Depressive symptoms, trait aggression, and cardiovascular reactivity to a laboratory stressor

Physiological reactions to and recovery from acute stressors: the roles of chronic anxiety and stable resources

Background

Research has shown that employees subjected to acute stressors at work can suffer devastating repercussions. However, little is known about how employees who are experiencing ongoing chronic anxiety or have stable resources respond to acute stressors, particularly regarding their physiological responses to these situations. This study examines the physiological effects of an acute stressor when workers are already under chronic anxiety (i.e., cognitive anxiety and somatic anxiety) or when they have a stable resource (i.e., job control).

Participants and procedure

Data were collected from 230 full-time employees working at three major oil companies in Brazil. First, demographic, anxie-ty, and job control measures were collected via questionnaire. Later, muscle tension, skin temperature, and heart rate were collected during a simulated task to assess the physiological response to stress. Hypotheses were tested by repeated measures general linear modeling.

Results

The findings indicated that when employees were exposed to an acute stressor, those with chronic cognitive and somatic anxiety exhibited more heightened physiological responses than those lower on chronic anxiety. Further, compared to those with low control, employees with stable, high control over their work experienced a lower physiological reaction to the acute stressor.

Conclusions

Chronic anxiety generates high levels of physiological arousal and hyper-responsiveness to acute environmental stressors. Also, employees possessing stable resources, such as job control, experience reduced physiological responsivity to an acute stressor.

Emotional processing prospectively modulates the impact of anxiety on COVID-19 pandemic-related post-traumatic stress symptoms: an ERP study

BACKGROUND

Considering that the elevated distress caused by the COVID-19 pandemic, in some cases, led to post-traumatic stress symptoms (PTSS), it has been proposed as a specific traumatic event. The present longitudinal study investigated pre-pandemic motivated attention to emotional stimuli, as indexed by Late Positive Potential (LPP) amplitude, in relation with the potential differential role of anxiety and depressive symptoms in predicting PTSS severity related to the COVID-19 pandemic.

METHODS

A total of 79 university students initially completed self-report measures of depression and anxiety along with a passive viewing task of emotional (pleasant, unpleasant) and neutral pictures while electroencephaloghic activity was recorded. In December 2020, 57 participants completed a questionnaire assessing PTSS.

RESULTS

Significant interactions between anxiety and LPP emerged in predicting pandemic-related PTSS, where greater anxiety symptoms predicted PTSS only in individuals with greater LPP to unpleasant or with reduced LPP to pleasant stimuli.

LIMITATIONS

The prevalence of the female sex, the relatively young age of the participants, as well as the fact that they were all enrolled in a University course might not allow the generalization of the findings.

CONCLUSIONS

Taken together, the present longitudinal study provided novel evidence on EEG predictors of pandemic-related PTSS that might be useful for the prevention and treatment of PTSS. Indeed, assessing anxiety symptoms and pre-trauma LPP to emotional stimuli might be a useful target for identifying individuals that are more vulnerable to the development of PTSS during times of crisis.

Heart Rate and Skin Conductance Associations with Physical Aggression, Psychopathy, Antisocial Personality Disorder and Conduct Disorder: An Updated Meta-Analysis

The associations between physiological measures (i.e., heart rate and skin conductance) of autonomic nervous system (ANS) activity and severe antisocial spectrum behavior (AB) were meta-analyzed. We used an exhaustive partitioning of variables relevant to the ANS-AB association and investigated four highly relevant questions (on declining effect sizes, psychopathy subscales, moderators, and ANS measures) that are thought to be transformative for future research on AB. We investigated a broad spectrum of physiological measures (e.g., heart rate (variability), pre-ejection period) in relation to AB. The search date for the current meta-analysis was on January 1^st, 2020, includes 101 studies and 769 effect sizes. Results indicate that effect sizes are heterogeneous and bidirectional. The careful partitioning of variables sheds light on the complex associations that were obscured in previous meta-analyses. Effects are largest for the most violent offenders and for psychopathy and are dependent on the experimental tasks used, parameters calculated, and analyses run. Understanding the specificity of physiological reactions may be expedient for differentiating between (and within) types of AB.

Social affiliation moderates the link between depressive symptoms and heart rate variability in healthy middle-aged and older individuals: An intensive ecologic momentary assessment study

Depressive symptoms have been associated with lower cardiac autonomic control, thus contributing to cardiovascular diseases, especially among older adults. Interpersonal factors have been found to attenuate physiologic stress responses, but little is known about whether these factors (e.g., perceived affiliation) would moderate the relation of depressive symptoms and cardiovascular activation. The present research aimed to investigate the interplay of depressive symptoms and momentary-assessed interpersonal perceptions on cardiac vagal tone as indexed by heart rate variability (HRV). The sample consisted of 78 late middle-aged and older community-dwelling participants (48.7% male, mean age = 59.15 years). Participants reported on depressive symptoms and other personal characteristics by questionnaire. Perceptions of interpersonal affiliation, ambulatory HRV, and contextual variables were recorded using ecologic momentary assessment and portable electrocardiogram (ECG) monitoring device throughout 1 week (with a maximum of seven times daily). Multilevel analyses found that depressive symptoms were correlated with lower HRV, whereas momentary interpersonal perceptions of higher affiliation were associated with elevated HRV. A significant association was revealed between depressive symptoms and momentary affiliation perceptions on HRV. When individuals were involved in social interactions with higher affiliation, the effect of depressive symptoms on reducing HRV was attenuated. These findings suggested that the effects of subthreshold depressive symptoms on vagal control of the heart could be altered by the quality of interpersonal experiences.

Febrile and sleep responses to an immune challenge are affected by trait aggressiveness in rats

Sleep is altered in response to an immune challenge: non-rapid eye movement (NREM) sleep is increased and fragmented, REM sleep is inhibited. Sleep and immune response are affected by stress: several stressors inhibit sleep and increase waking time; stress-induced cortisol secretion affects the immune response, with immunosuppressive effects. Different levels of trait aggressiveness are associated with specific patterns of neuroendocrine and autonomic stress responsiveness. Aim of this study was to test the hypothesis that trait aggressiveness, by affecting response to stressors, modifies sleep alterations induced by the activation of the immune response. To this aim, rats were selected on the basis of their latency time to attack a male intruder in the resident-intruder test. Animals were instrumented for chronic recordings of sleep-wake activity and injected, intraperitoneally, with an immune challenge (250 μg/kg lipopolysaccharide - LPS, a component of gram-negative bacterial cell wall). Here we report that high aggressive (HA) rats responded to an immune challenge with a 24-h long increase in cortical brain temperature. During the first 12 post-injection hours, HA rats also responded with a prolonged increase in NREM sleep amount, and a 5-h long and continuous inhibition of REM sleep. In HA rats, the LPS-induced increase in the amount of time spent in NREM sleep was due to an increase in the number of episodes of this sleep phase, without any change in the bout duration. The LPS-induced REM sleep inhibition observed in HA rats was due to a decrease in both the number and duration of REM sleep bouts. In HA rats, during REM sleep, LPS administration significantly reduced the power of the EEG theta band. In non-aggressive (NA) rats, in response to LPS administration, cortical brain temperature was increased only for two hours, NREM sleep was unaffected, and REM sleep inhibition was scattered along the first 8 post-injection hours. The LPS-induced changes in the number of NREM sleep bouts of NA rats were limited to few and scattered hours, with a change in bout duration only in a single hour. A combination of decreases, in few hours, in both REM sleep bouts and their duration contributed to the REM sleep inhibition observed in NA rats. In NA rats, the power of EEG theta band was not modified, during REM sleep, by LPS administration. Gross motor activity was inhibited in both HA and NA rats. Results of this study show that trait aggressiveness affects febrile and sleep responses to an immune challenge.

Aggression, Social Stress, and the Immune System in Humans and Animal Models

Social stress can lead to the development of psychological problems ranging from exaggerated anxiety and depression to antisocial and violence-related behaviors. Increasing evidence suggests that the immune system is involved in responses to social stress in adulthood. For example, human studies show that individuals with high aggression traits display heightened inflammatory cytokine levels and dysregulated immune responses such as slower wound healing. Similar findings have been observed in patients with depression, and comorbidity of depression and aggression was correlated with stronger immune dysregulation. Therefore, dysregulation of the immune system may be one of the mediators of social stress that produces aggression and/or depression. Similar to humans, aggressive animals also show increased levels of several proinflammatory cytokines, however, unlike humans these animals are more protected from infectious organisms and have faster wound healing than animals with low aggression. On the other hand, subordinate animals that receive repeated social defeat stress have been shown to develop escalated and dysregulated immune responses such as glucocorticoid insensitivity in monocytes. In this review we synthesize the current evidence in humans, non-human primates, and rodents to show a role for the immune system in responses to social stress leading to psychiatric problems such as aggression or depression. We argue that while depression and aggression represent two fundamentally different behavioral and physiological responses to social stress, it is possible that some overlapped, as well as distinct, pattern of immune signaling may underlie both of them. We also argue the necessity of studying animal models of maladaptive aggression induced by social stress (i.e., social isolation) for understanding neuro-immune mechanism of aggression, which may be relevant to human aggression.

Sympathetic vasomotor tone is associated with depressive symptoms in young females: a potential link between depression and cardiovascular disease

BACKGROUND

Although increased sympathetic nervous system (SNS) activity is commonly associated with major depressive disorder (MDD) and cardiovascular disease (CVD), a biomarker linking these two entities remains elusive. We therefore evaluated the relationship between depressive symptoms and cardiovascular modulation by heart rate variability (HRV), brachial blood pressure (BP), ambulatory BP (ABP), and low frequency component of systolic BP variability (LFSBP), a surrogate of sympathetic vasomotor tone. We hypothesized that LFSBP would be the strongest predictor of depressive symptoms compared with HRV and BP measurements.

METHODS

Eighty young healthy female subjects (20.51 ± 2.82 years) were evaluated for depressive symptoms using the Center for Epidemiologic Studies Depression Scale (CES-D). Data collection was conducted after a 10-minute resting period. Beat-to-beat BPs were recorded for 5-minute at baseline (BASE) followed by a 3-minute cold pressor test (CPT). ABP was obtained for 24 hours.

RESULTS

Hierarchical multiple regression analyses indicated that LFSBP at BASE was a stronger predictor of CES-D variance than BP and HRV indices, with LFSBP uniquely accounting for 8.1% of variance in CES-D scores during laboratory beat-by-beat BP assessments and 44.7% in ABP assessments. Individuals with acute depression scores (n = 12; CES-D ≥ 16) had significantly higher (P < 0.001) mean LFSBP values (6.66 ± 2.54 mm Hg(2)) than the remaining sample (3.32 ± 2.2 mm Hg(2)), whereas no other significant differences were detected in any of the other cardiovascular variables. Cardiovascular responses to CPT did not predict CES-D scores.

CONCLUSIONS

These findings suggest that LFSBP could be a biomarker of neurovascular functioning with potential clinical implications for understanding the interaction between MDD and CVD.

Vagal withdrawal and susceptibility to cardiac arrhythmias in rats with high trait aggressiveness

Personality characteristics, e.g. aggressiveness, have long been associated with an increased risk of cardiac disease. However, the underlying mechanisms remain unclear. In this study we used a rodent model for characterizing cardiac autonomic modulation in rats that differ widely in their level of aggressive behavior. To reach this goal, high-aggressive (HA, n = 10) and non-aggressive (NA, n = 10) rats were selected from a population (n = 121) of adult male Wild-type Groningen rats on the basis of their latency time to attack (ALT, s) a male intruder in a resident-intruder test lasting 600 s. In order to obtain information on their cardiac autonomic modulation, ECG recordings were subsequently obtained via radiotelemetry at rest, during stressful stimuli and under autonomic pharmacological manipulations, and analyzed by means of time- and frequency-domain indexes of heart rate variability. During resting conditions, HA rats (ALT<90 s) displayed reduced heart rate variability, mostly in terms of lower vagal modulation compared to NA rats (ALT>600 s). Exposure to stressful stimuli (i.e. restraint and psychosocial stress) provoked similar tachycardic responses between the two groups. However, under stress conditions HA rats displayed a reduced vagal antagonism and an increased incidence of tachyarrhythmias compared to NA rats. In addition, beta-adrenergic pharmacological stimulation induced a much larger incidence of ventricular tachyarrhythmias in HA rats compared to NA counterparts. These findings are consistent with the view that high levels of aggressive behavior in rats are associated to signs of cardiac autonomic impairment and increased arrhythmogenic susceptibility that may predict vulnerability to cardiac morbidity and mortality.

Depressive symptoms contribute to increased wave reflection during cold pressor test in young adult men

BACKGROUND

Major depressive disorder (MDD) is associated with increased cardiovascular risk. Although cardiovascular hyperactivity to stressors (e.g., cold pressor test (CPT)) is common in those with MDD, the aortic hemodynamic (AH) responses to sympatho-stimulation in healthy individuals with higher depressive scores (HDS) are not well understood. We hypothesized that individuals with HDS, compared with those with low depressive scores (LDS), would have greater changes in AH during the CPT.

METHODS

Thirty-five male participants (mean age, 22.3±0.7 years) completed a self-report measure of depressive symptoms and were classified as having an HDS or LDS. Radial waveforms were then obtained by means of applanation tonometry. The testing protocol consisted of a 10-minute seated rest, 5 minutes of baseline measurements, a 3-minute CPT, and a 3-minute recovery period.

RESULTS

At baseline, no differences were found between the LDS (n=16) and HDS (n=19) groups on any variables studied. During CPT, there was a significant group-by-time interaction for aortic mean blood pressure (HDS vs. LDS = 107±3mm Hg vs. 96±3mm Hg; P = 0.008); augmentation index (HDS vs. LDS =19% ± 3% vs. 11% ± 2%; P = 0.02), a surrogate of wave reflection; and systolic time interval (HDS vs. LDS = 2295±78mm Hg/s.min(-1) vs. 1919±74mm Hg/s.min(-1); P = 0.001), a marker of myocardial work, such that the HDS group had significantly higher responses than the LDS group.

CONCLUSIONS

HDS may be associated with cardiac hyperactivity during sympatho-stimulation, contributing to increased central blood pressure, wave reflection, and myocardial work. Prospective studies to unveil mechanisms explaining increased AH in healthy individuals with high depressive symptomatology are warranted.

Depressive symptoms and attenuated physiological reactivity to laboratory stressors

There is evidence that depressive symptoms are associated with attenuated physiological reactivity to active stressors. However, it is not known whether blunted reactivity in depressed individuals is stressor-specific. We examined cardiovascular and electrodermal reactivity in non-clinical participants with varying levels of depressive symptoms to different active and passive stressors. Depressive symptoms were inversely related to both blood pressure and skin conductance reactivity during a public speaking task and the viewing of the speech video. However, no effects were found during a cold pressor task. Together these findings suggest that depressive symptoms are related to attenuated sympathetic nervous system reactivity in response to self-relevant stressors.