Cumulative stress pathophysiology in schizophrenia as indexed by allostatic load

Linking childhood allostatic load, early adversity and the emergence of mental health symptoms in early adulthood: Analysis of the ALSPAC longitudinal birth cohort

BACKGROUND

It has been well-established that the allostatic load (AL) index, a cumulative score of multi-system dysregulation in response to chronic stress, is significantly increased at the time of a psychiatric diagnosis. However, no studies have investigated if there is an association between the AL index in childhood and the later development of mental health symptoms in young adults.

METHODS

Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC), a population cohort from Bristol, United Kingdom, we investigated the AL index at age 9 years and the risks for mental health symptoms at age 24 years. We used multinomial logistic regression analysis to investigate the association between AL threshold (categorised into bottom third: AL index ≤ 7, middle third: AL index = 7.1-9.9, and top third: AL index ≥ 10) and mental health symptoms while adjusting for sex, the age of mother at delivery, and social class. We used a relative risk ratio (RRR) and 95 % confidence interval(CI) for each variable. We further investigated the association between adverse childhood experiences (ACEs) and mental health symptoms.

RESULTS

We identified a significant association between sex and mental health symptoms, with more females (59 % vs 41 %) showing mental health symptoms than males. We found no direct association between the AL index at age 9 and the later development of mental health symptoms. However, an RRR analysis showed that individuals in the middle and the top third of the AL index had an RRR of 1.99 and 2.20, respectively, to develop mental health symptoms if they were females. We found that individuals who experienced ACE had a much higher risk of developing mental health symptoms as young adults, with the adjusted RRR of 5.39 (95 % CI: 3.00;9.67), 6.79 (95 % CI: 2.55; 18.1), and 2.10 (95 % CI: 0.37;11.8) for neglect, physical and sexual abuse, respectively, in individuals with mood disorder symptoms. The adjusted RRR for neglect and physical and sexual abuse in individuals with psychotic symptoms was 0.99 (95 % CI: 0.37; 2.59), 2.92 (95 % CI: 0.35; 24.4), and 10.5 (95 % CI: 0.99; 112), respectively.

CONCLUSION

Although the AL index in childhood was not directly associated with the later development of psychotic and mood disorder symptoms in this cohort, females in the higher tertiles of the AL index measured at 9 years of age had an elevated risk of mental health symptoms as young adults. In line with previous work, a strong association was identified between childhood adversity and mental health symptoms in young adulthood. These results highlight the importance of considering the impact of early stress on biological embedding and the later emergence of mental health problems, especially in females.

Effects of antidepressant type on allostatic load of male and female psychiatric outpatients

Sex differences and antidepressant use are not systematically accounted for in studies measuring physiological dysregulations associated with chronic stress and allostatic load (AL) in neuropsychiatry. Critically, assessing commonly prescribed antidepressant medications, such as selective serotonin reuptake inhibitors (SSRIs) and selective serotonin and norepinephrine reuptake inhibitors (SNRIs) could help monitor potential iatrogenic effects on AL and health that are associated with prolonged antidepressant use. The objective of this exploratory analysis was to investigate how male and female psychiatric outpatients using either SSRIs or SNRIs differ in their AL indices. To achieve this, we used data from a larger project collecting administrative, medical, and biological data among psychiatric outpatients of the Anjou Clinic for Mood and Anxiety Disorders, based in Montreal, Canada (n = 116). Sociodemographic variables included age and birth-assigned sex. We calculated AL using 10 biomarkers reflecting cardiovascular (systolic blood pressure, diastolic blood pressure, pulse) and metabolic (glucose, creatinine, total cholesterol, high density lipoprotein cholesterol (HDL), total cholesterol/HDL ratio, triglycerides, body mass index) functioning. Psychiatric medications were classified using the Anatomical and Therapeutic Classification system. We found that relative to female outpatients, male outpatients showed significantly higher AL levels. In addition, relative to SSRI users, SNRI users had significantly higher AL levels. However, there were no interactions effects between birth-assigned sex and antidepressant types on AL. We discuss the potential clinical implications of our findings, as well as directions for future studies that aim to investigate AL among male and female patients using antidepressants.

Association between allostatic load and cardiac structural and functional abnormalities in young adults with serious mental disorders

OBJECTIVE

Allostatic load refers to the pathophysiological consequences of uncompensated adaptation to chronic stress. Few studies have investigated the effect of allostatic load on cardiac health in patients with serious mental disorders (SMDs), a population at high risk of cardiac mortality. Herein we evaluated associations between allostatic load and cardiac structure and function in young adults with SMDs.

METHOD

A total of 106 participants aged younger than 45 years underwent echocardiographic study, blood biochemistry examination, and blood cell count analysis. Echocardiographic imaging was conducted in accordance with recommendations of the American Society of Echocardiography and European Association of Cardiovascular Imaging. Allostatic load index was calculated using 15 measures representing cardiovascular, metabolic, and inflammatory or oxidative stress markers.

RESULTS

The SMD group exhibited a significantly higher allostatic load index than did control (Cohen's d = 0.59). Additionally, they exhibited a greater left ventricular relative wall thickness (LVRWT, Cohen's d = 0.39) and a less favorable mitral valve E/A ratio (Cohen's d = 0.31), left ventricular ejection fraction (Cohen's d = 0.51), and global longitudinal strain (Cohen's d = 0.71). After demographic and clinical characteristics were adjusted for, multiple linear regression revealed that allostatic load index was positively associated with LVRWT (β = 0.255) and negatively associated with mitral valve E/A ratio (β = -0.247) in the SMD group.

CONCLUSIONS

This is the first study to suggest that allostatic load may play a critical role in accelerated adverse cardiac remodeling among young patients with SMDs. Future studies should elucidate the underlying mechanisms.

Correlation of allostatic load and perceived stress with clinical features in first-episode schizophrenia

BACKGROUND

Stress plays an important role in the etiology of schizophrenia. However, the mechanisms by which chronic physiological stress and perceived stress relate to the clinical features of schizophrenia may differ. We aimed to elucidate the relationships among chronic physiological stress indexed by allostatic load (AL), perceived stress, and clinical symptoms in individuals with first-episode schizophrenia (FES).

METHODS

Individuals with FES (n = 90, mean age = 28.26years old, 49%female) and healthy controls (111, 28.88, 51%) were recruited. We collected data of 13 biological indicators to calculate the AL index, assessed subjective stress with the Perceived Stress Scale-14 (PSS-14), and compared AL and perceived stress between groups. Patients with FES were also evaluated with the Positive and Negative Syndrome Scale (PANSS) and the Calgary Depression Scale for Schizophrenia (CDSS).

RESULTS

Individuals with FES had higher AL and PSS score than healthy controls. There were no significant correlations between AL and PSS score in either patients or controls. Among individuals with FES, the AL index was associated with the severity of positive symptoms, while the PSS score was positively associated with CDSS score. Both elevated AL and PSS were correlated with the occurrence of schizophrenia.

CONCLUSIONS

Physiological stress, as reflected by AL, may be more related to positive symptoms, while perceived stress appear to be associated with depressive symptoms in individuals with FES. Longitudinal studies are necessary to explore the relationships between interventions for different stressor types and specific clinical outcomes in FES.

Subcortical structures associated with childhood trauma and perceived stress in schizophrenia

BACKGROUND

Childhood trauma influences the clinical features of schizophrenia. In this study, we examined how childhood trauma and perceived stress are associated with clinical manifestations and subcortical gray matter volumes (GMVs) in patients with schizophrenia.

METHODS

We recruited 127 patients with schizophrenia and 83 healthy controls for assessment of early childhood trauma, perceived stress, and clinical symptoms. With structural brain imaging, we identified the GMVs of subcortical structures and examined the relationships between childhood trauma, perceived stress, clinical symptoms, and subcortical GMVs.

RESULTS

Compared to controls, patients with schizophrenia showed higher levels of childhood trauma and perceived stress. Patients with schizophrenia showed significantly smaller amygdala and hippocampus GMVs as well as total cortical GMVs than age-matched controls. Childhood trauma score was significantly correlated with the severity of clinical symptoms, depression, perceived stress, and amygdala GMVs. Perceived stress was significantly correlated with clinical symptoms, depression, and hippocampus and amygdala GMVs. Further, the association between childhood trauma (emotional neglect) and stress coping ability was mediated by right amygdala GMV in patients with schizophrenia.

CONCLUSIONS

Patients with schizophrenia had more exposure to early-life trauma and poorer stress coping. Both childhood trauma and perceived stress were associated with smaller amygdala volumes. The relationship between early-life trauma and perceived stress was mediated by right amygdala GMV in patients with schizophrenia. These findings together suggest the long-term effects of childhood trauma on perceived stress and the subcortical volumetric correlates of the effects in schizophrenia.

Comparing Predictors and Outcomes of Higher Allostatic Load across Zoo-Housed African Great Apes

Stressors over the lifespan can contribute to physiological dysregulation, or allostatic load. Allostatic load has been studied in humans using allostatic load indices (ALIs) for over 25 years, but the same methods are rarely applied to other species. We constructed an ALI for zoo-housed western lowland gorillas, chimpanzees, and bonobos and tested potential predictors of and health outcomes associated with allostatic load. Allostatic load scores ranged from 0–6 for gorillas and chimpanzees and 0–7 for bonobos. Age was significantly associated with allostatic load in gorillas and chimpanzees but not bonobos. Cumulative stressful events were positively associated with allostatic load in chimpanzees. Wild-caught gorillas had higher allostatic load than zoo-born conspecifics, but rearing differences between zoo-born animals were not significant for any species. Age may affect associations of allostatic load with stressful events and birthplace as results change when it is included as a covariate. Allostatic load was not retained in best-fit models for risk of all-cause morbidity, cardiac disease, or mortality risk. Some analyses herein were limited by the use of retrospective data, such as reason for sample collection and length of records provided for individual animals. Nevertheless, these data indicate additional research is needed to optimize ALIs for non-human primates.

Physical, Psychiatric, and Social Comorbidities of Individuals with Schizophrenia Living in the Community in Japan

The physical, psychiatric, and social comorbidities interfere with the everyday activities of community-dwelling individuals with schizophrenia and increase the risk of their readmission. However, these comorbidities have not been investigated comprehensively in Japan. We conducted a self-reported internet survey in February 2022 to identify individuals aged 20-75 years with and without schizophrenia using a prevalence case-control study. The survey compared physical comorbidities such as being overweight, hypertension, and diabetes; psychiatric comorbidities such as depressive symptoms and sleep disturbances; social comorbidities such as employment status, household income, and social support between participants with and without schizophrenia. A total of 223 participants with schizophrenia and 1776 participants without schizophrenia were identified. Participants with schizophrenia were more likely to be overweight and had a higher prevalence of hypertension, diabetes, and dyslipidemia than participants without schizophrenia. Additionally, depressive symptoms, unemployment, and non-regular employment were more prevalent in participants with schizophrenia than those without schizophrenia. These results highlight the necessity of comprehensive support and interventions addressing physical, psychiatric, and social comorbidities in individuals with schizophrenia in the community. In conclusion, effective interventions for managing comorbidities in individuals with schizophrenia are necessary to enable them to continue to live in the community.

Biological hypotheses, risk factors, and biomarkers of schizophrenia

Both the discovery of biomarkers of schizophrenia and the verification of biological hypotheses of schizophrenia are an essential part of the process of understanding the etiology of this mental disorder. Schizophrenia has long been considered a neurodevelopmental disease whose symptoms are caused by impaired synaptic signal transduction and brain neuroplasticity. Both the onset and chronic course of schizophrenia are associated with risk factors-induced disruption of brain function and the establishment of a new homeostatic setpoint characterized by biomarkers. Different risk factors and biomarkers can converge to the same symptoms of schizophrenia, suggesting that the primary cause of the disease can be highly individual. Schizophrenia-related biomarkers include measurable biochemical changes induced by stress (elevated allostatic load), mitochondrial dysfunction, neuroinflammation, oxidative and nitrosative stress, and circadian rhythm disturbances. Here is a summary of selected valid biological hypotheses of schizophrenia formulated based on risk factors and biomarkers, neurodevelopment, neuroplasticity, brain chemistry, and antipsychotic medication. The integrative neurodevelopmental-vulnerability-neurochemical model is based on current knowledge of the neurobiology of the onset and progression of the disease and the effects of antipsychotics and psychotomimetics and reflects the complex and multifactorial nature of schizophrenia.

Allostatic Load Measurement: A Systematic Review of Reviews, Database Inventory, and Considerations for Neighborhood Research

BACKGROUND

Neighborhoods are critical to understanding how environments influence health outcomes. Prolonged environmental stressors, such as a lack of green spaces and neighborhood socioeconomic disadvantage, have been associated with higher allostatic load levels. Since allostatic load levels experienced earlier in life have stronger associations with mortality risk, neighborhoods may be uniquely suited to monitor and mitigate the impacts of environmental stressors. Researchers often study allostatic load in neighborhoods by utilizing administrative boundaries within publicly accessible databases as proxies for neighborhoods.

METHODS

This systematic review of reviews aims to identify commonly used biomarkers in the measurement of allostatic load, compare measurement approaches, inventory databases to study allostatic load, and spotlight considerations referenced in the literature where allostatic load is studied in neighborhoods. The review was conducted using the search term "allostatic load" in the MEDLINE, CINAHL, and PsychINFO databases. The search results were filtered to include reviews.

RESULTS

The search returned 499 articles after deduplication. Overall, 18 synthesis reviews met the inclusion criteria and were retained for extraction. The synthesis reviews analyzed represented 238 studies published from 1995 to 2020. The original ten biomarkers were most often used to measure allostatic load. More recently, body mass index and C-reactive protein have additionally been frequently used to measure allostatic load burden.

CONCLUSIONS

The scientific contributions of this study are that we have identified a clear gap in geographic considerations when studying allostatic load. The implication of this study is that we have highlighted geographic concepts when conducting neighborhood-level research using administrative databases as a neighborhood proxy and outlined emerging future trends that can enable future study of allostatic load in the neighborhood context.

Schizophrenia: the new etiological synthesis

Schizophrenia has been an evolutionary paradox: it has high heritability, but it is associated with decreased reproductive success. The causal genetic variants underlying schizophrenia are thought to be under weak negative selection. To unravel this paradox, many evolutionary explanations have been suggested for schizophrenia. We critically discuss the constellation of evolutionary hypotheses for schizophrenia, highlighting the lack of empirical support for most existing evolutionary hypotheses-with the exception of the relatively well supported evolutionary mismatch hypothesis. It posits that evolutionarily novel features of contemporary environments, such as chronic stress, low-grade systemic inflammation, and gut dysbiosis, increase susceptibility to schizophrenia. Environmental factors such as microbial infections (e.g., Toxoplasma gondii) can better predict the onset of schizophrenia than polygenic risk scores. However, researchers have not been able to explain why only a small minority of infected people develop schizophrenia. The new etiological synthesis of schizophrenia indicates that an interaction between host genotype, microbe infection, and chronic stress causes schizophrenia, with neuroinflammation and gut dysbiosis mediating this etiological pathway. Instead of just alleviating symptoms with drugs, the parasite x genotype x stress model emphasizes that schizophrenia treatment should focus on detecting and treating possible underlying microbial infection(s), neuroinflammation, gut dysbiosis, and chronic stress.

Recent findings on subjective well-being and physical, psychiatric, and social comorbidities in individuals with schizophrenia: A literature review

AIM

Care for people with schizophrenia is shifting the locus from long-stay mental hospitals to nonspecialized community-based settings. Knowledge on the care is not a sole property of psychiatric specialists. Community healthcare workers who do not specialize in psychiatry are recommended to learn more about schizophrenia. This review aimed to summarize recent findings on subjective well-being and physical, psychiatric, and social comorbidities in individuals with schizophrenia.

METHODS

A literature review was conducted. We retrieved findings from existing systematic reviews and meta-analyses as our preferred method. When data were not available, we referred to other types of studies.

RESULTS

As per our review, individuals with schizophrenia demonstrated poor subjective well-being, happiness, and life satisfaction despite individual differences. Pharmacotherapy caused weight gain and constipation, whereas race and hospitalization might affect weight reduction. Individuals with schizophrenia demonstrated poor oral health, a high prevalence of noncommunicable diseases, and unique eating behaviors. Depression, sleep disorders, smoking, and alcohol and drug consumption were frequently found in the individuals. Research findings regarding problematic internet and smartphone use and stress perception were limited. Low health literacy and neglect of preventable behaviors were frequently seen in individuals with schizophrenia. They tended to be less educated, poor, unemployed, unmarried/unattached, and had poor social cognition, resulting in little social support and a small social network.

CONCLUSION

Retrieving recent data, we confirmed that individuals with schizophrenia had poor subjective well-being and suffer from various physical, psychiatric, and social comorbidities.

Could CRP be a differential biomarker of illness stages in schizophrenia? A systematic review and meta-analysis

BACKGROUND

Patients with schizophrenia display peripheral inflammation but the impact of illness phase is not clear. Our meta-analysis investigated the difference in CRP levels between patients with schizophrenia and controls according to their illness phase.

METHODS

After a systematic search, all studies measuring CRP in patients with schizophrenia and controls were included. Standardized mean differences were calculated between patients and controls according to illness phase. The influence of sociodemographic and clinical variables on our results was investigated using a meta-regression analysis.

RESULTS

Fifty studies were included in this meta-analysis. Patients with schizophrenia had higher CRP levels than controls in the acute (p < 0.00001) and stable (p < 0.00001) stage of their disease. Patients with acute exacerbation of schizophrenia had higher CRP levels than stable patients (p = 0.02) but this difference did not persist when considering antipsychotic-medicated patients in both phases. Meta-regressions found that the increase of CRP in acutely ill patients as compared to controls was influenced by age (p < 0.01), BMI (p = 0.01) and first episode (p = 0.02), whereas the increase in CRP levels of stable patients as compared to controls was moderated by BMI (p = 0.004).

CONCLUSIONS

In conclusion, this meta-analysis provides strong evidence that patients with schizophrenia have higher CRP levels than controls, but also show an increase in inflammatory response in the acute stage of the disease as compared to the stable stage. CRP could thus be considered as a state marker and a trait marker of the disease.

Allostatic load and systemic comorbidities in psychiatric disorders

Psychiatric disorders are complex, disabling, and chronic conditions that are often accompanied by one or more systemic medical comorbidities. In this narrative review, we provide an overview of the allostatic load concept, which represents a multi-system dysregulation in response to chronic stress and link it to systemic comorbidities associated with psychiatric disorders. We synthesized published literature gathered using Medline (Ovid), Scopus, and PsychInfo and identified a high frequency of systemic comorbidities for both mood and psychotic disorders. The identified cardiovascular, metabolic, and immune comorbidities may represent the result of chronic wear and tear caused by a complex interaction between chronic psychosocial stress, health risk behaviors, pharmacological stressors, and the biological systems involved in the development of allostatic load. These findings support the notion that psychiatric disorders should be re-conceptualized as systemic disorders, affecting the brain and systemic biological pathways in an interconnected fashion to result in systemic comorbidities. We suggest that the multi-systemic and multi-dimensional approach that drives the allostatic load concept should be considered for understanding comorbidities in vulnerable psychiatric patients.

Heightened risk factors in the midst of the pandemic: Supporting individuals with psychosis during COVID-19

PURPOSE

This article aims to describe distinct vulnerabilities to the psychosocial stress from coronavirus disease 2019 (COVID-19) on individuals with psychosis and provide practical ways to reduce the vulnerabilities.

CONCLUSION

Societal changes and stress have come in the wake of the COVID-19. Individuals with psychosis are more susceptible to stress, cognitive biases, and lack social support. Practitioners working with individuals with psychosis are in a unique position to offer ways to reduce risk.

PRACTICE IMPLICATIONS

Care during the pandemic requires practitioners to pay particular attention to magnified risk factors to individuals with psychosis and create a plan to offer adjunct support.

Psychosocial stress and neuroendocrine biomarker concentrations among women living with or without HIV

OBJECTIVE

Women living with HIV (WLWH) experience psychosocial stress related to social-structural vulnerabilities. To investigate neuroendocrine pathways linking stress and increased cardiovascular disease risk among WLWH, we evaluated associations between psychosocial stress (i.e., perceived stress, posttraumatic stress, and experiences of race- and gender-based harassment) and a composite neuroendocrine biomarker index among WLWH and women without HIV.

METHODS

In 2019-2020, Women's Interagency HIV Study participants in Washington, DC completed a questionnaire and provided blood and 12-hour overnight urine samples for testing of serum dehydroepiandrosterone sulfate (DHEA-S) and urinary free cortisol, epinephrine, and norepinephrine. Psychosocial stress was measured using the Perceived Stress Scale, PTSD Checklist-Civilian Version, and Racialized Sexual Harassment Scale. Latent profile analysis was used to classify participants into low (38%), moderate (44%), and high (18%) stress groups. Composite biomarker index scores between 0-4 were assigned based on participants' number of neuroendocrine biomarkers in high-risk quartiles (≥75th percentile for cortisol, epinephrine, and norepinephrine and ≤25th percentile for DHEA-S). We evaluated associations between latent profile and composite biomarker index values using multivariable linear regression, adjusting for socio-demographic, behavioral, metabolic, and HIV-related factors.

RESULTS

Among 90 women, 62% were WLWH, 53% were non-Hispanic Black, and median age was 55 years. In full multivariable models, there was no statistically significant association between psychosocial stress and composite biomarker index values among all women independent of HIV status. High (vs. low) psychosocial stress was positively associated with higher mean composite biomarker index values among all monoracial Black women (adjusted β = 1.32; 95% CI: 0.20-2.43), Black WLWH (adjusted β = 1.93; 95% CI: 0.02-3.83) and Black HIV-negative women (adjusted β = 2.54; 95% CI: 0.41-4.67).

CONCLUSIONS

Despite a null association in the overall sample, greater psychosocial stress was positively associated with higher neuroendocrine biomarker concentrations among Black women, highlighting a plausible mechanism by which psychosocial stress could contribute to cardiovascular disease risk.

Allostatic Load and Its Impact on Health: A Systematic Review

INTRODUCTION

Allostatic load refers to the cumulative burden of chronic stress and life events. It involves the interaction of different physiological systems at varying degrees of activity. When environmental challenges exceed the individual ability to cope, then allostatic overload ensues. Allostatic load is identified by the use of biomarkers and clinical criteria.

OBJECTIVE

To summarize the current knowledge on allostatic load and overload and its clinical implications based on a systematic review of the literature.

METHODS

PubMed, PsycINFO, Web of Science, and the Cochrane Library were searched from inception to December 2019. A manual search of the literature was also performed, and reference lists of the retrieved articles were examined.We considered only studies in which allostatic load or overload were adequately described and assessed in either clinical or non-clinical adult populations.

RESULTS

A total of 267 original investigations were included. They encompassed general population studies, as well as clinical studies on consequences of allostatic load/overload on both physical and mental health across a variety of settings.

CONCLUSIONS

The findings indicate that allostatic load and overload are associated with poorer health outcomes. Assessment of allostatic load provides support to the understanding of psychosocial determinants of health and lifestyle medicine. An integrated approach that includes both biological markers and clinimetric criteria is recommended.

Allostatic load and mental health: a latent class analysis of physiological dysregulation

This study explored the associations between specific profiles of biological dysregulation and mental health outcomes in a national, community sample of healthy adults in the United States. A latent class analysis of data from the Midlife Development in the United States study (n = 1,757) was conducted to determine classes of biological dysregulation. Multinomial logistic regressions of class membership were employed to determine associations with measures related to depression, including whether or not individuals had sought treatment, Center for Epidemiological Studies Depression Scale, and both the generalized distress and anhedonia subscales of the Mood and Anxiety Symptoms Questionnaire. Four classes of dysregulation emerged: baseline/low dysregulation, metabolic and inflammatory dysregulation, parasympathetic dysregulation, and SAM pathway dysregulation. Individuals who met the criteria for depression measures were more likely to be in the metabolic and immune dysregulation and parasympathetic dysregulation groups as compared to the baseline group. The results suggest that mental health outcomes, such as depression, are differentially associated with specific profiles of biological dysregulation. A more nuanced approach to profiles of dysregulation could better inform treatment decisions.Lay summaryHigher levels of allostatic load, which represents the cumulative wear and tear of exposure to stress, are associated with increased rates of depression and anhedonia. Specifically, parasympathetic dysregulation and immunometabolic dysregulation are associated with negative mental health outcomes.

A systematic review and realist synthesis on toilet paper hoarding: COVID or not COVID, that is the question

OBJECTIVE

To explore whether the coronavirus disease 2019 (COVID-19) pandemic is associated with toilet paper hoarding and to assess which risk factors are associated with the risk of toilet paper hoarding.

DESIGN

A systematic review and realist review were conducted.

DATA SOURCES

PubMed, Web of Science, Scopus and PsycINFO were searched (systematic review). PubMed, pre-prints and grey literature were also searched (realist review). The databases were searched from inception until October 2020.

STUDY SELECTION

There were no restrictions on the study design.

OUTCOMES AND MEASURES

For the systematic review, toilet paper hoarding was the main outcome, and pathological use of toilet paper was the secondary outcome. For the realist review, the context-mechanisms-outcome (CMO) scheme included the COVID-19 pandemic (context), four proposed mechanisms, and one outcome (toilet paper hoarding). The four potential mechanisms were (1) gastrointestinal mechanisms of COVID-19 (e.g. diarrhoea), (2) social cognitive biases, (3) stress-related factors (mental illnesses, personality traits) and (4) cultural aspects (e.g. differences between countries).

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

All studies of human populations were considered (including general population studies and clinical studies of patients suffering from mental health problems).

RESULTS

The systematic review identified 14 studies (eight studies for the main outcome, six studies for the secondary outcome). Three surveys identified the role of the COVID-19 threat in toilet paper hoarding in the general population. One study pointed to an association between a personality trait (conscientiousness) and toilet paper buying and stockpiling as well as an additional significant indirect effect of emotionality through the perceived threat of COVID-19 on toilet paper buying and stockpiling. Six case reports of pathological use of toilet paper were also identified, although none of them were associated with the COVID-19 pandemic. The realist review suggested that of all the mechanisms, social cognitive biases and a bandwagon effect were potential contributors to toilet paper hoarding in the general population. The stressful situation (COVID-19 pandemic) and some personality traits (conscientiousness) were found to be associated with toilet paper hoarding. Cultural differences were also identified, with relatively substantial effects of toilet paper hoarding in several Asian regions (Australia, Japan, Taiwan and Singapore).

CONCLUSIONS

The COVID-19 pandemic has been associated with a worldwide increase in toilet paper hoarding. Social media and social cognitive biases are major contributors and might explain some differences in toilet paper hoarding between countries. Other mental health-related factors, such as the stressful situation of the COVID-19 pandemic, fear of contagion, or particular personality traits (conscientiousness), are likely to be involved.

REGISTRATION

PROSPERO CRD42020182308.

Relationship between allostatic load and clinical outcomes in youth at ultra-high risk for psychosis in the NEURAPRO study

Individuals at ultra-high risk (UHR) for psychosis have an elevated risk of developing psychosis and other psychiatric outcomes. Risk biomarkers can assist in delineating individual risk and allow better prediction of longer-term outcomes. The aim of the present study was to examine if allostatic load (AL), a multisystem index of neuroendocrine, cardiovascular, immune and metabolic dysregulation, is associated with clinical outcomes in youth at UHR for psychosis. AL was measured in 106 participants of the NEURAPRO study (n = 70 female, n = 36 male; mean age 17.21, SD 2.37), a multicentre randomized-controlled trial of long-chain omega-3 polyunsaturated fatty acids versus placebo in people at UHR for psychosis. Psychiatric symptoms and social and occupational functioning were assessed at baseline and 6 and 12 months after study intake. Multivariate linear and logistic regression models were used to test the relationship between AL and clinical outcomes. High AL at baseline was associated with poor social and occupational functioning at 6 months (β = -0.224, p = 0.025) and with more severe manic symptoms at 6 months (β = 0.207, p = 0.026), taking into account relevant covariates including age and smoking status. No significant associations were observed at the 12-month follow-up assessment or with any other clinical outcome measures. Our data provide initial evidence for a link between AL and impaired functioning in individuals at UHR for psychosis. Further studies are needed to evaluate AL as a potential predictor of early treatment response.

Allostatic load, emotional hyper-reactivity, and functioning in individuals with bipolar disorder

OBJECTIVES

Diagnosis and management of bipolar disorder (BD) are limited by the absence of available biomarkers. Allostatic load (AL) represents the strain that stress, including the effects of acute phases and inter-episode chronic mood instability, exerts on interconnected biological systems. This study aimed to operationalize an AL index and explore whether it could be relevant to better characterize BD patients with and without emotional hyper-reactivity particularly those at higher risk of immune-cardiometabolic dysregulation and functional impairment.

METHODS

Levels of biomarkers of chronic inflammation (hsCRP and albumin), cardiovascular (systolic/diastolic blood pressure) and metabolic functions (fasting glucose, glycosylated hemoglobin, total cholesterol, LDL, HDL, and triglycerides) were measured in 1072 adult BD outpatients. Patients were classified in two groups (with/without emotional hyper-reactivity) assessed by the Multidimensional Assessment of Thymic States scale. An Allostatic Load Index for BD (BALLI), comprising six biomarkers, was constructed using data-driven biomarker selection.

RESULTS

BALLI showed 81.1% accuracy with good sensitivity (81%) and specificity (81.2%) for characterizing BD patients presenting emotional hyper-reactivity, elevated risk of inflammation (increased hsCRP, hypoalbuminemia) and cardiometabolic disturbances (hypertension, hyperglycemia, and hypertriglyceridemia). Patients classified by the BALLI as presenting emotional hyper-reactivity had significantly lower global and cognitive functioning than those without emotional hyper-reactivity (P < .0001).

CONCLUSIONS

A multidimensional approach based on a simple AL score (eg, BALLI) and dimensions of behavior (eg, emotional hyper-reactivity) alongside mood is clinically relevant. AL index could be a useful tool to detect multisystemic physiological dysregulations in BD patients with/without emotional hyper-reactivity particularly those at higher risk of immune-cardiometabolic disturbances and functional impairment.

Allostatic load and women's brain health: A systematic review

Allostatic load represents the 'wear and tear' of chronic stress on the brain and body that may differ between men and women. A small but growing number of studies are assessing allostatic load in relation to mental health. The objective of this systematic review was to (1) assess sex differences in allostatic load and (2) identify allostatic load associations that are specific to women. We systematically searched for allostatic load studies that included psychosocial causes and/or psychiatric consequences. Our search focused on allostatic load studies that disaggregated by sex and that include women. Sixty-two studies were included in this systematic review. First, men appear to have higher allostatic load than women. Second, women show gender-specific variation for numerous factors such as age, race/ethnicity, adversities, social support, and health behaviors that influence associations between allostatic load and mental health. Recommendations are made to guide researchers advance sex and gender approaches.

Academic achievement and schizophrenia: a systematic meta-analysis

BACKGROUND

Cognitive impairments in childhood are associated with increased risk of schizophrenia in later life, but the extent to which poor academic achievement is associated with the disorder is unclear.

METHODS

Major databases were searched for articles published in English up to 31 December 2019. We conducted random-effects meta-analyses to: (1) compare general academic and mathematics achievement in youth who later developed schizophrenia and those who did not; (2) to examine the association between education level achieved and adult-onset schizophrenia; and, (3) compare general academic achievement in youth at-risk for schizophrenia and typically developing peers. Meta-regression models examined the effects of type of academic assessment, educational system, age at assessment, measurement of educational level attained, school leaving age, and study quality on academic achievement and education level among individuals with schizophrenia.

RESULTS

Meta-analyses, comprising data of over four million individuals, found that: (1) by age 16 years, those who later developed schizophrenia had poorer general academic (Cohen's d = -0.29, p ⩽ 0.0001) and mathematics achievement (d = -0.23, p = 0.01) than those who did not; (2) individuals with schizophrenia were less likely to enter higher education (odds ratio = 0.49, p ⩽ 0.0001); and, (3) youth reporting psychotic-like experiences and youth with a family history of schizophrenia had lower general academic achievement (d = -0.54, p ⩽ 0.0001; d = -0.39, p ⩽ 0.0001, respectively). Meta-regression analyses determined no effect modifiers.

DISCUSSION

Despite significant heterogeneity across studies, various routinely collected indices of academic achievement can identify premorbid cognitive dysfunction among individuals who are vulnerable for schizophrenia, potentially aiding the early identification of risk in the population.

A history of childhood trauma and allostatic load in patients with psychotic disorders with respect to stress coping strategies

Elevated allostatic load (AL) index, which is a cumulative measure of biological dysregulations associated with stress exposure, has been demonstrated in patients with psychosis. However, it remains unknown whether a history of childhood trauma (CT) might contribute to elevated AL index in psychosis. Therefore, we aimed to investigate the association between AL index, a history of CT and coping styles in patients with psychotic disorders. Participants were 65 patients with schizophrenia-spectrum disorders and 56 healthy controls (HCs). The AL index was computed based on percentile distributions of 15 biomarkers in HCs. The AL index was significantly higher in patients with psychosis. A history of parental antipathy was associated with elevated AL index in both groups of participants. A history of any categories of CT and sexual abuse were associated with higher AL index only in patients with psychosis. Social diversion (seeking social interactions in case of stressful experiences) mediated the association between sexual abuse and the AL index in the group of patients. There was a significant direct effect of sexual abuse on the AL index (this specific CT was associated with higher AL index). However, indirect effect of sexual trauma on AL through social diversion was opposite to direct effect. Childhood adversities, especially sexual abuse and parental antipathy, might contribute to elevated AL index in patients with psychosis. The effect of sexual abuse on the AL index might be specific to psychosis. Engagement in social interactions in case of stressful situations might alleviate biological dysregulations associated with CT.

Choroid Plexus Enlargement and Allostatic Load in Schizophrenia

Although schizophrenia is a brain disorder, increasing evidence suggests that there may be body-wide involvement in this illness. However, direct evidence of brain structures involved in the presumed peripheral-central interaction in schizophrenia is still unclear. Seventy-nine previously treatment-naïve first-episode schizophrenia patients who were within 2-week antipsychotics initial stabilization, and 41 age- and sex-matched healthy controls were enrolled in the study. Group differences in subcortical brain regional structures measured by MRI and the subclinical cardiovascular, metabolic, immune, and neuroendocrine biomarkers as indexed by allostatic load, and their associations were explored. Compared with controls, patients with schizophrenia had significantly higher allostatic load (P = .001). Lateral ventricle (P < .001), choroid plexus (P < .001), and thalamus volumes (P < .001) were significantly larger, whereas amygdala volume (P = .001) was significantly smaller in patients. The choroid plexus alone was significantly correlated with higher allostatic load after age, sex, education level, and the total intracranial volume were taken into account (t = 3.60, P < .001). Allostatic load was also significantly correlated with PANSS positive (r = 0.28, P = .016) and negative (r = -0.31, P = .008) symptoms, but in opposite directions. The peripheral multisystemic and central nervous system abnormalities in schizophrenia may interact through the choroid plexus during the early stage of the illness. The choroid plexus might provide a sensitive structural biomarker to study the treatment and prevention of brain-periphery interaction abnormalities in schizophrenia.

Stress, Allostatic Load, and Psychosis: One Step Forward in Research But Where to Go Next?

Stress exposure leads to the activation of several biological mechanisms that have been termed allostasis. These processes enable adaptation to novel situations; however; their prolonged activation exerts systemic and detrimental effects called the allostatic load (AL). The AL concept represents one of useful paradigms to describe biological consequences of chronic stress that might lead to a number of disease outcomes. The AL index, which is a collective measure of cardiovascular, metabolic, neuroendocrine, and immune dysregulations associated with stress exposure, has been found to predict morbidity and mortality in non-clinical populations. Consequently, it has been proposed that the AL concept might be a useful framework to describe biological consequences of chronic stress exposure in patients with psychotic disorders. This perspective article is an overview of studies investigating the AL index and its clinical correlates in patients with psychotic disorders. These studies have consistently reported elevated AL index in patients at the early and chronic course of psychosis. In addition, the AL index has been associated with a higher severity of positive and depressive symptoms, working memory impairments, and lower general functioning. The article provides some critical appraisal of studies in this field and indicates several future directions for investigating the AL concept in psychosis.

The Role of Hippocampal Functional Connectivity on Multisystem Subclinical Abnormalities in Schizophrenia

OBJECTIVE

Schizophrenia is associated with excess medical mortality: patients have an average life expectancy one to two decades shorter than the general population. This study investigates the relationship between aberrant hippocampal resting-state functional connectivity in schizophrenia and cumulative subclinical effects of chronic stress on metabolic, cardiovascular, and immune function using the allostatic load index.

METHODS

Cumulative stress was estimated using allostatic load total score (range, 0-13) in 46 patients with schizophrenia and 31 controls matched for age and sex (patients: age = 36.1 [13.7] years, sex = 32/14 male/female; controls: age = 35.5 [14.1], sex = 21/10 male/female). Hippocampal functional connectivity was assessed using resting-state functional magnetic resonance imaging; hippocampal structural connectivity was assessed using fornix fractional anisotropy. Linear regression analysis was used a) to test the hypothesis that aberrant hippocampal resting-state functional connectivity in schizophrenia (identified in analysis of schizophrenia - control differences) is associated with elevated allostatic load scores in patients and b) to determine the association between fornix fractional anisotropy with allostatic load.

RESULTS

In patients, higher allostatic load was significantly associated with reduced resting functional connectivity between the left hippocampus and right cingulate cortex and left precentral gyrus, but higher connectivity between the right hippocampus and left cerebellum lobe VI (corrected p values <. 05). In controls, reductions in both hippocampal structural connectivity and hippocampal-cingulate functional connectivity were associated with higher allostatic load scores.

CONCLUSIONS

These findings support basic neuroscience evidence that cumulative stress and hippocampal function are closely connected and suggest that abnormal hippocampal functional communication in schizophrenia may be related to elevated multisystem subclinical medical issues in patients as indexed by allostatic load.

Schizophrenia Mortality: Barriers to Progress

Individuals with schizophrenia die, on average, 20 years before their peers, with 'natural causes' accounting for 80% of premature deaths. The aim of this narrative review is to address this phenomenon from the perspective of known factors that contribute to long life. The relevant literature from the last decade was searched in PubMed and Google Scholar databases. Four factors have been shown to be common to centarians, people who live to be a hundred: genes, life style behaviors that favor a healthy heart, social support, and a subjective purpose in life. The latter three factors are potentially modifiable but, in the context of schizophrenia, there are barriers to change, namely poverty, illness symptoms, stress, stigma, and side effects of antipsychotic medication. Barriers to change need to be addressed before substantial progress can be made in increasing the health and mortality risk of people with schizophrenia.

Allostatic load index and its clinical correlates at various stages of psychosis

Accumulating evidence indicates systemic biological dysregulations in patients with psychosis that have been conceptualized as the "allostatic load" (AL) index. We aimed to investigate the AL index in 37 subjects at familial high risk of psychosis (FHRP), 42 first-episode psychosis (FEP) patients, 25 acutely relapsed schizophrenia (SCZ-AR) patients and 42 healthy controls (HCs), taking into account psychopathology and cognitive impairment. The AL index was calculated based on 15 biomarkers (cardiovascular markers, anthropometric measures, inflammatory markers, glucose homeostasis parameters, lipids and steroids). Cognition was assessed using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). The AL index was significantly higher in patients with psychosis and FHR-P individuals compared to HCs. Patients with FEP and FHR-P individuals had similar AL index. Moreover, the AL index was significantly higher in SCZ-AR patients compared to other groups of participants. Higher AL index was associated with more severe general psychopathology and depressive symptoms, lower scores of attention (total score, digit span and digit coding tasks) and semantic fluency, as well as worse general functioning in patients with psychosis. There was a significant negative correlation between the AL index and the scores of attention (total score and digit coding task) in FHR-P individuals. No significant correlations between the AL index and cognition were found in HCs. Our results indicate that biological dysregulations, captured by the AL index, appear already in FHR-P individuals and progress with psychotic exacerbations. Elevated AL index might contribute to cognitive impairments in FHR-P individuals and patients with psychosis.

The rat cumulative allostatic load measure (rCALM): a new translational assessment of the burden of stress

Determinants of lifetime health are complex and emphasize the need for robust predictors of disease risk. Allostatic load (AL) has become a clinical framework to estimate the cumulative biological burden associated with chronic stress. To assist knowledge translation in the developmental origins of health and disease field, clinically valid methods for reliable AL assessment in experimental models are urgently needed. Here, we introduce the rat cumulative allostatic load measure (rCALM), as a new preclinical knowledge translation tool to assess the burden of chronic stress. First, we identified an array of stress-associated physiological markers that are particularly sensitive to hypothalamic-pituitary-adrenal axis dysregulation by ancestral prenatal stress. Second, we determined which of these markers are susceptible to an intervention by environmental enrichment (EE) to mitigate AL. The markers most responsive to stress and EE therapy were assembled to become operationalized in the rCALM. Third, the new rCALM was validated for the ability to indicate future disease risks. The results show that the rCALM estimates the burden of chronic stress and serves as a proxy to estimate stress resilience and vulnerability to disease. Using the rCALM we showed that enrichment therapy can offset the adverse health outcomes linked to a high AL. Thus, the rCALM provides a model for the development of new test strategies that facilitate knowledge translation in preclinical animal models.

Elevated allostatic load early in the course of schizophrenia

Stress plays a significant role in schizophrenia from disease onset to exacerbation of psychotic symptoms. Allostatic load (AL) is a measure of cumulative stress to the organism. This study is an extension of our previous work on AL and its relationship to brain structures. Here, we further determined whether elevated AL is a function of illness chronicity, or if it is already present early in the course of schizophrenia. AL was compared in schizophrenia patients early in the illness (within 5 years of disease onset), patients with chronic schizophrenia (more than 5 years of illness), and two groups of healthy controls that were age-and sex-matched to the two patient groups. This work is presented with an expanded sample and includes about two-thirds of the participants who were previously reported. We found that patients with early psychosis had significantly elevated AL score compared with their age-matched controls (p = 0.005). Chronic course patients also had elevated AL compared with age-matched controls (p = 0.003). Immune and stress hormone AL subcomponents were nominally higher in early-stage patients compared with controls (p = 0.005 and 0.04, respectively). Greater AL was also associated with more severe positive psychotic symptoms in early-stage patients (r = 0.54, p = 0.01). Elevated levels of allostatic load are already present in the early years of the schizophrenia illness, particularly in patients with more severe psychotic symptoms. AL may be a useful evaluation for the need of early intervention on psychosomatic comorbidity.

Diverse definitions of the early course of schizophrenia-a targeted literature review

Schizophrenia is a debilitating psychiatric disorder and patients experience significant comorbidity, especially cognitive and psychosocial deficits, already at the onset of disease. Previous research suggests that treatment during the earlier stages of disease reduces disease burden, and that a longer time of untreated psychosis has a negative impact on treatment outcomes. A targeted literature review was conducted to gain insight into the definitions currently used to describe patients with a recent diagnosis of schizophrenia in the early course of disease ('early' schizophrenia). A total of 483 relevant English-language publications of clinical guidelines and studies were identified for inclusion after searches of MEDLINE, MEDLINE In-Process, relevant clinical trial databases and Google for records published between January 2005 and October 2015. The extracted data revealed a wide variety of terminology and definitions used to describe patients with 'early' or 'recent-onset' schizophrenia, with no apparent consensus. The most commonly used criteria to define patients with early schizophrenia included experience of their first episode of schizophrenia or disease duration of less than 1, 2 or 5 years. These varied definitions likely result in substantial disparities of patient populations between studies and variable population heterogeneity. Better agreement on the definition of early schizophrenia could aid interpretation and comparison of studies in this patient population and consensus on definitions should allow for better identification and management of schizophrenia patients in the early course of their disease.

Decreased use of active coping styles contributes to elevated allostatic load index in first-episode psychosis

Accumulating evidence indicates that stress plays an important role in the development of psychotic disorders. Recent studies have revealed that patients with first-episode psychosis (FEP) present systemic biological dysregulations related to stress-exposure in terms of elevated allostatic load (AL) index. However, the mechanisms underlying this observation remain unknown. Therefore, in this study we aimed to investigate the AL index with respect to stress coping strategies in 36 FEP patients and 31 matched controls. We found significantly higher AL index in FEP patients compared to controls after co-varying for potential confounding factors. Patients with FEP were less likely to use active and task-focused coping. Lower odds of using these coping styles, planning as well as positive reinterpretation and growth were related to higher AL index in FEP patients, but not in controls. Depressive symptoms were associated with lower likelihood of using task-focused coping as well as positive reinterpretation and growth. Additionally, depressive symptoms were related to higher AL index. Finally, depressive symptoms mediated the effects of task-focused coping as well as positive reinterpretation and growth on the AL index. Our results confirm systemic biological dysregulation indexed as AL in FEP patients. Lower odds of using active coping styles might contribute to higher AL index via the mediating effect of depressive symptoms in patients with FEP. Longitudinal studies are required to establish causal inferences between coping styles, depressive symptoms and the AL index in early psychosis.

Allostatic load is associated with psychotic symptoms and decreases with antipsychotic treatment in patients with schizophrenia and first-episode psychosis

Current pathophysiological models of schizophrenia suggest that stress contributes to the etiology and trajectory of the disorder. We investigated if allostatic load (AL), an integrative index of neuroendocrine, immune and metabolic dysregulation in response to chronic stress, is elevated in patients with schizophrenia (SCZ) and first-episode psychosis (FEP) and related to psychotic symptoms and social and occupational functioning. Additionally, we assessed the temporal dynamics of AL in response to treatment with second-generation antipsychotics. AL, psychotic symptoms and psychosocial functioning were assessed in a longitudinal design in patients with SCZ (n = 28), FEP (n = 28), and healthy controls (n = 53) at baseline and 6 and 12 weeks after commencement of antipsychotic therapy. AL at baseline was higher in patients with SCZ and FEP relative to controls, but not different between patients with SCZ and FEP. Adjusting for age and smoking, we found that positive symptoms were positively correlated with AL and psychosocial functioning was negatively correlated with AL at trend level. Linear mixed model analysis demonstrated that AL decreased after treatment was commenced in patients with SCZ and FEP between the baseline assessment and the 6 and 12-week follow-up. AL was not predictive of treatment response or symptomatic remission. Our data provide evidence for cumulative physiological dysregulation in patients with SCZ and FEP that is linked to the experience of current positive psychotic symptoms. AL could be a useful tool to monitor biological signatures related to chronic stress and unhealthy behaviors in schizophrenia.

Stress induced cortisol release and schizotypy

Cortisol is involved in preparing the body's response for stress. However, in those at risk for mental health problems, abnormal cortisol release following stress has been reported. In particular, we are yet to fully understand how stress leads to an exacerbation of symptoms and progression of risk in those who express psychosis proneness or schizotypy. Using the Trier Social Stress Test, we examined the effect of experimentally induced psychosocial stress on cortisol release in otherwise healthy individuals with schizotypal traits. This cross-sectional study included 58 individuals (32.76% male, mean age 22.43). Schizotypy was assessed by total Schizotypal Personality Questionnaire score and we additionally captured ratings of subjective stress. Salivary cortisol was collected over six time points spread prior to and after stress induction and was available for analysis in 39 individuals (28.21% male, mean age 22.77). Those with high schizotypal traits exhibited higher baseline cortisol levels (5.18 nmoL vs 3.71 nmoL). However, those with high schizotypal traits also displayed reduced mean cortisol release (2.02 nmoL vs 5.11 nmoL) and had a delayed cortisol release peak following psychosocial stress. These results indicate those with high schizotypal traits do not display physiological readiness following psychosocial stressors, perhaps due to an already taxed stress system.

vmPFC activation during a stressor predicts positive emotions during stress recovery

Despite accruing evidence showing that positive emotions facilitate stress recovery, the neural basis for this effect remains unclear. To identify the underlying mechanism, we compared stress recovery for people reflecting on a stressor while in a positive emotional context with that for people in a neutral context. While blood-oxygen-level dependent data were being collected, participants (N = 43) performed a stressful anagram task, which was followed by a recovery period during which they reflected on the stressor while watching a positive or neutral video. Participants also reported positive and negative emotions throughout the task as well as retrospective thoughts about the task. Although there was no effect of experimental context on emotional recovery, we found that ventromedial prefrontal cortex (vmPFC) activation during the stressor predicted more positive emotions during recovery, which in turn predicted less negative emotions during recovery. In addition, the relationship between vmPFC activation and positive emotions during recovery was mediated by decentering-the meta-cognitive detachment of oneself from one's feelings. In sum, successful recovery from a stressor seems to be due to activation of positive emotion-related regions during the stressor itself as well as to their downstream effects on certain cognitive forms of emotion regulation.

How Well Do We Understand the Long-Term Health Implications of Childhood Bullying?

Once dismissed as an innocuous experience of childhood, bullying is now recognized as having significant psychological effects, particularly with chronic exposure. Victims of bullying are at risk for a number of psychiatric disturbances, and growing evidence suggests that the pathophysiological effects of bullying, as with other forms of trauma and chronic stress, create additional health risks. We review the literature on the known sequelae of bullying, including psychiatric and physiological health effects, with a focus on implications for the victim. In addition, since it is now well established that early and chronic exposure to stress has a significant negative impact on health outcomes, we explore the implications of this research in relation to bullying and victimization in childhood. In particular, we examine how aspects of the stress response, via epigenetic, inflammatory, and metabolic mediators, have the capacity to compromise mental and physical health, and to increase the risk of disease. Research on the relevant mechanisms associated with bullying and on potential interventions to decrease morbidity is urgently needed.

Psychoneuroimmunology of mental disorders

The immune system is a key element in the organism's defence system and participates in the maintenance of homeostasis. There is growing interest in the aetiopathogenic and prognostic implications of the immune system in mental disorders, as previous studies suggest the existence of a dysregulation of the immune response and a pro-inflammatory state in patients with mental disorders, as well as an increased prevalence of neuropsychiatric symptoms in patients suffering from autoimmune diseases or receiving immune treatments. This study aims to conduct a narrative review of the scientific literature on the role of Psychoneuroimmunology in mental disorders, with special focus on diagnostic, prognostic and therapeutic issues. The development of this body of knowledge may bring in the future important advances in the vulnerability, aetiopathogenic mechanisms, diagnosis and treatment of some mental disorders.

Fornix Structural Connectivity and Allostatic Load: Empirical Evidence From Schizophrenia Patients and Healthy Controls

OBJECTIVE

The fornix is a white matter tract carrying the fibers connecting the hippocampus and the hypothalamus, two essential stress-regulatory structures of the brain. We tested the hypothesis that allostatic load (AL), derived from a battery of peripheral biomarkers indexing the cumulative effects of stress, is associated with abnormalities in brain white matter microstructure, especially the fornix, and that higher AL may help explain the white matter abnormalities in schizophrenia.

METHODS

Using 13 predefined biomarkers, we tested AL in 44 schizophrenic patients and 33 healthy controls. Diffusion tensor imaging was used to obtain fractional anisotropy (FA) values of the fornix and other white matter tracts.

RESULTS

AL scores were significantly elevated in patients compared with controls (F(3,77) = 7.87, p = .006). AL was significantly and inversely correlated with FA of fornix in both controls (r = -.58, p = .001) and patients (r = -.36, p = .023). Several nominally significant (p < .05 but did not survive Bonferroni correction for multiple comparison) correlations were also observed between AL and FA of other white matter tracts in schizophrenic patients. However, the fornix was the only tract exhibiting a correlation with AL in both groups.

CONCLUSIONS

These results provide initial evidence that allostatic processes are linked to fornix microstructure in clinical participants.

Allostatic load in early pregnancy is associated with poor sleep quality

BACKGROUND

Allostatic load (AL) measures the cumulative impact of chronic stress and is associated with adverse health outcomes. A novel scoring system has previously been developed for AL in early pregnancy that is associated with pre-eclampsia. It was hypothesized that AL, as identified by the present model, is associated with psychosocial stressors and, specifically, poor sleep quality.

METHODS

Women were selected from a low-risk, community-dwelling study population who enrolled at <15 weeks gestation. Nine physiologic components were divided among the domains of cardiovascular, metabolic, and inflammatory function. Spearman's rank correlations were used to examine the association of AL with age, income, the Revised Prenatal Distress Questionnaire (NuPDQ), Inventory of Depressive Symptoms (IDS), and Pittsburgh Sleep Quality Index (PSQI). The Wilcoxon rank-sum test was used to compare AL by race and educational attainment.

RESULTS

A total of 103 women were identified, with: a mean age of 29.8 ± 5.0 years, 17.5% black, and mean gestational age 12.2 ± 1.1 weeks. Allostatic load was positively correlated with the PSQI (ρ = 0.23, p = 0.018). There were no associations with age, income, prenatal distress, race, or depression scores. College-educated women had lower AL compared with those with less education (0.57 ± 0.43 vs 0.81 ± 0.55, p = 0.045).

CONCLUSION

Higher AL, measured by the pregnancy-specific model, was associated with poorer sleep quality and lower educational attainment, both of which were considered to be chronic stressors. These relationships were consistent with previous findings in non-pregnant populations, and suggest that AL may be useful for capturing the physiologic impact of chronic stress in early pregnancy.

Allostatic load and reduced cortical thickness in schizophrenia

Structural imaging studies have consistently found reduced gray matter thickness of the cerebral cortex in schizophrenia, a finding that is evident in first episode psychosis and may be progressive in some cases. Although genetic predisposition and medication effects may contribute to cortical thinning, we hypothesize that the cumulative effects of stress may represent an environmental factor impacting brain morphology in schizophrenia. We examined the relationship between allostatic load, an index of peripheral biomarkers representing the cumulative effects of stress, and cortical thickness. Allostatic load was calculated for 44 patients with schizophrenia spectrum disorders (SSD) and 33 normal controls (NC) based on 13 cardiovascular, neuroendocrine, immune, and metabolic measurements. Controlling for age, SSD had significantly elevated allostatic load as compared with NC (p=0.008). Controlling for age, whole brain average cortical thickness was lower in SSD patients compared to NC (p=0.008). However, once allostatic load was accounted for, the group difference in cortical thickness became marginal (p=0.058). Exploratory analyses on subcomponents of allostatic load suggested that elevated immune marker C-reactive protein, stress hormones, and cardiovascular indices within allostatic load were more strongly associated with reduced cortical thickness in SSD. In NC, only the association between immune marker C-reactive protein and cortical thickness was replicated. These results support the hypothesis that allostatic load may account for some of the gray matter deficits observed in schizophrenia. Among the allostatic indices, the inflammatory mechanism appears particularly relevant to cortical thickness in both schizophrenia patients and normal controls.

Comparison of serum carnitine levels and clinical correlates between outpatients and acutely hospitalised individuals with bipolar disorder and schizophrenia: A cross-sectional study

OBJECTIVES

We sought to compare serum carnitine levels and clinical correlates between stable outpatients and acutely hospitalised individuals with diagnoses of bipolar disorder and schizophrenia.

METHODS

We obtained clinical information as well as serum levels for total and free carnitine, high-density lipoprotein (HDL) and triglycerides in 60 consenting individuals.

RESULTS

We found higher total serum carnitine levels in our outpatient group in comparison to acutely hospitalised psychiatric patients, with a statistically significant P value of 0.045. Metabolic syndrome was more prevalent in the outpatient (37.9%) versus inpatient group (16.1%). We identified significantly higher carnitine levels in patients who met the criteria for metabolic syndrome in comparison to the patients without metabolic syndrome, with respective P values for total and free carnitine of 0.0048 and 0.0029.

CONCLUSIONS

This study revealed a complex relationship among carnitine metabolism, metabolic syndrome and behavioural outcomes. Future studies of carnitine metabolism in the context of mental illness as well as metabolic syndrome are warranted.

Abnormal glycemic homeostasis at the onset of serious mental illnesses: A common pathway

OBJECTIVE

Patients with serious mental illnesses exhibit a reduced lifespan compared with the general population, a finding that can not solely rely on high suicide risk, low access to medical care and unhealthy lifestyle. The main causes of death are medical related pathologies such as type 2 diabetes mellitus and cardiovascular disease; however pharmacological treatment might play a role.

MATERIAL AND METHODS

We compared a two hour glucose load in naïve patients at the onset of a serious mental illness (N=102) (84 patients with a first episode of schizophrenia and related disorders, 6 with a first episode of bipolar I disorder and 12 with a first episode of major depression disorder) with another psychiatric diagnose, adjustment disorder (N=17) and matched controls (N=98).

RESULTS

Young patients with serious mental illness showed an increased two hour glucose load compared with adjustment disorder and the control group. Mean two hour glucose values [±standard deviation] were: for schizophrenia and related disorders 106.51mg/dL [±32.0], for bipolar disorder 118.33mg/dL [±34.3], for major depressive disorder 107.42mg/dL [±34.5], for adjustment disorder 79.06mg/dL[±24.4] and for the control group 82.11mg/dL [±23.3] (p<0.001).

CONCLUSIONS

Our results reflect an abnormal metabolic pathway at the onset of the disease before any pharmacological treatment or other confounding factors might have taken place. Our results suggest a similar glycemic pathway in serious mental illnesses and the subsequent need of primary and secondary prevention strategies.

Psychosis following traumatic brain injury and cannabis use in late adolescence

BACKGROUND

Both cannabis and traumatic brain injury (TBI) pose risks on the developing brain, including a potential increased vulnerability for developing psychosis. Recent reports detail an upward trend in both adolescent cannabis use and the concentration of THC, the most potent psychoactive component in cannabis. Similarly, it is estimated that 1.7 million Americans incur a TBI each year. Previously trivialized as a minor nuisance, attitudes towards TBIs are changing as researchers and the public recognize TBIs' possible long-lasting sequelae.

CASE REPORT

Two cases are presented of adolescent patients with histories of TBI and self-reported heavy, recreational cannabis use who developed symptoms of psychosis.

DISCUSSION

Similar neuronal signaling pathways involved in cannabis ingestion and TBI recovery, specifically CB1 receptors of the endocannabinoid system, as well as the allostatic load model provide context for the two presented cases. Given the cases and theories presented, we believe that cannabis use may act as a neurological stressor and risk factor for psychosis outweighing its possible benefits as a therapeutic solution for pain in late adolescent and young adult populations.

SIGNIFICANCE

The presented cases provide further support for the compounded risk of developing psychosis following TBI and cannabis use.