Patients with posttraumatic stress disorder (PTSD) exhibit smaller regional brain volumes in commonly reported regions including the amygdala and hippocampus, regions associated with fear and memory processing. In the current study, we have conducted a voxel-based morphometry (VBM) meta-analysis using whole-brain statistical maps with neuroimaging data from the ENIGMA-PGC PTSD working group.

T1-weighted structural neuroimaging scans from 36 cohorts (PTSD n = 1309; controls n = 2198) were processed using a standardized VBM pipeline (ENIGMA-VBM tool). We meta-analyzed the resulting statistical maps for voxel-wise differences in gray matter (GM) and white matter (WM) volumes between PTSD patients and controls, performed subgroup analyses considering the trauma exposure of the controls, and examined associations between regional brain volumes and clinical variables including PTSD (CAPS-4/5, PCL-5) and depression severity (BDI-II, PHQ-9).

PTSD patients exhibited smaller GM volumes across the frontal and temporal lobes, and cerebellum, with the most significant effect in the left cerebellum (Hedges’ g = 0.22, pcorrected = .001), and smaller cerebellar WM volume (peak Hedges’ g = 0.14, pcorrected = .008). We observed similar regional differences when comparing patients to trauma-exposed controls, suggesting these structural abnormalities may be specific to PTSD. Regression analyses revealed PTSD severity was negatively associated with GM volumes within the cerebellum (pcorrected = .003), while depression severity was negatively associated with GM volumes within the cerebellum and superior frontal gyrus in patients (pcorrected = .001).

PTSD patients exhibited widespread, regional differences in brain volumes where greater regional deficits appeared to reflect more severe symptoms. Our findings add to the growing literature implicating the cerebellum in PTSD psychopathology.

The macro-social and environmental conditions in which people live, such as the level of a country’s development or inequality, are associated with brain-related disorders. However, the relationship between these systemic environmental factors and the brain remains unclear. We aimed to determine the association between the level of development and inequality of a country and the brain structure of healthy adults.

We conducted a cross-sectional study pooling brain imaging (T1-based) data from 145 magnetic resonance imaging (MRI) studies in 7,962 healthy adults (4,110 women) in 29 different countries. We used a meta-regression approach to relate the brain structure to the country’s level of development and inequality.

Higher human development was consistently associated with larger hippocampi and more expanded global cortical surface area, particularly in frontal areas. Increased inequality was most consistently associated with smaller hippocampal volume and thinner cortical thickness across the brain.

Our results suggest that the macro-economic conditions of a country are reflected in its inhabitants’ brains and may explain the different incidence of brain disorders across the world. The observed variability of brain structure in health across countries should be considered when developing tools in the field of personalized or precision medicine that are intended to be used across the world.

Ketamine exerts potent but transient antidepressant effects in treatment-resistant depression (TRD). Combinations of ketamine and psychotherapy have attracted interest, but no trial has investigated a psychedelic model of ketamine–psychotherapy for TRD to our knowledge.

This secondary analysis of a randomised clinical trial (RCT) explores the therapeutic effects and experiential mechanisms of the Montreal Model of ketamine–psychotherapy for TRD, with or without music.

A two-centre, single-blinded, RCT conducted in Montreal, Canada, between January 2021 and August 2022 (NCT04701866). Participants received ketamine–psychotherapy for TRD – six subanaesthetic infusions over 4 weeks and psychological support – with either music or matched non-music support during ketamine doses, as per random group assignments. The primary therapeutic outcome was the Montgomery–Åsberg Depression Rating Scale, assessed by blinded raters. Psychedelic-like experiences, evaluated by the Mystical Experience Questionnaire and Emotional Breakthrough Inventory, and their session-by-session relationships with depression were explored with multilevel, time-lagged covariate models with autoregressive residuals.

Thirty-two participants with severe and highly comorbid TRD, including high rates of personality disorder and suicidality, received 181 ketamine infusions. Therapeutic outcomes and psychedelic experiences did not differ between music (n = 15) and non-music (n = 17) interventions. Both groups experienced significant reductions in clinician-rated and self-reported depression (d = 1.2 and d = 0.87, respectively; p < 0.001), anxiety (d = 0.8, p < 0.001) and suicidality (d = 0.4, p < 0.05) at 4 weeks, fully maintained at 8-week follow-up. Ketamine experiences were highly emotional and mystical. Converging analyses supported mystical-like ketamine experiences as mechanisms of its antidepressant effects.

This trial found large and notably sustained benefits of ketamine–psychotherapy for severe TRD, with or without music, and psychedelic experiences of comparable intensity to those observed with psilocybin. Mystical-like experiences may particularly contribute to ketamine’s immediate and persistent psychiatric benefits.

Outbreaks of Pseudomonas aeruginosa infections have been linked to water-related sources. We describe the investigation of a suspected outbreak of five P. aeruginosa infections in pediatric oncology patients in 2021 that triggered a retrospective review and prospective monitoring of additional cases, environmental sampling, and bacterial genomic analysis.

Pediatric oncology center.

Medical records of patients with P. aeruginosa were reviewed and staff were interviewed to identify common exposures. Environmental samples were cultured for P. aeruginosa. Patient and environmental isolates underwent whole genome sequencing and core genome multi-locus sequence typing (cgMLST) and sequences were added to a previously existing library of P. aeruginosa clinical isolates collected in 2017 and onwards to determine strain relatedness.

During 2019–2022, 82 patients with 110 episodes of P. aeruginosa infections were identified and 132 isolates of P. aeruginosa were sequenced. Twenty-three environmental samples were collected, of which two grew P. aeruginosa in culture. CgMLST demonstrated four multi-patient isolate clusters but no genetic relatedness among the isolates from the patients in the suspected outbreak. Two sink-derived isolates from 2021 were genetically related to patient-derived isolates from 2018 and 2017.

Sequencing revealed there is no common source or linkage between the isolates of the suspected P. aeruginosa outbreak in 2021. However, it revealed genetic relatedness of previous patient strains to later strains collected from hospital sinks, suggesting persistent colonization of a reservoir with P. aeruginosa.

During the COVID-19 pandemic, virtual physician visits rapidly increased among community-dwelling older persons living with dementia (PLWD) in Ontario. Rural residents often have less access to medical care compared to their urban counterparts, and it is unclear whether access to virtual care was equitable between PLWD in urban versus rural locations.

Using population-based health administrative data and a repeated cross-sectional study design, we identified and described community-dwelling PLWD between March 2020 and August 2022 in Ontario, Canada. Poisson regression was used to calculate rate ratios (RR) and 95% confidence intervals comparing rates of virtual visits between rural and urban PLWD by key physician specialties: family physicians, neurologists and psychiatrists/geriatricians.

Of 122,751 PLWD in our cohort, 9.2% (n = 11,304) resided in rural areas. Rural PLWD were slightly younger compared to their urban counterparts (mean age = 81 vs. 82 years; standardized difference = 0.16). There were no differences across areas by sex or income quintile. In adjusted models, rates of virtual visits were significantly lower for rural compared to urban PLWD across all specialties: family physicians (RR = 0.71 [0.69–0.73]), neurologists (RR = 0.79 [0.75–0.83]) and psychiatrists/geriatricians (RR = 0.72 [0.68–0.76]).

PLWD in rural areas had significantly lower rates of virtual family physician, neurologist and psychiatrist/geriatrician visits compared to urban dwellers during the study period. This finding raises important issues regarding access to primary and specialist healthcare services for rural PLWD. Future work should explore barriers to care to improve health care access among PLWD in rural communities.