Experimentally induced psychosocial stress in schizophrenia spectrum disorders: A systematic review

Examining the psychobiological response to acute social stress across clinical stages and symptom trajectories in the early psychosis continuum

The stress-vulnerability model has been repeatedly highlighted in relation to the risk, onset and course of psychosis, and has been independently studied in clinical high-risk (CHR) and first-episode psychosis (FEP) populations. Notable in this literature, however, is that there are few studies directly comparing markers of stress response across progressive stages of illness. Here we examined the psychobiological response to the Trier Social Stress Test in 28 CHR (mean age 19.1) and 61 FEP (age 23.0) patients, in order to understand the stage(s) or trajectories in which differences in subjective stress or physiological response occur. The overall clinical sample had greater perceived stress and blunted cortisol (FEP + CHR, n = 89, age 21.7) compared with healthy controls (n = 45, age 22.9). Additional analyses demonstrated elevated heart rate and systolic blood pressure in FEP compared with CHR, but there were no further differences in physiological parameters (cortisol, heart rate, or blood pressure) between stage- or trajectory-based groups. Together, this suggests that individual stress response markers may differentially emerge at particular stages en route to psychosis - and demonstrates how stage-based analyses can shed light on the emergence and evolution of neurobiological changes in mental illness.

The association between psychosocial stress, interpersonal sensitivity, social withdrawal and psychosis relapse: a systematic review

Psychosis is associated with a high risk of relapse, with 67% of clients relapsing within one year following a first episode. In light of the high personal, social, and healthcare costs of the illness, it is paramount to understand the risk factors associated with psychosis relapse. The current systematic review aims to critically review the role of psychosocial stress in psychosis relapse in individuals with an established psychotic disorder. This review systematically searched Ovid (PsycINFO, EMBASE, MEDLINE) literature databases from inception until 28th February 2022. Sixteen studies were eligible for inclusion. Most studies found that individuals with psychosis demonstrate high levels of psychosocial stress and are more likely to be socially withdrawn compared to healthy controls or other clinical presentations. Most studies reported a statistically significant association between psychosocial stress and psychosis relapse, as well as between social withdrawal and psychosis relapse. However, no studies examined the association between high levels of interpersonal sensitivity and psychosis relapse. Individuals with psychosis tend to experience high levels of psychosocial stress and social withdrawal, and these appear to increase the risk of psychosis relapse. Due to high levels of heterogeneity within the literature, we could only conduct a narrative synthesis of the findings. Future studies would benefit from employing a meta-analytic approach.

Is daily-life stress reactivity a measure of stress recovery? An investigation of laboratory and daily-life stress

Typical measures of laboratory reactivity (i.e. difference between control and stress) and recovery (i.e. difference between stress and post-stress) were compared with a conventional measure of daily-life reactivity, best known as event-related stress. Fifty-three healthy individuals between 19 and 35 years of age took part in a laboratory session where stress was induced using the repeated Montreal Imaging Stress Task and 8 days of experience sampling method. Measures of negative affect, heart rate (HR), HR variability, and skin conductance level were collected. Findings show no strong associations between laboratory and daily life measures with the exception of laboratory affective recovery and daily life reactivity. Findings and their implications are discussed.

White matter in prolonged glucocorticoid response to psychological stress in schizophrenia

Stress is implicated in psychosis etiology and exacerbation, but pathogenesis toward brain network alterations in schizophrenia remain unclear. White matter connects limbic and prefrontal regions responsible for stress response regulation, and white matter tissues are also vulnerable to glucocorticoid aberrancies. Using a novel psychological stressor task, we studied cortisol stress responses over time and white matter microstructural deficits in schizophrenia spectrum disorder (SSD). Cortisol was measured at baseline, 0-, 20-, and 40-min after distress induction by a psychological stressor task in 121 SSD patients and 117 healthy controls (HC). White matter microstructural integrity was measured by 64-direction diffusion tensor imaging. Fractional anisotropy (FA) in white matter tracts were related to cortisol responses and then compared to general patterns of white matter tract deficits in SSD identified by mega-analysis. Differences between 40-min post-stress and baseline, but not acute reactivity post-stress, was significantly elevated in SSD vs HC, time × diagnosis interaction F_2.3,499.9 = 4.1, p = 0.013. All SSD white matter tracts were negatively associated with prolonged cortisol reactivity but all tracts were positively associated with prolonged cortisol reactivity in HC. Individual tracts most strongly associated with prolonged cortisol reactivity were also most impacted in schizophrenia in general as established by the largest schizophrenia white matter study (r = -0.56, p = 0.006). Challenged with psychological stress, SSD and HC mount similar cortisol responses, and impairments arise in the resolution timeframe. Prolonged cortisol elevations are associated with the white matter deficits in SSD, in a pattern previously associated with schizophrenia in general.

Training coping skills and coping with stress self-efficacy for successful daily functioning and improved clinical status in patients with psychosis: A randomized controlled pilot study

Due to the symptom diversity and pervasive function impairments (e.g. in perception, cognition, language, affect, behavior, daily and social functioning and sense of self), recurrent relapses, elevated disability, high rates of (co)morbidity, heightened premature mortality and high burden of care of psychotic disorders, psychosocial interventions are part of patients' standard care. There is growing evidence on the relevance of self-efficacy for well-being and functioning among these patients, but specific coping with stress self-efficacy has rarely been investigated. This study explored the outcomes of an intervention for the improvement of coping resources based on training in coping skills and coping with stress self-efficacy. Fourteen adult volunteers with schizophrenia (n = 12) or schizoaffective disorder (n = 2) were matched in clinical and sociodemographic characteristics and randomly assigned to the study groups. The intervention group received the training-with 15 twice per week sessions (8 weeks)-along with their pharmacological therapy; the control group received their prescribed drug therapy. Participants completed self-reports on coping with stress self-efficacy, perceived successful daily functioning based on coping skills and clinical status (Expanded Brief Psychiatric Rating Scale). Trained patients showed a significant increase in coping with stress self-efficacy and reported greater successful functioning status, and significant improvements in their clinical status were also observed. All these enhancements remained at 3-month and 6-month follow-ups. The intervention condition interacted with coping with stress self-efficacy and perceived coping functioning in explaining improvements in clinical status: in the treatment group, greater coping with stress self-efficacy translated into enhanced daily functioning, and this improvement predicted better clinical status. These findings stress the relevance of promoting coping resources in psychotic disorders and provide preliminary evidence for the potential benefits of coping with stress self-efficacy.

Association of acute psychosocial stress with oxidative stress: Evidence from serum analysis

Growing evidence implicates an association between psychosocial stress and oxidative stress (OxSt) although there are not yet reliable biomarkers to study this association. We used a Trier Social Stress Test (TSST) and compared the response of a healthy control group (HC; N=10) against the response of a schizophrenia group (SCZ; N=10) that is expected to have higher levels of OxSt. Because our previous study showed inconsistent changes in conventional molecular markers for stress responses in the neuroendocrine and immune systems, we analyzed the same serum samples using a separate reducing capacity assay that provides a more global measurement of OxSt. This assay uses the moderately strong oxidizing agent iridium (Ir) to probe a sample's reducing capacity. Specifically, we characterized OxSt by this Ir-reducing capacity assay (Ir-RCA) using two measurement modalities (optical and electrochemical) and we tuned this assay by imposing an input voltage sequence that generates multiple output metrics for data-driven analysis. We defined five OxSt metrics (one optical and four electrochemical metrics) and showed: (i) internal consistency among each metric in the measurements of all 40 samples (baseline and post TSST for N=20); (ii) all five metrics were consistent with expectations of higher levels of OxSt for the SCZ group (three individual metrics showed statistically significant differences); and (iii) all five metrics showed higher levels of OxSt Post-TSST (one metric showed statistically significant difference). Using multivariant analysis, we showed that combinations of OxSt metrics could discern statistically significant increases in OxSt for both the SCZ and HC groups 90 min after the imposed acute psychosocial stress.

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Ir-reducing capacity assay (Ir-RCA) provides a robust global measure of oxidative stress in serum.

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The multiple oxidative stress (OxSt) output metrics of this Ir-RCA are useful for data-driven analysis.

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The combination of OxSt metrics can discern significant increases in OxStwithin 90 mins of an imposed psychosocial stress.

Mild-to-moderate schizotypal traits relate to physiological arousal from social stress

Schizotypy denotes psychosis-like experiences, such as perceptual aberration, magical ideation, and social anxiety. Altered physiological arousal from social stress is found in people with high schizotypal traits. Two experiments aimed to determine the relationship of schizotypy to physiological arousal from social stress. Experiment 1 tested the hypotheses that heart rate from social stress would be greater in high, than mild-to-moderate, schizotypal traits, and disorganized schizotypy would explain this effect because of distress from disorganisation. Experiment 1 tested social stress in 16 participants with high schizotypal traits and 10 participants with mild-to-moderate schizotypal traits. The social stress test consisted of a public speech and an informal discussion with strangers. The high schizotypal group had a higher heart rate than the mild-to-moderate schizotypal group during the informal discussion with strangers, but not during the public speech. Disorganized schizotypy accounted for this group difference. Experiment 2 tested the hypothesis that mild-to-moderate schizotypal traits would have a linear relationship with physiological arousal from social stress. Experiment 2 tested 24 participants with mild-to-moderate schizotypal traits performing the abovementioned social stress test while their heart rate and skin conductance responses were measured. Mild-to-moderate schizotypal traits had a linear relationship with physiological arousal during the discussion with strangers. Distress in disorganized schizotypy may explain the heightened arousal from close social interaction with strangers in high schizotypy than mild-to-moderate schizotypy. Mild-to-moderate schizotypal traits may have a linear relationship with HR during close social interaction because of difficulty with acclimatizing to the social interaction.

Acute Physiological and Psychological Stress Response in Youth at Clinical High-Risk for Psychosis

Deficits in stress-response systems are a characteristic of schizophrenia and psychosis spectrum illnesses, and recent evidence suggests that this impairment may be evident in those at clinical high-risk (CHR) for the development of a psychotic disorder. However, there is limited research specifically investigating biological and subjective stress reactivity in CHR individuals. In the present study, 38 CHR individuals and group of 38 control individuals participated in the Trier Social Stress Test (TSST), an experimentally induced psychosocial stressor. Changes in salivary cortisol and alpha amylase, as well as self-reported units of distress (SUDS), were evaluated. Interestingly, the TSST did not induce a change in cortisol levels in either group, though the CHR group did show higher overall cortisol levels throughout the TSST (pre-anticipation period through recovery period). However, indicative of an effective task manipulation, the TSST did illicit an increase in alpha amylase in both groups. CHR participants exhibited higher levels of subjective stress prior to the stressor compared to the control group and CHR SUDs did not significantly increase in response to the stressor. In contrast, the control group showed an increase in SUDS in response to the stressor. Notably, SUDS for the control group post task mirrored the levels CHR youth endorsed prior to the stressor. Taken together, these findings suggest that there may be a functional relationship between persistently elevated cortisol and chronic high levels of subjective distress in CHR individuals.

"Seat of the soul"? The structure and function of the pineal gland in women with alleged spirit possession-Results of two experimental studies

BACKGROUND

Cultural traditions attribute to pineal gland an important role for spiritual experiences. Mediumship and spirit possession are cultural phenomena found worldwide which have been described as having dissociative and psychotic-like characteristics, but with nonpathological aspects. A sympathetic activation pattern in response to spirit possession has been reported in some studies, but empirical data on pineal gland is scarce in this context.

METHODS

We aimed to investigate pineal gland and pituitary volumes, as well as urinary 6-sulfatoxymelatonin levels in 16 alleged mediums (Medium Group-MG) compared with 16 healthy nonmedium controls (Control Group) (Experiment 1). Furthermore, we aimed to evaluate urinary 6-sulfatoxymelatonin and stress reactivity in GM (n = 10) under different physiological conditions (Experiment 2).

RESULTS

In Experiment 1, MG presented higher scores of anomalous experiences, but there were no between-group differences regarding mental health or subjective sleep quality. Similar pineal gland and pituitary volumes were observed between groups. There were no between-group differences in urinary 6-sulfatoxymelatonin collected under equivalent baseline conditions. In Experiment 2, the rise of anxiety and heart rate in response to mediumistic experience was intermediate between a nonstressful control task (reading) and a stressful control task (Trier Social Stress Test-TSST). No significant differences were observed in 6-sulfatoxymelatonin urinary levels between the three conditions. The pattern of stress reactivity during the TSST was normal, but with an attenuated salivary cortisol response.

CONCLUSION

The normal neuroimaging and stress reactivity findings in MG contrast with the abnormal results usually observed in subjects with psychotic and dissociative disorders.

Efficacy and cognitive effect of sarcosine (N-methylglycine) in patients with schizophrenia: A systematic review and meta-analysis of double-blind randomised controlled trials

BACKGROUND

Sarcosine (N-methylglycine), a type 1 glycine transporter inhibitor (GlyT1), has shown therapeutic potential for treating schizophrenia; however, studies have reported conflicting results. This meta-analysis aimed to explore the efficacy and cognitive effect of sarcosine for schizophrenia.

METHODS

In this study, PubMed, Cochrane Systematic Reviews, and Cochrane Collaboration Central Register of Controlled Clinical Trials were searched electronically for double-blinded randomised controlled trials that used sarcosine for treating schizophrenia. We used the published trials up to November 2019 to investigate the efficacy of sarcosine in schizophrenia. We pooled studies by using a random-effect model for comparing sarcosine treatment effects. Patients who were diagnosed with schizophrenia according to the criteria of the Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition were recruited. Clinical improvement and cognitive function scores between baseline and after sarcosine use were compared using the standardised mean difference (SMD) with 95% confidence intervals (CIs). The heterogeneity of the included trials was evaluated through visual inspection of funnel plots and through the I² statistic.

RESULTS

We identified seven trials with 326 participants with schizophrenia meeting the inclusion criteria. All these studies evaluated the overall clinical symptoms, and four of them evaluated overall cognitive functions. Sarcosine use achieved more significant effects than the use of its comparators in relieving overall clinical symptoms (SMD = 0.51, CI = 0.26-0.76, p < 0.01). Moreover, studies with the low Positive and Negative Syndrome Scale range of 70-79 showed significant effect size (ES)s of 0.67 (95% CI: 0.03-1.31, p = 0.04). In addition, trials enrolling patients with stable clinical symptoms had significant ESs: 0.53 (95% CI: 0.21-0.85, p < 0.01). Add-on sarcosine combined with first- and second-generation antipsychotics, except clozapine, had a positive effect. For overall cognitive functions, sarcosine showed a positive but insignificant effect compared with its comparators (SMD = 0.27, CI = -0.06 to 0.60, p = 0.10). The effects were correlated with increased female proportions and decreased illness duration, albeit nonsignificantly.

CONCLUSIONS

The meta-analysis suggests that sarcosine may be associated with treatment effect on overall clinical symptoms in patients with schizophrenia but not cognitive functions.

The Role of Zebrafish and Laboratory Rodents in Schizophrenia Research

Schizophrenia is a severe disorder characterized by positive, negative and cognitive symptoms, which are still not fully understood. The development of efficient antipsychotics requires animal models of a strong validity, therefore the aims of the article were to summarize the construct, face and predictive validity of schizophrenia models based on rodents and zebrafish, to compare the advantages and disadvantages of these models, and to propose future directions in schizophrenia modeling and indicate when it is reasonable to combine these models. The advantages of rodent models stem primarily from the high homology between rodent and human physiology, neurochemistry, brain morphology and circuitry. The advantages of zebrafish models stem in the high fecundity, fast development and transparency of the embryo. Disadvantages of both models originate in behavioral repertoires not allowing specific symptoms to be modeled, even when the models are combined. Especially modeling the verbal component of certain positive, negative and cognitive symptoms is currently impossible.

The Fragile Brain: Stress Vulnerability, Negative Affect and GABAergic Neurocircuits in Psychosis

Persons with schizophrenia exhibit sensitivity to stress and negative affect (NA), both strongly correlated with poor functional outcome. This theoretical review suggests that NA reflects a "fragile brain," ie, vulnerable to stress, including events not experienced as stressful by healthy individuals. Based on postmortem evidence of altered gamma-aminobutyric acid (GABA) function in parvalbumin positive interneurons (PVI), animal models of PVI abnormalities and neuroimaging data with GABAergic challenge, it is suggested that GABAergic disruptions weaken cortical regions, which leads to stress vulnerability and excessive NA. Neurocircuits that respond to stressful and salient environmental stimuli, such as the hypothalamic-pituitary-adrenal axis and the amygdala, are highly dysregulated in schizophrenia, exhibiting hypo- and hyper-activity. PVI abnormalities in lateral prefrontal cortex and hippocampus have been hypothesized to affect cognitive function and positive symptoms, respectively; in the medial frontal cortex (dorsal anterior cingulate cortex and dorsal medial prefrontal cortex), these abnormalities may lead to vulnerability to stress, NA and dysregulation of stress responsive systems. Given that postmortem PVI disruptions have been identified in other conditions, such as bipolar disorder and autism, stress vulnerability may reflect a transdiagnostic dimension of psychopathology.

Cortisol stress response in psychosis from the high-risk to the chronic stage: a systematic review

OBJECTIVES

We review studies of whether cortisol levels following psychosocial stress exposure differ between patients with psychosis and healthy control subjects.

METHODS

Original research published between 1993 and February 2019 was included in the literature search. Studies that used experimentally induced psychosocial stress and reported stress response measures of plasma or saliva cortisol levels in patients at any stage of illness (i.e. high risk, first episode and chronic phase) were included.

RESULTS

A total of 17 studies were included. Although there was evidence of inconsistencies in measures, we observed moderate evidence of an association with stress-induced cortisol blunting response across studies.

CONCLUSIONS

This review highlights recent evidence of blunting of cortisol response following experimentally induced psychosocial stress. While there was some evidence of this blunted response across illness types and stages, the strongest evidence was observed for those with chronic schizophrenia. Due to the low number of studies, in particular in bipolar disorder, much work is still needed to accurately characterise the biological effects of stress in psychosis.

The Trier Social Stress Test in first episode psychosis patients: Impact of perceived stress, protective factors and childhood trauma

Psychosis has been associated with abnormalities in hypothalamic-pituitary-adrenal axis functioning, which may emerge through heightened stress sensitivity following early life adversity - ultimately resulting in illness onset and progression. The present study assessed cortisol levels during an established psychosocial stress task and their association with current stress perception, putative protective factors and adverse childhood experiences in patients with a first episode of psychosis (FEP). A total of 100 volunteers participated in the study, 57 of whom were patients with a FEP (mean age 23.9 ± 3.8) and 43 healthy community controls (mean age 23.2 ± 3.9). Salivary cortisol, heart rate and blood pressure were measured at eight time points before and after the Trier Social Stress Test. Subjective stress and protective factors were assessed with the Perceived Stress Scale, the Self-Esteem Rating Scale and the Brief COPE. Early life adversity was assessed with the Childhood Trauma Questionnaire. Patients compared to controls showed significantly lower cortisol levels (F = 7.38; p = .008) throughout the afternoon testing period, but no difference in the cortisol response to the TSST. Heart rate was elevated and protective factors were lower in patients compared to controls. Attenuated cortisol levels were associated with higher levels of perceived stress, poor protective factors and more physical neglect during childhood. Our results suggest that attenuated baseline cortisol levels and not a blunted response during an acute stress task might be an indicator of heightened stress vulnerability and poor resilience in psychosis. The possible influence of childhood adversity and antipsychotic medication is discussed.

Modulation of HPA axis response to social stress in schizophrenia by childhood trauma

HPA axis functioning plays an important role in the etiology of schizophrenia spectrum disorders (SSD). However, only few studies have examined HPA axis responsivity to psychosocial stress in SSD, and results are heterogeneous. Furthermore, childhood trauma is known to influence psychopathology and treatment outcome in SSD, but studies on the influence of childhood trauma on stress related HPA axis activity are missing. The purpose of this study was to investigate cortisol response to a psychosocial stress challenge in SSD patients, and to examine its association with severity of childhood trauma. The present study included 25 subacutely ill patients with a current episode of a chronic SSD and 25 healthy controls. Participants underwent the modified Trier Social Stress Test, and salivary cortisol levels were assessed. The childhood trauma questionnaire was used to assess severity of adverse life events. Overall, cortisol response was blunted in the patient group compared to the control group (p<0.01). Furthermore, we identified two patient subgroups (cortisol responders (n=12) vs. non-responders (n=13) to the modified TSST) that differed in their severity of childhood trauma experience: responders had experienced more emotional abuse in their past (p<0.042). Therefore, childhood trauma might influence stress-related HPA axis activity in SSD. Our data contribute to the hypothesis that severity of childhood trauma may be of pathophysiological relevance in schizophrenia. In addition, it may be an overlooked factor contributing to inconsistent findings regarding HPA axis response to psychosocial stress in SSD.