The Translational Future of Stress Neurobiology and Psychosis Vulnerability: A Review of the Evidence

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.

Admissions for psychosis following agency-notified child maltreatment at 40-year-follow-up: Results from the Childhood Adversity and Lifetime Morbidity (CALM) cohort

There is substantial evidence of an association between self-reported child maltreatment (CM) and subsequent psychosis in retrospective data. Such findings may be affected by recall bias. Prospective studies of notifications to statutory agencies address recall bias but are less common and subject to attrition bias. These studies may therefore be underpowered to detect significant associations for some CM types such as sexual abuse. This study therefore linked administrative health data to a large birth cohort that included notifications to child protection agencies. We assessed psychiatric outcomes of CM as measured by inpatient admissions for non-affective psychoses (ICD10 codes F20-F29) to both public and private hospitals in Brisbane, Australia. Follow-up was up to 40 years old. There were 6087 cohort participants whose data could be linked to the administrative health data. Of these, 10.1 % had been the subject of a CM notification. Seventy-two participants (1.2 %) had been admitted for non-affective psychosis by 40-year follow-up. On adjusted analysis, all notified and substantiated types of CM were associated with admissions for non-affective psychosis. This included neglect, physical, sexual or emotional abuse, as well as notifications for multiple CM types. For instance, there was a 2.72-fold increase in admissions following any agency notification (95 % CI = 1.53-4.85). All maltreatment types therefore show a significant association with subsequent admissions for psychosis up to the age of 40. Screening for CM in individuals who present with psychosis is, therefore, indicated, as well as greater awareness that survivors of CM may be at higher risk of developing psychotic symptoms.

Psychosocial stress moderates the relationship between cerebrospinal fluid lactate dehydrogenase and the duration of untreated psychosis in first-episode psychosis

Introduction

Previous research has shown that lower lactate dehydrogenase (LDH) concentrations in cerebrospinal fluid (CSF) are associated with longer prodromal symptoms in first-episode psychosis (FEP). We aimed to study whether there is a relationship between the duration of untreated psychosis (DUP) and LDH and other CSF biomarkers in FEP and whether stressful life events moderate this association.

Methods

Ninety-five inpatients with FEP and with less than 6 weeks of antipsychotic treatment were included in the study. All participants were informed about the nature of the study, which was approved by the local ethics committee, and signed an informed consent form. A lumbar puncture was performed at index admission (baseline) to measure CSF parameters (glucose, total protein, LDH). The DUP was assessed with the Quick Psychosis Onset and Prodromal Symptoms Inventory (Q-POPSI). Stressful life events (SLEs) in the previous 6 months were assessed with the List of Threatening Experiences. We dichotomized the SLE variable into having experienced at least one SLE or no experience of SLEs. Statistical analyses were performed with SPSS v. 25.0. Total protein and LDH concentrations were natural log transformed (ln) to reduce skewness. Multiple linear regression analyses were conducted to explore the association between the DUP and CSF parameters (considered the dependent variable). Age, sex, DUP and SLEs were considered independent variables. We tested the DUP by SLE interaction. Significant interactions were included in the final model. The threshold for significance was set at p<0.05.

Results

Fifty-four FEP patients (56.8%) reported an SLE in the previous 6 months. There were no significant differences in the DUP between patients with or without SLEs. There were no significant differences in CSF biomarkers between the SLE groups. In the multiple linear regression analyses, we found a significant DUP by SLE interaction effect on CSF LDH concentrations (standardized beta= -0.320, t= -2.084, p= 0.040). In patients with SLEs, a shorter DUP was associated with higher CSF LDH concentrations and vice versa. No significant associations were found between the DUP or SLEs and other CSF biomarkers (glucose, total proteins).

Conclusions

Our study suggests that psychosocial stress moderates the relationship between the onset of psychosis and CSF biomarkers related to bioenergetic systems.