Blunted responses to stress and reward: Reflections on biological disengagement?

Social network size moderates the association between loneliness and cardiovascular reactivity to acute stress

Loneliness and objective measures of social isolation (e.g., social network size) have been associated with increased risk of cardiovascular disease (CVD). However, the evidence is mixed and the precise causal mechanisms remain unclear. Cardiovascular reactivity (CVR) to acute stress has been posited as a proposed mechanism. This study aimed to investigate: (i) effects of loneliness and social isolation on CVR to stress and, (ii) whether the loneliness - CVR relationship was moderated by social network size. Two hundred and six participants from the Pittsburgh Cold Study underwent a modified version of the Trier Social Stress Task. Cardiovascular measures of systolic (SBP) and diastolic blood pressure (DBP) and heart rate (HR) were taken throughout the laboratory stress trial. Hierarchical regression analyses found that social network size was positively associated with DBP reactivity (β = 0.19 95 % CI [0.05, 0.29] p = 0.005), while loneliness was not. In addition, social network size moderated the loneliness - DBP reactivity relationship such that a higher number of outer social network ties were beneficial at lower levels of loneliness but not higher. The current study contributes new evidence linking loneliness and social network size to cardiovascular psychophysiology but raises questions about the loneliness - CVD relationship. The findings confirm the importance of social network size and highlight that the characteristics of the networks may be more important than the number of networks.

"I was very sad, but not depressed": phenomenological differences between adjustment disorder and a major depressive episode

Introduction

Adjustment disorder (AD) is a diagnosis that must be differentiated from major depressive episode (MDE) because of the therapeutic implications. The aim of this study is to understand the experience of patients who in their lifetime have been diagnosed with AD as well as MDE to establish the characteristics of each disorder.

Methods

A descriptive phenomenological approach was used with in-depth interviews to four patients and the method proposed by Colaizzi to understand the experiences and reach the description of both disorders.

Results

Three women and one man, with advanced schooling were interviewed. The participants emphasized the existence of differences that were grouped in: the attribution made by the individual, the theme of cognitions, the variability in the course, the possibility of mood modulation, the syndrome severity, the presence of hopelessness and the perceived course.

Conclusion

Phenomenological differences were found in the subjective experience of MDE and AD. The MDE would be described as an intense state of generalized shutdown of the subject's own life, with little response to events, and the AD, as a dynamic reaction attributed to a stressful event, with high variability in the course of symptoms due to the dependence on such event, with the preserved hope that it will end.

Comparison between the Effects of Acute Physical and Psychosocial Stress on Feedback-Based Learning

Stress modulates feedback-based learning, a process that has been implicated in declining mental function in aging and mental disorders. While acute physical and psychosocial stressors have been used interchangeably in studies on feedback-based learning, the two types of stressors involve distinct physiological and psychological processes. Whether the two types of stressors differentially influence feedback processing remains unclear. The present study compared the effects of physical and psychosocial stressors on feedback-based learning. Ninety-six subjects (Mage = 19.11 years; 50 female) completed either a cold pressor task (CPT) or mental arithmetic task (MAT), as the physical or psychosocial stressor, while electrocardiography and blood pressure were measured to assess cardiovascular stress reactivity (CVR). Self-ratings on the emotional valence of the stressors were also obtained. A probabilistic learning task was given prior to and after the stressors. Accuracy in selecting positive (Go accuracy) and avoiding negative stimuli (No-go accuracy) were recorded as learning outcomes. Repeated measures ANOVA and multiple regressions were used to compare the effects of two stressors and examine the effects of CVR and valence on the learning outcomes. The results showed that although the effects of CPT and MAT on feedback processing were not different, CVR and valence influenced Go and No-go accuracy, respectively. The results suggest that stress-modulated feedback-based learning involves multiple pathways and underscore the link between CVR and reward sensitivity. The findings have clinical implications and may contribute to a better understanding of human behavioral systems.

Cardiovascular reactions to acute psychological stress and academic achievement

Cardiovascular reactions to acute psychological stress have been associated with cognitive function. However, previous work has assessed cardiovascular reactions and cognitive function in the laboratory at the same time. The present study examined the association between cardiovascular reactions to acute psychological stress in the laboratory and academic performance in final year high school students. Heart rate, blood pressure, stroke volume, and cardiac output reactions to an acute psychological stress task were measured in 131 participants during their final year of high school. Performance on high school A‐levels were obtained the following year. Higher heart rate and cardiac output reactivity were associated with better A‐level performance. These associations were still statistically significant after adjusting for a wide range of potentially confounding variables. The present results are consistent with a body of literature suggesting that higher heart rate reactions to acute psychological stress are associated with better cognitive performance across a variety of domains.

The present study is the first to examine the associations between cardiovascular reactions to stress in the laboratory and academic achievement. Additionally, it is the first to examine a more comprehensive hemodynamic profile of cardiovascular reactivity (e.g., cardiac output) with cognitive function. The present results are consistent with a body of literature suggesting that higher heart rate reactions to acute psychological stress are associated with better cognitive performance across a variety of domains.

Cortisol in early childhood moderates the association between family routines and observed affective balance in children from low-income backgrounds

The study of emotion regulation often addresses control of negative emotion. Researchers have proposed that affective balance is an indicator of emotion regulation that incorporates the role of positive emotion in the context of negative emotional experiences. Environmental and individual factors, such as family processes and biological stress regulation, are known to shape emotion regulation. The present study investigated whether child diurnal cortisol, an indicator of biological stress regulation, moderated the association between family routines and observed affective balance. Children (N = 222; M age = 4.70 years, SD = 0.60) from low-income households provided saliva samples to measure diurnal cortisol and completed a behavioral task designed to elicit negative emotions. Affective balance was defined as the difference score between the proportion of positive and negative emotional expressions displayed during the task. A higher affective balance score indicated greater positive compared with negative emotional displays. Simple slope analyses indicated that for children with a low morning cortisol intercept, more frequent family routines were associated with more affective balance. This pattern was not observed in children with average or high morning cortisol. Positive family routines may play an important role in shaping affective balance among children with disrupted cortisol levels from low-income backgrounds.

Affective and Autonomic Reactivity During Parent-Child Interactions in Depressed and Non-Depressed Mothers and Their Adolescent Offspring

Depression presents risks that are profound and intergenerational, yet research on the association of depression with the physiological processes that might be associated with impaired mental and physical health has only recently been contextualized within the family environment. Participants in this multi-method case-control study were 180 mother-adolescent dyads (50% mothers with a history of depression treatment and current depressive symptoms). In order to examine the association between maternal depression and affective and autonomic reactivity amongst these mothers and their adolescent offspring we collected self-reported measures of positive and negative affect, as well as measures of cardiovascular and electrodermal autonomic activity, during mother-adolescent interaction tasks. Findings indicated that depressed mothers and their adolescent offspring exhibited greater self-reported negative affect reactivity during a problem-solving interaction and blunted (i.e., low) sympathetic activity as measured via skin conductance level across both interaction tasks. These effects remained significant after controlling for a range of potential covariates, including medication use, sex, age, adolescents own mental health symptoms, and behavior of the other interactant, along with correcting for multiple comparisons. Findings indicate that depressed mothers and their adolescent offspring both exhibit patterns of affect and physiology during interactions that are different from those of non-depressed mothers and their offspring, including increased negative affect reactivity during negative interactions and blunted sympathetic activity across both positive and negative interactions. These findings have potential implications for understanding the role of family processes in the intergenerational transmission of risk for depressive disorders.

Race-Based Stress Reactions and Recovery: Pilot Testing a Racial Trauma Meditation

Twenty-six Black collegians were exposed to a vicarious racial harassment stimulus (VRHS) then randomized into a Black Lives Matter Meditation for Healing Racial Trauma condition or a silence control condition. Heart rate (HR) was recorded throughout the experiment. Semi-structured interviews were then conducted to elicit participants’ appraisal of the VRHS and meditation. Using a Qual:Quan mixed methods experimental design, this pilot study qualitatively categorized how participants (1) described their reactions to the VRHS and (2) appraised the meditation. Participants described three types of race-based stress reactions and reported mostly positive appraisal of the meditation, although some indicated that it would not be a preferred coping strategy. To triangulate the quantitative findings, we found a significant increase in HR during VRHS. The meditation group displayed statistically significant reductions in HR from stimulus to the end of meditation; however, there were no statistically significant differences between the control and meditation groups. Results have implications for understanding and facilitating race-based stress recovery.

Integrated and diurnal indices of maternal pregnancy cortisol in relation to sex-specific parasympathetic responsivity to stress in infants

Maternal hypothalamic-pituitary-adrenal axis activity may prenatally program sex-specific stress-response pathways. We investigated associations between maternal cortisol during pregnancy and infant parasympathetic responsivity to stress among 204 mother-infant pairs. Cortisol indices included 3rd trimester hair cortisol, as well as diurnal slope and area under the curve, derived from saliva samples collected during pregnancy. Mother-infant dyads participated in the Repeated Still-Face Paradigm (SFP-R) at age 6 months. We calculated respiration-adjusted respiratory sinus arrhythmia (RSA_c ), an indicator of parasympathetic activation, from infant respiration and cardiac activity measured during the SFP-R. We used multivariable linear mixed models to examine each cortisol index in relation to infant RSA_c and investigated sex differences using cross-product terms. Diurnal cortisol indices were not associated with RSA_c . There was no association between hair cortisol and baseline RSA_c . However, hair cortisol was associated with sex-specific changes in RSA_c over the SFP-R such that, among girls, parasympathetic withdrawal was reduced with increasing prenatal exposure to cortisol. Consistently higher levels of prenatal cortisol exposure may lead to dampened parasympathetic responsivity to stress during infancy, particularly among girls. Maternal hair cortisol may be particularly valuable for studying the effects of prenatal cortisol exposure on infant autonomic reactivity.

The developmental precursors of blunted cardiovascular responses to stress

Blunted cardiovascular responses to stress have been associated with both mental and physical health concerns. This multi-method, longitudinal study examined the role of chronic social-developmental stress from adolescence onward as a precursor to these blunted stress responses. Using a diverse community sample of 184 adolescents followed from age 13 to 29 along with friends and romantic partners, this study found that high levels of parental psychological control at age 13 directly predicted a blunted heart rate response and indirectly predicted blunted respiratory sinus arrhythmia (RSA) reactivity under stress. Heart rate effects were mediated via indicators of a developing passive response style, including observational measures of withdrawal during conflict with friends and romantic partners, social disengagement, and coping with stressors by using denial. RSA effects were mediated via withdrawal during conflict with romantic partners and coping by using denial. The current findings are interpreted as suggesting a mechanism by which a key social/developmental stressor in adolescence may alter relational and ultimately physiological patterns of stress responding into adulthood.

Stress responding and stress-related changes in cue reactivity in heavy smokers, problem gamblers, and healthy controls

Addictions, both substance and behavioral, have been conceptualized as involving similar biopsychosocial processes with different opportunistic expressions. A maladaptive stress response in combination with craving or urges to engage in the addictive behavior may be among the underlying factors common to behavioral and substance addictions. The current study compared the neuroendocrine (cortisol) and subjective responses to stress of gamblers and smokers to healthy controls. We assessed if participants responded differently to smoking or gambling cues before and after a psychosocial stressor. To this end, the subjective urges/cravings of all participants were measured in response to smoking or gambling cues versus neutral cues, once under normal conditions and again after exposure to a stressor. Salivary cortisol was measured prior to, immediately following, and 10 minutes after conclusion of the stressor. Smokers and gamblers showed a similar blunted cortisol response to the acute stressor that differed from the control group's response. Following a stressor, subjective craving in smokers increased whereas gamblers' urges decreased. In smokers, a blunted cortisol and subjective stress response were related to increased urges. In contrast, for gamblers, changes in cortisol levels were unrelated to urges, and higher subjective stress was associated with decreased urges. In conclusion, individuals with a substance and a behavioral addiction share common patterns of reactivity to stress. However, while the stressor enhanced cue-related craving in smokers, it generally had the opposite effect on gamblers. Further research is necessary to elucidate the complicated patterns of similarities and differences that underlie substance and behavioral addictions.

Striatal responsiveness to reward under threat-of-shock and working memory load: A preliminary study

INTRODUCTION

Reward and stress are important determinants of motivated behaviors. Striatal regions play a crucial role in both motivation and hedonic processes. So far, little is known on how cognitive effort interacts with stress to modulate reward processes. This study examines how cognitive effort (load) interacts with an unpredictable acute stressor (threat-of-shock) to modulate motivational and hedonic processes in healthy adults.

MATERIALS AND METHODS

A reward task, involving stress with unpredictable mild electric shocks, was conducted in 23 healthy adults aged 20-37 (mean age: 24.7 ± 0.9; 14 females) during functional magnetic resonance imaging (fMRI). Manipulation included the use of (a) monetary reward for reinforcement, (b) threat-of-shock as the stressor, and (c) a spatial working memory task with two levels of difficulty (low and high load) for cognitive load. Reward-related activation was investigated in a priori three regions of interest, the nucleus accumbens (NAcc), caudate nucleus, and putamen.

RESULTS

During anticipation, threat-of-shock or cognitive load did not affect striatal responsiveness to reward. Anticipated reward increased activation in the ventral and dorsal striatum. During feedback delivery, both threat-of-shock and cognitive effort modulated striatal activation. Higher working memory load blunted NAcc responsiveness to reward delivery, while stress strengthened caudate nucleus reactivity regardless reinforcement or load.

CONCLUSIONS

These findings provide initial evidence that both stress and cognitive load modulate striatal responsiveness during feedback delivery but not during anticipation in healthy adults. Of clinical importance, sustained stress exposure might go along with dysregulated arousal, increasing therefore the risk for the development of maladaptive incentive-triggered motivation. This study brings new insight that might help to build a framework to understand common stress-related disorders, given that these psychiatric disorders involve disturbances of the reward system, cognitive deficits, and abnormal stress reactivity.

Repressors exhibit lower cortisol reactivity to group psychosocial stress

Repressors are well-known to monitor potential psychosocial threats to their self-esteem and self-concept. In research, repressors are traditionally categorised as those scoring low on trait anxiety and high on defensiveness (as measured by social desirability scales). Examining repressors' cortisol reactivity to a group socio-evaluative laboratory stressor could be an important way to extend work on the classic 'repressor dissociation', which proposes that this group experience higher levels of physiological stress, but lower levels of subjective affect, during stressful situations. Research however has focused mainly on repressors' higher, more risk-prone levels of autonomic, rather than hypothalamic-pituitary-adrenal (HPA), reactivity to stressful stimuli. We assessed cortisol reactivity using a group-based acute psychosocial stressor, the Trier Social Stress Test for groups (TSST-G), which required participants to individually perform public speaking and mental arithmetic tasks in front of up to six other group members, as well as an evaluative panel of judges. Seventy-seven healthy young females (mean age ± SD: 20.2 ± 3.2 years) took part, of which 64 met the conventional criterion for a response to the TSST-G (<15.5% increase from baseline sample). The Stress-Arousal Checklist was completed pre- and post-TSST-G. Participants also completed the Perceived Stress Scale, the Trait Anxiety Inventory and the Marlow-Crowne Social Desirability Scale. The latter two measures were used to provide a categorisation of repressive coping style. Participants identified as repressive copers exhibited significantly lower cortisol reactivity during the TSST-G. Repressors also self-reported less subjective stress. These findings provide some evidence against the notion of the repressor dissociation and are discussed in terms of how cortisol hyporeactivity may be a pathway through which repressive coping adversely affects health.

Diminished cardiovascular stress reactivity is associated with lower levels of social participation

Diminished cardiac reactions to acute psychological stress are associated with adverse behavioral and health-relevant outcomes. It has been proposed that diminished cardiac reactivity may be a marker for deficits in motivational functioning both at the biological and behavioral levels. Social participation reflects the frequency with which individuals participate in social events and has motivational components. As such, it is a distinct construct from other constructs such as social integration, which measures the number of social roles an individual has. Additionally, lower levels of social participation and diminished reactivity have been associated with similar adverse health outcomes. Therefore, it is possible that diminished cardiac reactivity is associated with lower levels of social participation. We aimed to examine whether diminished cardiovascular reactivity in response to an acute lab stressor was associated with reported social participation. The analyses were conducted using publicly available data from the Pittsburgh Cold Study 3 (PCS3). The PCS3 was a prospective viral-challenge study, which included participants completing an in-lab social evaluative stressor (N = 202, Age = M = 29.71, SD = 10.66) and measuring cardiovascular responses at baseline and in response to the stressor. Separate regression analyses for each cardiovascular variable (SBP, DBP, MAP, and HR) demonstrated that lower cardiovascular reactivity was associated with less social participation. These associations were still evident following adjustment for respective baseline cardiovascular levels, age, sex, race, depressive symptomology, body mass index, socioeconomic status, smoking status, and levels of social integration (R2 changes: ≥ 0.017; ps ≤ 0.02) The findings provide initial evidence that blunted cardiac reactivity may be a precursor to low levels of social participation.

Drug-induced stress responses and addiction risk and relapse

A number of studies have assessed the effects of psychoactive drugs on stress biology, the neuroadaptations resulting from chronic drug use on stress biology, and their effects on addiction risk and relapse. This review mainly covers human research on the acute effects of different drugs of abuse (i.e., nicotine, cannabis, psychostimulants, alcohol, and opioids) on the hypothalamic-pituitary-adrenal (HPA) axis and the autonomic nervous system (ANS) responses. We review the literature on acute peripheral stress responses in naïve or light recreational users and binge/heavy or chronic drug users. We also discuss evidence of alterations in tonic levels, or tolerance, in the latter relative to the former and associated changes in the phasic stress responses. We discuss the impact of the stress system tolerance in heavy users on their response to drug- and stress-related cue responses and craving as compared to control subjects. A summary is provided of the effects of glucocorticoid responses and their adaptations on brain striatal and prefrontal cortices involved in the regulation of drug seeking and relapse risk. Finally, we summarize important considerations, including individual difference factors such as gender, co-occurring drug use, early trauma and adversity and drug use history and variation in methodologies, that may further influence the effects of these drugs on stress biology.

The behavioural, cognitive, and neural corollaries of blunted cardiovascular and cortisol reactions to acute psychological stress

Recent research shows that blunted cardiovascular and cortisol reactions to acute psychological stress are associated with adverse behavioural and health outcomes: depression, obesity, bulimia, and addictions. These outcomes may reflect suboptimal functioning of the brain's fronto-limbic systems that are needed to regulate motivated behaviour in the face of challenge. In support of this, brain imaging data demonstrate fronto-limbic hypoactivation during acute stress exposure. Those demonstrating blunted reactions also show impairments of motivation, including lower cognitive ability, more rapid cognitive decline, and poorer performance on motivation-dependent tests of lung function. Persons exhibiting blunted stress reactivity display well established temperament characteristics, including neuroticism and impulsivity, characteristic of various behavioural disorders. Notably, the outcomes related to blunted stress reactivity are similar to those that define Reward Deficiency Syndrome. Accordingly, some individuals may be characterised by a broad failure in cardiovascular and cortisol responding to both stress and reward, reflecting fronto-limbic dysregulation. Finally, we proffer a model of blunted stress reactivity, its antecedents and sequelae, and identify future research priorities.

Pre-ejection period reactivity to reward is associated with anhedonic symptoms of depression among adolescents

Pre-ejection period (PEP) reactivity to reward has been posited as a specific index of behavioral approach and incentive motivation, suggesting it might be uniquely associated with the affective and motivational deficits of anhedonia. This study evaluated PEP reactivity to a reward task as a predictor of depressive symptoms among adolescents, examining global depressive symptoms as well as specific anhedonic and nonanhedonic symptoms clusters. Participants included 76 adolescents, ages 11-15 years (52% female). This study found marginal support for an association between PEP reactivity to reward and concurrent anhedonia symptoms, but no association with nonanhedonic or the global scale. Findings are discussed in terms of potential associations between peripheral psychophysiological measures and dopaminergic functioning and also the utility of this measure for future research on anhedonia.

Blunted cardiac stress reactors exhibit relatively high levels of behavioural impulsivity

Blunted physiological reactions to acute psychological stress are associated with a range of adverse health and behavioural outcomes. This study examined whether extreme stress reactors differ in their behavioural impulsivity. Individuals showing blunted (N=23) and exaggerated (N=23) cardiovascular reactions to stress were selected by screening a healthy student population (N=276). Behavioural impulsivity was measured via inhibitory control and motor impulsivity tasks. Blunted reactors exhibited greater impulsivity than exaggerated reactors on both stop-signal, F(1,41)=4.99, p=0.03, ηp(2)=0.108, and circle drawing, F(1,43)=4.00, p=0.05, η p(2)=0.085, tasks. Individuals showing blunted cardiovascular stress reactions are characterized by greater impulsivity which may contribute to their increased susceptibility to outcomes such as obesity and addiction.

Ginseng and Ginkgo Biloba Effects on Cognition as Modulated by Cardiovascular Reactivity: A Randomised Trial

Background

There is some evidence to suggest that ginseng and Ginkgo biloba can improve cognitive performance, however, very little is known about the mechanisms associated with such improvement. Here, we tested whether cardiovascular reactivity to a task is associated with cognitive improvement.

Methodology/Principal findings

Using a double-blind, placebo controlled, crossover design, participants (N = 24) received two doses of Panax Ginseng (500, 1000 mg) or Ginkgo Biloba (120, 240 mg) (N = 24), and underwent a series of cognitive tests while systolic, diastolic, and heart rate readings were taken. Ginkgo Biloba improved aspects of executive functioning (Stroop and Berg tasks) in females but not in males. Ginseng had no effect on cognition. Ginkgo biloba in females reversed the initial (i.e. placebo) increase in cardiovascular reactivity (systolic and diastolic readings increased compared to baseline) to cognitive tasks. This effect (reversal) was most notable after those tasks (Stroop and Iowa) that elicited the greatest cardiovascular reactivity during placebo. In males, although ginkgo also decreased cardiovascular readings, it did so from an initial (placebo) blunted response (i.e. decrease or no change from baseline) to cognitive tasks. Ginseng, on the contrary, increased cardiovascular readings compared to placebo.

Conclusions/Significance

These results suggest that cardiovascular reactivity may be a mechanism by which ginkgo but not ginseng, in females is associated with certain forms of cognitive improvement.

Trial Registration

ClinicalTrials.gov NCT02386852

Reactivity to Social Stress in Subclinical Social Anxiety: Emotional Experience, Cognitive Appraisals, Behavior, and Physiology

Recent research indicates that subclinical social anxiety is associated with dysfunctions at multiple psychological and biological levels, in a manner that seems reminiscent of social anxiety disorder (SAD). This study aimed to describe multidimensional responses to laboratory-induced social stress in an analog sample selected for social anxiety symptoms. State anxiety, cognitive biases related to negative social evaluation, speech anxiety behaviors, and cortisol reactivity were assessed in the Trier Social Stress Test (TSST). Results showed that social anxiety symptoms were associated with increased state anxiety, biased appraisals related to the probability and cost of negative social evaluations, behavioral changes in facial expression that were consistent with speech anxiety, and lower cortisol reactivity. In addition, multiple interrelations between responses in the TSST were found, with positive associations between subjective experience, cognitive appraisals, and observable behavior, as well as negative associations between each of the former two types of response and cortisol reactivity. These results show that in response to social stressors, subclinical social anxiety is associated with significant changes in emotional experience, cognitive appraisals, behaviors, and physiology that could parallel those previously found in SAD samples.

Emotional non-acceptance links early life stress and blunted cortisol reactivity to social threat

Early life stress (ELS) has been recently associated with blunted cortisol reactivity and emotion dysregulation, but no study until now examined whether these characteristics are related. The main goal of this study was to examine the potential mediator role of emotion dysregulation in the relation between ELS and cortisol reactivity to social threat. Only women who were free of psychiatric and endocrine disorders, had regular menstrual cycle and did not use oral contraceptives were selected for this study (N=62). After filling in ELS and multidimensional emotion dysregulation measures, participants underwent the Trier Social Stress Test during which cortisol and autonomic responses were assessed. Most participants (85.5%) reported one or more major stressful events (i.e., physical abuse, sexual abuse, major parental conflicts, death of a family or close friend, severe illness) experienced before age 17. ELS was negatively associated with cortisol reactivity and positively associated with skin conductance level (SCL) reactivity, but it did not influence heart rate and respiratory sinus arrhythmia. In addition, ELS was positively related to emotional non-acceptance (i.e., a tendency to develop secondary emotional responses to one's negative emotions), and the latter was negatively related to cortisol responses and positively related to SCL responses. Bootstrapping analyses indicated that emotional non-acceptance was a significant mediator in the relationships between ELS and both cortisol and SCL responses. Emotional non-acceptance is thus one of the psychological mechanisms underlying blunted cortisol and increased sympathetic reactivity in young healthy volunteers with a history of ELS.

Integrative commentary: implications of blunted reactivity

The previous issue of the International Journal of Psychophysiology was a special issue that collected some of the latest emerging evidence on blunted reactivity and its relationships with a variety of negative health outcomes. This commentary on the special issue briefly reviews each of the contributions and then provides some thoughts on the general themes that run through these papers. The findings from the special issue suggest that both lower and higher than expected cardiovascular and neuroendocrine responses to active psychological challenges may be maladaptive and differentially associated with adverse health sequelae.