European Child & Adolescent Psychiatry

Background Although an expansive body of evidence exists on children's mental health during the COVID-19 pandemic, it is largely restricted to the early phases and lockdowns. This study examines longitudinal changes in child and youth mental health symptoms across two years of the COVID-19 pandemic, with data collection strategically timed to capture variability in pandemic restrictions. Methods A population-based longitudinal study of 1,261 children and youth aged 4-17 years followed prospectively from January 2021 to December 2022, with five waves of data collected in Ontario, Canada. Latent growth curve modelling was used to estimate trajectories of parent-reported mental health symptoms and identify baseline and time-varying covariates associated with variable trajectories. Findings Mental health symptoms were elevated and stable during lockdowns, followed by significant reductions as pandemic restrictions loosened, particularly for oppositional defiant and inattention/hyperactivity symptoms compared to internalizing symptoms. Children without pre-existing clinician diagnosed physical, mental or neurodevelopmental conditions and those not in lockdown at baseline demonstrated relative increases in mental health symptoms during lockdowns; and girls, compared to boys, demonstrated smaller reductions in internalizing symptoms as restrictions loosened. Concurrent and lagged associations between parental distress and children's mental health symptoms varied across the pandemic. Interpretation Variation in symptom trajectories by mental health domain, gender, pandemic restrictions and pre-existing diagnosed conditions underscores the need for tailored, equity-informed pandemic planning and response. Policies designed to optimize the balance between the need to reduce viral community transmission whilst limiting pandemic lockdowns may mitigate adverse impacts on child and youth mental health. Funding Ontario Ministry of Health

Introduction: The Nationwide Quality of Life Scale (NQLS) is a brief, mental-health focused quality of life (QoL) scale with seven items that are non-overlapping with symptom scales. We developed a parent version (P-NQLS), obtained national norms, and calculated psychometric properties for the P-NQLS. Methods: Parents (N=2251) of children aged 6-18 years who were representative of the U.S. population on key demographics completed the P-NQLS along with measures of depression, suicidality, internalizing, externalizing, and attention symptoms. We assessed the P-NQLS's factor structure through exploratory factor analysis (EFA) and evaluated its internal reliability and convergent validity. Age- and sex-specific norms were established using GAMLSS with BCPE distributions and P-spline smoothers, with percentile curves and tables (5th-95th) provided. Results: EFA suggested a one-factor solution for P-NQLS in the national sample. The scale showed good internal consistency (Cronbach's alpha=0.85). P-NQLS total scores (M=20.7, SD=4.7, range=0-28, higher scores indicate higher QoL) were negatively correlated (all p<.0001) with depression (Pearson's r=-0.47), suicidality (r=-0.50), internalizing (r=-0.43), externalizing (r=-0.41), and attention (r=-0.37) symptoms. P-NQLS scores declined steadily with age in both sexes, with the most pronounced decreases (3-5 points) observed at lower percentiles (5th, 10th), suggesting greater age-related decline among children with lower baselines. Females scored slightly higher than males across most ages and percentile levels, though the differences were within one point. Conclusions: The newly created P-NQLS, a 7-item parent-reported QoL scale with one underlying factor, demonstrates strong reliability and validity and has robust national norms for youth aged 6-18.

Background. Adolescence and young adulthood represent critical developmental stages during which mental disorders often emerge, with the potential to impede perceived quality of life. Spirituality (i.e., the search for the sacred) and self-regulation (i.e., intrinsic processes regulating emotions, thoughts, and behaviors) are recognized as protective factors for mental health. However, their dynamic interplay remains largely unexplored, particularly in real-life and in real-time among youths. This study, developed with the help of young partners, addresses this gap by investigating the longitudinal associations between spirituality, self-regulation, and mental health using an ecological momentary assessment (EMA) approach. Methods and analysis. We plan to recruit 120 adolescents and young adults (aged 16 to 20, expected attrition rate of 20%) from the community to complete a qualitative semi-structured interview assessing their beliefs, spiritual or religious activities, role models, and meaning in life. In addition, participants will take part in a multi-wave intensive longitudinal study. Trait-level assessments will be conducted at two time points, three months apart, to capture between-person differences. Additionally, to assess within-person dynamics, participants will complete EMA surveys four times daily over 10 consecutive days in two waves, also three months apart. Measures will include facets of spirituality (e.g., beliefs, meaning, collective consciousness), self-regulation (e.g., self-control, emotional regulation, impulsivity), as well as mental health indicators (emotional and behavioral symptoms) and quality of life. Qualitative data will be analyzed through a thematic analysis method, whereas quantitative associations will be assessed using Linear Mixed Models (LMM) and network analyses. Ethics and dissemination. Ethical approval has been obtained, and data collection begun in May 2025. Findings will be disseminated through open access peer-reviewed journals, conferences on adolescent mental health, and shared with practitioners, educators, and youth organizations. Results will also be made accessible to the general public. This study aims to inform personalized preventive and therapeutic interventions by elucidating real-time mechanisms linking spirituality, self-regulation, and mental health in youths.

ObjectiveThere is little longitudinal research investigating links between violence exposure and mental disorders among children in low- and middle-income countries (LMICs), despite high rates of violence. We examined cross-sectional and longitudinal violence-mental health associations among children in a large South African birth cohort, the Drakenstein Child Health Study, including direct clinical interviews capturing childrens mental disorders. MethodIn this birth cohort (N=974), we assessed lifetime violence exposure and four subtypes (witnessed community, community victimization, witnessed domestic, domestic victimization) at ages 4.5 and 8-years via caregiver reports. At 8-years, caregivers completed the Child Behaviour Checklist; and psychiatric disorders were assessed using the Mini-International Neuropsychiatric Interview for Children and Adolescents, a self-report measure. We tested for associations using linear/logistic regressions, adjusted for confounders. ResultsMost children (91%) had experienced violence by 8-years. Cross-sectionally, total violence exposure was associated with total (B =0.49 [95% CI 0.32, 0.66]), internalizing (0.32 [0.17, 0.47]), and externalizing problems (0.46 [0.31, 0.61]), and with increased odds of disorder at 8 years (aOR=1.09 [1.05, 1.13]). Longitudinally, total violence exposure up to 4.5-years was associated with total (B=0.27 [0.03, 0.52]), internalizing (0.24 [0.04. 0.44]), and externalizing scores (0.23 [0.008, 0.45]) at 8-years, but not with increased risk of psychiatric disorders. The strongest and most consistent associations were observed for domestic versus community violence subtypes. ConclusionOur strong cross-sectional but weaker longitudinal findings suggest that recent violence exposures may be more critical than early exposures for childrens mental health. Longitudinal exploration of other violence-affected LMIC populations is urgently needed.

Background: Early adolescence is a common period of onset for depressive symptoms. In part, this may reflect a developmental manifestation of individual's genetic propensities as they undergo physiological and hormonal changes and interact with new environments. Many commonly proposed mechanisms assume direct effects of an individual's own genes on emerging variation in their depressive symptomatology. However, estimates of genetic influence based on analyses in unrelated individuals capture not only direct genetic effects but also genetic effects from parents and other biologically related family members. Aim: In data from the Norwegian Mother, Father and Child Cohort (MoBa), we used linear mixed models to distinguish developmentally-stable and adolescence-specific direct and parental indirect genetic effects. We examined effects of polygenic scores for major depressive disorder (MDD), ADHD, anxiety disorders, and educational attainment (EA) on depressive symptoms, which were assessed by maternal reports at ages 8 and 14. Results: Children's own MDD polygenic scores showed adolescence-specific effects on depressive symptoms ( b_PGS*wave=0.041, [95% CI: 0.017, 0.065]). Developmentally-stable direct effects from children's polygenic scores for MDD (b=0.016, [0.006, 0.039]), ADHD (b=0.024, [0.008, 0.041]) and EA (b=-0.02, [ -0.038, -0.002]) were also evident. The only evidence of indirect genetic effects was a stable effect of maternal EA polygenic scores (b=0.04, [0.024, 0.054]). Conclusion: Direct genetic effects linked to genetic liability to MDD accounted for emerging variation in depressive symptoms in adolescence. These results imply that specific etiological mechanisms related to MDD may become particularly relevant for depressive symptoms during early adolescence compared to at earlier ages.

AimAutistic children have a high but varied prevalence of internalizing and externalizing problems. This study aimed to identify the subtypes of internalizing and externalizing problems among autistic preschool children in Japan, examine their temporal stability, and investigate differences in participation in daily life and family outcomes across these subtypes. MethodsA prospective cohort study was conducted with 275 caregivers of autistic children aged 51-75 months. Internalizing and externalizing problems were assessed using the Strengths and Difficulties Questionnaire. ResultsLatent transition analysis identified five subtypes: Low-symptom, High-emotional, Externalizing, Comorbid, and Peer-difficulty groups. Membership in the High-emotional and Externalizing groups was relatively stable over time, whereas the Peer-difficulty group showed frequent transitions to subtypes with higher levels of internalizing or externalizing problems. Significant differences in participation in daily life and family outcomes were observed across subtypes, but these patterns were inconsistent with a simple gradient of symptom levels. ConclusionsThe novel findings that the temporal stability of subtype membership varied and that differences in participation in daily life and family outcomes were observed across the subtypes suggest that the heterogeneity of internalizing and externalizing problems may be associated with variations in childrens participation in daily life and family outcomes over time. Plain Language SummaryAutistic preschool children often experience emotional and behavioral difficulties, but the way these difficulties manifest varies widely across individuals. This study aimed to identify the patterns of these difficulties, examine how they change over time, and investigate how participation in daily life and family outcomes differ across autistic preschool children. We conducted a study with 275 caregivers of autistic children aged 4-6 years in Japan. From caregiver reports of childrens emotional and behavioral difficulties, five distinct patterns were identified: a group with mainly emotional difficulties, a group with mainly behavioral difficulties, a group with both types of difficulties, a group with relatively low levels of difficulties, and a group characterized primarily by peer-related difficulties. Our findings suggest that different patterns of emotional and behavioral difficulties are associated with differences in childrens participation in daily life and family outcomes. These differences could not be explained simply by the overall severity of difficulties but rather reflect distinct patterns based on the type of difficulty. The results indicate that autistic children face diverse difficulties that change over time.

Objective: Childhood poverty is a high-risk context that involves diverse adversities, making it difficult to understand how poverty confers later psychopathology risk and why some children remain resilient despite growing up in poverty. To address this heterogeneity, we quantified adversity-linked vulnerability as adversity-psychopathology coupling and tested whether childhood poverty amplifies this coupling and whether multilevel inhibitory-control profiles stratify vulnerability and resilience within poverty-exposed youth. Methods: We analyzed 10,112 youth (48.4% female; mean age = 9.92 years) from the Adolescent Brain Cognitive Development Study, linking baseline cumulative early-life adversity (ELA) to later behavioral problems across 4 waves. In the stop-signal task fMRI subsample of 7,401 youth, semi-supervised clustering of inhibitory-control activation identified neurofunctional subtypes within poverty-exposed youth. We also tested temperamental inhibitory control as an additional moderator. Results: Childhood poverty amplified the association between cumulative ELA and behavioral problems at baseline ({Delta}{beta} = 0.088; P < .001) and across follow-up waves. Two neurofunctional subtypes were identified within poverty-exposed youth: subtype-1 showed greater vulnerability than higher-income peers ({Delta}{beta} = 0.149; P < .001), whereas subtype-2 showed attenuated vulnerability and did not differ from higher-income peers ({Delta}{beta} = 0.049; P = .135); this pattern persisted longitudinally. Among poverty-exposed youth in subtype-2 with high temperamental inhibitory control, the association between cumulative ELA and later behavioral problems was no longer significant. Conclusions: Childhood poverty strengthened the translation of adversity burden into later behavioral problems, but inhibitory-control profiles differentiated higher- and lower-risk pathways within poverty, highlighting inhibitory control as a candidate target for prevention.

BackgroundMindfulness-based interventions (MBIs) have been increasingly adopted in educational settings to support cognitive development in youth. Executive function (EF)--encompassing inhibitory control, working memory, and cognitive flexibility--is a plausible target of MBI given its reliance on attention regulation. However, prior reviews have yielded mixed conclusions, partly due to inconsistent construct definitions and the pooling of heterogeneous outcome measures. ObjectivesTo (1) estimate the pooled effect of MBI on EF in youth aged 3-18 years using only construct-validated, direct EF measures, (2) examine potential moderators including age group, EF domain, and risk of bias, and (3) test dose-response relationships via meta-regression on intervention duration. MethodsWe searched PubMed, PsycINFO, CINAHL, Scopus, and Web of Science from inception to March 2026, supplemented by reference-list searches from two existing systematic reviews and a scoping review. Only English-language publications were eligible. Eligible studies were randomised controlled trials (RCTs) or quasi-RCTs of MBI (excluding yoga-only interventions) in typically developing youth, with at least one direct behavioural or computerised EF outcome. Risk of bias was assessed using Cochrane RoB 2. Hedges g was computed for each study, and pooled using a DerSimonian-Laird random-effects model. Subgroup analyses by age group, EF domain, and risk of bias were conducted, alongside leave-one-out sensitivity analyses, Eggers regression test, trim-and-fill, and Knapp-Hartung-adjusted meta-regression on intervention duration. Evidence certainty was rated using GRADE. ResultsThirteen RCTs (nine school-age, four preschool; total N = 1,560) met inclusion criteria. The pooled effect was g = 0.365 (95% CI 0.264 to 0.465; p < .00001), with negligible heterogeneity (I2 = 0.0%; Q = 6.76, p = .87). Effects were consistent across age groups (school-age g = 0.389; preschool g = 0.318) and EF domains (inhibitory control, working memory, cognitive flexibility; pbetween = .60). Meta-regression on intervention duration (4-20 weeks) was non-significant (p = .79). The effect was robust in leave-one-out analyses, in the low risk-of-bias subgroup (g = 0.361; k = 8), and after trim-and-fill adjustment (g = 0.354). The 95% prediction interval (0.252 to 0.477) was entirely positive. GRADE certainty was rated MODERATE, downgraded once for risk of bias. ConclusionsMBIs appear to produce a small, statistically significant improvement in EF in youth aged 3-18 years, with moderate certainty of evidence per the GRADE framework. The effect is consistent across preschool and school-age samples and across EF domains, with no significant dose-response relationship within the 4-20 week range studied. Emerging mediation evidence suggests that EF improvement may serve as an important pathway through which MBI supports emotion regulation, though this requires replication. Further large-scale, pre-registered RCTs with active control conditions and longitudinal follow-up are warranted.

Background Diagnosis and treatment monitoring of attention-deficit/hyperactivity disorder (ADHD) largely rely on subjective assessments, highlighting the need for objective markers. Voice features and speech embeddings represent promising candidates for such markers, as they may capture alterations in speech production relevant to ADHD. However, it remains unclear which speech features are most informative for distinguishing ADHD and monitoring treatment effects, and which speech tasks most reliably elicit such differences. Methods Twenty-seven children with ADHD and 27 age-matched neurotypical controls completed six speech tasks across two study visits. Children with ADHD were unmedicated at baseline (first visit) and were assessed under prescribed methylphenidate treatment at follow-up, whereas controls underwent repeated assessment without intervention. Established acoustic voice features (eGeMAPS) and high-dimensional speech embeddings (WavLm, Whisper) were extracted and analysed using linear mixed models to examine baseline group differences and group-by-time interaction effects reflecting medication-associated change patterns. Results At baseline, children with ADHD differed significantly from controls in frequency, spectral, and temporal voice features, characterized by lower and more variable pitch, altered spectral properties, and reduced rhythmic stability. Group-by-time interaction effects indicated medication-associated modulation in the ADHD group, including reduced loudness variability and increased precision of vowel articulation at follow-up, changes not observed in controls. Speech embeddings revealed additional baseline and interaction effects beyond established acoustic features. Free speech tasks, particularly picture description, yielded the most robust and consistent effects. Conclusion Children with ADHD differed from neurotypical controls in vocal features at baseline and showed distinct longitudinal change patterns consistent with medication-related change. These findings support further investigation of speech-based measures as candidate digital phenotypes and potential digital biomarkers in ADHD, with picture description emerging as a particularly promising task for future clinical assessment protocols.

Objective: Autistic individuals may face elevated risk for PTSD, yet the degree to which this risk differs by sex remains unknown. We examined the association between autism and incident PTSD, characterized sex differences in risk, identified high-risk subgroups, and described post-diagnosis clinical trajectories. Method: We conducted a population-based matched cohort study using Swedish national registers. Individuals born 1990 through 2010 were followed from age 6 years through December 31, 2017. Autistic individuals (N=42,862) were matched 1:10 to controls (N=412,251) on sex and birth year. Cox proportional hazards regression estimated hazard ratios (HRs) for incident PTSD. Among those who developed PTSD, we compared care utilization, hospitalization rates, and persistence of care contacts. Results: During mean follow-up of 5.1 years, 401 autistic individuals (0.9%) and 903 controls (0.2%) developed PTSD (incidence rates: 18.3 vs 4.2 per 10,000 person-years). Autism was associated with 4.4-fold increased PTSD risk (HR=4.37; 95% CI, 3.93-4.86). Risk was higher among females (HR=4.79) than males (HR=3.39; P interaction=.006). Among autistic individuals, comorbid ADHD conferred additional risk (HR=1.38; 95% CI, 1.14-1.68). Ten-year cumulative incidence reached 6.0% among autistic females with ADHD. Autistic individuals with PTSD had higher care utilization (mean visits: 5.0 vs 3.9; P<.001), more psychiatric hospitalizations (27.9% vs 19.8%; P=.002), and more persistent courses (24.8% vs 12.3% with contacts in all 3 post-diagnosis years; P=.001). Conclusion: Autism is associated with substantially elevated PTSD risk, particularly among females with comorbid ADHD. When PTSD occurs, autistic individuals experience more severe and persistent clinical courses, supporting targeted screening and sustained follow-up.

BackgroundEarly-life adversity (ELA) is a risk factor for enduring pain in youth and is associated with alterations in brain morphology and function. However, it remains unclear whether ELA-related neurobiological changes contribute to the development of enduring pain in early adolescence. MethodsUsing data from the Adolescent Brain Cognitive Development (ABCD) Study, we examined multimodal magnetic resonance imaging (MRI) markers in children assessed at baseline (ages 9-11 years) and at 2-year follow-up (ages 11-13 years). ELA exposure was defined at baseline to maximise temporal separation between early adversity and later enduring pain. Participants with enduring pain at follow-up (n = 322) were compared to matched pain-free controls (n = 644). Structural MRI, diffusion MRI (fractional anisotropy, mean diffusivity), and resting-state functional connectivity data were analysed. Linear models tested main effects of enduring pain, ELA, and their interaction on brain metrics, controlling for relevant covariates. ResultsELA exposure was associated with smaller caudate and nucleus accumbens volumes, and reduced surface area of the left rostral middle frontal gyrus. No significant effects of enduring pain or ELA-by-enduring pain interaction were observed across grey matter, white matter, or functional connectivity measures. ConclusionsELA was associated with alterations in fronto-striatal regions in late childhood, but these changes were not linked to enduring pain in early adolescence. These findings suggest that ELA-related neurobiological alterations may represent early markers of vulnerability rather than concurrent correlates of enduring pain. Longitudinal follow-up is needed to determine whether these alterations contribute to later chronic pain risk.

Early childhood mental health problems are common and difficult to detect due to reliance on caregiver reports of often unobservable symptoms. This study quantified threat response movement patterns during a 30-second laboratory threat induction task using wearable inertial sensors. Movement patterns were used to examine (1) changes in stimuli response across the task (task validity) and (2) associations with symptom severity (clinical validity). Sacral accelerometer and gyroscope data were analyzed from 91 children aged 4-8 years during the brief task, 48.4% of whom had a mental health diagnosis. Consistent with task validity, Turning Speed varied across task phases differing in potential threat intensity. Consistent with clinical validity, internalizing symptoms were associated with smaller Turning Angle, possibly indicating vigilance. This effect was moderated by comorbid externalizing symptoms, such that children with high internalizing and high externalizing symptoms exhibited larger Turning Angles, possibly indicating avoidance. Findings demonstrate that brief wearable-enabled tasks can capture subtle objective behavioral markers of threat responses and underscore the importance of considering comorbid symptom dimensions in early childhood mental health screening.

Introduction The aim of this study was to determine the annual age- and sex-specific prevalence of gender-affirming hormone and puberty blocker use among young people with a gender incongruence (GI) diagnosis in Norway. Methods We integrated data from multiple Norwegian national registers to perform a nationwide register-based study of individuals with known sex assigned at birth who were born in the period 1975-2017 and resident in Norway for all or part of the period 2008-2022. We first calculated the annual age- and sex-specific incidence of GI diagnoses in the population. Then, we calculated the annual age- and sex-specific prevalence of androgen, estrogen, and puberty blocker use among individuals with a GI diagnosis who were under age 25 (for androgens and estrogens) or 18 (for puberty blockers) in the year that they collected the prescription. Results The incidence of GI diagnoses has increased among youth in Norway, most notably since 2015 and with the largest increase among teens assigned female at birth. The prevalence of feminizing and masculinizing hormone therapy has increased in this period as well, but mainly among the oldest teens and young adults. The prevalence of puberty suppression is mostly low but has also increased since 2015, especially in recent years among teens assigned male at birth. Conclusion The prevalence of gender-affirming hormone and puberty blocker use has increased among transgender youth in Norway, concurrently with an increase in the incidence of GI diagnoses.

Understanding depressive symptoms dynamics and their determinants is crucial for designing effective mental health support initiatives. This study compared two methods for describing youth depressive symptoms trajectories and investigated associations of early-life factors (maternal education, maternal perinatal depression, domestic violence, physical, emotional, or sexual abuse, bullying victimisation, psychiatric disorder) with trajectory features. Prospective data from 8,264 mostly White European participants (54% female), including self-reported Short Moods and Feelings Questionnaires on ten occasions between 10-25 years, were used. Trajectories were summarised using functional principal component analysis (FPCA) and P-splines linear mixed-effect (PLME) models. Estimated derivatives were used to obtain magnitude and age of peak symptoms and peak symptoms velocity. Both methods performed comparably, but PLME models tended to over-smooth trajectories. Peak symptoms and peak velocity were higher and occurred >1 year earlier in females than males. All early-life factors were associated with higher peak symptoms, and most associated with higher and earlier peak velocity. Abuse and bullying additionally associated with earlier age of peak symptoms. FPCA is a useful alternative for characterising depressive symptoms trajectories and informing time-sensitive preventative measures to reduce impact of depression before symptoms reach their peak. Early-life stressors may accelerate timeline and intensity of symptoms escalation during adolescence. Lay summaryUnderstanding development of depressive symptoms and factors shaping them is crucial for designing effective mental health support initiatives. This study used data from over 8,000 young people regularly followed up from before birth to compare two cutting-edge methods for describing depressive symptoms trajectories and examined how known risk factors for adulthood depression relate to the severity and rate of change of depressive symptoms in adolescence. We found that both methods performed well and that the peaks in depressive symptoms and their rate of change were, on average, higher and occurred over a year earlier in females than males. Our findings additionally suggest that early-life stressors (e.g., abuse, bullying) may accelerate the development of depression, highlighting the importance of early prevention.

Progress in pharmacological treatment development for neurodevelopmental disorders is hindered by a misalignment between targeted mechanisms, outcome measures, and trial designs. This study was initiated as a post-trial access pathway for bumetanide and later expanded with treatment-naive participants. Within this framework, we implemented a parent-cocreated sensory outcome measure set (PROMset) in an unmasked, multiple-baseline single-case experimental design with randomized baseline periods of 2-12 weeks, followed by 6 months of bumetanide treatment (up to 1.5 mg twice daily). Participants (7-19 years) had atypical sensory reactivity and a diagnosis of ASD, ADHD, epilepsy, or TSC. The primary outcome was a PROMset comprising seven PROMIS item banks assessing anxiety, depressive symptoms, sleep disturbance, fatigue, sleep-related impairment, cognitive function, and peer relationships. Secondary outcomes included SSP, SRS-2, RBS-R, and ABC. Of 113 enrolled participants (mean age 13.2 [SD 2.7], 64% male), 102 completed the trial and 95 had analyzable PROMsets. At baseline, PROMset scores showed substantial impairment across domains (mean deviation =9.0 T-score points, p<.001) and correlated with sensory reactivity (SSP; r=-0.40, p<.001). Individual-level analyses showed improvement in 24-41% of participants per PROM domain, most frequently in anxiety and depressive symptoms (41% and 38%; mean across-case Cohen's d=-1). Overall, 83% improved on at least one domain. Group-level analyses showed improvement across all secondary outcomes (p<.001), with superiority over historic placebo for RBS-R and SSP. Integrating PROMsets with individualized trial designs can reveal clinically meaningful changes, supporting a more sensitive and patient-centered framework for treatment evaluation in heterogeneous populations.

Aims: Youth loneliness is a prevalent global health concern with lifelong health ramifications. Schools, as children's primary peer environments, are promising settings for loneliness interventions. However, school-based interventions are highly heterogeneous and no review to date has evaluated their effect on loneliness specifically. Methods: A systematic review was conducted to identify studies of school-based interventions measuring loneliness as an outcome in children and young people aged up to 18. Meta-analyses were conducted using a random-effects model to pool effect sizes and examine the significance of intervention characteristics and study design. Reported implementation factors were extracted and narratively synthesised. Results: Thirty-eight studies were included in meta-analysis, of which 19 were randomized controlled trials, ten were non-randomized controlled, and nine were single group studies. A small-to-moderate effect estimate was found, Hedges' g = -0.42 [95% CI: -0.71, -0.13], p = .006, and sub-group analyses indicated that differences in study design and quality did not result in significantly different effect estimates. Psychological interventions, followed by social and emotional skills training, produced significantly higher effects estimates compared with other intervention types. Conclusions: Findings indicate that school-based interventions are effective in reducing youth loneliness. However, study heterogeneity, reporting inconsistencies, and a wide prediction interval indicates this finding should be interpreted with caution. Future research may benefit from improved measurement and reporting of implementation factors, particularly dosage and fidelity.

BackgroundThe mechanisms underpinning associations between sleep and psychiatric conditions are poorly understood, partly due to challenges with longitudinal sleep studies outside the laboratory. Children and young people with rare genetic conditions caused by micro-deletions or -duplications (Copy Number Variants or CNVs) have increased risk of disrupted sleep and poorer neurodevelopmental (ND) outcomes. The Sleep Detectives study aims to investigate this by tracking behavioural and neurophysiological signatures of sleep health in young people with ND risk or ND-CNVs. To optimally achieve this, we have worked with families with ND-CNVs and charity partners to co-design our tools, methods, study protocol, and materials. MethodWe established a Lived Experience Advisory Group (LEAP) with nine parents and 13 children and young people with ND-CNVs, alongside representatives of UK charities Max Appeal and Unique. Together, the research team and LEAP co-designed two in-person family workshops in which we collected feedback on the acceptability of sleep monitoring devices, the design of bespoke cognitive tasks, and overall study protocol. Informal interviews and surveys were conducted with LEAP members and researchers, to enable the team to reflect and learn from their Patient/Public Involvement (PPI) experiences. ResultsKey outputs included pre-workshop invitation and briefing materials and insights that iteratively refined the main study design, including the need for flexibility to increase accessibility, selection of sleep devices, customisation of cognitive tasks, and choice of language in documents. The PPI process was highly valued by LEAP members, workshop attendees, and the research team. One investigator described the PPI work as "reinvigorating my love of research by helping me focus on science that matters". Participating families also established peer support networks. ConclusionsInvolving families affected by ND-CNVs in co-designing the Sleep Detectives study maximised opportunities for acceptability, accessibility and scalability. The research team gained inspiration and deeper understanding of the impact of ND-CNVs on families. Families gained awareness about research, established connections with each other and peer support, and were enthusiastic about future research involvement. This experience empowered families to engage more deeply with the research process and helped the PPI work to be more impactful and inclusive. Plain English summaryChildren and young people with rare genetic conditions caused by small deletion or duplication of genetic material are more likely to experience sleep difficulties such as insomnia, restless sleep, and tiredness. They also show an increased likelihood of neurodevelopmental conditions such as learning disability and autism, and mental health issues such as anxiety. The Sleep Detectives team wanted to explore how these genetic conditions affect childrens sleep, cognition and psychiatric health. To make sure that the project design was well suited to the children and young people that would be invited to participate, the team worked closely with families to design the study. Parents and caregivers of affected children and young people were invited to join a Lived Experience Advisory Panel (LEAP), together with charity representatives and Sleep Detective researchers, to co-design two hands-on workshops, and advise on study design. Children and young people and parents/caregivers attending the workshops tried out and provided feedback on tools and devices that the research team were developing. They also advised on the arrangements and support families might need whilst taking part, and on the study protocol. This collaborative approach helped ensure the study design was optimally suited for the recruitment and participation of children and young people and their families. This report documents our public involvement work for the Sleep Detectives study, illustrating the difference the partnership between researchers and families has made to the project, and the wider benefits for all concerned.

Objective: While ADHD symptoms often decline from childhood into adulthood, the underlying neurobiological mechanisms, such as altered brain maturation or neural reorganization, remain incompletely understood. This study investigated how grey matter development relates to ADHD symptom trajectories into adulthood. Method: We analyzed data of individuals with ADHD and controls from the longitudinal Dutch NeuroIMAGE cohort, utilizing dimensional ADHD symptom scores (Conners Parent Rating Scale) from three waves and T1-weighted structural MRI scans from the final two waves. Using General Linear Models with permutation-based inference, we examined: 1) cross-sectional associations between ADHD symptoms and vertex-wise cortical thickness and surface area, and subcortical volumes at Wave 1 (n = 765, mean age = 16.95 years); and 2) longitudinal associations between symptom progression and brain morphometric changes (Wave 0 to 1: n = 644, mean age = 11.55-17.24 years; Wave 1 to 2: n = 149, mean age = 16.45-20.11 years). Results: Cross-sectionally, at Wave 1, more ADHD symptoms were related to widespread reductions in surface area, most prominently in the frontal cortex, and smaller volumes of the cerebellum, amygdala, and hippocampus. Longitudinally, symptom improvement from Wave 1 to Wave 2 was associated with stronger reductions in surface area, particularly in prefrontal and occipital regions, and with more pronounced cortical thinning across multiple brain regions. Conclusion: These findings suggest an association between symptom trajectories and structural brain changes, indicating that clinical improvement in ADHD behaviors might coincide with ongoing neural refinement during the transition to adulthood.

Adult ADHD is increasingly recognized across the lifespan, yet the psychometric equivalence of the Adult ADHD Self-Report Scale (ASRS) remains unverified for older populations. This study examined age-related Differential Item Functioning (DIF) in 600 adults (n = 100 per decade, ages 20-80) who completed the 18-item ASRS. Using a bi-factor Graded Response Model, we extracted latent ADHD trait scores ({omega}H = .895) and assessed DIF via ordinal logistic regression with adaptive age modeling. Five of 18 items exhibited significant uniform DIF. At equivalent latent severity, older adults were less likely to endorse hyperactivity symptoms in Part A (fidgeting, feeling "driven by a motor") but more likely to endorse specific symptoms in Part B (careless mistakes, misplacing items, interrupting). From ages 20 to 80, expected Part A scores decreased by 1.36 points (~0.27 per decade), while Part B scores increased by 1.15 points (~0.23 per decade). These findings indicate a phenotypic redistribution of ADHD symptoms as individuals age. Because the 6-item Part A screener serves as the primary clinical gatekeeper, its concentration of negative DIF suggests standard screening practice may systematically underestimate ADHD severity in older adults. We recommend using the full 18-item ASRS when screening older populations and suggest that developing age-adjusted norms would improve diagnostic accuracy.

Background Hospital admissions for mental health (MH) and stress related presentations (SRP; symptoms without a clear medical cause which may be psychosomatic in nature) among children and young people (CYP) have risen over time. Rehospitalisation contributes to service costs, may indicate gaps in community based care, and can also disrupt education and social development. Methods This retrospective cohort study used NHS Hospital Episode Statistics to identify all CYP aged 10 to 25 with >1 MH/SRP related hospital admissions in England between 1 April 2014 and 31 March 2018, with follow up until 31 March 2019. Admissions were classified from ICD10 codes into internalising, externalising, personality, and eating disorders, psychosis, self-harm, substance use, postpartum, or potentially psychosomatic diagnostic groups. Outcomes included 30 day all cause readmission, 1 year all cause readmission, and 1 year MH/SRP-specific rehospitalisation. Time to rehospitalisation, and number of MH/SRP readmissions were also evaluated. Clinical and sociodemographic characteristics associated with rehospitalisation were assessed using regression models, time to rehospitalisation using Kaplan Meier analyses, and diagnostic transitions were visualised using Sankey diagrams. Results Of 492,061 CYP with hospital admission for MH/SRP, approximately one third were rehospitalised within one year. Females, older CYP and those from more deprived areas had higher odds of all cause readmission. The odds of MH/SRP rehospitalisation were highest among those aged 14 to 15 years. Co occurring chronic physical health conditions, personality and eating disorders were associated with higher odds, and shorter time, to readmission. Conclusions Rehospitalisation following MH/SRP admissions is common and socioeconomically patterned among CYP. Targeted discharge planning and continuity of care interventions are needed, particularly for high risk CYP admitted with eating and personality disorders.