The brain can be represented as a network, with nodes as brain regions and edges as region-to-region connections. Nodes with the most connections (hubs) are central to efficient brain function. Current findings on structural differences in Major Depressive Disorder (MDD) identified using network approaches remain inconsistent, potentially due to small sample sizes. It is still uncertain at what level of the connectome hierarchy differences may exist, and whether they are concentrated in hubs, disrupting fundamental brain connectivity.

We utilized two large cohorts, UK Biobank (UKB, N = 5104) and Generation Scotland (GS, N = 725), to investigate MDD case–control differences in brain network properties. Network analysis was done across four hierarchical levels: (1) global, (2) tier (nodes grouped into four tiers based on degree) and rich club (between-hub connections), (3) nodal, and (4) connection.

In UKB, reductions in network efficiency were observed in MDD cases globally (d = −0.076, pFDR = 0.033), across all tiers (d = −0.069 to −0.079, pFDR = 0.020), and in hubs (d = −0.080 to −0.113, pFDR = 0.013–0.035). No differences in rich club organization and region-to-region connections were identified. The effect sizes and direction for these associations were generally consistent in GS, albeit not significant in our lower-N replication sample.

Our results suggest that the brain's fundamental rich club structure is similar in MDD cases and controls, but subtle topological differences exist across the brain. Consistent with recent large-scale neuroimaging findings, our findings offer a connectomic perspective on a similar scale and support the idea that minimal differences exist between MDD cases and controls.

In persons with severe psychiatric disorders, distinct neurocognitive profiles hold differential associations to positive, negative and disorganized symptom dimensions of psychosis. These patterns portend specific functional outcomes, treatment efficacy, and prognoses. Similar associations have not been established in multimorbid samples in which persons present with a complex array of psychiatric symptoms. The objective of this study was to (1) establish neurocognitive profiles in a multimorbid, marginalized sample and (2) investigate their pattern(s) of association with psychiatric symptom dimensions and psychosocial outcomes.

Participants (n=370; Mage = 45 years; 74% male) were precariously housed, substance-using adults with multimorbidity, recruited from Single-Room Occupancy hotels and a community court within the Downtown Eastside of Vancouver, BC, Canada. Data were collected as part of a longitudinal examination consisting of annual, bi-annual, and monthly neurocognitive, psychosocial, and psychiatric assessments. Neurocognitive scores were combined into five cognitive domains (Attentional Control [AC]; Processing Speed [PS]; Fluid Reasoning [Problem Solving and Reversal Learning; Gf]; Encoding and Retrieval [ER]; and Decision Making [DM]) and submitted to a latent profile analysis. The resulting profiles capturing neurocognition were validated on sociodemographic and clinical variables. Finally, the profiles were compared across previously validated, population-distinct factors derived from the Positive and Negative Syndrome Scale (PANSS), as well as on measures of psychosocial functioning.

An optimal goodness-of-fit was reached for a three-profile model (BLRT=127.86, p=.01). Profile 1 (n=207, 55.9%) showed stronger neurocognition (all p<.05), with a within-profile strength in Gf (p<.001). With the exception of ER, Profile 2 (n=109, 29.5%) exhibited inferior neurocognition across all indicators compared to Profile 1 (all p <.05); yet showed a relative, within-profile strength in Gf (p < .01). Profile 3 (n=54, 14.6%) generally displayed comparable impairments to Profile 2. Additionally, their performance on Gf was remarkably low compared to Profiles 1 and 2 (p<.001). Psychiatrically, compared to Profile 1, Profile 2 exhibited more positive/disorganized symptoms and general psychopathology, as well as higher total PANSS (all p <.05), whereas Profile 3 showed the poorest insight/awareness (p<.01). Profiles 2 and 3 had lower levels of adaptive functioning and work productivity compared to Profile 1 (all p<.01).

Three neurocognitive profiles were detected in a sample of precariously housed adults with multimorbidity: one profile of comparatively higher neurocognitive capacity, with less symptoms of psychosis and better psychosocial functioning; a second profile of comparatively poorer neurocognition and psychosocial functioning, with more symptoms of psychosis; and a third profile with a severe deficit in fluid reasoning and poor insight and awareness. Given their poor insight, the third profile may be comprised of particularly vulnerable persons at greater risk of unmet healthcare needs. Interventions to improve these individuals' understanding of their personal health risks might facilitate their capacity to access services. Conversely, individuals from Profile 2 may benefit from outreach programs focusing on medication access and adherence to address their symptoms of psychosis. In sum, our findings suggest that the confluence of neurocognition and psychiatric symptoms may implicate unique treatment approaches and outcomes in precariously-housed persons with multimorbid conditions.

Cognitive dysfunction is prominent in homeless and precariously housed persons, and memory dysfunction is the most pervasive domain. The presence of multimorbid physical and mental illness suggests that several underlying mechanisms of memory impairment may be at play. The serial position phenomenon describes the tendency to best recall the beginning (primacy effect) and last (recency effect) words on a supra-span wordlist. Recency recall engages executive and working-memory systems, whereas primacy recall depends on long-term memory. This study investigates memory dysfunction in a homeless and precariously housed sample by identifying and characterizing unique subtypes of serial position profiles on a test of verbal memory.

Data were used from a 20-year study of homeless and precariously housed adults recruited from an impoverished neighbourhood in Vancouver, Canada. Participants were sub-grouped according to their serial position profile on the Hopkins Verbal Learning Test-Revised using a latent profile analysis (LPA; n = 411). Paired samples t-tests were conducted to determine differences in percent recall from each word-list region within classes. Linear regression analyses were used to examine between-class differences in mean serial position scores and other cognitive measures (memory, attention, processing speed, cognitive control). Covariates included age, sex, and education.

LPA identified two profiles characterized by (1) reduced primacy relative to recency (RP; n = 150); and (2) reduced recency relative to primacy (RR; n = 261). Pairwise comparisons within the RP class showed that recency was better than primacy (p < .001, d = .66) and middle recall (p < .001, d = .52), with no difference between primacy and middle recall (p = .68, d = .04). All pairwise comparisons differed within the RR class (primacy > middle recall: p < .001, d = 1.85; primacy > recency recall: p < .001, d = 1.32; middle > recency recall: p < .05, d = .132). The RP class had worse performance on measures of total immediate (ß = .47, p < .001) and delayed verbal recall (ß = .32, p < .001); processing speed (ß = .20, p < .001); and cognitive control (ß = .22, p < .001). The RR class made more repetition errors (ß = .25, p < .001).

These findings support substantial heterogeneity in memory functioning in homeless and precariously housed individuals. The RP profile was characterized by poorer cognitive functioning across several domains, which suggests multiple contributions to memory impairment, including dysfunction of long-term memory circuitry. The RR profile with their higher number of repetition errors, may experience difficulties with self-monitoring in verbal learning. Subsequent studies will explore the neurobiological underpinnings of these subgroups to further characterize profiles and identify targets for cognitive intervention.

Precariously housed individuals are exposed to multiple adverse factors negatively impacting neurocognitive functioning. Additionally, this population is subjected to poor life outcomes, such as impaired psychosocial functioning. Neurocognitive functioning plays an important role in psychosocial functioning and may be especially critical for precariously housed individuals who face numerous barriers in their daily lives. However, few studies have explicitly examined the cognitive determinants of functional outcomes in this population. Cognitive intraindividual variability (IIV) involves the study of within-person differences in neurocognitive functioning and has been used as marker of frontal system pathology. Increased IIV has been associated with worse cognitive performance, cognitive decline, and poorer everyday functioning. Hence, IIV may add to the predictive utility of commonly used neuropsychological measures and may serve as an emergent predictor of poor outcomes in at-risk populations. The objective of the current study was to examine IIV as a unique index of the neurocognitive contributions to functional outcomes within a large sample of precariously housed individuals. It was hypothesized that greater IIV would be associated with poorer current (i.e., baseline) and long-term (i.e., up to 12 years) psychosocial functioning.

Four hundred and thirty-seven adults were recruited from single-room occupancy hotels located in the Downtown Eastside of Vancouver, Canada (Mage = 44 years, 78% male) between November 2008 and November 2021. Baseline neurocognitive functioning was assessed at study enrolment. Scores from the Social and Occupational Functioning Assessment Scale (SOFAS), the Role Functioning Scale (RFS), the physical component score (PCS) and the mental component score (MCS) of the 36-Item Short Form Survey Instrument were obtained at participants’ baseline assessments and at their last available follow-up assessment to represent baseline and long-term psychosocial functioning, respectively. Using an established formula, an index of IIV was derived using a battery of standardized tests that broadly assessed verbal learning and memory, sustained attention, mental flexibility, and cognitive control. A series of multiple linear regressions were conducted to predict baseline and long-term social and role functioning (average across SOFAS and RFS scores), and PCS and MCS scores from IIV. In each of the models, we also included common predictors of functioning, including a global cognitive composite score, age, and years of education.

The IIV index and the global composite score did not explain a significant proportion of the variance in baseline and long-term social and role functioning (p > .05). However, IIV was a significant predictor of baseline (B = -3.84, p = .021) and long-term (B = -3.58, p = .037) PCS scores, but not MCS scores (p > .05). The global composite score did not predict baseline or long-term PCS scores.

IIV significantly predicted baseline and long-term physical functioning, but not mental functioning or social and role functioning, suggesting that IIV may be a sensitive marker for limitations in everyday functioning due to physical health problems in precariously housed individuals. Critically, the present study is the first to show that IIV may be a useful index for predicting poor long-term health-related outcomes in this population compared to traditional neuropsychological measures.

The long-term cumulative impact of exposure to childhood adversity is well documented. There is an increasing body of literature examining protective factors following childhood adversity. However, no known reviews have summarised studies examining protective factors for broad psychosocial outcomes following childhood adversity.

To summarise the current evidence from longitudinal studies of protective factors for adult psychosocial outcomes following cumulative exposure to childhood adversity.

We conducted a formal systematic review of studies that were longitudinal; were published in a peer-reviewed journal; examined social, environmental or psychological factors that were measured following a cumulative measure of childhood adversity; and resulted in more positive adult psychosocial outcomes.

A total of 28 studies from 23 cohorts were included. Because of significant heterogeneity and conceptual differences in the final sample of articles, a meta-analysis was not conducted. The narrative review identified that social support is a protective factor specifically for mental health outcomes following childhood adversity. Findings also suggest that aspects of education are protective factors to adult socioeconomic, mental health and social outcomes following childhood adversity. Personality factors were protective for a variety of outcomes, particularly mental health. The personality factors were too various to summarise into meaningful combined effects. Overall GRADE quality assessments were low and very low, although these scores mostly reflect that all observational studies are low quality by default.

These findings support strategies that improve connection and access to education following childhood adversity exposure. Further research is needed for the roles of personality and dispositional factors, romantic relationship factors and the combined influences of multiple protective factors.

To promote equity for intersectionally disaster-vulnerable individuals and address three literature gaps: (1) incremental effects of collective and self-efficacy as preparedness predictors, (2) differentiation of fear and perceived severity of a disaster, and (3) clarification of the relationship between fear and preparedness.

Due to infection risks associated with communal housing, early in the coronavirus disease (COVID-19) pandemic, many universities permitted students to remain in campus housing only if they were housing insecure, including many international students. We surveyed intersectionally-vulnerable students and their partners at a southeast US university, N = 54, who were international (77.8%), Asian (55.6%), and/or housing insecure at baseline (79.6%). In 14 waves from May–October 2020, we assessed pandemic preparedness/response behaviors (PPRBs) and potential PPRB predictors.

We examined within- and between-person effects of fear, perceived severity, collective efficacy, and self-efficacy on PPRBs. Within-person perceived severity and collective efficacy both significantly, positively predicted greater PPRBs. All effects of fear and self-efficacy were not significant.

Perceived severity and confidence that one’s actions positively impact one’s community fluctuated throughout the pandemic and are linked to greater PPRB engagement. Public health messages and interventions to improve PPRB may benefit from emphasizing collective efficacy and accuracy over fear.

Researchers at the Centers for Disease Control and Prevention monitor unplanned school closure (USC) reports through online systematic searches (OSS) to assist public health emergency responses. We counted the additional reports identified through social media along with OSS to improve USC monitoring.

Facebook and Twitter data of public-school districts and private schools in counties affected by California wildfires in October and December of 2017 and January of 2018 were retrieved. We computed descriptive statistics and performed multivariable logistic regression for both OSS and social media data.

Among the 362 public-school districts in wildfire-affected counties, USCs were identified for 115 (32%) districts, of which OSS identified 104 (90%), Facebook, 59 (52%), and Twitter, 37 (32%). These data correspond to 4622 public schools, among which USCs were identified for 888 (19.2%) schools, of which OSS identified 722 (81.3%), Facebook, 496 (55.9%), and Twitter, 312 (35.1%). Among 1289 private schools, USCs were identified for 104 schools, of which OSS identified 47 (45.2%), Facebook, 67 (64.4%), and Twitter, 29 (27.9%). USC announcements identified via social media, in addition to those via OSS, were 11 public school districts, 166 public schools, and 57 private schools.

Social media complements OSS as additional resources for USC monitoring during disasters.

Psychotic-like experiences (PLEs) are risk factors for the development of psychiatric conditions like schizophrenia, particularly if associated with distress. As PLEs have been related to alterations in both white matter and cognition, we investigated whether cognition (g-factor and processing speed) mediates the relationship between white matter and PLEs.

We investigated two independent samples (6170 and 19 891) from the UK Biobank, through path analysis. For both samples, measures of whole-brain fractional anisotropy (gFA) and mean diffusivity (gMD), as indications of white matter microstructure, were derived from probabilistic tractography. For the smaller sample, variables whole-brain white matter network efficiency and microstructure were also derived from structural connectome data.

The mediation of cognition on the relationships between white matter properties and PLEs was non-significant. However, lower gFA was associated with having PLEs in combination with distress in the full available sample (standardized β = −0.053, p = 0.011). Additionally, lower gFA/higher gMD was associated with lower g-factor (standardized β = 0.049, p < 0.001; standardized β = −0.027, p = 0.003), and partially mediated by processing speed with a proportion mediated of 7% (p = < 0.001) for gFA and 11% (p < 0.001) for gMD.

We show that lower global white matter microstructure is associated with having PLEs in combination with distress, which suggests a direction of future research that could help clarify how and why individuals progress from subclinical to clinical psychotic symptoms. Furthermore, we replicated that processing speed mediates the relationship between white matter microstructure and g-factor.

The objective of this study was to investigate changes in serum biomarkers of acute brain injury, including white matter and astrocyte injury during chronic foetal hypoxaemia. We have previously shown histopathological changes in myelination and neuronal density in fetuses with chronic foetal hypoxaemia at a level consistent with CHD.

Mid-gestation foetal sheep (110 ± 3 days gestation) were cannulated and attached to a pumpless, low-resistance oxygenator circuit, and incubated in a sterile fluid environment mimicking the intrauterine environment. Fetuses were maintained with an oxygen delivery of 20–25 ml/kg/min (normoxemia) or 14–16 ml/kg/min (hypoxaemia). Myelin Basic Protein and Glial Fibrillary Acidic Protein serum levels in the two groups were assessed by ELISA at baseline and at 7, 14, and 21 days of support.

Based on overlapping 95% confidence intervals, there were no statistically significant differences in either Myelin Basic Protein or Glial Fibrillary Acidic Protein serum levels between the normoxemic and hypoxemic groups, at any time point. No statistically significant correlations were observed between oxygen delivery and levels of Myelin Basic Protein and Glial Fibrillary Acidic Protein.

Chronic foetal hypoxaemia during mid-gestation is not associated with elevated serum levels of acute white matter (Myelin Basic Protein) or astrocyte injury (Glial Fibrillary Acidic Protein), in this model. In conjunction with our previously reported findings, our data support the hypothesis that the brain dysmaturity with impaired myelination found in fetuses with chronic hypoxaemia is caused by disruption of normal developmental pathways rather than by direct cellular injury.