Cortisol reactivity to experimentally manipulated psychosocial stress in young adults at varied risk for depression

Toward stressor-free stress estimation: The integrated information theory explains the information dynamics of stress

Recent neurological studies have revealed several detailed stress mechanisms. However, the latent variables behind stress study still interpret stress responses as difficult. Therefore, we propose a stressor-free method of stress evaluation using Integrated Information Theory (IIT) to address these issues. We conducted experiments inducing acute stress responses against tasks with three levels of difficulty, easy, moderate, and difficult, to verify the IIT in stress study. The moderate condition was related to active coping with stress. By contrast, the easy and difficult conditions are related to passive stress coping. Especially, the easy condition seemed to cause boredom. Our results revealed that the degree of entangled system fluctuation was associated with the subjective ratings for the tasks. Interestingly, our method could also evaluate stress as a state of boredom that had not received much research attention. Our method can be an alternative stress estimation method to overcome the latent variable problem.

Genetic and environmental influences on alpha amylase stress reactivity and shared genetic covariation with cortisol

Salivary alpha amylase (sAA) is a common measure of stress reactivity, primarily reflecting sympathetic nervous system activity. Salivary cortisol is also a reliable, frequently used biomarker of stress and reflects the hypothalamic-pituitary-adrenal (HPA) axis response. This study examined heritability across varying metrics of sAA in response to a social evaluative stressor, the Trier Social Stress Test (TSST). The goal of this study was to estimate genetic and environmental influences on measurements of sAA stress reactivity. Moreover, we evaluated the shared genetic covariation between sAA and cortisol. Participants included twins aged 15-20 years (54% female). We measured alpha amylase and cortisol reactivity to the TSST via serial salivary cortisol samples collected pre- and post-TSST. Modest to moderate heritability estimates (11-64%) were observed across measures purported to capture alpha amylase stress reactivity (peak, area under the curve, baseline-to-peak change). Findings also indicate that sAA baseline and peak are primarily influenced by a shared genetic factor. There was no evidence of shared genetic influences between sAA and cortisol. These findings suggest the genetic control of the HPA and Sympathetic Adreno-Medullar axis are genetically independent of one another despite both playing a role in response to stressors.

Investigating adverse daily life effects following a psychosocial laboratory stress task, and the moderating role of Psychopathology

Laboratory stress tasks are necessary to closely investigate the stress response in a controlled environment. However, to our knowledge, no study has tested whether participating in such tasks can pose any daily life adverse effect. Fifty-three healthy participants (46 women) took part in a laboratory session where stress was induced using a typical psychosocial stressor: the repeated Montreal Imaging Stress Task (rMIST). Average levels of negative affect (NA), heart rate (HR), root mean square of successive differences (RMSSD), and skin conductance level (SCL), as well as reactivity across all these parameters as measured with the experience sampling method (ESM) in the four days prior to the laboratory session were compared with the four days following the session. We also assessed whether vulnerability to psychopathology moderated these associations. Findings showed that the task did not pose any significant adverse effect on participants. However, there was an unexpected increase in average RMSSD and a decrease in average SCL pre- to post- task. In addition, more vulnerable individuals were more likely to experience an increase in average levels of NA in the days following the task compared to the days preceding it. Our findings suggest that laboratory stress tasks may pose a significant risk to more vulnerable individuals.

Sex differences in cortisol levels in depression: A systematic review and meta-analysis

Higher prevalence of depression in females might be associated with sex-specific cortisol levels. Evidence exists that cortisol levels differ between healthy females and males, however a sex-specific association in depression has not been systematically assessed. Thus, the current study quantifies the existing literature on different cortisol parameters, i.e., basal cortisol, hair cortisol, cortisol awakening response (CAR), and cortisol stress reactivity comparing depressed females and males as well as sex-specific comparisons with healthy controls. Following an extensive literature research, fifty original articles were included. Depressed females had significantly higher hair cortisol, higher CAR, and lower cortisol stress reactivity compared to depressed males. In comparison with sex-matched controls, female patients had significantly higher evening basal cortisol, higher CAR and lower cortisol stress reactivity, and male patients had significantly higher general, morning and evening basal cortisol. Overall, sex as a fundamental driver of cortisol levels in depression needs to be taken into account.

Acculturative Stress and Self-rated Health among Hispanic Emerging Adults: Examining the Moderating Effects of the Social Environment and Social Support

Little is known about the impact of sociocultural stressors such as acculturative stress on self-rated health among Hispanics. We aimed to examine (a) associations between acculturative stress and self-rated health, and (b) the moderating effects of the community of settlement (i.e., Maricopa County, AZ and Miami-Dade County, FL) and social support on the association between acculturative stress and self-rated health. A hierarchical multiple regression model and moderation analyses were conducted using a cross-sectional sample of 200 Hispanic emerging adults from Arizona and Florida. Findings indicate that higher levels of pressure to acculturate are associated with lower levels of self-rated health. Community of settlement functioned as a moderator whereby pressure to acculturate was only associated with lower levels of self-rated health in Maricopa County. Lastly, a three-way interaction indicated that emotional social support mitigated the association between pressure to acculturate and self-rated health in Maricopa County. This study highlights the importance of accounting for community of settlement when examining associations between acculturative stress and health-related outcomes. A finding that may have implications for interventions is that social support may help to counteract the effects of acculturative stress.

Rethinking the risk for depression using the RDoC: A psychophysiological perspective

Considering that the classical categorical approach to mental disorders does not allow a clear identification of at-risk conditions, the dimensional approach provided by the Research Domain Criteria (RDoC) is useful in the exploration of vulnerability to psychopathology. In the RDoC era, psychophysiological models have an important role in the reconceptualization of mental disorders. Indeed, progress in the study of depression vulnerability has increasingly been informed by psychophysiological models. By adopting an RDoC lens, this narrative review focuses on how psychophysiological models can be used to advance our knowledge of the pathophysiological mechanisms underlying depression vulnerability. Findings from psychophysiological research that explored multiple RDoC domains in populations at-risk for depression are reviewed and discussed. Future directions for the application of psychophysiological research in reaching a more complete understanding of depression vulnerability and, ultimately, improving clinical utility, are presented.

Cortisol Reactivity and Socially Anxious Behavior in Previously Institutionalized Youth

The current study investigated the association between cortisol stress reactivity to a social stressor and observed socially anxious behaviors both concurrently and over time among previously institutionalized (PI) (N = 132; ages 7-17) youth and a comparison non-adopted (NA) sample (N = 176). Cortisol reactivity was captured during the Trier Social Stress Test for Children (TSST-C; Yim et al., 2015) and youths' social anxiety behaviors were coded during the speech portion of the TSST-C. Autoregressive cross-lagged panel models with structured residuals showed that for PI youth, greater cortisol reactivity predicted increases in socially anxious behavior during the TSST-C across three sessions. However, greater cortisol reactivity was negatively associated with concurrent social anxiety behavior. Thus, increases in cortisol reactivity across adolescence may aid in behavioral control in social situations in the short-term but may exacerbate PI youths' socially anxious behavior over time. No significant associations emerged for NA youth.

Pubertal stress recalibration and later social and emotional adjustment among adolescents: The role of early life stress

The current study investigated whether recalibration of the hypothalamic-pituitary -adrenocortical (HPA) axis stress response in youth who had previously experienced early life stress (ELS) would predict socioemotional adjustment in a follow-up assessment approximately 2-4 years later when youth were 12- to 21-years old. The sample consisted of previously institutionalized (PI) (N = 96) youth and a comparison non-adopted (NA) group (N = 117). Youth were 16 years old on average at the time of the follow-up assessment. Parent and youth-reported measures were used to assess youth's internalizing symptoms and emotion regulation. Parent-reported measures were used to assess youth's externalizing symptoms. We tested whether showing cortisol increases (vs. not) across the peripubertal period was associated with later social and emotional adjustment differently for PI and NA youth. Significant interactions emerged showing that for PI youth only, increases in cortisol reactivity across the peripubertal period was associated with poorer subsequent socioemotional functioning.

Indirect effects of HPA axis dysregulation in the association between peer victimization and depressed affect during early adolescence

OBJECTIVE

Previous research has identified a link between peer victimization and depressive symptoms during adolescence. The goal of the current study is to examine the possible indirect effects of HPA axis dysregulation in the link between adolescent peer victimization and depressive symptoms.

METHOD

A total of 113 boys (n = 61) and girls (n = 52) participants from grade 5 (M age = 10.31 years) and grade 6 (M age = 11.33 years) who were predominantly European-Canadian completed self-report measures of peer victimization and depressed affect as well as, measures of salivary cortisol and self-reports of negative experiences collected in conjunction with one another five times per day over the course of four school days.

RESULTS

Multi-level structural equation modeling found that peer victimization was indirectly associated with depressive symptoms via blunted cortisol reactivity (i.e. increases in cortisol in response to a negative event) but only at high rates of chronic peer victimization.

CONCLUSION

The findings suggest that future studies should focus on HPA axis dysregulation for better understand the development, as well as the stability of depression over time and that interventions targeting peer victimization may want to put a special focus on those who are chronically experiencing peer victimization over time.

Coordination between frontolimbic resting state connectivity and hypothalamic-pituitary-adrenal axis functioning in adolescents with and without depression

Depression is associated with abnormalities in Hypothalamic-Pituitary-Adrenal (HPA) axis functioning and neural circuitry that underlie the stress response. Resting-state functional connectivity (RSFC) between frontolimbic brain regions captures intrinsic connections that may set the stage for the rallying and regulating of the HPA axis system. This study examined the association between cortisol stress response and frontolimbic (amygdala and ventral and dorsal medial prefrontal cortex [vmPFC and dmPFC respectively]) RSFC in 88 (Age: M = 15.95, SD = 2.04; 71.60% female) adolescents with (N = 55) and without (N = 33) major depressive disorder (MDD). We collected salivary cortisol in the context of a modified Trier Social Stress Test (TSST) paradigm. Key findings were that adolescents with depression and healthy controls showed different patterns of association between amygdala and vmPFC RSFC and HPA functioning: while healthy controls showed a positive relationship between frontolimbic connectivity and cortisol levels that may indicate coordination across neural and neuroendocrine systems, adolescents with depression showed a minimal or inverse relationship, suggesting poor coordination of these systems. Results were similar when examining non-suicidal self-injury subgroups within the MDD sample. These findings suggest that the intrinsic quality of this frontolimbic connection may be related to HPA axis functioning. In MDD, inverse associations may represent a compensatory response in one system in response to dysfunction in the other. Longitudinal multilevel research, however, is needed to disentangle how stress system coordination develops in normal and pathological contexts and how these systems recover with treatment.

Associations between stress reactivity and behavior problems for previously institutionalized youth across puberty

Megan Gunnar's pubertal stress recalibration hypothesis was supported in a recent study of previously institutionalized (PI) youth such that increases in pubertal stage were associated with increases in cortisol stress reactivity. This work provides evidence that puberty may open up a window of recalibration for PI youth, resulting in a shift from a blunted to a more typical cortisol stress response. Using the same sample (N = 132), the current study aimed to elucidate whether increases in cortisol are associated with increases in adaptive functioning or whether they further underlie potential links to developmental psychopathology. Specifically, we examined the bidirectional associations between cortisol stress reactivity and both internalizing and externalizing symptoms across three timepoints during the pubertal period. Youth reported on their own internalizing symptoms and parents reported on youths' externalizing symptoms. Cortisol reactivity was assessed during the Trier social stress test. Analyses revealed no associations between cortisol reactivity and externalizing symptoms across puberty for PI youth. However, longitudinal bidirectional associations did emerge for internalizing symptoms such that increases in cortisol reactivity predicted increases in internalizing symptoms and increases in internalizing symptoms predicted increases in cortisol reactivity. Findings suggest that recalibrating to more normative levels of cortisol reactivity may not always be associated with adaptive outcomes for PI youth.

Interpersonal Stress Severity Longitudinally Predicts Adolescent Girls' Depressive Symptoms: the Moderating Role of Subjective and HPA Axis Stress Responses

In recent decades, stress response models of adolescent depression have gained attention, but it remains unclear why only certain adolescents are vulnerable to the depressogenic effects of stress while others are not. Building on evidence that affective and physiological responses to stress moderate the impact of stress exposure on depression, the current study examined whether the interaction between severity of interpersonal stress, subjective affective reactivity, and hypothalamic-pituitary-adrenal (HPA) axis reactivity to an acute, in-vivo psychosocial stressor prospectively predicted depressive symptoms nine months later. Hypotheses were examined with a clinically-oversampled group of 182 adolescent girls (aged 12-16) to ensure an examination of the widest possible range of risk. Self-report measures of affect and salivary cortisol samples were collected before and after an in-vivo stress task to assess affective reactivity and HPA axis reactivity, respectively. Severity of interpersonal stress between baseline and nine months was assessed using a semi-structured interview and was objectively coded for severity and content theme (i.e., interpersonal vs. non-interpersonal). Results indicate that experiences of severe interpersonally-themed stress predict elevated levels of depressive symptoms longitudinally only for adolescent girls with elevated affective reactivity to stress, and suggest that these deleterious effects of stress are most exacerbated for girls with elevated physiological responses to stress. Findings suggest that it may be critical to examine both affective and physiological stress responses when assessing risk for depression in adolescents.

Stress-induced cortisol reactivity as a predictor of success in treatment for affective dimensions

BACKGROUND

Response rates to first-line treatments for depression and anxiety remain unsatisfactory. Identification of predictors or moderators that can optimize treatment matching is of scientific and clinical interest. This study examined the role of prolonged laboratory-induced stress cortisol reactivity as a predictor of outcome for a treatment of affective dimensions (TAD). Patients received 15-sessions of a treatment targeting reductions in negative affect or increases in positive affect (Craske et al., 2019). A second aim was to examine whether treatment type would moderate the association between cortisol reactivity and treatment outcome.

METHODS

Thirty-five participants underwent a 36-minute intermittent stress induction task composed of a mental arithmetic task and a fear-potentiated startle task one week before treatment initiation. Cortisol was collected at five-time points with reactivity being quantified as peak during the task minus basal level of cortisol the evening before the assessment. Using multilevel modeling, we examined the associations between cortisol reactivity and slopes of symptom improvement.

RESULTS

Cortisol reactivity was related to treatment outcome, with average and higher levels of stress-induced cortisol response predicting greater decreases in symptoms throughout treatment and 6-month follow-up. Treatment condition differences (moderation) were not observed in the effect of cortisol reactivity on symptoms.

CONCLUSION

Our findings demonstrate the impact of greater cortisol stress reactivity on treatment outcome. Future studies should investigate how to enhance this therapeutic benefit through capitalizing on endogenous diurnal fluctuations or exogenous cortisol manipulation.

Effects of Aerobic Exercise on Cortisol Stress Reactivity in Response to the Trier Social Stress Test in Inpatients with Major Depressive Disorders: A Randomized Controlled Trial

Physical activity is associated with a favourable (blunted) cortisol stress reactivity in healthy people. However, evidence from experimental study and with psychiatric patients is missing. This study examines whether exercise training impacts on cortisol stress reactivity in inpatients with major depressive disorder (MDD). These new insights are important because the stress reactivity of healthy people and patients with severe symptoms of depression might differ. Methods: The study was designed as a randomized controlled trial (trial registration number: NCT02679053). In total, 25 patients (13 women, 12 men, mean age: 38.1 12.0 years) completed a laboratory stressor task before and after a six-week intervention period. Nine samples of salivary free cortisol were taken before and after the Trier social stress test (TSST). Fourteen participants took part in six weeks of aerobic exercise training, while 11 patients were allocated to the control condition. While the primary outcome of the study was depressive symptom severity, the focus of this paper is on one of the secondary outcomes (cortisol reactivity during the TSST). The impact of aerobic exercise training was examined with a repeated-measures analysis of variance. We also examined the association between change in depression and cortisol response via correlational analysis. Cortisol reactivity did not change from baseline to post-intervention, either in the intervention or the control group. Participation in six weeks of aerobic exercise training was not associated with participants' cortisol reactivity. Moreover, depressive symptom change was not associated with change in cortisol response. Aerobic exercise training was not associated with patients' stress reactivity in this study. Because many patients initially showed a relatively flat/blunted cortisol response curve, efforts might be needed to find out which treatments are most efficient to promote a normalization of HPA axis reactivity.

Neuroendocrine and Inflammatory Effects of Childhood Trauma Following Psychosocial and Inflammatory Stress in Women with Remitted Major Depressive Disorder

The dysregulation of the inflammatory and neuroendocrine systems seen in major depressive disorder (MDD) may persist after remission and this is associated with a higher risk of relapse. This vulnerable subgroup may be characterized by a history of childhood trauma. In a single-blind randomized placebo-controlled crossover study, 21 women with remitted recurrent MDD and 18 healthy controls were exposed to psychosocial stress (Trier social stress test) or inflammatory stress (typhoid vaccine), or both, to investigate the effects of childhood trauma on the neuroendocrine and inflammatory responses. Childhood trauma was assessed using the Childhood Trauma Questionnaire and participants were dichotomized into a traumatized and non-traumatized group. Serum adrenocorticotropic hormone (ACTH), cortisol, interferon (IFN)-γ, tumor necrosis factor (TNF)-α, and interleukin (IL)-6 were measured at regular intervals after each intervention. The effects of trauma, time, and intervention on these parameters were modeled by fitting linear mixed models. Childhood trauma in itself did not have a main effect on the outcome measurements. However, an interactional effect of trauma with stressor type was found in the remitted MDD group: trauma was associated with higher cortisol levels only after adding immunological to psychosocial stress, and with lower TNF-α levels in response to vaccination. This suggests the existence of a vulnerable trauma-associated MDD endophenotype.

Mother-infant dyadic dysregulation and postpartum depressive symptoms in low-income Mexican-origin women

The current study evaluated a mechanistic pathway by which prenatal stress increases the risk of postpartum depressive (PPD) symptoms via observed dyadic emotional, behavioral, and attentional dysregulation and associated cortisol responses during mother-infant interactions.

METHODS

Participants included 322 low-income Mexican American mother-infant dyads. Depressive symptoms, economic hardship, and negative life events were assessed at a prenatal visit. Dysregulation in dyadic (mother-infant) interactions and cortisol responses to mother-infant interaction were evaluated at 12 weeks after the birth. Twenty-four weeks after the birth, PPD symptoms were predicted from prenatal stress (negative life events and economic hardship) and prenatal depressive symptoms, mediated through dyadic dysregulation and maternal and infant cortisol responses.

RESULTS

More negative life events in the prenatal period predicted more dyadic dysregulation at 12 weeks postpartum. Dyadic dysregulation and economic hardship predicted elevated 12-week infant cortisol total response and reactivity, and higher total infant cortisol response predicted higher maternal PPD symptoms at 24 weeks. Maternal cortisol response was not associated with dyadic dysregulation, either form of prenatal stress, or PPD symptoms.

CONCLUSION

The results indicate the salience of early psychosocial processes and mother-infant relationship challenges for subsequent maternal affective well-being.

Impact of early life adversity on the stress biobehavioral response during nicotine withdrawal

Exposure to early life adversity (ELA) is associated with increased subsequent risk for addiction and relapse. We examined changes in psychobiological responses to stress in dependent smokers and nonsmoking controls and evaluated how history of early adversity may exacerbate acute changes during nicotine withdrawal and acute stress. Smokers were randomly assigned to one of two conditions; 24 h withdrawal (66 smokers) from smoking and all nicotine-containing products or smoking ad libitum (46 smokers) prior to an acute laboratory stress induction session; and 44 nonsmokers provided normal referencing. The laboratory session included a baseline rest, stress and recovery periods. Plasma and saliva samples for the measurement stress hormones and cardiovascular and self-report mood measures were collected multiple times during the session. Multivariate analysis confirmed that all groups showed stress-related increases in negative mood, cardiovascular measures and stress hormones, particularly smokers in the withdrawal condition. Individuals with high ELA showed greater adrenocorticotropic hormone (ACTH), but lower plasma and salivary cortisol levels, than those with low ELA. Cortisol differences were abolished during tobacco withdrawal. These findings demonstrate that ELA moderates the effects of withdrawal on stress-related biobehavioral changes.

Cortisol stress reactivity across psychiatric disorders: A systematic review and meta-analysis

The hypothalamus-pituitary-adrenal (HPA) axis and its end product cortisol are essential for an adequate response to stress. Considering the role of stress as a risk factor for psychiatric disorders, it is not surprising that cortisol stress reactivity has frequently been investigated in patients versus healthy individuals. However, the large heterogeneity in measures of the cortisol stress response has hampered a systematic evaluation of the evidence. We here report of a systematic literature review and meta-analysis on cortisol reactivity to psychosocial stress across psychiatric disorders. Original data from authors were obtained to construct standardized cortisol outcomes (the areas under the curve with respect to increase (AUCi) and ground (AUCg)) and to examine the influence of sex and symptomatic state on cortisol stress reactivity. Fourteen studies on major depressive disorder (MDD) (n=1129), 9 on anxiety disorders (n=732, including social anxiety disorder (SAD), posttraumatic stress disorder, panic disorder and mixed samples of anxiety disorders) and 4 on schizophrenia (n=180) were included that used the Trier Social Stress Test or an equivalent psychosocial stress task. Sex-dependent changes in stress reactivity were apparent in MDD and anxiety disorders. Specifically, women with current MDD or an anxiety disorder exhibited a blunted cortisol stress response, whereas men with current MDD or SAD showed an increased cortisol response to psychosocial stress. In individuals with remitted MDD, altered cortisol stress reactivity was less pronounced in women and absent in men. For schizophrenia, cortisol stress reactivity was blunted in both men and women, but the number of studies was limited and showed evidence for publication bias. These findings illustrate that sharing individual data to disentangle the effects of sex, symptom levels and other factors is essential for further understanding of the alterations in cortisol stress reactivity across psychiatric disorders.

Acute stress impairs frontocingulate activation during error monitoring in remitted depression

Deficits in cognitive control are a hallmark characteristic of depression, however less is known about the degree to which they persist beyond symptom remission and might contribute to symptom recurrence in remitted individuals (rMDD). Evidence indicates that stress interferes with cognitive control, highlighting a potential mechanism by which stress precipitates depression relapse. Therefore, this study examined whether stress exposure elicits deficits in error monitoring - a component of cognitive control thought to be particularly implicated in the ability to adaptively respond to negative feedback - in individuals with rMDD. Unmedicated individuals with rMDD (n=30) and healthy controls (n=34) performed an Eriksen Flanker task before and 45min after an acute stressor while 128-channel event-related potentials (ERPs) were recorded. Flanker interference effects and post-error adjustments were examined, and ERP analyses focused on the error-related negativity (ERN) and error positivity (Pe). Standardized low resolution electromagnetic tomography (sLORETA) was used to examine stress-induced changes in current source density. Individuals with rMDD showed blunted cortisol reactivity to the stressor, coupled with heightened self-reported stress reactivity. Although no significant effects of group or stress were observed in scalp-level ERPs, source-level analyses indicated that among the rMDD group only, stress caused a reduction in activation in frontocingulate regions critically implicated in error monitoring. The magnitude of stress-induced decreases in frontocingulate activation correlated with heightened self-reported stress reactivity, and also predicted heightened levels of stress and depression 18 months later in the entire sample. These findings suggest that individuals with rMDD show a stress-induced disruption in frontocingulate function that is linked to heightened stress reactivity, and this disruption prospectively predicts heightened levels of future stress and depressive symptomatology.

Characterizing emotional dysfunction in borderline personality, major depression, and their co-occurrence

This research aimed to characterize patterns of emotional reactivity and dysregulation in borderline personality, depression, and their co-occurrence. In study 1, 488 young adult women from the community were categorized into four groups based on self-reported major depressive disorder (MDD) and borderline personality disorder (BPD) symptoms (Low BPD/Low MDD; Low BPD/High MDD; High BPD/Low MDD; High BPD/High MDD). Immediate and prolonged subjective emotional reactivity to a laboratory stressor were assessed, and participants completed self-report and behavioral measures of emotion dysregulation. Study 2 extended these findings, examining emotional reactivity and dysregulation in a clinical population of 176 substance dependent patients with diagnoses of BPD and MDD and including a biological index of emotional reactivity. Results revealed greater prolonged fear reactivity in the High BPD/High MDD (vs. Low BPD/Low MDD) group in study 1, and greater prolonged anxiety and negative affect reactivity in both High BPD groups (vs. Low BPD/Low MDD and Low BPD/High MDD groups) in study 2 (but no differences in cortisol reactivity). Results also demonstrated greater subjective (but not behavioral) emotion dysregulation in the High BPD/High MDD (vs. Low BPD/Low MDD) group in study 1 and both High BPD groups (vs. both Low BPD groups) in study 2. Finally, the High BPD/High MDD group reported greater difficulties controlling impulsive behaviors compared with all other groups in study 1 and the Low BPD groups in study 2. Findings suggest that BPD pathology (but not MDD pathology alone) is characterized by greater prolonged emotional (especially anxiety/fear-related) reactivity and heightened emotion dysregulation.

Evidence for the role of corticotropin-releasing factor in major depressive disorder

Major depressive disorder (MDD) is a devastating disease affecting over 300 million people worldwide, and costing an estimated 380 billion Euros in lost productivity and health care in the European Union alone. Although a wealth of research has been directed toward understanding and treating MDD, still no therapy has proved to be consistently and reliably effective in interrupting the symptoms of this disease. Recent clinical and preclinical studies, using genetic screening and transgenic rodents, respectively, suggest a major role of the CRF1 gene, and the central expression of CRF1 receptor protein in determining an individual's risk of developing MDD. This gene is widely expressed in brain tissue, and regulates an organism's immediate and long-term responses to social and environmental stressors, which are primary contributors to MDD. This review presents the current state of knowledge on CRF physiology, and how it may influence the occurrence of symptoms associated with MDD. Additionally, this review presents findings from multiple laboratories that were presented as part of a symposium on this topic at the annual 2014 meeting of the International Behavioral Neuroscience Society (IBNS). The ideas and data presented in this review demonstrate the great progress that has been made over the past few decades in our understanding of MDD, and provide a pathway forward toward developing novel treatments and detection methods for this disorder.

Striatal Hypersensitivity During Stress in Remitted Individuals with Recurrent Depression

BACKGROUND

Increased sensitivity to stress and dysfunctional reward processing are two primary characteristics of major depressive disorder (MDD) that may persist after remission. Preclinical work has established the pivotal role of the striatum in mediating both stress and reward responses. Human neuroimaging studies have corroborated these preclinical findings and highlighted striatal dysfunction in MDD in response to reward but have yet to investigate striatal function during stress, in particular in individuals with recurrent depression.

METHODS

A validated mild psychological stress task involving viewing of negative stimuli during functional magnetic resonance imaging was conducted in 33 remitted individuals with a history of recurrent major depressive disorder (rMDD) and 35 matched healthy control subjects. Cortisol and anxiety levels were assessed throughout scanning. Stress-related activation was investigated in three striatal regions: caudate, nucleus accumbens, and putamen. Psychophysiologic interaction analyses probed connectivity of regions with central structures of the neural stress circuitry, such as the amygdala and hippocampus.

RESULTS

The task increased cortisol and anxiety levels, although to a greater extent in rMDD individuals than healthy control subjects. In response to the negative stimuli, rMDD individuals, but not controls, also exhibited significantly potentiated caudate, nucleus accumbens, and putamen activations and increased caudate-amygdala and caudate-hippocampus connectivity.

CONCLUSIONS

The findings highlight striatal hypersensitivity in response to a mild psychological stress in rMDD, as manifested by hyperactivation and hyperconnectivity with the amygdala and hippocampus. Striatal hypersensitivity during stress might thus constitute a trait mark of depression, providing a potential neural substrate for the interaction between stress and reward dysfunction in MDD.

Two prospective studies of changes in stress generation across depressive episodes in adolescents and emerging adults

The stress generation hypothesis was tested in two different longitudinal studies examining relations between weekly depression symptom ratings and stress levels in adolescents and emerging adults at varied risk for depression. The participants in Study 1 included 240 adolescents who differed with regard to their mothers' history of depressive disorders. Youth were assessed annually across 6 years (Grades 6-12). Consistent with the depression autonomy model, higher numbers of prior major depressive episodes (MDEs) were associated with weaker stress generation effects, such that higher levels of depressive symptoms predicted increases in levels of dependent stressors for adolescents with two or more prior MDEs, but depressive symptoms were not significantly related to dependent stress levels for youth with three or more prior MDEs. In Study 2, the participants were 32 remitted-depressed and 36 never-depressed young adults who completed a psychosocial stress task to determine cortisol reactivity and were reassessed for depression and stress approximately 8 months later. Stress generation effects were moderated by cortisol responses to a laboratory psychosocial stressor, such that individuals with higher cortisol responses exhibited a pattern consistent with the depression autonomy model, whereas individuals with lower cortisol responses showed a pattern more consistent with the depression sensitization model. Finally, comparing across the two samples, stress generation effects were weaker for older participants and for those with more prior MDEs. The complex, multifactorial relation between stress and depression is discussed.