Childhood adversity and cortical thickness and surface area in a population at familial high risk of schizophrenia

The neural, stress hormone and inflammatory correlates of childhood deprivation and threat in psychosis: A systematic review

Childhood adversity increases the risk of developing psychosis, but the biological mechanisms involved are unknown. Disaggregating early adverse experiences into core dimensions of deprivation and threat may help to elucidate these mechanisms. We therefore systematically searched the literature investigating associations between deprivation and threat, and neural, immune and stress hormone systems in individuals on the psychosis spectrum. Our search yielded 74 articles, from which we extracted and synthesized relevant findings. While study designs were heterogeneous and findings inconsistent, some trends emerged. In psychosis, deprivation tended to correlate with lower global cortical volume, and some evidence supported threat-related variation in prefrontal cortex morphology. Greater threat exposure was also associated with higher C-reactive protein, and higher and lower cortisol measures. When examined, associations in controls were less evident. Overall, findings indicate that deprivation and threat may associate with partially distinct biological mechanisms in the psychosis spectrum, and that associations may be stronger than in controls. Dimensional approaches may help disentangle the biological correlates of childhood adversity in psychosis, but more studies are needed.

Childhood adversity and psychotic disorders: Epidemiological evidence, theoretical models and clinical considerations

While genetic factors play a critical role in the risk for schizophrenia and other psychotic disorders, increasing evidence points to the role of childhood adversity as one of several environmental factors that can significantly impact the development, manifestations and outcome of these disorders. This paper reviews the epidemiological evidence linking childhood adversity and psychotic disorders and explores various theoretical models that seek to explain the connection. We discuss neurobiological parallels between the impact of childhood trauma and psychosis on the brain and then explore the impact of childhood adversity on different domains of clinical presentation. Finally, implications for prevention and treatment are considered, both on individual and structural levels.

Comparisons of Voxel-Based Morphometric Brain Volumes of Individuals with Methamphetamine-Induced Psychotic Disorder and Schizophrenia Spectrum Disorder and Healthy Controls

BACKGROUND

Several psychological and neurological pathways are described to explain the emergence and maintenance of psychiatric disorders, and changes in brain volumes and brain activity are observed as correlates of psychiatric disorders. In the present study, we investigated if and to what extent specific voxel-based morphometric brain volume differences could be observed among individuals with methamphetamine-induced psychosis (MAIP) and schizophrenia spectrum disorder (SSD) compared to healthy controls.

METHODS

A total of 69 individuals took part in the present study. Of those, 26 were diagnosed with MAIP, 23 with SSD, and 20 were healthy controls. After a thorough psychiatric assessment, participants underwent brain volume measurement.

RESULTS

Compared to healthy controls, participants with MAIP had smaller volumes for left caudate and left and right parahippocampal gyrus. Compared to healthy controls, participants with SSD had smaller volumes for the gray and white matter, left amygdala, left hippocampus, left parahippocampal gyrus, left putamen, and the total volume. Compared to individuals with MAIP, individuals with SSD had a lower white matter brain volume.

CONCLUSIONS

The pattern of results suggests that individuals with MAIP and SSD showed specific and regional brain atrophies on the left hemisphere, always compared to healthy controls. Given the cross-sectional design, it remains undisclosed if specific and regional brain atrophies were the cause or the consequence of the psychiatric issues.

Impact of childhood adversity on corticolimbic volumes in youth at clinical high-risk for psychosis

Childhood adversity is among the strongest risk factors for psychosis-spectrum disorders, though the nature and specificity of the biological mechanisms underlying this association remains unclear. Previous research reveals overlaps in the volumetric alterations observed in both adversity-exposed individuals and in psychosis-spectrum populations, highlighting the possibility that deviations in corticolimbic gray matter development may be one mechanism linking adversity and psychosis. Given that childhood adversity encompasses a wide range of adverse experiences, there is also a critical need to examine whether these different types of experiences have unique effects on corticolimbic regions. This study examined the association between childhood adversity and cortical, hippocampal, and amygdalar volume in a large sample of youth at clinical-high risk (CHR) for psychosis. We utilized a novel differentiated adversity approach that distinguishes exposures along dimensions of threat (e.g., abuse) and deprivation (e.g., poverty, neglect) to test for differential associations. Participants were drawn from the North American Prodromal Longitudinal Study (NAPLS) and completed an MRI scan and a retrospective assessment of childhood adversity at baseline. We found that deprivation exposure, but not threat, was uniquely associated with smaller cortical volume and smaller right hippocampal volume in CHR youth. These associations were masked in a generalized risk model that utilized a total adversity score. The findings suggest that deprivation exposures during childhood contribute to the subtle volumetric reductions observed in clinical high-risk samples and highlight the importance of disentangling different dimensions of adversity.

Interactive effects of genetic polymorphisms and childhood adversity on brain morphologic changes in depression

The etiology of depression is characterized by the interplay of genetic and environmental factors and brain structural alteration. Childhood adversity is a major contributing factor in the development of depression. Interactions between childhood adversity and candidate genes for depression could affect brain morphology via the modulation of neurotrophic factors, serotonergic neurotransmission, or the hypothalamus-pituitary-adrenal (HPA) axis, and this pathway may explain the subsequent onset of depression. Childhood adversity is associated with structural changes in the hippocampus, amygdala, anterior cingulate cortex (ACC), and prefrontal cortex (PFC), as well as white matter tracts such as the corpus callosum, cingulum, and uncinate fasciculus. Childhood adversity showed an interaction with the brain-derived neurotrophic factor (BDNF) gene Val66Met polymorphism, serotonin transporter-linked promoter region (5-HTTLPR), and FK506 binding protein 51 (FKBP5) gene rs1360780 in brain morphologic changes in patients with depression and in a non-clinical population. Individuals with the Met allele of BDNF Val66Met and a history of childhood adversity had reduced volume in the hippocampus and its subfields, amygdala, and PFC and thinner rostral ACC in a study of depressed patients and healthy controls. The S allele of 5-HTTLPR combined with exposure to childhood adversity or a poorer parenting environment was associated with a smaller hippocampal volume and subsequent onset of depression. The FKBP5 gene rs160780 had a significant interaction with childhood adversity in the white matter integrity of brain regions involved in emotion processing. This review identified that imaging genetic studies on childhood adversity may deepen our understanding on the neurobiological background of depression by scrutinizing complicated pathways of genetic factors, early psychosocial environments, and the accompanying morphologic changes in emotion-processing neural circuitry.

Are structural brain changes in schizophrenia related to antipsychotic medication? A narrative review of the evidence from a clinical perspective

Some observational studies and literature reviews suggest that antipsychotic drug use is associated with loss of grey or white matter in patients with schizophrenia, whereas others have contradicted this finding. Here, I summarize and critique the available evidence and put it in the context of clinical practice. This narrative review pools evidence from observational and experimental studies in humans and animals on the relationship between antipsychotic medication use and brain structure and function in patients with schizophrenia. To summarize, the observational evidence in patients with schizophrenia and the experimental evidence in animals suggest that antipsychotic drugs can cause reductions in brain volume, but differ as to where those effects are manifest. The experimental evidence in patients is inconclusive. There is stronger and more consistent evidence that other factors, such as alcohol and cannabis use, are likely causes of progressive brain changes in schizophrenia. Overall, I argue the case against antipsychotics is not proven and the jury is out on any significance of putative antipsychotic-induced brain changes. Taken in the context of strong evidence from clinical trials that antipsychotic drugs have beneficial effects on symptoms, function, relapse and cognition, and observational evidence that treatment normalizes other imaging indices and reduces mortality, the balance of probabilities is that antipsychotic drugs do not cause adverse structural brain changes in schizophrenia.

Effects of environmental risks and polygenic loading for schizophrenia on cortical thickness

There are established differences in cortical thickness (CT) in schizophrenia (SCZ) and bipolar (BD) patients when compared to healthy controls (HC). However, it is unknown to what extent environmental or genetic risk factors impact on CT in these populations. We have investigated the effect of Environmental Risk Scores (ERS) and Polygenic Risk Scores for SCZ (PGRS-SCZ) on CT. Structural MRI scans were acquired at 3T for patients with SCZ or BD (n=57) and controls (n=41). Cortical reconstructions were generated in FreeSurfer (v5.3). The ERS was created by determining exposure to cannabis use, childhood adverse events, migration, urbanicity and obstetric complications. The PGRS-SCZ were generated, for a subset of the sample (Patients=43, HC=32), based on the latest PGC GWAS findings. ANCOVAs were used to test the hypotheses that ERS and PGRS-SCZ relate to CT globally, and in frontal and temporal lobes. An increase in ERS was negatively associated with CT within temporal lobe for patients. A higher PGRS-SCZ was also related to global cortical thinning for patients. ERS effects remained significant when including PGRS-SCZ as a fixed effect. No relationship which survived FDR correction was found for ERS and PGRS-SCZ in controls. Environmental risk for SCZ was related to localised cortical thinning in patients with SCZ and BD, while increased PGRS-SCZ was associated with global cortical thinning. Genetic and environmental risk factors for SCZ appear therefore to have differential effects. This provides a mechanistic means by which different risk factors may contribute to the development of SCZ and BD.