School Violence Exposure as an Adverse Childhood Experience: Protocol for a Nationwide Study of Secondary Public Schools.

BACKGROUND: Poor mental health and adverse childhood experiences (ACEs) predict extensive adverse outcomes in youth, including increases in long-term risk for chronic disease and injury, impaired emotional development, and poor academic outcomes. Exposure to school violence, specifically intentional gun violence, is an increasingly prevalent ACE. The anticipation of school shootings has led to the implementation of school safety and security interventions that may increase anxiety, depression, and other indicators of poor mental well-being among students and staff alike. Despite this, the association between exposure to existing school safety interventions and early adolescent student mental health outcomes, while accounting for one's history of ACEs, has not been previously investigated. OBJECTIVE: The study protocol described here aims to determine whether there is a significant difference in the prevalence of mental health outcomes, perceived school safety, and academic engagement between adolescent students (grades 6-12) at schools who have experienced a school shooting and those who have not; whether existing interventions to promote school safety and security are associated with poor mental health outcomes among students and school staff; and what the strength of the association between school safety interventions and mental health outcomes among students and teachers is in schools that have experienced a school shooting versus schools that have never experienced a school shooting. METHODS: This observational study will collect cross-sectional survey data from a nationwide sample of students, teachers, and principals at 12 secondary public schools across the United States. The participants come from 6 randomly selected exposure schools that have either experienced a recent (<2 years ago) intentional school shooting or have experienced an intentional school shooting less recently (>2 years ago). Data from these schools are being directly compared with 6 secondary schools that have never experienced a school shooting. RESULTS: Institutional review board approval for this research project was obtained and the study subsequently began its recruitment and data collection phase in January 2024. Data collection is currently ongoing and the expected completion date is January 2025. The analytic plan is designed to determine if the strength of the association between school safety interventions and mental health outcomes differs among students and school staff in schools with varying levels of school violence exposure. Analyses will be used to evaluate the role of ACEs on the relationships among exposure to an intentional school shooting, exposure to school safety strategies, and student outcomes (ie, mental health and well-being, perceptions of school safety, and educational outcomes). CONCLUSIONS: The results from this study promise to generate meaningful and novel findings on the extent to which having a prior history of ACEs moderates the relationships among exposure to intentional school gun violence, school safety strategies, and student outcomes (ie, mental health and well-being, and perceptions of school safety). TRIAL REGISTRATION: ClinicalTrials.gov NCT06153316; https://clinicaltrials.gov/study/NCT06153316. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/56249.

The Icelandic Prevention Model Evaluation Framework and Implementation Integrity and Consistency Assessment.

The Icelandic Prevention Model (IPM) follows a systematic but flexible process of community capacity building, data collection, analysis, dissemination, and community-engaged decision-making to guide the data-informed selection, prioritization, and implementation of intervention strategies in preventing adolescent substance use. This paper describes two new evaluation tools intended to assess the: 1) integrity of IPM implementation, and 2) unique aspects of IPM implementation in different community contexts. These evaluation tools include a: 1) five-phase IPM Evaluation Framework for Assessing Value Across Communities, Cultures, and Outcomes (IPM-EF); and 2) 10-Step IPM Implementation Integrity and Consistency Assessment (IPM-IICA) that utilizes both quantitative (scored) and qualitative (narrative) data elements to characterize implementation integrity and consistency at both community coalition and school community levels. The IPM-EF includes five phases. Phase 1: Describe the Intervention Context; Phase 2a: Document the Extent to Which the 10 Steps of the IPM were Implemented (using the IPM-IICA scored); Phase 2b: Document the Unique Community-Specific Methods Used within the 10 Steps of the IPM to Tailor Local Intervention Delivery (using the IPM-IICA narrative); Phase 3: Measure Changes in Community Risk and Protective Factors; Phase 4: Measure the Outcomes Associated with the IPM; and Phase 5: Investigate Multiple Full Cycles Over Time.

Development and Validation of a Stroke Literacy Assessment Test for Community Health Workers.

Community health workers (CHWs) are increasingly being required to perform complex health care activities, especially in community cardiovascular disease and stroke prevention. However, currently, there are no psychometrically validated instruments for assessing CHW competencies in these roles. This article describes the development and validation of the stroke literacy assessment test (SLAT)-pertaining to the Life's Simple Seven (LS7) risk factors for stroke-for evaluating CHWs' competencies in the context of education and training programs. The SLAT was developed using an iterative instrument design protocol, followed by empirically testing the instrument in 68 CHWs from the Columbia University Institute for Training Outreach and Community Health (InTOuCH) in New York. Data collection began in March 2021 and continued through May 2021. The evaluation was based on four types of validity evidence: (a) content validation with expert reviews of items and overall domain, (b) validation on examinee response processes with cognitive interviews, (c) item validation and diagnostic analysis, and (d) validity evidence based on expected directional group differences. In addition, the internal consistency reliability of the total test scores, with the best functioning items, were evaluated. Two such iterative cycles yielded a 34-item, written structured response test that assesses the factual knowledge and application levels of cognition, and demonstrates sufficient validity and reliability (Cronbach's α = .69) for use with CHWs specializing in stroke prevention efforts. The SLAT is a novel, valid, and reliable instrument that contributes to filling a critical gap in rigorous competency assessments for CHWs deployed in chronic disease prevention.

Understanding Social, Cultural, and Religious Factors Influencing Medical Decision-Making on BRCA1/2 Genetic Testing in the Orthodox Jewish Community.

INTRODUCTION: Although the prevalence of a pathogenic variant in the BRCA1 and BRCA2 genes is about 1:400 (0.25%) in the general population, the prevalence is as high as 1:40 (2.5%) among the Ashkenazi Jewish population. Despite cost-effective preventive measures for mutation carriers, Orthodox Jews constitute a cultural and religious group that requires different approaches to BRCA1 and BRCA2 genetic testing relative to other groups. This study analyzed a dialog of key stakeholders and community members to explore factors that influence decision-making about BRCA1 and BRCA2 genetic testing in the New York Orthodox Jewish community. METHODS: Qualitative research methods, based on Grounded Theory and Narrative Research, were utilized to analyze the narrative data collected from 49 key stakeholders and community members. A content analysis was conducted to identify themes; inter-rater reliability was 71%. RESULTS: Facilitators of genetic testing were a desire for preventive interventions and education, while barriers to genetic testing included negative emotions, feared impact on family/romantic relationships, cost, and stigma. Views differed on the role of religious leaders and healthcare professionals in medical decision-making. Education, health, and community were discussed as influential factors, and concerns were expressed about disclosure, implementation, and information needs. CONCLUSION: This study elicited the opinions of Orthodox Jewish women (decision-makers) and key stakeholders (influencers) who play critical roles in the medical decision-making process. The findings have broad implications for engaging community stakeholders within faith-based or culturally distinct groups to ensure better utilization of healthcare services for cancer screening and prevention designed to improve population health.

The relationship between sleep quantity, sleep quality and weight loss in adults: A scoping review.

Sleep is hypothesized to interact with weight gain and loss; however, modelling this relationship remains elusive. Poor sleep perpetuates a cascade of cardiovascular and metabolic consequences that may not only increase risk of adiposity, but also confound weight loss efforts. We conducted a scoping review to assess the research on sleep and weight loss interventions. We searched six databases for studies of behavioural weight loss interventions that included assessments of sleep in the general, non-clinical adult human population. Our synthesis focused on dimensions of Population, Intervention, Control, and Outcomes (PICO) to identify research and knowledge gaps. We identified 35 studies that fell into one of four categories: (a) sleep at baseline as a predictor of subsequent weight loss during an intervention, (b) sleep assessments after a history of successful weight loss, (c) concomitant changes in sleep associated with weight loss and (d) experimental manipulation of sleep and resulting weight loss. There was some evidence of improvements in sleep in response to weight-loss interventions; however, randomized controlled trials of weight loss interventions tended not to report improvements in sleep when compared to controls. We conclude that baseline sleep characteristics may predict weight loss in studies of dietary interventions and that sleep does not improve because of weight loss alone. Future studies should enrol large and diverse, normal, overweight and obese short sleepers in trials to assess the efficacy of sleep as a behavioural weight loss treatment.

Capnography-Assisted Learned, Monitored (CALM) breathing therapy for dysfunctional breathing in COPD: A bridge to pulmonary rehabilitation.

BACKGROUND: Although dyspnea is a primary symptom of chronic obstructive pulmonary disease (COPD), its treatment is suboptimal. In both COPD and acute anxiety, breathing patterns become dysregulated, contributing to abnormal CO2, dyspnea, and inefficient recovery from breathing challenges. While pulmonary rehabilitation (PR) improves dyspnea, only 1-2% of patients access it. Individuals with anxiety who use PR have worse outcomes. METHODS: We present the protocol of a randomized controlled trial designed to determine the feasibility and acceptability of a new, four-week mind-body intervention that we developed, called "Capnography-Assisted Learned, Monitored (CALM) Breathing," as an adjunct to PR. Eligible participants are randomized in a 1:1 ratio to either CALM Breathing program or Usual Care. CALM Breathing consists of 10 core, slow breathing exercises combined with real time biofeedback (of end-tidal CO2, respiratory rate, and airflow) and motivational interviewing. CALM Breathing promotes self-regulated breathing, linking CO2 changes to dyspnea and anxiety symptoms and targeting breathing efficiency and self-efficacy in COPD. Participants are randomized to CALM Breathing or a Usual Care control group. RESULTS: Primary outcomes include feasibility and acceptability metrics of recruitment efficiency, participant retention, intervention adherence and fidelity, PR facilitation, patient satisfaction, and favorable themes from interviews. Secondary outcomes include breathing biomarkers, symptoms, health-related quality of life, six-minute walk distance, lung function, mood, physical activity, and PR utilization and engagement. CONCLUSION: By disrupting the cycle of dyspnea and anxiety, and providing a needed bridge to PR, CALM Breathing may address a substantive gap in healthcare and optimize treatment for patients with COPD.

Effect of the COVID-19 pandemic on adolescent mental health and substance use up to March, 2022, in Iceland: a repeated, cross-sectional, population-based study.

BACKGROUND: Poor mental health in the first year of the COVID-19 pandemic has been well documented in adolescents; however, less is known about the longer-term effect of the pandemic. We aimed to examine adolescent mental health and substance use as well as covariates associated with these outcomes 1 year or more into the pandemic. METHODS: A nationwide sample of adolescents aged 13-18 years enrolled in school in Iceland were invited to complete surveys administered during October-November or February-March, 2018, October-November, 2020, February-March or October-November, 2021, and February-March 2022. The survey was in Icelandic for all administrations and offered to adolescents aged 13-15 years in English in 2020 and 2022 and in Polish in 2022. Surveys assessed depressive symptoms (Symptom Checklist-90); mental wellbeing (Short Warwick Edinburgh Mental Wellbeing Scale); and the frequency of cigarette smoking, e-cigarette use, and alcohol intoxication. Covariates comprised age, gender, and migration status as determined by language spoken at home, level of social restrictions based on residency, parental social support, and sleep duration (≥8 h nightly). Weighted mixed-effect models were used to determine the effect of time and the covariates on mental health and substance use. The main outcomes were assessed in all participants with more than 80% of the necessary data, and multiple imputation was used to handle missing data. Bonferroni corrections were used to adjust for multiple testing and analyses were considered significant at a p value of <0·0017. FINDINGS: 64 071 responses were submitted and analysed between 2018 and 2022. Elevated depressive symptoms and worsened mental wellbeing across girls and boys aged 13-18 years were observed to have been maintained up to 2 years into the pandemic (p>0·0017). Alcohol intoxication initially decreased during the pandemic but increased again as social restrictions eased (p<0·0001). No changes were observed in cigarette smoking and e-cigarette use during the COVID-19 pandemic. Higher levels of parental social support and an average sleep duration of 8 h or more per night were associated with mental health better outcomes and less substance use (p<0·0001). Social restrictions and migration background were inconsistently associated with the outcomes. INTERPRETATION: Population-level prevention targeting adolescent depressive symptoms should be prioritised in health policy in the wake of COVID-19. FUNDING: Icelandic Research Fund.

A national survey of dental hygiene faculty perspectives on diversity, equity, and inclusion.

PURPOSE/OBJECTIVES: To investigate potential unconscious bias among dental hygiene educators and identify baseline perceptions of race and racism. METHODS: Dental hygiene programs in the USA were clustered into 4 geographic regions from which 2 programs were sampled from each region. The 20-item, Color-Blind Racial Attitudes Scale (CoBRAS) electronic survey was sent to educators from each of the selected programs in 2022. The CoBRAS instrument measures contemporary racism and stereotyping in 3 subcategories: Unawareness of Racial Privilege, Institutional Discrimination, and Blatant Racial Issues. Scores range from 20-120, with higher scores indicating elevated levels of denial of racism. Descriptive statistics and one-way ANOVA were performed. The level of significance was set to α = 0.05. RESULTS: Of the 172 potential respondents, 89 (52%) completed all of the survey questions. The majority of the respondents were White, female and from the Northeast (74.2%, 93.3%, and 61.8% respectively). The mean CoBRAS score (55.73) indicated moderate levels of color-blind racial attitudes. Race was a significant variable in perceptions of racial dynamics and racism with statistically significant differences between groups by race and ethnicity as demonstrated by one-way ANOVA (F[6,82] = 3.469, p = 0.004). CONCLUSIONS: Moderate levels of color-blind racial attitudes among dental hygiene educators were found, indicating a presence of cognitive aspects of stereotyping related to race. The demographic data collected adds to the existing evidence of a lack of diversity among dental hygiene faculty.

Cardiovascular Disease and Stroke-Focused Competency Assessment Tools for Community Health Workers in the United States: A Scoping Review.

Cardiovascular disease (CVD) and stroke are major contributors to chronic disease burden in the United States. Despite the high prevalence of stroke, 90% of all stroke events are preventable and can be attributed to seven key modifiable risk factors (MRFs)-high blood pressure (BP), high cholesterol, diabetes mellitus (DM), smoking, obesity, unhealthy diet, and physical inactivity. In the United States, stroke prevention interventions led by community health workers (CHWs) have been proven to be highly effective in preventing the onset of MRFs. We conducted a scoping review of the competency assessment methods used in CVD and stroke-focused CHW training programs. We searched six online databases: PubMed, Cochrane, CINAHL, Embase, Web of Science, and HaPI, from all available years until January 2021. Of the 1,774 initial articles found, we identified 30 eligible articles to be included in the review. Nine of these studies used previously validated instruments, whereas the remaining 21 studies used tools from the training curriculum or independently developed instruments. Only five of these validated tools reported psychometric properties; none of them were designed for the CHW population. Our scoping review of literature revealed that CHW-specific competency assessment methods were limited, with few or no domain-referenced tools on CVD or stroke risk factors that complied with established measurement standards. We conclude that there is an urgent need for the development of a comprehensive and valid assessment instrument in CVD and stroke prevention to evaluate CHW performance and optimize their credibility, representing important first steps toward integrating CHWs into health care systems.

Assessing descriptions of scalability for hypertension control interventions implemented in low-and middle-income countries: A systematic review.

BACKGROUND: The prevalence of hypertension continues to rise in low- and middle-income- countries (LMICs) where scalable, evidence-based interventions (EBIs) that are designed to reduce morbidity and mortality attributed to hypertension have yet to be fully adopted or disseminated. We sought to evaluate evidence from published randomized controlled trials using EBIs for hypertension control implemented in LMICs, and identify the WHO/ExpandNet scale-up components that are relevant for consideration during "scale-up" implementation planning. METHODS: Systematic review of RCTs reporting EBIs for hypertension control implemented in LMICs that stated "scale-up" or a variation of scale-up; using the following data sources PubMed/Medline, Web of Science Biosis Citation Index (BCI), CINAHL, EMBASE, Global Health, Google Scholar, PsycINFO; the grey literature and clinicaltrials.gov from inception through June 2021 without any restrictions on publication date. Two reviewers independently assessed studies for inclusion, conducted data extraction using the WHO/ExpandNet Scale-up components as a guide and assessed the risk of bias using the Cochrane risk-of-bias tool. We provide intervention characteristics for each EBI, BP results, and other relevant scale-up descriptions. MAIN RESULTS: Thirty-one RCTs were identified and reviewed. Studies reported clinically significant differences in BP, with 23 studies reporting statistically significant mean differences in BP (p < .05) following implementation. Only six studies provided descriptions that captured all of the nine WHO/ExpandNet components. Multi-component interventions, including drug therapy and health education, provided the most benefit to participants. The studies were yet to be scaled and we observed limited reporting on translation of the interventions into existing institutional policy (n = 11), cost-effectiveness analyses (n = 2), and sustainability measurements (n = 3). CONCLUSION: This study highlights the limited data on intervention scalability for hypertension control in LMICs and demonstrates the need for better scale-up metrics and processes for this setting. TRIAL REGISTRATION: Registration PROSPERO (CRD42019117750).

Behavioral Activation, Depression, and Promotion of Health Behaviors: A Scoping Review.

Diverse approaches to the treatment of depressive disorders are necessary to improve evidence-based practice and maximize treatment outcomes. As a result, a range of behaviors and other factors associated with the onset and course of depressive disorders should be examined more comprehensively. Behavioral activation (BA) is a treatment approach to these disorders that can be tailored to address certain health behaviors within the context of depression in an attempt to promote health behaviors whose adoption and maintenance can prove complementary in the treatment of depression. We conducted a scoping review of published studies in which BA-based interventions were used to promote certain health behaviors in individuals with depression. Our search of Medline and the Web of Science identified 336 potential candidate studies. Following screening and with the application of inclusion and exclusion criteria to isolate potentially eligible full-text records, we ultimately identified and evaluated 20 papers that report the nature and efficacy of these modified interventions. Across various domains, including substance use, exercise, medication adherence, and occupational and social success, we found evidence that many-but not all-of the studies we reviewed demonstrated that BA-based interventions were efficacious in promoting the health behavior of interest as well as reducing depressive symptomatology in participants. Implications for more widespread dissemination of such interventions, especially via mobile and web-based platforms due to their accessibility and affordability, are discussed. More research on the feasibility and efficacy of BA-based interventions tailored toward various determinants of health behavior and comorbidities of depressive disorders is warranted.

Substance Use Among Youth During the COVID-19 Pandemic: a Systematic Review.

PURPOSE OF REVIEW: To review the literature on the trends in substance use among youth during the coronavirus SARS-CoV-2 (COVID-19) pandemic. RECENT FINDINGS: The pandemic has given rise to concerns about the mental health and social well-being of youth, including its potential to increase or exacerbate substance use behaviors. This systematic review identified and included 49 studies of use across alcohol, cannabis, tobacco, e-cigarettes/vaping, and other drugs, and unspecified substances. The majority of studies across all categories of youth substance use reported reductions in prevalence, except in the case of other drugs and unspecified drug and substance use, which included three studies that reported an increase in use and three studies that reported decrease in use. Overall, the results of this review suggest that the prevalence of youth substance use has largely declined during the pandemic. Youth substance use in the post-pandemic years will require monitoring and continued surveillance.

Association of the built environment and neighborhood resources with obesity-related health behaviors in older veterans with hypertension.

OBJECTIVE: To evaluate the association of the built environment and neighborhood resources with exercise, diet, and body mass index (BMI). METHOD: Person-level data were collected from 533 veterans with uncontrolled hypertension. Neighborhood measures were: (a) census-tract level walkability; and (b) healthy food proximity (HFP). Robust or logistic regression (adjusting for age, race, education, comorbidity, and clustered by provider) was used to evaluate associations between neighborhood and exercise duration (hours/week), exercise adherence (% adherent), saturated fat index (0-10), Healthy Eating Index (HEI; 0-100), HEI adherence (≥ 74 score), stage of change (SOC) for exercise and diet (% in action/maintenance), BMI (kg/m²), and obesity (BMI ≥ 30 kg/m²). RESULTS: The adjusted difference in HEI score (standard error [SE]) between the highest and lowest walkability tertiles was 3.67 (1.35), p = .006; the corresponding comparison for the saturated fat index was 1.03 (.50), p = .041 and BMI was -1.12 (.45), p = .013. The adjusted odds ratio (OR; 95% confidence intervals [CI]) between the highest and lowest walkability tertiles for HEI adherence was 2.16 [1.22, 3.82], p = .009 and for action/maintenance for exercise SOC was 1.78 [1.15, 2.76], p = .011. The adjusted difference (SE) between the highest and lowest HFP tertiles for exercise duration was .65 (.31), p = .03. The adjusted OR [95% CI] between the highest and lowest HFP tertiles for exercise adherence was 1.74 [1.08, 2.79], p = .023 and for action/maintenance for exercise SOC was 1.75 [1.10, 2.79], p = .034. CONCLUSIONS: Geographical location is associated with exercise and diet. Environment-tailored health recommendations could promote healthier lifestyles and decrease obesity-related cardiovascular disease. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Population Health Status of the Republic of Kazakhstan: Trends and Implications for Public Health Policy.

The Republic of Kazakhstan began undergoing a political, economic, and social transition after 1991. Population health was declared an important element and was backed with a substantial commitment by the central government to health policy. We examine key trends in the population health status of the Republic of Kazakhstan and seek to understand them in relation to the ongoing political, economic, and social changes in society and its aspirations in health policy. We used the Global Burden of Disease database and toolkit to extract and analyze country-specific descriptive data for the Republic of Kazakhstan to assess life expectancy, child mortality, leading causes of mortality, disability-adjusted life years, and causes and number of years lived with disability. Life expectancy declined from 1990 to 1996 but has subsequently recovered. Ischemic heart disease, stroke, and chronic obstructive pulmonary disease remain among the leading causes of death; child mortality for children under 5 years has declined; and cardiovascular risk factors account for the greatest cause of disability. Considering its socioeconomic development over the last two decades, Kazakhstan continues to lag behind OECD countries on leading health indictors despite substantial investments in public health policy. We identify seven strategic priorities to improve the efficiency and effectiveness of the health care system.

Adolescent well-being amid the COVID-19 pandemic: Are girls struggling more than boys?

BACKGROUND: Differential effects of the coronavirus SARS-CoV-2 (COVID-19) pandemic and associated public restrictions on adolescent girls and boys are emerging but have not been elucidated. This study examined gender differences across broad indicators of adolescent well-being during the COVID-19 pandemic in Iceland, and explored potential explanations for these differences. METHODS: In total, 523 youth (56.5% girls) born in Iceland in 2004 completed measures on mental health problems (depressive symptoms, anger and suicide attempts) and measures designed for this study to assess broad indicators of adolescent well-being (e.g., day-to-day life, academic performance, family and peer relationships, and mental and physical health) and behavioral changes during the COVID-19 pandemic. Mental health problems during the pandemic were compared to expected scores based on nationwide ratings of same-aged peers in 2018. RESULTS: Although both boys and girls appeared affected, girls reported a greater negative impact across all the broad indicators of well-being and behavioral change during COVID-19 than boys, and their depressive symptoms were above and beyond the expected nationwide scores (t(1514) = 4.80, p < .001, Cohen's d = 0.315). Higher depressive symptoms were associated with increased passive social media use and decreased connecting with family members via telephone or social media among girls, and decreased sleeping and increased online gaming alone among boys. Concern about others contracting COVID-19, changes in daily and school routines, and not seeing friends in person were among the primary contributors to poor mental health identified by youth, particularly girls. CONCLUSIONS: Adolescents were broadly negatively affected by the COVID-19 pandemic and accompanying restrictions; however, this negative impact was more pronounced in girls. The findings suggest that a steady routine and remaining socially connected may help youth cope with the uncertainty and social restrictions associated with a pandemic. Moreover, healthcare providers, teachers, and other professionals should pay close attention to depressive symptoms among girls during a pandemic.

Investing in Public Health Infrastructure to Address the Complexities of Homelessness.

Homelessness is now recognized as a significant public health problem in North America and throughout advanced economies of the world. The causes of homelessness are complex but the lack of affordable housing, unemployment, poverty, addiction, and mental illness all contribute to the risk for homelessness. We argue that homelessness is increasingly exacerbated by system-wide infrastructure failures occurring at the municipal, state, and federal government levels and whose catastrophic impacts on population health and the response to the COVID-19 pandemic are the consequence of the decades-long devolution of government and neglect to invest in public infrastructure, including a modern public health system.

Depressive symptoms, mental wellbeing, and substance use among adolescents before and during the COVID-19 pandemic in Iceland: a longitudinal, population-based study.

BACKGROUND: Adolescence represents a crucial developmental period in shaping mental health trajectories. In this study, we investigated the effect of the COVID-19 pandemic on mental health and substance use during this sensitive developmental stage. METHODS: In this longitudinal, population-based study, surveys were administered to a nationwide sample of 13-18-year-olds in Iceland in October or February in 2016 and 2018, and in October, 2020 (during the COVID-19 pandemic). The surveys assessed depressive symptoms with the Symptom Checklist-90, mental wellbeing with the Short Warwick Edinburgh Mental Wellbeing Scale, and the frequency of cigarette smoking, e-cigarette use, and alcohol intoxication. Demographic data were collected, which included language spoken at home although not ethnicity data. We used mixed effects models to study the effect of gender, age, and survey year on trends in mental health outcomes. FINDINGS: 59 701 survey responses were included; response rates ranged from 63% to 86%. An increase in depressive symptoms (ß 0·57, 95% CI 0·53 to 0·60) and worsened mental wellbeing (ß -0·46, 95% CI -0·49 to -0·42) were observed across all age groups during the pandemic compared with same-aged peers before COVID-19. These outcomes were significantly worse in adolescent girls compared with boys (ß 4·16, 95% CI 4·05 to 4·28, and ß -1·13, 95% CI -1·23 to -1·03, respectively). Cigarette smoking (OR 2·61, 95% CI 2·59 to 2·66), e-cigarette use (OR 2·61, 95% CI 2·59 to 2·64), and alcohol intoxication (OR 2·59, 95% CI 2·56 to 2·64) declined among 15-18-year-olds during COVID-19, with no similar gender differences. INTERPRETATION: Our results suggest that COVID-19 has significantly impaired adolescent mental health. However, the decrease observed in substance use during the pandemic might be an unintended benefit of isolation, and might serve as a protective factor against future substance use disorders and dependence. Population-level prevention efforts, especially for girls, are warranted. FUNDING: Icelandic Research Fund. TRANSLATION: For the Icelandic translation of the abstract see Supplementary Materials section.