Components of schizophrenia liability affect the growth of psychological stress sensitivity following major life events

Exploring causal mechanisms of psychosis risk

Robust epidemiological evidence of risk and protective factors for psychosis is essential to inform preventive interventions. Previous evidence syntheses have classified these risk and protective factors according to their strength of association with psychosis. In this critical review we appraise the distinct and overlapping mechanisms of 25 key environmental risk factors for psychosis, and link these to mechanistic pathways that may contribute to neurochemical alterations hypothesised to underlie psychotic symptoms. We then discuss the implications of our findings for future research, specifically considering interactions between factors, exploring universal and subgroup-specific factors, improving understanding of temporality and risk dynamics, standardising operationalisation and measurement of risk and protective factors, and developing preventive interventions targeting risk and protective factors.

Mindfulness-based interventions for patients with schizophrenia spectrum disorders: A systematic review of the literature

BACKGROUND

Mindfulness-based interventions (MBIs) have emerged as secular practices, including elements of mindfulness-based stress reduction (MBSR) and mindfulness-based cognitive therapy (MBCT). While MBIs have been widely adopted for physical and mental illness, only a few available programs are explicitly adapted for psychosis. However, previous reviews have reported the vital heterogeneity regarding treatment program structure. Therefore, this review aims to compare the structure of different mindfulness protocols applied to patients with schizophrenia spectrum disorder (SSD).

METHODS

A systematic search was conducted up to March 2023 in PubMed, Embase and PsycInfo. Following our protocol (CRD 42023253356), we followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) checklist.

RESULTS

We included 22 randomized controlled trials (RCTs) involving 1500 patients SSD. All programs varied in structure, session components, duration, and instructor experience. While MBSR-like programs focused on stress reactivity, MBCT-like programs addressed primary symptoms of psychosis and relapse prevention. Despite the heterogeneity of programs, some common mechanisms emerged, including attention training, emotion and stress regulation, decentering, self-compassion, and cognitive restructuring.

CONCLUSIONS

The critical heterogeneity found limits the interpretation of results. However, most recent trials present fewer risks of bias and more homogenous programs. Findings suggested potential benefits, such as reduced negative symptoms, increased well-being, and decreased hospitalization rates. For future studies, authors should align on more congruent MBIs programs for patients with SSD. Further research is needed to identify optimal mindfulness teaching approaches for patients with psychosis and investigate specific mechanisms of action, relevant processes, and optimal doses in varying settings.

Disparities in Psychosis Risk Symptoms for New Zealand Māori May Be Explained by Systemic Stressors and Inappropriate Conceptualization of Culturally Normative Experiences

BACKGROUND AND HYPOTHESIS

Māori, the indigenous peoples of New Zealand, experience increased rates of psychotic disorders and first-episode psychosis. However, it is unclear whether they also present with increased psychosis risk symptoms, such as subclinical psychotic-like experiences (PLEs). Measurement of risk symptoms is key for early intervention. Further, it is unclear if systemic factors such as the increased rates of social adversity and discrimination or cultural biases contribute to this disparity in psychosis rates.

STUDY DESIGN

This study surveyed 466 18- to 30-year olds in New Zealand, and compared Māori to non-Māori participant responses on the Prodromal Questionnaire Brief, alongside the history of childhood trauma, discrimination, and financial adversity.

STUDY RESULTS

Māori reported a higher number of PLEs compared to non-Māori-however, this was not associated with increased distress related to these experiences. The increased number of psychosis-like experiences reported by Māori was likely explained by systemic factors such as childhood trauma, discrimination, and financial stress. Māori were more likely to report that the PLEs were positive.

CONCLUSIONS

Measurement of psychosis risk for Māori is nuanced, and increased scores on these tools may reflect pathologizing potentially normative experiences for Māori, such as spiritual encounters or discrimination, alongside the impact of increased rates of systemic discrimination, trauma, and financial stress.

The moderating role of hair cortisol in the association of early and recent stress with stress-related phenotypes

Background

Increased hair cortisol concentrations (HCC) have been found in clinical samples of schizophrenia, first episode psychosis and clinical risk for psychosis, but evidence of such is scarce in schizotypy. High HCC are supposed to reflect elevated chronic stress. However, HCC were not directly associated with adversity measures and stress-related phenotypes in previous research. This study tested whether HCC moderated the association between a comprehensive range of psychosocial stressors with several stress-related phenotypes in a sample of nonclinical young adults. It was expected that stressors, either distal (i.e., early-life) or recent, would be associated with subclinical features, particularly for those with elevated HCC, reflecting the effects of a potential biological sensitization to stress.

Methods

The sample comprised 132 nonclinical young adults belonging to the Barcelona Longitudinal Investigation of Schizotypy Study (BLISS). Participants completed a questionnaire of childhood adversity and two complementary measures of recent life events, tapping threatening vs. more general life events. Both the frequency and subjective impact (positive vs. negative) of general life events were also assessed. Psychotic (i.e., schizotypy, suspiciousness) and non-psychotic (i.e., depression, anxiety) subclinical features as well as appraisals of perceived stress were examined. Hierarchical linear regressions and simple slope analyses were computed.

Results

HCC moderated the effects of both early and recent stress on suspiciousness as well as the effects of recent life events on perceived stress, such that those with higher HCC presented increased suspiciousness and perceived stress at higher levels of stress exposure. Positive, but not negative, recent life events were associated with decreased perceived stress and depression, and these associations were moderated by low HCC, indicating a buffering effect for those with a non-impaired HPA axis.

Conclusion

In line with the neural diathesis-stress model, results highlight the role of the interplay between the HPA axis and exposure to stressful experiences in exacerbating psychosis features and extend evidence to the nonclinical expression of the psychosis continuum. In addition, findings support the protective effect of positive experiences in decreasing stress appraisals and affective disturbances, which is consistent with emerging research about the relevance of positive factors in reducing the likelihood of psychopathological outcomes.

A systematic review and meta-analysis of the association between emotional stress reactivity and psychosis

AIM

Emotional stress reactivity may be a mediating factor in the association between trauma and psychosis. This review aimed to (i) identify, summarise and critically evaluate the link between emotional stress reactivity and psychotic experiences (ii) examine evidence for a 'dose-response' relationship between stress reactivity and psychosis in the wider psychosis phenotype (i.e., sub-clinical symptoms).

METHODS

Electronic database searches (PsychINFO, MEDLINE, EMBASE) were conducted for studies which investigated the link between stress reactivity and psychosis, psychotic symptoms, or a vulnerability to developing psychosis (wider phenotype). Cross-sectional, experimental and experience sampling method study designs were eligible for inclusion.

RESULTS

Fourty five eligible articles were identified (N participants = 8830). Narrative synthesis showed that increased emotional stress reactivity was associated with psychosis and subclinical psychotic experiences across all study designs, however, findings were inconsistent across studies. The preliminary meta-analysis (k = 4, n = 383) showed increases in emotional stress reactivity was associated with higher negative affect in response to event-related stress, in those with psychosis compared to controls (mean difference in beta coefficients = 0.05, 95% CI 0.02-0.08, p = .004). However, this difference was small with a considerable degree of heterogeneity (p = .001, I²  = 81%) so results should be interpreted with caution.

CONCLUSIONS

Overall, the evidence suggests that there is a link between emotional stress reactivity and psychosis in those with psychosis, those at high risk of developing psychosis and in relation to subclinical psychotic-like experiences in the general population.

Increased plasma level of kynurenic acid in drug-free patients with first-episode schizophrenia compared to patients with chronic schizophrenia and healthy controls: preliminary data

BACKGROUND

Kynurenic acid (KYNA) is a metabolite of tryptophan (TRP). KYNA levels have been reported with controversial findings in patients with schizophrenia.

AIM

This study aimed to investigate the probable effects of medication and illness chronicity on peripheral KYNA levels in schizophrenia.

METHODS

We assessed peripheral (plasma) TRP metabolite levels in 38 drug-free patients with first-episode schizophrenia (FES), 65 patients with chronic schizophrenia (CHS), and 70 healthy controls by using high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The symptom severity of patients was evaluated by using the Positive and Negative Syndrome Scale (PANSS). Finally, we analyzed the association of TRP metabolites with symptom severity.

RESULTS

We found significantly higher KYNA levels in FES patients than in both healthy controls (p < 0.01) and CHS patients (p < 0.05). No significant association was observed between plasma TRP metabolite levels and PANSS scores in either FES or CHS patients.

CONCLUSIONS

In conclusion, elevated plasma KYNA levels may be a promising biomarker in FES patients. Medication and illness chronicity may affect peripheral KYNA levels with a currently unknown mechanism.

Negative schizotypy attenuates the effect of momentary stress on social dysfunction related to COVID-19 social distancing

Schizotypy is associated with a broad range of motivational and social dysfunctions. However, there is reason to suspect that negative schizotypy may limit social dysfunction in specific contexts that typically increase isolation and loneliness. We analyzed whether positive, negative and disorganized facets of schizotypy would mitigate detrimental reactions to stress in the context of a global stressor (the COVID-19 pandemic) that has widely necessitated social and physical isolation. Responses to two measures of schizotypy were compared to ecological momentary assessments of social dysfunction for 85 undergraduates using multilevel modelling techniques. Negative schizotypy moderated the relation between momentary stress and loss of social support, such that negative schizotypy limited the magnitude of social dysfunction stemming from increases in momentary stress. This pattern was not seen for other facets of schizotypy. Implications for the treatment and measurement of schizotypy symptoms are discussed.

Correlates of obsessive-compulsive and related disorders symptom severity during the COVID-19 pandemic

We investigated changes in the severity of obsessive-compulsive and related disorders (OCRDs) symptoms as a result of the COVID-19 pandemic. An Amazon Mechanical Turk sample of 829 individuals was evaluated with a series of instruments assessing the severity of the OCRDs before and during the pandemic. Additional questionnaires about sociodemographic factors, personal and family histories of OCRD, COVID-19 related events, compulsivity and impulsivity traits, schizotypal symptoms, and the severity of depression, anxiety and stress levels, were also used. Participants reported that OCD, hoarding disorder (HD) and skin picking disorder (SPD) symptoms significantly worsened during the pandemic along with increased disability, more affective symptoms and reduced quality of life. Female gender, a higher number of COVID-19 related stressful events, and higher pre-COVID-19 fear of harm and symmetry symptoms predicted more severe OCD symptoms during the pandemic, whereas lack of a HD diagnosis by a mental health professional and more severe schizotypal symptoms predicted worsened hoarding symptoms. Greater compulsivity traits were associated with more severe COVID-19 pandemic obsessive-compulsive and hoarding symptoms. These data indicate that the immense distress resulting from the COVID-19 included significant deterioration of OCRDs' symptoms, particularly of OCD, HD and SPD. It was also possible to identify a pre-pandemic profile of people most at risk of pandemic-related deterioration in OCRDs' symptoms, which may prove valuable for preventative initiatives in relation to the likely future waves of COVID-19 or of other communicable diseases. Future studies should follow up these findings longitudinally.

Nonclinical psychotic-like experiences and schizotypy dimensions: Associations with hippocampal subfield and amygdala volumes

Schizotypy and psychotic‐like experiences (PLE) form part of the wider psychosis continuum and may have brain structural correlates in nonclinical cohorts. This study aimed to compare the effects of differential schizotypy dimensions, PLE, and their interaction on hippocampal subfields and amygdala volumes in the absence of clinical psychopathology. In a cohort of 367 psychiatrically healthy individuals, we assessed schizotypal traits using the Oxford‐Liverpool Inventory of Life Experiences (O‐LIFE) and PLE using the short form of the Prodromal Questionnaire (PQ‐16). Based on high‐resolution structural MRI scans, we used automated segmentation to estimate volumes of limbic structures. Sex and total intracranial volume (Step 1), PLE and schizotypy dimensions (Step 2), and their interaction terms (Step 3) were entered as regressors for bilateral amygdala and hippocampal subfield volumes in hierarchical multiple linear regression models. Positive schizotypy, but not PLE, was negatively associated with left amygdala and subiculum volumes. O‐LIFE Impulsive Nonconformity, as well as the two‐way interaction between positive schizotypy and PLE, were associated with larger left subiculum volumes. None of the estimators for right hemispheric hippocampal subfield volumes survived correction for multiple comparisons. Our findings support differential associations of hippocampus subfield volumes with trait dimensions rather than PLE, and support overlap and interactions between psychometric positive schizotypy and PLE. In a healthy cohort without current psychosis risk syndromes, the positive association between PLE and hippocampal subfield volume occurred at a high expression of positive schizotypy. Further studies combining stable, transient, and genetic parameters are required.

From Womb to Neighborhood: A Racial Analysis of Social Determinants of Psychosis in the United States

The authors examine U.S.-based evidence that connects characteristics of the social environment with outcomes across the psychosis continuum, from psychotic experiences to schizophrenia. The notion that inequitable social and economic systems of society significantly influence psychosis risk through proxies, such as racial minority and immigrant statuses, has been studied more extensively in European countries. While there are existing international reviews of social determinants of psychosis, none to the authors' knowledge focus on factors in the U.S. context specifically-an omission that leaves domestic treatment development and prevention efforts incomplete and underinformed. In this review, the authors first describe how a legacy of structural racism in the United States has shaped the social gradient, highlighting consequential racial inequities in environmental conditions. The authors offer a hypothesized model linking structural racism with psychosis risk through interwoven intermediary factors based on existing theoretical models and a review of the literature. Neighborhood factors, cumulative trauma and stress, and prenatal and perinatal complications were three key areas selected for review because they reflect social and environmental conditions that may affect psychosis risk through a common pathway shaped by structural racism. The authors describe evidence showing that Black and Latino people in the United States suffer disproportionately from risk factors within these three key areas, in large part as a result of racial discrimination and social disadvantage. This broad focus on individual and community factors is intended to provide a consolidated space to review this growing body of research and to guide continued inquiries into social determinants of psychosis in U.S. contexts.

Psychotic Like Experiences are Associated with Suicide Ideation and Behavior in 9 to 10 Year Old Children in the United States

Those experiencing psychotic like experiences (PLEs) are at higher risk for suicide ideation and behavior. However, it is unclear if PLEs are related to suicide ideation and behavior in children, and whether other factors such as impulsivity or emotion dysregulation might moderate the relationship. We hypothesize that PLEs are associated with suicide ideation and behavior, with impulsivity and emotion dysregulation moderating this relationship, in middle childhood. History of PLEs, suicide ideation and behavior, depression, emotion dysregulation, and impulsivity were assessed for 10,624 children aged 9 to 10.9 years (47.8% female, 34.4% minority race, 20.0% Hispanic) as part of the Adolescent Brain Cognitive Development℠ study. Hypotheses about associations between variables were assessed using hierarchical linear modeling. PLEs were associated with suicide ideation and suicide behavior even when controlling for depression severity. Emotion dysregulation and impulsivity were also associated with suicide ideation and moderated the relationship between PLEs and suicide ideation. Variation in suicide ideation due to impulsivity and emotion dysregulation appears to be strongest when people are experiencing low levels to no PLEs. Only impulsivity and PLEs were associated with suicide behavior. Depression was associated with suicide ideation, but not suicide behavior. PLEs may be an important risk factor for suicide ideation and behavior in 9 to 10-year-old children, comparable to adult and adolescent populations. When considering prevention of suicidality, these data suggest that considering the relations between PLEs, impulsivity and emotion dysregulation may be important.

Suicide behavior is associated with childhood emotion dysregulation but not trait impulsivity in first episode psychosis

Historically, research on suicide behavior has not included those experiencing first episode psychosis (FEP), hindering prevention efforts for this population. Emotion dysregulation and impulsivity represent two mechanisms that contribute to suicide, but these have not been examined in FEP. We hypothesize that the combination of trait impulsivity and childhood emotion dysregulation are associated with suicide behavior (SB) and ideation (SI) in those experiencing FEP. Participants were recruited from an Early Psychosis Program (N=80, ages 12-32, 65% male). Clinician ratings of symptoms and history of SI and SB were obtained at baseline. Participants also completed self-report measures of childhood emotion dysregulation and trait impulsivity. Regression analyses examined whether childhood emotion dysregulation and trait impulsivity individually or in combination were associated with SI and SB, and the severity of SI and SB. Childhood emotion dysregulation was significantly associated with a history of SB and its severity, but not SI. Attention impulsivity was associated with the severity of SI. However, other impulsivity types, and interactions were not associated with a history of SI or SB. This suggests childhood emotion dysregulation is a potential target for prevention of SB in FEP, while trait impulsivity may be less important in this effort.