008 to 2011. Patients met The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure criteria and had a hypertension diagnosis. Kaplan-Meier analysis estimated the probability of achieving control for patients with and without anxiety and/or depression. Cox proportional hazard models were fit to identify predictors of time to control.

RESULTS

Overall, 13% (n = 573) had a baseline diagnosis of anxiety and/or depression. Those with anxiety and/or depression demonstrated more primary care and specialty visits than those without either condition. After adjustment, patients with anxiety and/or depression had faster rates of hypertension control (hazard ratio [HR] 1.22; 1.07-1.39] than patients without either diagnosis. Other associations of faster hypertension control included female gender (HR 1.32; 1.20-1.44), absence of tobacco use (HR 1.17; 1.03-1.33), Medicaid use (HR 1.27; 1.09-1.49), and a higher Adjusted Clinical Group Risk Score (HR 1.13; 1.10-1.17), a measure of healthcare utilization.

CONCLUSION

Greater healthcare utilization among patients with anxiety and/or depression may contribute to faster hypertension control.

Autonomic nervous system dysfunction in psychiatric disorders and the impact of psychotropic medications: a systematic review and meta-analysis

BACKGROUND

Autonomic nervous system (ANS) dysfunction is a putative underlying mechanism for increased cardiovascular disease risk in individuals with psychiatric disorders. Previous studies suggest that this risk may be related to psychotropic medication use. In the present study we systematically reviewed and analyzed published studies of heart rate variability (HRV), measuring ANS output, to determine the effect of psychiatric illness and medication use.

METHODS

We searched for studies comparing HRV in physically healthy adults with a diagnosed psychiatric disorder to controls and comparing HRV pre- and post-treatment with a psychotropic medication.

RESULTS

In total, 140 case-control (mood, anxiety, psychosis, dependent disorders, k = 151) and 30 treatment (antidepressants, antipsychotics; k = 43) studies were included. We found that HRV was reduced in all patient groups compared to controls (Hedges g = -0.583) with a large effect for psychotic disorders (Hedges g = -0.948). Effect sizes remained highly significant for medication-free patients compared to controls across all disorders. Smaller and significant reductions in HRV were observed for specific antidepressants and antipsychotics.

LIMITATIONS

Study quality significantly moderated effect sizes in case-control analyses, underscoring the importance of assessing methodological quality when interpreting HRV findings.

CONCLUSION

Combined findings confirm substantial reductions in HRV across psychiatric disorders, and these effects remained significant even in medication-free individuals. Reductions in HRV may therefore represent a significant mechanism contributing to elevated cardiovascular risk in individuals with psychiatric disorders. The negative impact of specific medications on HRV suggest increased risk for cardiovascular disease in these groups, highlighting a need for treatment providers to consider modifiable cardiovascular risk factors to attenuate this risk.

Role of peripheral vascular resistance for the association between major depression and cardiovascular disease

Major depression and cardiovascular diseases are 2 of the most prevalent health problems in Western society, and an association between them is generally accepted. Although the specific mechanism behind this comorbidity remains to be elucidated, it is clear that it has a complex multifactorial character including a number of neuronal, humoral, immune, and circulatory pathways. Depression-associated cardiovascular abnormalities associate with cardiac dysfunctions and with changes in peripheral resistance. Although cardiac dysfunction in association with depression has been studied in detail, little attention was given to structural and functional changes in resistance arteries responsible for blood pressure control and tissue perfusion. This review discusses recent achievements in studies of depression-associated abnormalities in resistance arteries in humans and animal experimental models. The changes in arterial structure, contractile and relaxing functions associated with depression symptoms are discussed, and the role of these abnormalities for the pathology of major depression and cardiovascular diseases are suggested.

Depression and the Link with Cardiovascular Disease

This review provides an outline of the association between major depressive disorder (MDD) and coronary heart disease (CHD). Much is known about the two individual clinical conditions; however, it is not until recently, biological mechanisms have been uncovered that link both MDD and CHD. The activation of stress pathways have been implicated as a neurochemical mechanism that links MDD and CHD. Depression is known to be associated with poorer outcomes of CHD. Psychological factors, such as major depression and stress, are now known as risk factors for developing CHD, which is as important and is independent of classic risk factors, such as hypertension, diabetes mellitus, and cigarette smoking. Both conditions have great socioeconomic importance given that depression and CHD are likely to be two of the three leading causes of global burden of disease. Better understanding of the common causal pathways will help us delineate more appropriate treatments.

Examining Endothelial Function and Platelet Reactivity in Patients with Depression before and after SSRI Therapy

Although it is recognized that patients with major depressive disorder (MDD) are at increased risk of developing cardiovascular disease (CVD) the mechanisms responsible remain unknown. Endothelial dysfunction is one of the first signs of CVD. Using two techniques, flow-mediated dilatation in response to reactive hyperemia and laser Doppler velocimetry with iontophoresis, we examined endothelial function in the forearm before and after serotonin-specific reuptake inhibitor (SSRI) treatment in 31 patients with MDD. Measurement of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, soluble P-selectin, and noradrenaline in plasma was also performed. Prior to treatment, markers of endothelial and vascular function and platelet reactivity were within the normal range. Following SSRI therapy (95 ± 5 days) symptoms of depression were reduced (paired difference between pre- and post-treatment Hamilton rating -18 ± 1, P < 0.001) with 19 patients recovered and 4 remitted. There occurred no significant change in markers of endothelial or vascular function following SSRI therapy. The improvement in Hamilton depression rating in response to therapy could be independently predicted by the baseline arterial plasma noradrenaline concentration (r (2) = 0.36, P = 0.003). In this cohort of patients with MDD, SSRI therapy did not influence endothelial function or markers of vascular or platelet reactivity. Patient response to SSRI therapy could be predicted by the initial circulating level of noradrenaline, with noradrenaline levels being lower in responders.

Central actions of serotonin and fluoxetine on the QT interval of the electrocardiogram in trout

QT interval of the electrocardiogram (ECG) is a measure of the duration of the ventricular depolarization and repolarization. In humans, prolongation of the QT interval is a known clinical risk factor for the development of ventricular arrhythmias including ‘Torsades de Pointes’ and possible sudden cardiac death. After oral administration, fluoxetine (FLX), as well as other selective serotonin (5-hydroxytryptamine, 5-HT) reuptake inhibitors can affect cardiac autonomic control, including the QT interval. However, the action of centrally administered FLX on the QT interval has never been explored. Consequently, using the unanesthetized trout as an animal model, we sought to compare the effects of intracerebroventricular (i.c.v.) injection of FLX (5, 15 or 25 µg) on the QT interval of the ECG with the effects observed following i.c.v. injection of 5-HT (0.05, 0.5 or 5 nmol). The QT interval was corrected for the R–R interval. The highest doses of centrally administered FLX and 5-HT induced a prolongation of the corrected QT (QTc) interval reaching a maximum value of 5–10 min after injection (+8% and +6% respectively, P < 0.05). The intra-arterial (i.a.) injections of 5-HT and FLX were without significant effect on the QTc. The i.a. injection of blockers of the autonomic nervous system indicated that the sympathetic nervous system modulated the QTc interval. In conclusion, our data demonstrate that for the first time in any animal species, cardiac electrophysiology is sensitive to central 5-HT and that FLX within the brain may disrupt the autonomic control of ventricular repolarization.

Incident depression increases medical utilization in Medicaid patients with hypertension

Hypertension is an important risk factor for cardiovascular disease and occurs disproportionately among patients with depression. Few studies have rigorously examined outcomes specifically among hypertensive patients with newly diagnosed comorbid depression.

AIM

We hypothesized that incident depression would exacerbate hypertensive disease and that this would be evident through greater utilization of medical services than would otherwise occur in the absence of depression.

METHODS

Claims data for hypertensive patients enrolled in Maryland Medicaid (2005-2010) were used to estimate the change in annualized utilization following incident depression, compared to a matched cohort of hypertensive patients never diagnosed with depression. Multivariate regression was used to adjust for changes in antihypertensive medications, adherence and comorbidity that followed depression onset.

RESULTS

While medical utilization increased after incident depression, additional encounters tended to be for nonacute medical care and there was no significant increase in encounters specifically for cardiovascular or hypertension-related conditions.

DISCUSSION

The results contribute to the discussion on the relationship between depression and cardiovascular disease and will inform future studies that aim to look at longer term outcomes in patients with hypertension.

Depression and cardiovascular disease: an update on how course of illness may influence risk

Depression constitutes a novel and independent risk factor for cardiovascular disease, which despite extensive support in the literature has been underappreciated. While much of the evidence for depression as a risk factor for cardiovascular disease is based on studies following myocardial infarction, the elevated vascular risk conveyed by depression is not confined to periods following acute coronary syndromes. For that matter, the risk appears across mood disorders with evidence for even greater risk in bipolar disorder. This review summarizes the literature linking depressive disorders to cardiovascular mortality with a focus on how the course of illness of mood disorders may influence this risk. Mood disorders may influence risk over decades of illness in a dose-response to symptom burden, or the persistence of affective symptomatology. This may be mediated through changes in the activity of the autonomic nervous system, the hypothalamic-pituitary-adrenal axis, and inflammatory cytokines. Whether treatment of depression can mitigate this risk is not established although there are suggestions to support this contention, which could be better studied with more effective treatments of depression and larger standardized samples. Directions for future study of mechanisms and treatment are discussed. Regardless of causal mechanisms, persons with depressive disorders and other risk factors for vascular disease represent a neglected, high-risk group for cardiovascular events. In addition to the appropriate treatment for depression, screening and optimized management of traditional risk factors for cardiovascular diseases is necessary.

Blood pressure values and depression in hypertensive individuals at high cardiovascular risk

BACKGROUND

Hypertension and depression are both important risk factors for cardiovascular diseases. Nevertheless, the association of blood pressure on and depression has not been completely established. This study aims to analyze whether depression may influence the control of blood pressure in hypertensive individuals at high cardiovascular risk.

METHODS

Cross-sectional study, embedded within the PREDIMED clinical trial, of 5954 hypertensive patients with high cardiovascular risk factor profiles. The relationship between blood pressure control and depression was analyzed. A multivariate analysis (logistic and log-linear regression), adjusting for potential confounders (socio-demographic factors, body mass index, lifestyle, diabetes, dyslipidemia, and antihypertensive treatment), was performed.

RESULTS

Depressive patients, with and without antidepressant treatment, had better blood pressure control (OR: 1.28, CI 95%: 1.06-1.55, and OR: 1.30, CI 95%: 1.03-1.65, respectively) than non-depressive ones. Regarding blood pressure levels, systolic blood pressure values (mmHg) were found to be lower in both treated and untreated depressive patients (Log coefficient Beta: -1.59, 95% CI: -0.50 to -2.69 and Log coefficient Beta: -3.49, 95% CI: -2.10 to -4.87, respectively).

CONCLUSIONS

Among hypertensive patients at high cardiovascular risk, the control of blood pressure was better in those diagnosed with depression.

TRIAL REGISTRATION

Unique identifier: ISRCTN35739639.

Methylation of the SLC6a2 gene promoter in major depression and panic disorder

Reduced function of the noradrenaline transporter (NET) has been demonstrated in patients with major depressive disorder (MDD) and panic disorder. Attempts to explain NET dysfunction in MDD and panic disorder by genetic variation in the NET gene SLC6a2 have been inconclusive. Transcriptional silencing of the SLC6a2 gene may be an alternative mechanism which can lead to NET dysfunction independent of DNA sequence. The objective of this study was to characterise the DNA methylation state of the SLC6a2 gene promoter in patients with MDD and panic disorder. SLC6a2 promoter methylation was also analysed before and after antidepressant treatment. This study was performed with DNA from blood, using bisulphite sequencing and EpiTYPER methylation analyses. Patients with MDD or panic disorder were not found to differ significantly from healthy controls in the pattern of methylation of the SLC6a2 gene promotor. While significant correlations between methylation levels at some CpG sites and physiological measures were identified, overall the variation in DNA methylation between patients was small, and the significance of this variation remains equivocal. No significant changes in SLC6a2 promoter methylation were observed in response to antidepressant treatment. Further in-depth analysis of alternative mechanisms of transcriptional regulation of the SLC6a2 gene in human health and disease would be of value.

Relations of depressive symptoms and antidepressant use to body mass index and selected biomarkers for diabetes and cardiovascular disease

OBJECTIVES

We investigated whether depressive symptoms and antidepressant use are associated with biomarkers for glucose dysregulation and inflammation, body mass index (BMI), and waist circumference.

METHODS

Postmenopausal women were recruited into the Women's Health Initiative from 1993 to 1998, and data were collected at regular intervals through 2005. We used multiple linear regression models to examine whether depressive symptoms and antidepressant use are associated with BMI, waist circumference, and biomarkers.

RESULTS

Analysis of data from 71, 809 women who completed all relevant baseline and year 3 assessments showed that both elevated depressive symptoms and antidepressant use were significantly associated with higher BMI and waist circumference. Among 1950 women, elevated depressive symptoms were significantly associated with increased insulin levels and measures of insulin resistance. Analyses of baseline data from 2242 women showed that both elevated depressive symptoms and antidepressant use were associated with higher C-reactive protein levels.

CONCLUSIONS

Monitoring body habitus and other biomarkers among women with elevated depression symptoms or taking antidepressant medication may be prudent to prevent diabetes and cardiovascular disease.

Chronic fluoxetine reduces autonomic control of cardiac rhythms in rats with congestive heart failure

Up to 40% of patients with heart failure develop depression, and depression is an independent risk factor for cardiovascular mortality in this patient population. Consequently, increasing numbers of patients with heart failure are treated with antidepressants. Selective serotonin reuptake inhibitors are typically the antidepressant of choice since this drug class has limited cardiovascular toxicity. However, little is known about the effects of selective serotonin reuptake inhibitors on autonomic cardiac regulation in congestive heart failure (CHF). Here, indexes of cardiac autonomic control were evaluated before and during chronic fluoxetine (FLX) treatment (20 mg·kg−1·day−1, 5 wk) in rats that developed CHF after coronary artery ligation. FLX reduced the low-frequency (LF) component of heart rate variability (HRV; P < 0.01) as well as the sympathetic contribution to LF HRV ( P < 0.01) in both CHF and sham-operated rats. Both FLX and CHF reduced high-frequency HRV ( P < 0.01). Spontaneous baroreflex gain was decreased in CHF rats 8 wk after ligation ( P < 0.01). Cross-spectral coherence between the interbeat interval and mean arterial pressure was reduced in the LF domain 3 wk after ligation in CHF rats ( P < 0.01) and was further reduced after chronic FLX treatment ( P < 0.01). Plasma catecholamines and LF blood pressure variability were not affected by FLX. Chronotropic responses to both efferent vagal nerve stimulation and isoproterenol administration were reduced in CHF rats and by FLX ( P < 0.01), whereas inotropic responses to isoproterenol were reduced only in CHF rats ( P < 0.01). These data indicate that chronic FLX reduces the responsiveness to autonomic output controlling cardiac rhythm and may further compromise autonomic regulation of cardiac function in CHF.

Heart rate variability in patients with fully remitted major depressive disorder

OBJECTIVE

Cardiac autonomic dysregulation has been reported in major depressive disorder (MDD), but scarce studies investigated that in fully remitted MDD.

METHODS

To examine cardiac autonomic function in remitted MDD, 470 unmedicated individuals with a diagnosis of MDD earlier in life and 462 healthy volunteers, aged 18-65 years, were recruited for a case-control analysis. Cardiac autonomic function was evaluated by measuring heart rate variability (HRV) parameters. Frequency-domain indices of HRV were obtained. The obtained results were evaluated in association with personality traits assessed by the Tridimensional Personality Questionnaire.

RESULTS

In patients with remitted MDD, no differences in RR intervals and all frequency-domain indices of HRV could be detected as compared with controls. Stratified analyses by the presence of a history of suicide ideation (the SI+ vs. the SI-subgroup) revealed decreased cardiac vagal control in the SI+ subgroup. The correlation analysis revealed an inverse relation between HRV levels and the harm avoidance score (which has been suggested to be associated with serotonergic activity), mainly attributable to the robust association in the SI+ subgroup.

CONCLUSION

Our study shows that cardiac autonomic dysregulation is not shown in remitted MDD patients as a whole but is limited to the subgroup of remitted MDD patients with a history of suicidal ideation. In view of the higher risk for cardiac complications in these vulnerable individuals, one might consider the treatment to restore their autonomic function.

Interleukin-6, C-reactive protein and interleukin-10 after antidepressant treatment in people with depression: a meta-analysis

BACKGROUND

Cross-sectional studies support an association between depression and inflammatory markers. However, little is known of their relationship in the context of antidepressant treatment. Our aim was to explore via meta-analysis whether antidepressant treatment is associated with a reduction in three inflammatory markers associated with depression.

METHOD

A computerized search of EMBASE, Medline, PsycINFO and Cochrane Library databases was completed using subject headings for depression and either interleukin-6, C-reactive protein or interleukin-10, selecting studies which reported circulating levels of inflammatory markers before and after antidepressant treatment for people with depression. Outcome and moderator variables were coded for analysis, including inflammatory marker change, depression severity change, age, gender ratio, assay brand, treatment response and weight change.

RESULTS

Pooled effect sizes showed a significant decrease in interleukin-6 (n=14, d=-0.42, p=0.02), marginally significant decrease in C-reactive protein (n=8, d=-0.57, p=0.05) and a non-significant decrease in interleukin-10 (n=3, d=-0.45, p=0.14) after treatment. High levels of heterogeneity were observed, which may be associated with clinical variations between the studies such as weight gain, anxiety, incomplete remission and other individual differences and co-morbidities.

CONCLUSIONS

The findings of this meta-analysis indicate that there may be a normalization of overactive inflammatory processes following antidepressant treatment.

Taking the Perspective that a Depressive State Reflects Inflammation: Implications for the Use of Antidepressants

This paper reviews both the evidence that supports the characterization of depression as an inflammatory disorder and the different biochemical mechanisms that have been postulated for the connection between inflammation and depression. This association offers credible explanation for the short term efficacy of antidepressants, which have short term anti-inflammatory effects. Evidence for those anti-inflammatory effects is discussed. Evidence of the contrary long-term effects of antidepressants, which increase rather than decrease inflammation, is also reviewed. It is argued that this increase in inflammation would predict an increase in chronicity among depressed patients that have been treated with antidepressants drugs, which has been noted in the literature. A brief discussion of alternatives for decreasing inflammation, some of which have demonstrated efficacy in ameliorating depression, is presented.

Depression and incident stroke in women

BACKGROUND AND PURPOSE

Depression has been associated with an increased risk of coronary heart disease, but prospective data for the association with stroke are limited.

METHODS

We followed-up 80 574 women aged 54 to 79 years in Nurses' Health Study without a history of stroke from 2000 to 2006. Depressive symptoms were assessed at multiple time points by a Mental Health Index score (1992, 1996, and 2000), and clinical significant depressive symptoms were defined as a score≤52. Antidepressant medication use was asked biennially beginning in 1996, and physician-diagnosed depression was reported biennially beginning in 2000. Depression was defined as currently reporting or having a history of any of these 3 conditions.

RESULTS

During 6 years of follow-up, 1033 incident strokes were documented (538 ischemic, 124 hemorrhagic, and 371 unknown strokes). Having a history of depression was associated with a multivariate-adjusted hazard ratio (HR) of 1.29 (95% confidence interval [CI], 1.13-1.48) for total stroke. Women who used antidepressant medications were at increased risk for stroke, whether they also had a Mental Health Index score≤52 or diagnosed depression (HR, 1.39; 95% CI, 1.15-1.69) or not (HR, 1.31; 95% CI, 1.03-1.67). Furthermore, for each cycle, participants who reported current depression had an increased risk of stroke (HR, 1.41; 95% CI, 1.18-1.67), whereas individuals who only had a history of depression were at nonsignificantly elevated risk (HR, 1.23; 95% CI, 0.97-1.56) compared with women who never reported a diagnosis of depression or antidepressant medication use.

CONCLUSIONS

Our results suggest that depression is associated with a moderately increased risk of subsequent stroke.

The Utility of Animal Models in Understanding Links between Psychosocial Processes and Cardiovascular Health

A bidirectional association between mood disorders and cardiovascular disease has been described; however, the neurobiological mechanisms that underlie this link have not been fully elucidated. The purpose of this review is first to describe some of the important behavioral neurobiological processes that are common to both mood and cardiovascular disorders. Second, this review focuses on the value of conducting research with animal models (primarily rodents) to investigate potential behavioral, physiological, and neural processes involved in the association of mood disorders and cardiovascular disease. In combination with findings from human research, the study of mechanisms underlying mood and cardiovascular regulation using animal models will enhance our understanding of the association of depression and cardiovascular disease, and can promote the development of novel interventions for individuals with these comorbid conditions.

Anti-depressant medication use and C-reactive protein: results from two population-based studies

The use of anti-depressant medication has been linked to cardiovascular disease (CVD). We examined the association between anti-depressant medication use and a marker of low grade systemic inflammation as a potential pathway linking anti-depressant use and CVD in two population based studies. Data were collected in a representative sample of 8131 community dwelling adults (aged 47.4±15.9 years, 46.7% male) from the Scottish Health Surveys (SHS). The use of anti-depressant medication was coded according to the British National Formulary and blood was drawn for the measurement of C-reactive protein (CRP). In a second study, we attempted to replicate our findings using longitudinal data from the Whitehall II study (n=4584, aged 55.5±5.9 years, mean follow-up 5.5 years). Antidepressants were used in 5.6% of the SHS sample, with selective serotonin reuptake inhibitors (SSRIs) being the most common. There was a higher risk of elevated CRP (>3 mg/L) in users of tricyclic antidepressant (TCA) medication (multivariate adjusted odds ratio (OR)=1.52, 95% CI, 1.07-2.15), but not in SSRI users (multivariate adjusted OR=1.07, 95% CI, 0.81-1.42). A longitudinal association between any antidepressant use and subsequent CRP was confirmed in the Whitehall cohort. In summary, the use of anti-depressants was associated with elevated levels of systemic inflammation independently from the symptoms of mental illness and cardiovascular co-morbidity. This might be a potential mechanism through which antidepressant medication increases CVD risk. Further data are required to explore the effects of dosage and duration of antidepressant treatment.

Antidepressant medication use and future risk of cardiovascular disease: the Scottish Health Survey

AIMS

The association between antidepressant use and risk of cardiovascular disease (CVD) remains controversial, particularly in initially healthy samples. Given that antidepressants such as selective serotonin reuptake inhibitors (SSRIs) are now prescribed not only for depression, but also for a wide range of conditions, this issue has relevance to the general population. We assessed the association between antidepressant medication use and future risk of CVD in a representative sample of community-dwelling adults without known CVD.

METHODS AND RESULTS

A prospective cohort study of 14 784 adults (aged 52.4 ± 11.9 years, 43.9% males) without a known history of CVD was drawn from the Scottish Health Surveys. Of these study participants, 4.9% reported the use of antidepressant medication. Incident CVD events (comprising CVD death, non-fatal myocardial infarction, coronary surgical procedures, stroke, and heart failure) over 8-year follow-up were ascertained by a linkage to national registers; a total of 1434 events were recorded. The use of tricyclic antidepressants (TCAs) was associated with elevated risk of CVD [multivariate-adjusted hazard ratio (HR) = 1.35, 95% confidence interval (CI), 1.03-1.77] after accounting for a range of covariates. There was a non-significant association between TCA use and coronary heart disease events (969 events, multivariate-adjusted HR = 1.24, 95% CI, 0.87-1.75). The use of SSRIs was not associated with CVD. Neither class of drug was associated with all-cause mortality risk.

CONCLUSION

Although replication is required, the increased risk of CVD in men and women taking TCAs was not explained by existing mental illness, which suggests that this medication is associated with an excess disease burden.

Impact of depression and antidepressant treatment on heart rate variability: a review and meta-analysis

BACKGROUND

Depression is associated with an increase in the likelihood of cardiac events; however, studies investigating the relationship between depression and heart rate variability (HRV) have generally focused on patients with cardiovascular disease (CVD). The objective of the current report is to examine with meta-analysis the impact of depression and antidepressant treatment on HRV in depressed patients without CVD.

METHODS

Studies comparing 1) HRV in patients with major depressive disorder and healthy control subjects and 2) the HRV of patients with major depressive disorder before and after treatment were considered for meta-analysis.

RESULTS

Meta-analyses were based on 18 articles that met inclusion criteria, comprising a total of 673 depressed participants and 407 healthy comparison participants. Participants with depression had lower HRV (time frequency: Hedges' g = -.301, p < .001; high frequency: Hedges' g = -.293, p < .001; nonlinear: Hedges' g = -1.955, p = .05; Valsalva ratio: Hedges' g = -.712, p < .001) than healthy control subjects, and depression severity was negatively correlated with HRV (r = -.354, p < .001). Tricyclic medication decreased HRV, although serotonin reuptake inhibitors, mirtazapine, and nefazodone had no significant impact on HRV despite patient response to treatment.

CONCLUSIONS

Depression without CVD is associated with reduced HRV, which decreases with increasing depression severity, most apparent with nonlinear measures of HRV. Critically, a variety of antidepressant treatments do not resolve these decreases despite resolution of symptoms, highlighting that antidepressant medications might not have HRV-mediated cardioprotective effects and the need to identify individuals at risk among patients in remission.

Calcitonin gene-related peptide: A molecular link between obesity and migraine?

Epidemiological studies have begun to suggest obesity is a risk factor for chronic migraine, although no causal relationship has been established and risk factors for progression from episodic to chronic migraine remain unknown. The neuropeptide calcitonin gene-related peptide (CGRP) plays a important role in the pathophysiology of migraine. Here, the potential role of CGRP as a molecular link between obesity and migraine is reviewed. A mechanistic association is supported by several lines of evidence: 1) common markers are elevated in obesity and migraine, 2) adipose tissue secretes proinflammatory cytokines and adipocytokines that have been implicated in migraine pathophysiology and 3) elevated levels of CGRP have been found in plasma of obese individuals. We propose that CGRP released from trigeminal neurons may represent a biological link between obesity and migraine. Enhanced trigeminal CGRP production in obese susceptible individuals may lower the threshold necessary to trigger migraine attacks, leading to more frequent episodes and eventually to chronic migraine.

The 2009 Carl Ludwig Lecture: pathophysiology of the human sympathetic nervous system in cardiovascular diseases: the transition from mechanisms to medical management

Sympathetic nervous system responses typically are regionally differentiated, with activation in one outflow sometimes accompanying no change or sympathetic inhibition in another. Regional sympathetic activity is best studied in humans by recording from postganglionic sympathetic efferents (multiunit or single fiber recording) and by isotope dilution-derived measurement of organ-specific norepinephrine release to plasma (regional “norepinephrine spillover”). Evidence assembled in this review indicates that sympathetic nervous system abnormalities are crucial in the development of cardiovascular disorders, notably heart failure, essential hypertension, disorders of postural circulatory control causing syncope, and “psychogenic heart disease,” heart disease attributable to mental stress and psychiatric illness. These abnormalities involve persistent, adverse activation of sympathetic outflows to the heart and kidneys in heart failure and hypertension, episodic or ongoing cardiac sympathetic activation in psychogenic heart disease, and defective sympathetic circulatory reflexes in disorders of postural circulatory control. An important goal for clinical scientists is translation of knowledge of pathophysiology, such as this, into better treatment for patients. The achievement of this “mechanisms-to-management” transition is at differing stages of development with the different conditions. Clinical translation is mature in cardiac failure, knowledge of cardiac neural pathophysiology having led to introduction of β-adrenergic blockers, an effective therapy. With essential hypertension, perhaps we are on the cusp of effective translation, with recent successful testing of selective catheter-based renal sympathetic nerve ablation in patients with resistant hypertension, an intervention firmly based on demonstration of activation of the renal sympathetic outflow. With psychogenic heart disease and postural syncope syndromes, knowledge of the neural pathophysiology is emerging, but clinical translation remains for the future.

Cardiovascular abnormalities in patients with major depressive disorder: autonomic mechanisms and implications for treatment

This article provides a detailed review of the association of major depression with coronary heart disease (CHD), examines the biological variables underpinning the linkage and discusses the clinical implications for treatment. When considering the co-morbidity between major depressive disorder (MDD) and CHD it is important to differentiate between (i) the prevalence and impact of MDD in those with existing CHD and (ii) MDD as a risk factor for the development of CHD. Whether the same biological mechanisms are at play in these two instances remains unknown. Depression is common in patients with CHD. Importantly, depression in these patients increases mortality. There is also consistent evidence that MDD is a risk factor for the development of CHD. The relative risk of developing CHD is proportional to the severity of depression and is independent of smoking, obesity, hypercholesterolaemia, diabetes mellitus and hypertension. There is a clear need to identify the underlying neurochemical mechanisms responsible for MDD and their linkage to the heart and vascular system. Of particular interest are activation of stress pathways, including both the sympathetic nervous system and hypothalamic-pituitary-adrenal axis, and inflammatory-mediated atherogenesis. Elevated sympathetic activity, reduced heart rate variability and increased plasma cortisol levels have been documented in patients with MDD. In addition to direct effects on the heart and vasculature, activation of stress pathways may also be associated with increased release of inflammatory cytokines such as interleukin-6 and tumour necrosis factor-alpha. Elevated levels of C-reactive protein are commonly observed in patients with MDD. The majority of investigations examining treatment of depression following myocardial infarction have focused on safety and efficacy; there is little evidence to indicate that treating depression in these patients improves survival. Given that strategies for preventive therapy remain incompletely formulated, future research should focus on generating a better understanding of the neurobiology of MDD and heart disease as a basis for rational and effective therapy.