Cardiac vagal control in nonmedicated depressed women and nondepressed controls: impact of depression status, lifetime trauma history, and respiratory factors

Bidirectionality of LF when the movie makes you sad: Effects of negative emotions on heart rate variability among patients with major depression

OBJECTIVES

Heart rate variability (HRV) reflects the capacity to adapt to internal and environmental changes. Decreased HRV may indicate inadequate adaptive capacity. This study aims to investigate the relationship between the heart and brain's adaptive abilities, both at rest and when negative emotions are stimulated in depression.

SUBJECTS AND METHODS

The study included 30 patients (20 female, 10 male) with major depression (mean age = 29.8 ± 7.8) and 30 healthy controls, all of whom had similar characteristics in terms of age and gender, selected through convenience sampling. The patients were drug-free at the time of the assessment. Holter recordings were obtained while subjects watched videos stimulating anger, fear, sadness, and a neutral video, and at rest, HRV parameters were calculated. To control for interindividual variability and account for paired sampling, linear mixed effects models were employed.

RESULTS

Watching the 'sadness video' led to an increase in low frequency band (LF) [LF change (Control vs depression); Difference:-620.80 df:107 t:-2.093 P:0.039] and LF/high frequency band ratio (LF/HF) [LF/HF change (control vs depression group); Difference:-1.718 df:105 t:-2.374 P:0.020] in the depression group. The video led to a decrease in LF and LF/HF in the controls. Although the differences between the conditions and interactions with the group were significant, the effects were independent of depression severity.

CONCLUSION

In depression, brain's regulatory effect on the heart differed from controls in the sadness condition, possibly due to increased arousal levels in subjects with depression and their inability to suppress sympathetic activity when a state of sadness is stimulated.

Distinct physiological responses to social-evaluative stress in patients with major depressive disorder reporting a history of peer victimization

Peer victimization is a risk factor for the development of major depressive disorders, but little is known about the mechanisms. This study examined whether peer victimization alters physiological and affective responses to potentially threatening social stimuli. For this purpose, reactions to socially evaluative stimuli of depressive patients and healthy controls with varying histories of peer victimization were compared. In a social conditioning task, we studied heart rate responses to unconditioned socially negative and neutral evaluative video statements, followed by the heart rate reactions to conditioned stimuli, i.e. still images of the faces of the same actors. Diagnosis of depression and peer victimization were both associated with a more pronounced heart rate deceleration in response to unconditioned stimuli, irrespective of valence. The effect of peer victimization was stronger in depressive patients than in healthy controls. However, heart rate responses to the CSs were not related to depression or peer victimization. The results indicate a hypervigilant processing of social stimuli in depressive patients reporting histories of peer victimization. This distinct processing may be associated with inappropriate behavioral and emotional responses to social challenges, putting individuals at risk for depressive symptoms.

Effect of depression on phase coherence between respiratory sinus arrhythmia and respiration during sleep in patients with obstructive sleep apnea

Introduction: A high prevalence of major depressive disorder (MDD) among Obstructive Sleep Apnea (OSA) patients has been observed in both community and clinical populations. Due to the overlapping symptoms between both disorders, depression is usually misdiagnosed when correlated with OSA. Phase coherence between respiratory sinus arrhythmia (RSA) and respiration (λ RSA-RESP) has been proposed as an alternative measure for assessing vagal activity. Therefore, this study aims to investigate if there is any difference in λ RSA-RESP in OSA patients with and without MDD. Methods: Electrocardiograms (ECG) and breathing signals using overnight polysomnography were collected from 40 OSA subjects with MDD (OSAD+), 40 OSA subjects without MDD (OSAD-), and 38 control subjects (Controls) without MDD and OSA. The interbeat intervals (RRI) and respiratory movement were extracted from 5-min segments of ECG signals with a single apneic event during non-rapid eye movement (NREM) [353 segments] and rapid eye movement (REM) sleep stages [298 segments]. RR intervals (RRI) and respiration were resampled at 10 Hz, and the band passed filtered (0.10-0.4 Hz) before the Hilbert transform was used to extract instantaneous phases of the RSA and respiration. Subsequently, the λ RSA-RESP between RSA and Respiration and Heart Rate Variability (HRV) features were computed. Results: Our results showed that λ RSA-RESP was significantly increased in the OSAD+ group compared to OSAD- group during NREM and REM sleep. This increase was accompanied by a decrease in the low frequency (LF) component of HRV. Discussion: We report that the phase synchronization index between RSA and respiratory movement could provide a useful measure for evaluating depression in OSA patients. Our findings suggest that depression has lowered sympathetic activity when accompanied by OSA, allowing for stronger synchronization between RSA and respiration.

Toward personalized circuit-based closed-loop brain-interventions in psychiatry: using symptom provocation to extract EEG-markers of brain circuit activity

Symptom provocation is a well-established component of psychiatric research and therapy. It is hypothesized that specific activation of those brain circuits involved in the symptomatic expression of a brain pathology makes the relevant neural substrate accessible as a target for therapeutic interventions. For example, in the treatment of obsessive-compulsive disorder (OCD), symptom provocation is an important part of psychotherapy and is also performed prior to therapeutic brain stimulation with transcranial magnetic stimulation (TMS). Here, we discuss the potential of symptom provocation to isolate neurophysiological biomarkers reflecting the fluctuating activity of relevant brain networks with the goal of subsequently using these markers as targets to guide therapy. We put forward a general experimental framework based on the rapid switching between psychiatric symptom states. This enable neurophysiological measures to be derived from EEG and/or TMS-evoked EEG measures of brain activity during both states. By subtracting the data recorded during the baseline state from that recorded during the provoked state, the resulting contrast would ideally isolate the specific neural circuits differentially activated during the expression of symptoms. A similar approach enables the design of effective classifiers of brain activity from EEG data in Brain-Computer Interfaces (BCI). To obtain reliable contrast data, psychiatric state switching needs to be achieved multiple times during a continuous recording so that slow changes of brain activity affect both conditions equally. This is achieved easily for conditions that can be controlled intentionally, such as motor imagery, attention, or memory retention. With regard to psychiatric symptoms, an increase can often be provoked effectively relatively easily, however, it can be difficult to reliably and rapidly return to a baseline state. Here, we review different approaches to return from a provoked state to a baseline state and how these may be applied to different symptoms occurring in different psychiatric disorders.

Adversity's Impact on Adults' Self-Report and Physiological Difficulties with Emotion Regulation: Appraisal as a Moderating Mechanism

Globally, there is a high prevalence of adversity exposure, and there is evidence indicating a linear association between adversity exposure, particularly childhood adversity, and adults' psychological distress. To better understand this association, researchers have examined the role of emotion regulation abilities, which are thought to impact and underlie one's psychological well-being. The present study examined the association between childhood versus adulthood adversity exposure and self-reported difficulties with emotion regulation and physiological indicators of emotion regulation (e.g., resting respiratory sinus arrythmia [RSA], RSA reactivity, and RSA recovery). Further, the study assessed appraisal styles (i.e., patterns of subjective interpretations) across adverse life events as a possible moderator to help explain why some, but not all, exposed to adversity may display emotion regulation difficulties. Participants were 161 adults participating in a larger federally funded project. Results found no direct association between childhood or adulthood adversity exposure and self-reported or physiological indicators of difficulties with emotion regulation. However, adulthood adversity exposure was associated with stronger trauma appraisal styles, and stronger trauma appraisal styles were associated with greater self-reported difficulties with emotion regulation and greater RSA reactivity. Results also showed interactions between greater childhood adversity and stronger trauma appraisal styles for lower resting RSA and greater RSA recovery. The present study demonstrates that emotion regulation is complex, dynamic, and has multiple dimensions and that childhood adversity may impact internal regulatory processes, but only in conjunction with trauma appraisal styles, which are associated with adulthood adversity.

Cardiac Autonomic and Cardiac Vagal Control During and After Depressive and Happiness Autobiographical Memories in Patients With Major Depressive Disorder

BACKGROUND

Heart rate variability (HRV) and respiratory sinus arrhythmia (RSA) are indices of cardiac autonomic and cardiac vagal control (CVC), both of which are markers of emotional regulation and physical health. This study examined (1) the differences in cardiac autonomic regulation and CVC during baseline, depressive, and happiness autobiographical memory tasks between participants with major depressive disorder (MDD group) and healthy controls (HC group); (2) the associations between depressive symptoms and cardiac autonomic and CVC; and (3) the reactivity and recovery of cardiac autonomic and CVC between the MDD and HC groups.

METHODS

A total of 168 and 178 participants were included in the MDD and HC groups, respectively. Demographic data and the Beck Depression Inventory-II were collected before the experimental procedure. Lead II electrocardiograph (ECG) was measured during baseline, depressive, and happiness autobiographical memory tasks, and then interbeat intervals from ECG were converted to the time and frequency domains of HRV and RSA.

RESULTS

The participants in the MDD group showed lower HRV (including standard deviation of normal to normal intervals, low frequency, the natural logarithm of low frequency, and the natural logarithm of high frequency) and CVC (RSA and lnRSA) than those in the HC group. Depressive symptoms were positively correlated with heart rate and negatively correlated with the indices of cardiac autonomic and CVC. There was significantly increased reactivity and recovery of cardiac autonomic and CVC during and after depressive and happiness autobiographical memory tasks in the HC group, but not in the MDD group.

DISCUSSION

Participants with MDD had cardiac autonomic and CVC dysregulation, decreased reactivity, and did not recover to baseline after emotional provocations. These results can be the theoretical basis for clinical intervention by using HRV biofeedback to restore cardiac autonomic regulation and CVC during and after emotional events in the future.

Parental history of childhood maltreatment and child average RSA shape parent-child RSA synchrony

We examined whether dynamic parent-child RSA synchrony varied by individual differences in child average RSA and parental history of childhood maltreatment (CM), which has been linked to parental behavioral and physiological dysregulation. We also examined whether RSA synchrony was curvilinear, reflecting homeostatic regulation. Synchrony was defined as the dynamic association between parent and child RSA reactivity (change relative to their own mean) within epoch across a challenging task. Eighty-three mother-preschooler and 61 father-preschooler dyads participated. State-trait modeling showed that RSA synchrony was curvilinear such that significant relations were only found at lower and higher child reactivity. Children's higher task average RSA predicted maternal RSA augmentation and lower task average RSA predicted maternal RSA withdrawal, regardless of whether child reactivity in the moment was low or high, suggesting individual differences in child regulatory capacity were associated with dynamic maternal reactivity. When maternal CM history and child average RSA were both higher, mothers showed RSA augmentation. Father-child synchrony was not moderated by child average RSA but greater paternal CM history predicted fathers' greater RSA withdrawal regardless of whether child RSA reactivity was low or high. Findings offer novel insights into the nature and meaning of RSA synchrony with parents at risk.

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.

Emotion context insensitivity in depression: Toward an integrated and contextualized approach

Major depressive disorder (MDD) is characterized by pervasive mood disturbance as well as deficits in emotional processing, reactivity, and regulation. There is accumulating evidence that MDD is characterized by emotional patterns consistent with environmental disengagement, as reflected in attenuated positive and negative emotional reactivity, consistent with Emotion Context Insensitivity (ECI) theory. However, MDD individuals vary considerably in the extent to which they exhibit specific alterations in patterns of emotional responding. Emotions are complex, multicomponent processes that invoke responses across multiple functional domains and levels of analysis, including subjective experience, behavior, autonomic regulation, cognition, and neural processing. In this article, I review the current state of the literature on emotional responding and MDD from the lens of ECI. I focus on the importance of assessing emotional indices from multiple levels of analysis across development and contexts. I also discuss methodological and measurement issues that may contribute to inconsistent findings. In particular, I emphasize how psychophysiological measures can help elucidate emotional processes that underlie the pathophysiology of MDD as part of an integrated and contextualized approach.

Yohimbine-Induced Reactivity of Heart Rate Variability in Unmedicated Depressed Patients With and Without Adverse Childhood Experience

Stressful life events play a role in the pathogenesis of major depressive disorder (MDD) and many patients with MDD were exposed to developmental stress due to adverse childhood experiences (ACE). Furthermore, dysregulation of the autonomic nervous system and higher incidence of cardiovascular disease are found in MDD. In MDD, and independently in individuals with ACE, abnormalities in heart rate variability (HRV) have been reported. While these are often confounded, we systematically investigated them with a study which included MDD patients with/without ACE as well as healthy individuals with/without ACE. With this study, we investigated the influence of noradrenergic stimulation on HRV reactivity in unmedicated participants in a randomized, double-blind, repeated measures design. Our sample consisted of men and women with MDD and ACE (n = 25), MDD without ACE (n = 24), healthy participants with ACE (n = 27), and without ACE (n = 48). Participants received a 10 mg single dose of the alpha-2 antagonist yohimbine that increases noradrenergic activity or placebo on 2 separate days, with ECG recordings before and after drug administration at defined intervals. We found lower basal HRV in MDD and ACE: patients with MDD had reduced RMSSD whereas participants with ACE had lower LF-HRV. Contrary to our hypothesis, there was no effect of yohimbine. With this study, we were able to replicate previous findings on HRV differences in MDD and ACE. From the null effect of yohimbine, we conclude that the yohimbine-induced sympathetic activation is not a significant driver of HRV in MDD and ACE.

Processing speed and attention training modifies autonomic flexibility: A mechanistic intervention study

Adaptation capacity is critical for maintaining cognition, yet it is understudied in groups at risk for dementia. Autonomic nervous system (ANS) is critical for neurovisceral integration and is a key contributor to adaptation capacity. To determine the central nervous system's top-down regulation of ANS, we conducted a mechanistic randomized controlled trial study, using a 6-week processing speed and attention (PS/A)-targeted intervention. Eighty-four older adults with amnestic mild cognitive impairment (aMCI) were randomized to a 6-week PS/A-targeted intervention or an active control without PS/A. Utilizing repeated measures (i.e., PS/A test different from the intervention, resting and cognitive task-based ECG, and resting fMRI) at baseline, immediately post-intervention (post-test), and 6-month follow-up, we aimed to test whether PS/A causally influences vagal control of ANS via their shared central neural pathways in aMCI. We indexed vagal control of ANS using high-frequency heart rate variability (HF-HRV) extracted from ECG data. Functional brain connectivity patterns were extracted from fMRI using advanced statistical tools. Compared to the control group, the intervention group showed significant improvement in PS/A, HF-HRV, salience network (SN), central executive network (CEN), and frontal parietal network (FPN) connectivity at post-test; the effect on SN, CEN, and FPN remained at 6-month follow-up. Changes in PS/A and SN connectivity significantly predicted change in HF-HRV from baseline to post-test and/or 6-month-follow-up. Age, neurodegeneration, nor sex did not affect these relationships. This work provides novel support for top-down regulation of PS/A and associated SN on vagal control of ANS. Intervening PS/A may be a viable approach for promoting adaptation capacity in groups at risk for dementia.

Associations of depression severity with heart rate and heart rate variability in young adults across normative and clinical populations

Limitations of current depression treatments may arise from a lack of knowledge about unique psychophysiological processes that contribute to depression across the full range of presentations. This study examined how individual variations in heart rate (HR) and heart rate variability (HRV) are related to depressive symptoms across normative and clinical populations in 152 young adults (aged 18-35 years). Moderating effects of sex and antidepressant medication status were considered. Electrocardiogram data were collected during "vanilla" baseline and in response to positive and negative emotional cues. Linear regressions and repeated-measures mixed models were used to assess the relationships between Beck Depression Inventory-II (BDI-II) scores, sex, antidepressant use, and cardiovascular outcomes. Baseline models yielded significant main effects of BDI-II and sex on HR and significant interactions between antidepressant medication status and BDI-II on HRV outcomes. The main effects of BDI-II and sex on HR were no longer significant after controlling for cardiorespiratory fitness. Participants who denied current antidepressant use (n = 137) exhibited a negative association and participants who endorsed current antidepressant (n = 15) use exhibited a positive association between BDI-II scores and HRV. Emotional reactivity models were largely non-significant with the exception of a significant main effect of antidepressant medication status on high-frequency HRV reactivity. Results indicated antidepressant medication use may moderate the relationship between depression severity and cardiovascular functioning, but this requires replication given the modest proportion of medicated individuals in this study. Overall, findings suggest cardiovascular processes and cardiorespiratory fitness are linked to depression symptomatology and may be important to consider in depression treatment.

Heart rate and high frequency heart rate variability during stress as biomarker for clinical depression. A systematic review

The interaction of physical and mental vulnerability and environmental constraints is thought to foster the development of psychiatric disorders such as major depressive disorder (MDD). A central factor in the development of psychopathology is mental stress. Despite some evidence for parasympathetic withdrawal and sympathetic overactivity in MDD, the psychophysiological response to stress in depression is not clear-cut. Given the growing interest in heart rate and heart rate variability as indicators for remote monitoring of patients, it is important to understand how patients with MDD react to stress in a laboratory-controlled environment. We conducted a systematic review of studies using electrocardiography to derive heart rate and heart rate variability during stress in patients with clinical depression. We focused on well-validated stress tasks- the mental arithmetic stress task, the Trier social stress task and public speaking task- to minimize confounding effects due to the nature of the stressor. The majority of studies found hypo-reactivity during stress as a hallmark of depression as evidenced by lower fluctuation in heart rate and heart rate variability in the high-frequency band. We address the potential underlying biological mechanisms, the influence of covariates on these measures and briefly discuss the specificity and potential for remote monitoring by using these variables.

History of childhood emotional abuse predicts lower resting-state high-frequency heart rate variability in depressed women

Childhood emotional abuse impairs emotion regulation and increases risk for major depressive disorder in adulthood. Mounting evidence suggests that decreased resting-state high-frequency heart rate variability, an index of parasympathetic function, represents a transdiagnostic biomarker of emotion dysregulation. We propose that adults with histories of major depressive disorder and childhood emotional abuse represent a subpopulation at particularly high risk to exhibit deficits in parasympathetic control. The current report compared resting-state high-frequency heart rate variability across three groups: (1) depressed women who endorsed childhood emotional abuse (N = 11); (2) depressed women without childhood emotional abuse (N = 19), and (3) never-depressed women without childhood emotional abuse (N = 22). Participants completed childhood trauma self-reports and assessment of resting-state high-frequency heart rate variability. ANCOVAs comparing the three groups after controlling for health-related, psychiatric, and respiratory factors were significant. Depressed women with childhood emotional abuse exhibited lower high-frequency heart rate variability than both groups without childhood emotional abuse (d's ranging from 0.81-0.92). Surprisingly, psychiatric factors were non-significant predictors, indicating that childhood emotional abuse may have a unique impact on autonomic functioning. Future research on larger samples is needed to disentangle the relative and synergistic burdens of depression and childhood trauma on physiologic indicators of emotion dysregulation.

Childhood adversity predicts reduced physiological flexibility during the processing of negative affect among adolescents with major depression histories

BACKGROUND

Adversity during early development has been shown to have enduring negative physiological consequences. In turn, atypical physiological functioning has been associated with maladaptive processing of negative affect, including its regulation. The present study therefore explored whether exposure to adverse life events in childhood predicted maladaptive (less flexible) parasympathetic nervous system functioning during the processing of negative affect among adolescents with depression histories.

METHODS

An initially clinic-referred, pediatric sample (N=189) was assessed at two time points. At Time 1, when subjects were 10.17years old (SD=1.42), on average, and were depressed, parents reported on adverse life events the offspring experienced up to that point. At Time 2, when subjects were 17.18years old (SD=1.28), and were remitted from depression, parents again reported on adverse life events in their offspring's lives for the interim period. At time 2, subjects' parasympathetic nervous system functioning (quantified as respiratory sinus arrhythmia) also was assessed at rest, during sad mood induction, and during instructed mood repair.

RESULTS

Extent of adverse life events experienced by T1 (but not events occurring between T1 and T2) predicted less flexible RSA functioning 7years later during the processing of negative affect. Adolescents with more extensive early life adversities exhibited less vagal withdrawal following negative mood induction and tended to show less physiological recovery following mood repair.

CONCLUSIONS

Early adversities appear to be associated with less flexible physiological regulatory control during negative affect experience, when measured later in development. Stress-related autonomic dysfunction in vulnerable youths may contribute to the unfavorable clinical prognosis associated with juvenile-onset depression.

Inflexibility as a Vulnerability to Depression: A Systematic Qualitative Review

The study of vulnerabilities to depression typically identifies factors that are thought to be universally maladaptive or adaptive. In contrast, researchers recently have theorized that the ability to flexibly engage in different thoughts and behaviors that fit situational demands may be most indicative of psychological health. We review empirical evidence from 147 studies reporting associations between five components of flexibility (set-shifting, affective set-shifting, cardiac vagal control, explanatory flexibility, and coping flexibility) and depression and classify studies according to strength of study design. Evidence from correlational and case-controlled studies suggests cross-sectional relationships, but few prospective studies have been conducted. We discuss limitations of existing studies, identify new directions for programmatic research, and discuss implications that flexibility has for the prevention and treatment of depression.

Depression impacts the physiological responsiveness of mother-daughter dyads during social interaction

BACKGROUND

Maternal depression is associated with increased risk of psychiatric illness in offspring. While risk may relate to depressed mothers' difficulties regulating emotions in the context of interacting with offspring, physiological indicators of emotion regulation have rarely been examined during mother-child interactions-and never among mother-adolescent dyads in which both mother and adolescent have histories of major depressive disorder (MDD).

METHODS

We examined changes in high-frequency heart rate variability (HF-HRV), an indicator of parasympathetic (vagal) function that has been related to depression, stress, social engagement, and emotion regulation, in 46 mother-daughter dyads (23 in which both mother and daughter had an MDD history and 23 never-depressed controls). Hierarchical linear models evaluated changes in HF-HRV while mother-daughter dyads engaged in discussions about shared pleasant events and relationship conflicts.

RESULTS

While control dyads displayed positive slopes (increases) in HF-HRV during both discussions, MDD dyads displayed minimal change in HF-HRV across discussions. Among controls, HF-HRV slopes were positively correlated between mothers and daughters during the pleasant events' discussion. In contrast, HF-HRV slopes were negatively correlated between MDD mothers and daughters during both discussions.

CONCLUSIONS

Vagal responses observed in control mother-daughter dyads suggest a pattern of physiological synchrony and reciprocal positive social engagement, which may play a role in adolescent development of secure social attachments and healthy emotion regulation. In contrast, MDD mothers and daughters displayed diminished and discordant patterns of vagal responsiveness. More research is needed to understand the development and consequences of these patterns of parasympathetic responses among depressed mother-daughter dyads.

Atypical reactivity of heart rate variability to stress and depression across development: Systematic review of the literature and directions for future research

Heart rate variability has received growing attention in the depression literature, with several recent meta-analyses indicating that lower resting heart rate variability is associated with depression. However, the role of fluctuations in heart rate variability (or reactivity) in response to stress in depression remains less clear. The present review provides a systematic examination of the literature on heart rate variability reactivity to a laboratory-induced stressor task and depression, including 26 studies of reactivity in heart rate variability and clinical depression, remitted (or history of) depression, and subthreshold depression (or symptom-level depression) among adults, adolescents, and children. In addition to reviewing the findings of these studies, methodological considerations and conceptual gaps in the literature are addressed. We conclude by highlighting the importance of investigating the potential transactional relationship between heart rate variability reactivity and depression and possible mechanisms underlying this relationship.

Psychosocial and psychoneuroendocrinal aspects of Takotsubo syndrome

Great advances have been made in our understanding of Takotsubo syndrome in the past decade, but the aetiology of the condition remains incompletely understood. The most established theory, that catecholamine-mediated myocardial stunning is provoked by emotional or physiological stress, is supported by the presence of supraphysiological levels of plasma catecholamines in patients with Takotsubo syndrome. For this reason, the hyperexcitability of the autonomic nervous system under conditions of physical and emotional stress is often assessed in these patients. Observational studies have indicated that a predisposing influence of chronic or traumatic stress, anxiodepressive disorders, and maladaptive personality traits are linked to the pathogenesis of Takotsubo syndrome. Chronic stress can influence autonomic function through dysregulation of the hypothalamic-pituitary-adrenal axis and contribute to the development of cardiovascular disorders. In this Perspectives article, we discuss the current knowledge of the psychoneuroendocrinological and psychosocial mechanisms underlying the pathophysiology of Takotsubo syndrome.

Resting respiratory sinus arrhythmia is related to longer hospitalization in mood-disordered repetitive suicide attempters

OBJECTIVES

Our aims were (1) to measure respiratory sinus arrhythmia (RSA), a high-frequency spectrum component of heart rate variability (HRV) in mood-disordered suicide attempters and (2) to investigate the relationship of RSA to symptoms and length of hospitalization.

METHODS

Forty-nine female repetitive-suicide attempters with depressive disorder or bipolar disorder were recruited in a general hospital setting. Manic or psychotic patients were excluded. Resting RSA values were calculated from electrocardiogram data, and severity of clinical presentation shortly after admission and length of hospital stay were assessed.

RESULTS

RSA was positively associated with a higher Beck Scale for Suicidal Ideation score (r = 0.33 P = 0.019). Stepwise multiple regression analysis showed a significant correlation between RSA and hospitalization length after adjusting other variables (beta coefficient = 3.00; P = 0.030). Patients with a higher resting RSA had more prolonged hospitalizations (hospitalization beyond 30 days) after controlling for other variables (odds ratio = 5.08, P = 0.017).

CONCLUSIONS

Interaction between the environment and the autonomic nervous system is complex. Further and more comprehensive research is needed.

Vagal Recovery From Cognitive Challenge Moderates Age-Related Deficits in Executive Functioning

Decline in executive functioning (EF) is a hallmark of cognitive aging. We have previously reported that faster vagal recovery from cognitive challenge is associated with better EF. This study examined the association between vagal recovery from cognitive challenge and age-related differences in EF among 817 participants in the Midlife in the U.S. study (aged 35-86). Cardiac vagal control was measured as high-frequency heart rate variability. Vagal recovery moderated the association between age and EF (β = .811, p = .004). Secondary analyses revealed that older participants (aged 65-86) with faster vagal recovery had superior EF compared to their peers who had slower vagal recovery. In contrast, among younger (aged 35-54) and middle-aged (aged 55-64) participants, vagal recovery was not associated with EF. We conclude that faster vagal recovery from cognitive challenge is associated with reduced deficits in EF among older, but not younger individuals.

Heart Rate Variability and the Efficacy of Biofeedback in Heroin Users with Depressive Symptoms

Objective

Low heart rate variability (HRV) has been confirmed in heroin users, but the effects of heart-rate-variability–biofeedback in heroin users remain unknown. This study examined (1) correlations between depression and HRV indices; (2) group differences in HRV indices among a heroin-user group, a group with major depressive disorder but no heroin use, and healthy controls; and (3) the effects of heart-rate-variability–biofeedback on depressive symptoms, HRV indices, and respiratory rates within the heroin group.

Methods

All participants completed a depression questionnaire and underwent electrocardiogram measurements, and group differences in baseline HRV indices were examined. The heroin group underwent electrocardiogram and respiration rate measurements at baseline, during a depressive condition, and during a happiness condition, before and after which they took part in the heart-rate-variability–biofeedback program. The effects of heart-rate-variability–biofeedback on depressive symptoms, HRV indices, and respiration rates were examined.

Results

There was a negative correlation between depression and high frequency of HRV, and a positive correlation between depression and low frequency to high frequency ratio of HRV. The heroin group had a lower overall and high frequency of HRV, and a higher low frequency/high frequency ratio than healthy controls. The heart-rate-variability–biofeedback intervention increased HRV indices and decreased respiratory rates from pre-intervention to post-intervention.

Conclusion

Reduced parasympathetic and increased sympathetic activations were found in heroin users. Heart-rate-variability–biofeedback was an effective non-pharmacological intervention to restore autonomic balance.

Altered cardiorespiratory coupling in young male adults with excessive online gaming

INTRODUCTION

This study aimed to investigate changes in heart rate variability and cardiorespiratory coupling in male college students with problematic Internet use (PIU) excessive gaming type during action video game play to assess the relationship between PIU tendency and central autonomic regulation.

METHOD

Electrocardiograms and respiration were simultaneously recorded from 22 male participants with excessive online gaming and 22 controls during action video game play. Sample entropy (SampEn) was computed to assess autonomic regularity, and cross-SampEn was calculated to quantify autonomic coordination.

RESULTS

During video game play, reduced cardiorespiratory coupling (CRC) was observed in individuals with PIU excessive gaming type compared with controls, implicating central autonomic dysregulation. The PIU tendency was associated with the severity of autonomic dysregulation.

CONCLUSION

These findings indicate impaired CRC in PIU excessive gaming type, which may reflect alterations of central inhibitory control over autonomic responses to pleasurable online stimuli.

Atypical patterns of respiratory sinus arrhythmia index an endophenotype for depression

Can atypical patterns of parasympathetic nervous system activity serve as endophenotypes for depression? Using respiratory sinus arrhythmia (RSA) as an index of parasympathetic nervous system function, we examined this question in two studies: one involving mothers with and without depression histories and their offspring (at high and low risk for depression, respectively), and a further study of adolescent sibling pairs concordant and discordant for major depression. In both studies, subjects were exposed to sad mood induction; subjects' RSA was monitored during rest periods and in response to the mood induction. We used Gottesman and Gould's (2003) criteria for an endophenotype and a priori defined "atypical" and "normative" RSA patterns (combinations of resting RSA and RSA reactivity). We found that atypical RSA patterns (a) predicted current depressive episodes and remission status among women with histories of juvenile onset depression and healthy controls, (b) predicted longitudinal trajectories of depressive symptoms among high- and low-risk young offspring, (c) were concordant across mothers and their juvenile offspring, (d) were more prevalent among never-depressed youth at high risk for depression than their low-risk peers, and (e) were more concordant across adolescent sibling pairs in which both versus only one had a history of major depression. Thus, the results support atypical RSA patterns as an endophenotype for depression. Possible mechanisms by which RSA patterns increase depression risk and their genetic contributors are discussed.

Interoceptive dysfunction: toward an integrated framework for understanding somatic and affective disturbance in depression

Depression is characterized by disturbed sleep and eating, a variety of other nonspecific somatic symptoms, and significant somatic comorbidities. Why there is such close association between cognitive and somatic dysfunction in depression is nonetheless poorly understood. An explosion of research in the area of interoception-the perception and interpretation of bodily signals-over the last decade nonetheless holds promise for illuminating what have until now been obscure links between the social, cognitive-affective, and somatic features of depression. This article reviews rapidly accumulating evidence that both somatic signaling and interoception are frequently altered in depression. This includes comparative studies showing vagus-mediated effects on depression-like behaviors in rodent models as well as studies in humans indicating both dysfunction in the neural substrates for interoception (e.g., vagus, insula, anterior cingulate cortex) and reduced sensitivity to bodily stimuli in depression. An integrative framework for organizing and interpreting this evidence is put forward which incorporates (a) multiple potential pathways to interoceptive dysfunction; (b) interaction with individual, gender, and cultural differences in interoception; and (c) a developmental psychobiological systems perspective, emphasizing likely differential susceptibility to somatic and interoceptive dysfunction across the lifespan. Combined with current theory and evidence, it is suggested that core symptoms of depression (e.g., anhedonia, social deficits) may be products of disturbed interoceptive-exteroceptive integration. More research is nonetheless needed to fully elucidate the relationship between mind, body, and social context in depression.

Heart rate variability characteristics in a large group of active-duty marines and relationship to posttraumatic stress

OBJECTIVE

Heart rate variability (HRV), thought to reflect autonomic nervous system function, is lowered under conditions such as posttraumatic stress disorder (PTSD). The potential confounding effects of traumatic brain injury (TBI) and depression in the relationship between HRV and PTSD have not been elucidated in a large cohort of military service members. Here we describe HRV associations with stress disorder symptoms in a large study of Marines while accounting for well-known covariates of HRV and PTSD including TBI and depression.

METHODS

Four battalions of male active-duty Marines (n = 2430) were assessed 1 to 2 months before a combat deployment. HRV was measured during a 5-minute rest. Depression and PTSD were assessed using the Beck Depression Inventory and Clinician-Administered PTSD Scale, respectively.

RESULTS

When adjusting for covariates, including TBI, regression analyses showed that lower levels of high-frequency HRV were associated with a diagnosis of PTSD (β = -0.20, p = .035). Depression and PTSD severity were correlated (r = 0.49, p < .001); however, participants with PTSD but relatively low depression scores exhibited reduced high frequency compared with controls (p = .012). Marines with deployment experience (n = 1254) had lower HRV than did those with no experience (p = .033).

CONCLUSIONS

This cross-sectional analysis of a large cohort supports associations between PTSD and reduced HRV when accounting for TBI and depression symptoms. Future postdeployment assessments will be used to determine whether predeployment HRV can predict vulnerability and resilience to the serious psychological and physiological consequences of combat exposure.

Bupropion response on sleep quality in patients with depression: implications for increased cardiovascular disease risk

Depression could be an independent risk factor for cardiovascular disease. We assessed bupropion response in depressed patients by polysomnography (PSG) and cardiopulmonary coupling (CPC) variables. Nineteen subjects participated in a two-session, two consecutive night PSG protocol. Participants received either placebo or bupropion-SR 150 mg, orally, in a randomized, double-blind cross-over fashion on night two. Outcome variables were: sleep stages, REM latency, stable, unstable sleep and very low frequency coupling (VLFC). CPC analysis uses heart rate variability and the electrocardiogram's R-wave amplitude fluctuations associated with respiration to generate frequency maps. Bupropion increased REM latency (p=0.043) but did not impact PSG sleep continuity, architecture and CPC variables. A trend (p=0.092) was observed towards increasing VLFC duration. Bupropion increased the number of stable-unstable sleep transitions (p=0.036). Moderate to strong correlations between PSG and CPC variables were found on placebo and bupropion nights. Limitations include a small sample size, limited power to detect CPC changes and lack of normal controls for comparison. Increased stable-unstable sleep transitions and VLFC duration may indicate vulnerability to cardiovascular disease due to their association with low heart rate variability that has been associated with increased mortality raising the question whether the beneficial effects of the antidepressant medication outweighs the impact on cardiopulmonary dynamics.

Respiratory sinus arrhythmia as an index of vagal activity during stress in infants: respiratory influences and their control

Respiratory sinus arrhythmia (RSA) is related to cardiac vagal outflow and the respiratory pattern. Prior infant studies have not systematically examined respiration rate and tidal volume influences on infant RSA or the extent to which infants' breathing is too fast to extract a valid RSA. We therefore monitored cardiac activity, respiration, and physical activity in 23 six-month old infants during a standardized laboratory stressor protocol. On average, 12.6% (range 0–58.2%) of analyzed breaths were too short for RSA extraction. Higher respiration rate was associated with lower RSA amplitude in most infants, and lower tidal volume was associated with lower RSA amplitude in some infants. RSA amplitude corrected for respiration rate and tidal volume influences showed theoretically expected strong reductions during stress, whereas performance of uncorrected RSA was less consistent. We conclude that stress-induced changes of peak-valley RSA and effects of variations in breathing patterns on RSA can be determined for a representative percentage of infant breaths. As expected, breathing substantially affects infant RSA and needs to be considered in studies of infant psychophysiology.

The role of pulse oximetry in chiropractic practice: a rationale for its use

OBJECTIVE

Pulse oximetry is used regularly to assess oxygen saturation levels. The objective of this commentary is to discuss a rationale for using pulse oximetry in chiropractic practice.

DISCUSSION

Pulse oximetry may offer doctors of chiropractic a way to monitor patients' oxygen saturation levels. Quantification of saturation values with heart rate may give clinical aid to the management of chiropractic patients. Markedly reduced saturation levels may necessitate medical referral, whereas mildly reduced levels could lead to changes in chiropractic management.

CONCLUSIONS

Pulse oximetry has the potential to be an integral part of chiropractic practice.

Psychosocial features associated with lifetime comorbidity of major depression and anxiety disorders among a community sample of mid-life women: the SWAN mental health study

BACKGROUND

In clinical samples, comorbidity between depressive and anxiety disorders is associated with greater symptom severity and elevated suicide risk. Less is known, however, regarding the long-term psychosocial impact that a lifetime history of both major depressive disorder (MDD) and one or more anxiety disorders has in community samples. This report evaluates clinical, psychological, social, and stress-related characteristics associated with a lifetime history of MDD and anxiety.

METHODS

Data from 915 women aged 42-52 who were recruited as part of the the Study of Women's Health across the Nation (SWAN) Mental Health Study were used to examine clinical and psychosocial features across groups of women with a lifetime history of MDD alone, anxiety alone, both MDD and anxiety, or neither MDD nor anxiety.

RESULTS

As compared with women with a history of either MDD or anxiety alone, women with a comorbid history were more likely to report recurrent MDD, multiple and more severe lifetime anxiety disorders, greater depressive and anxiety symptoms, diminished social support, and more past-year distressing life events. Exploratory analyses indicated that women with a comorbid history also report more childhood abuse/neglect and diminished self-esteem, as compared with women with a history of either disorder alone.

CONCLUSIONS

Midlife women with a comorbid history that includes both MDD and anxiety disorders report diminished social support, more symptomatic distress, and a more severe and recurrent psychiatric history. Future research is needed to clarify the biological and psychosocial risk factors associated with this comorobid profile, and to develop targeted interventions for this at-risk group. Depression and Anxiety 00:1-8, 2012. © 2012 Wiley Periodicals, Inc.

Patterns of cardiorespiratory coordination in young women with recurrent major depressive disorder treated with escitalopram or venlafaxine

Evidence from previous studies suggests autonomic dysregulation in patients with major depressive disorder (MDD). Antidepressant treatment may also affect central autonomic function. We investigated whether the type of antidepressant might be associated with the pattern of cardiorespiratory coordination in non-depressed women with recurrent MDD. Resting electrocardiograms and respiratory signals were simultaneously recorded from 38 euthymic women with recurrent MDD who were treated with either escitalopram (n=19) or venlafaxine (n=19) monotherapy and from 38 healthy women. Linear measures of heart rate variability were extracted to assess cardiac autonomic control. Sample entropy (SampEn) was computed to assess the complexity of heart rate and respiratory signals, and cross-SampEn was calculated to measure the nonlinear interaction of both signals. Significant decreases in the cardiovagal tone and cardiorespiratory coupling of women with recurrent MDD receiving venlafaxine, and tendencies toward lower cardiovagal tone and cardiorespiratory coupling in women with recurrent MDD receiving escitalopram were observed when compared with healthy controls. Effect sizes for these differences were large between women receiving venlafaxine and healthy controls. We found a positive association between cardiorespiratory decoupling and venlafaxine dose. Norepinephrine-enhancement, within a therapeutic dose range, seems to be closely associated with decreased vagal tone and reduced nonlinear coupling between heart rate and respiration in euthymic women with recurrent MDD. However, the effects of serotonin enhancement on cardiovagal tone should be considered. Our results suggest that the pharmacodynamic properties of antidepressants may affect autonomic regulation of women with recurrent MDD even in euthymic state.

The integration of depressive behaviors and cardiac dysfunction during an operational measure of depression: investigating the role of negative social experiences in an animal model

OBJECTIVE

There is a bidirectional association between depression and cardiovascular disease. The neurobiological mechanisms underlying this association may involve an inability to cope with disrupted social bonds. This study investigated in an animal model the integration of depressive behaviors and cardiac dysfunction after a disrupted social bond and during an operational measure of depression, relative to the protective effects of intact social bonds.

METHODS

Depressive behaviors in the forced swim test and continuous electrocardiographic parameters were measured in 14 adult, female socially monogamous prairie voles (rodents), after 4 weeks of social pairing or isolation.

RESULTS

After social isolation, animals exhibited (all values are mean ± standard error of the mean; isolated versus paired, respectively) increased heart rate (416 ± 14 versus 370 ± 14 bpm, p < .05) and reduced heart rate variability (3.3 ± 0.2 versus 3.9 ± 0.2 ln(ms(2))). During the forced swim test, isolated animals exhibited greater helpless behavior (immobility = 106 ± 11 versus 63 ± 11 seconds, p < .05), increased heart rate (530 ± 22 versus 447 ± 15 bpm, p < .05), reduced heart rate variability (1.8 ± 0.4 versus 2.7 ± 0.2 ln(ms(2)), p < .05), and increased arrhythmias (arrhythmic burden score = 181 ± 46 versus 28 ± 12, p < .05).

CONCLUSIONS

The display of depressive behaviors during an operational measure of depression is coupled with increased heart rate, reduced heart rate variability, and increased arrhythmias, indicative of dysfunctional behavioral and physiological stress coping abilities as a function of social isolation. In contrast, social pairing with a sibling is behaviorally protective and cardioprotective. The present results can provide insight into a possible social mechanism underlying the association between depression and cardiovascular disease in humans.

The interactive effect of change in perceived stress and trait anxiety on vagal recovery from cognitive challenge

The present study tested the hypothesis that the change in state negative affect (measured as perceived stress) after cognitive challenge moderates the relationship of trait anxiety and anger to vagal recovery from that challenge. Cardiac vagal control (assessed using heart rate variability) and respiratory rate were measured in a sample of 905 participants from the Midlife in the United States Study. Cognitive challenges consisted of computerized mental arithmetic and Stroop color-word matching tasks. Multiple regression analyses controlling for the effects of the demographic, lifestyle, and medical factors influencing cardiac vagal control showed a significant moderating effect of change in perceived stress on the relationship of trait anxiety to vagal recovery from cognitive challenges (Beta=.253, p=.013). After adjustment for respiratory rate, this effect became marginally significant (Beta=.177, p=.037). In contrast, for the relationship of trait anger to vagal recovery, this effect was not significant either before (Beta=.141, p=.257) or after (Beta=.186, p=.072) adjusting for respiratory rate. Secondary analyses revealed that among the individuals with higher levels of trait anxiety, greater reductions in perceived stress were associated with greater increases in cardiac vagal control after the challenge. In contrast, among the individuals with lower levels of trait anxiety, changes in perceived stress had no impact on vagal recovery. Therefore, change in perceived stress moderates the relationship of trait anxiety, but not trait anger, to vagal recovery from cognitive challenge.