Camille Piguet

BACKGROUND Social media provides spaces to share postpartum experiences, seek advice and access support outside clinical settings. However, longitudinal and cross-country patterns in postpartum-related emotional language remain comparatively underexplored. OBJECTIVE This study characterised English-language #postpartum discourse over time and across countries and, as a secondary objective, explored whether its affective characteristics were associated with national perceived social connectedness among women. METHODS This descriptive study analysed English-language #postpartum tweets posted between January 2016 and January 2023, collected through academic access to the Twitter API. Tweet volume, engagement metrics, text valence (using VADER) and emotion-related language (using the NRC Emotion Lexicon) were summarized over time and by country. Exploratory ecological correlation analyses tested the hypothesis that higher national levels of perceived social connectedness among women would be associated with greater positive expression in postpartum-related online discourse, assessed using country-level mean VADER positive and negative scores. RESULTS Of 52’423 tweets retained for temporal analyses, 35’423 from 11 countries were included in geographic analyses, including high-, upper-middle-, and lower-middle-income countries, although 95.2% of geolocated tweets originated from high-income countries. The mean VADER compound score regarding 35’423 tweets included in geographic analysis was 0.18 (95% CI 0.18–0.19), with the highest country-level mean in Australia. Trust- and joy-associated language predominated, peaking in 2020, while fear-related language was also frequent. Among the 11 countries, perceived social connectedness was positively correlated with mean VADER positive scores (ρ = 0.63; p = 0.039), while its correlation with negative scores was negative but inconclusive (ρ = −0.51, p = 0.11). CONCLUSIONS English-language #postpartum tweets showed geographic and temporal variation in text valence and emotion-related language within a selective corpus dominated by high-income countries. These patterns describe online discourse and should not be interpreted as direct measures of maternal mental health. Exploratory findings suggest that perceived social connectedness may be related to the affective characteristics of postpartum-related online discourse, but this association requires investigation in larger, more representative and temporally aligned datasets. CLINICALTRIAL not applicable

Mindfulness-based interventions are known to enhance emotion regulation and stress management, yet their neural mechanisms remain incompletely understood. Effective coping strategies for emotion regulation and stress management would be particularly beneficial for healthcare students, frequently exposed to highly stressful situations. Based on prior work implicating hippocampal-somatomotor dynamics in emotion regulation, we tested whether Mindfulness-Based Cognitive Therapy for Life (MBCT-L) modulates hippocampal micro-coactivation patterns (μCAPs) in healthcare students. In a randomized controlled study including 161 healthcare students, 57 participants (39 females; mean age: 23±5 years old) completed resting-state fMRI before and after the 8-weeks intervention and were allocated to MBCT-L (N = 24) or a no-intervention control (N = 33) condition. Hippocampus-seeded CAPs analysis identified six recurrent patterns, including a somatomotor network. MBCT-L improved self-reported mindfulness, but no significant Group × Time interaction for hippocampus-somatomotor coactivation or resting physiological measures was found. In the MBCT-L group, higher hippocampus-somatomotor co-activity was associated with higher perceived importance of the intervention, perceived long-lasting benefits, and post-intervention mindfulness scores. This study suggests that the capacity to up-regulate hippocampus-somatomotor coactivation may index part of the individual benefit derived from mindfulness, supporting its role as a tool for emotion regulation and stress management.

Adolescence is marked by coordinated endocrine and brain maturation, yet how blood circulating steroid hormones relate to neurochemical change in the brain remains largely unknown. We combined longitudinal data from a novel fast whole-brain, high-resolution three-dimensional proton magnetic resonance spectroscopic imaging technique with repeated measurements of sexual hormones and adrenal steroids in the serum of 42 healthy adolescents (13-15 years; 24 females) totalizing 100 scan-visits. Longitudinal voxel-wise models separated within-individual changes from stable between-individual differences and controlled the false discovery rate across whole-brain tests. In the whole sample, increasing age was associated with higher N-acetylaspartate plus N-acetylaspartylglutamate within individuals, whereas age was positively associated with higher glutamate plus glutamine between individuals. We then observed a hormone-metabolite coupling that differed by sex and steroids. In males, within-individual increases in testosterone tracked frontal increases in glutamate plus glutamine and disseminated increases in total N-acetylaspartate. In females, higher mean estradiol between individuals was associated with higher frontal choline-containing compounds. Within-individual changes in cortisone were associated with myo-inositol and choline-containing compounds in a widespread sex-interaction effect, with positive coupling in males and negative in females. The cortisone/cortisol ratio showed a similar sex-interaction for choline-containing compounds. These findings reveal spatially distributed, sex-dependent links between steroid maturation and adolescent brain neurochemical composition and underscore the importance of differentiating within- and between-individual associations. These observational data extend predominantly structural descriptions of pubertal brain development by identifying distinct coupling of gonadal hormones with neuronal-metabolic markers and glucocorticoid interconversion with glia-weighted metabolites.

Sex differences in brain disorders span age at onset, symptom profiles, disease course and treatment response, and may partly reflect underlying differences in cellular metabolism. Indeed, in vivo evidence of sex-related neurometabolic variation remains sparse, with heterogenous and conflicting findings. Using fast high-resolution whole-brain three-dimensional magnetic resonance spectroscopic imaging, we mapped five brain metabolites in three independent cohorts of healthy participants (total n = 114). In a discovery sample of adolescents scanned at 3 Tesla (3T) (n = 61), males showed higher total N-acetylaspartate (tNAA) across widespread gray matter regions. Regional analyses further revealed opposing sex patterns with a complementary higher total creatine (tCr) observed in females, motivating examination of their ratio as an integrative metabolic index. The tNAA/tCr ratio was consistently higher in males in the discovery sample and this finding was replicated across two independent young-adult samples (3T, n = 26; 7T, n = 27), with a widespread gray and white matter distribution. This tNAA/tCr ratio may link neuronal mitochondrial metabolism with cellular energy buffering, positioning it as a potential index of bioenergetic balance relevant for conditions showing both sex differences and altered neurometabolism, notably multiple sclerosis, Alzheimer disease, and psychosis. Together, these findings reveal a reproducible, distributed metabolic sexual dimorphism in the human brain, and underscore the importance of accounting for sex-specific neurometabolic profiles in studies of brain health and disease.

Adolescence and emerging adulthood are developmental periods marked by rapid biological, cognitive, and social changes during which emotion dysregulation may intensify and be accompanied by maladaptive cognitive and/or behavioral strategies. This single-arm pilot study evaluated the feasibility and preliminary clinical outcomes of a brief group-based emotion regulation program for adolescents and young adults aged 16 to 20. Forty-six participants were recruited from outpatient child, adolescent, and adult psychiatry services within a university hospital setting. Clinician-administered diagnostic interviews, including the Mini International Neuropsychiatric Interview and the Structured Clinical Interview for DSM Axis II Disorders, were conducted at baseline only, whereas self-report measures and the Columbia–Suicide Severity Rating Scale were administered at baseline, post-intervention, and at three-month follow-up. Feasibility was supported by acceptability and engagement, reflected in attendance and retention rates. Participants reported a significant increase in adaptive cognitive emotion regulation strategies (Cognitive Emotion Regulation Questionnaire). Suicidal ideation and behaviors showed a marked and sustained decrease over time. These preliminary findings support the feasibility of this brief group-based intervention and suggest potential clinical benefits that would warrant further confirmation in controlled trials.

Obesity and behavioral impulsivity are highly heritable traits that share overlapping genetic risk and often co-occur in childhood. This study investigates whether maturation of the nucleus accumbens shell (NAC-shell) inhibitory-control circuit mediates shared vulnerability to both traits. Using state-of-the-art dynamic fMRI, we mapped NAC-shell development across 460 longitudinal assessments from childhood to adulthood, in 136 healthy controls and 126 individuals with 22q11.2 deletion syndrome (22q11DS), a genetic model conferring high risk for obesity and impulsivity. Blunted NAC-shell maturation predicted steeper BMI increases and persistent neurocognitive impulsivity, consistently mediating their association in both HC and 22q11DS populations. NAC-shell development explained both impulsivity/obesity genetic vulnerability linked to 22q11DS and familial correlations between affected/unaffected siblings. These findings propose NAC-shell maturation as a transdiagnostic endophenotype underlying obesity and self-regulation, bridging neurodevelopment, genetics, and behavior. They could inform future early-screening and precision preventive strategies for youth at risk of obesity and other impulsivity-related phenotypes.

Background: Impaired glymphatic clearance, the perivascular system supporting cerebrospinal and interstitial fluid exchange, has been implicated in neurodegenerative and psychiatric disorders. Diffusion tensor imaging along the perivascular space (DTI-ALPS) provides a non-invasive proxy for glymphatic-related processes, yet its role in psychiatric conditions remains uncertain. Methods: Following PRISMA guidelines, we systematically searched PubMed, PsycNET, and Embase for articles published up to September 25th, 2025. The protocol was pre-registered in PROSPERO (CRD420251155430). Studies reporting diffusion-based indices of glymphatic function in psychiatric populations were included. Standardised mean differences (Hedges’ g ) were calculated for patient-control comparisons and pooled using random-effects models. Heterogeneity, methodological moderators, and risk of bias were assessed. Results: Thirty-two studies met inclusion criteria for the systematic review, covering major psychiatric groups including mood disorders, autism spectrum disorder, ADHD, psychosis, sleep disorders, and substance-related conditions. Twenty-four studies (n = 2,855; 1,503 patients, 1,352 controls) reporting bilateral DTI-ALPS measures were included in the meta-analysis. The pooled random-effects model revealed a significant transdiagnostic reduction in DTI-ALPS index in psychiatric populations compared with healthy controls (Hedges’ g = –0.78, 95% CI –1.01 to –0.55, p < 0.0001). Between-study heterogeneity was substantial (I² = 86.3%), and there was evidence of small-study effects. Conclusions: Bilateral DTI-ALPS index showed a robust but heterogeneous reduction across psychiatric disorders. Together, these results suggest that impairments of perivascular diffusion, as indexed by DTI-ALPS, may reflect a shared transdiagnostic vulnerability across psychiatric conditions. Harmonised imaging pipelines and multimodal validation are needed to clarify the biological and clinical significance of these findings. SIGNIFICANCE STATEMENT: The search for reliable transdiagnostic biomarkers remains a central challenge in contemporary psychiatry, where heterogeneous symptom profiles often obscure shared biological pathways. The glymphatic system, a glia-dependent network regulating cerebrospinal and interstitial fluid exchange, has recently been proposed as a key mechanism linking vascular, immune, and metabolic pathways to mental illness. Diffusion tensor imaging along the perivascular space (DTI-ALPS) offers a non-invasive proxy for glymphatic function, yet its specificity and clinical relevance remain debated. This systematic review and meta-analysis provide, to our knowledge, the first quantitative synthesis of DTI-ALPS findings across psychiatric disorders, critically evaluating methodological assumptions and evidence for shared pathophysiological mechanisms. By clarifying the strengths and limitations of diffusion-based glymphatic imaging, this work establishes a mechanistic framework for future translational, interventional, and biomarker research in psychiatry.