Predicting the risk of depression among adolescents in Nepal using a model developed in Brazil: the IDEA Project

Prospective Follow-Up of Adolescents With and at Risk for Depression: Protocol and Methods of the Identifying Depression Early in Adolescence Risk Stratified Cohort Longitudinal Assessments

Objective

To present the protocol and methods for the prospective longitudinal assessments-including clinical and digital phenotyping approaches-of the Identifying Depression Early in Adolescence Risk Stratified Cohort (IDEA-RiSCo) study, which comprises Brazilian adolescents stratified at baseline by risk of developing depression or presence of depression.

Method

Of 7,720 screened adolescents aged 14 to 16 years, we recruited 150 participants (75 boys, 75 girls) based on a composite risk score: 50 with low risk for developing depression (LR), 50 with high risk for developing depression (HR), and 50 with an active untreated major depressive episode (MDD). Three annual follow-up assessments were conducted, involving clinical measures (parent- and adolescent-reported questionnaires and psychiatrist assessments), active and passive data sensing via smartphones, and neurobiological measures (neuroimaging and biological material samples). Retention rates were 96% (Wave 1), 94% (Wave 2), and 88% (Wave 3), with no significant differences by sex or group (p > .05). Participants highlighted their familiarity with the research team and assessment process as a motivator for sustained engagement.

Discussion

This protocol relied on novel aspects, such as the use of a WhatsApp bot, which is particularly pertinent for low- to-middle-income countries, and the collection of information from diverse sources in a longitudinal design, encompassing clinical data, self-reports, parental reports, Global Positioning System (GPS) data, and ecological momentary assessments. The study engaged adolescents over an extensive period and demonstrated the feasibility of conducting a prospective follow-up study with a risk-enriched cohort of adolescents in a middle-income country, integrating mobile technology with traditional methodologies to enhance longitudinal data collection.

Inflammation and immune system pathways as biological signatures of adolescent depression-the IDEA-RiSCo study

The biological mechanisms underlying the onset of major depressive disorder (MDD) have predominantly been studied in adult populations from high-income countries, despite the onset of depression typically occurring in adolescence and the majority of the world's adolescents living in low- and middle-income countries (LMIC). Taking advantage of a unique adolescent sample in an LMIC (Brazil), this study aimed to identify biological pathways characterizing the presence and increased risk of depression in adolescence, and sex-specific differences in such biological signatures. We collected blood samples from a risk-stratified cohort of 150 Brazilian adolescents (aged 14-16 years old) comprising 50 adolescents with MDD, 50 adolescents at high risk of developing MDD but without current MDD, and 50 adolescents at low risk of developing MDD and without MDD (25 females and 25 males in each group). We conducted RNA-Seq and pathway analysis on whole blood. Inflammatory-related biological pathways, such as role of hypercytokinemia/hyperchemokinemia in the pathogenesis of influenza (z-score = 3.464, p < 0.001), interferon signaling (z-score = 2.464, p < 0.001), interferon alpha/beta signaling (z-score = 3.873, p < 0.001), and complement signaling (z-score = 2, p = 0.002) were upregulated in adolescents with MDD compared with adolescents without MDD independently from their level of risk. The up-regulation of such inflammation-related pathways was observed in females but not in males. Inflammatory-related pathways involved in the production of cytokines and in interferon and complement signaling were identified as key indicators of adolescent depression, and this effect was present only in females.

Prevalence and relevant factors of depression among adolescents in Xinjiang, China: A cross-sectional survey

The aim of this study is to elucidate the prevalence of depression and examine the contributing factors to depression among adolescents in Xinjiang, China. A stratified cluster sampling methodology was employed in this study, with the sample size determined through consideration of prior studies on adolescent depression. Employing this approach, 6 schools were chosen from each prefecture-level city, designated as urban areas, and 3 schools were selected from each county. Subsequently, individual classes were treated as units, and a minimum of 80 students from each grade were surveyed within the entire class. The investigation of adolescents involved the administration of a questionnaire assessing the factors influencing depression, along with the Center for Epidemiologic Studies Depression Scale (CES-D). Multivariate linear regression was used to analyze the influencing factors of depression. The occurrence rates of depression were 12.17%, 13.05%, 12.32%, and 9.29% in junior middle school, senior middle school, vocational high school, and college, respectively. The corresponding CES-D scores were 10.54 ± 8.26, 11.20 ± 8.37, 12.17 ± 6.94, and 11.33 ± 6.28. Significant associations with the CES-D score were observed for gender, smoking, alcohol consumption, and spending more than 4 hours online daily across the educational levels mentioned. The risk of experiencing depressive symptoms was elevated among female junior and senior high school students who spent more than 4 hours daily on the internet, engaged in cigarette smoking, and consumed alcohol. The findings underscore the significance of targeting high-risk groups, particularly through home-school collaborations, to mitigate excessive internet use and consequently reduce the likelihood of depressive symptoms in students.

An MRI-based morphometric and structural covariance network study of Brazilian adolescents stratified by depression risk

OBJECTIVE

To explore differences in regional cortical morphometric structure between adolescents at risk for depression or with current depression.

METHODS

We analyzed cross-sectional structural neuroimaging data from a sample of 150 Brazilian adolescents classified as low-risk (n=50) or high-risk for depression (n=50) or with current depression (n=50) through a vertex-based approach with measurements of cortical volume, surface area and thickness. Differences between groups in subcortical volumes and in the organization of networks of structural covariance were also explored.

RESULTS

No significant differences in brain structure between groups were observed in whole-brain vertex-wise cortical volume, surface area or thickness. Also, no significant differences in subcortical volume were observed between risk groups. In relation to the structural covariance network, there was an indication of an increase in the hippocampus betweenness centrality index in the high-risk group network compared to the low-risk and current depression group networks. However, this result was only statistically significant when applying false discovery rate correction for nodes within the affective network.

CONCLUSION

In an adolescent sample recruited using an empirically based composite risk score, no major differences in brain structure were detected according to the risk and presence of depression.

Identifying Depression Early in Adolescence: assessing the performance of a risk score for future onset of depression in an independent Brazilian sample

OBJECTIVE

The Identifying Depression Early in Adolescence Risk Score (IDEA-RS) was recently developed in Brazil using data from the Pelotas 1993 Birth Cohort to estimate the individualized probability of developing depression in adolescence. This model includes 11 sociodemographic variables and has been assessed in longitudinal studies from four other countries. We aimed to test the performance of IDEA-RS in an independent, community-based, school-attending sample within the same country: the Brazilian High-Risk Cohort.

METHODS

Standard external validation, refitted, and case mix-corrected models were used to predict depression among 1442 youth followed from a mean age of 13.5 years at baseline to 17.7 years at follow-up, using probabilities calculated with IDEA-RS coefficients.

RESULTS

The area under the curve was 0.65 for standard external validation, 0.70 for the case mix-corrected model, and 0.69 for the refitted model, with discrimination consistently above chance for predicting depression in the new dataset. There was some degree of miscalibration, corrected by model refitting (calibration-in-the-large reduced from 0.77 to 0).

CONCLUSION

IDEA-RS was able to parse individuals with higher or lower probability of developing depression beyond chance in an independent Brazilian sample. Further steps should include model improvements and additional studies in populations with high levels of subclinical symptoms to improve clinical decision making.

Frontolimbic Network Topology Associated With Risk and Presence of Depression in Adolescents: A Study Using a Composite Risk Score in Brazil

BACKGROUND

There have been significant challenges in understanding functional brain connectivity associated with adolescent depression, including the need for a more comprehensive approach to defining risk, the lack of representation of participants from low- and middle-income countries, and the need for network-based approaches to model connectivity. The current study aimed to address these challenges by examining resting-state functional connectivity of frontolimbic circuitry associated with the risk and presence of depression in adolescents in Brazil.

METHODS

Adolescents in Brazil ages 14 to 16 years were classified into low-risk, high-risk, and depressed groups using a clinical assessment and composite risk score that integrates 11 sociodemographic risk variables. After excluding participants with excessive head movement, resting-state functional magnetic resonance imaging data of 126 adolescents were analyzed. We compared group differences in frontolimbic network connectivity using region of interest-to-region of interest, graph theory, and seed-based connectivity analyses. Associations between self-reported depressive symptoms and brain connectivity were also explored.

RESULTS

Adolescents with depression showed greater dorsal anterior cingulate cortex (ACC) connectivity with the orbitofrontal cortex compared with the 2 risk groups and greater dorsal ACC global efficiency than the low-risk group. Adolescents with depression also showed reduced local efficiency and a lower clustering coefficient of the subgenual ACC compared with the 2 risk groups. The high-risk group also showed a lower subgenual ACC clustering coefficient relative to the low-risk group.

CONCLUSIONS

These findings highlight altered connectivity and topology of the ACC within frontolimbic circuitry as potential neural correlates and risk factors of developing depression in adolescents in Brazil. This study broadens our understanding of the neural connectivity associated with adolescent depression in a global context.

Psychological and contextual risk factors for first-onset depression among adolescents and young people around the globe: A systematic review and meta-analysis

AIM

Identifying predictors for future onset of depression is crucial to effectively developing preventive interventions. We conducted a systematic review and meta-analysis to identify risk factors for first-onset depression among adolescents and young people.

METHODS

We searched MEDLINE (Ovid), PsycINFO, Cochrane Database, Web of Science, Lilacs, African Journals Online and Global Health (July 2009 to December 2020) for longitudinal studies assessing risk factors for first-onset depression among adolescents and young people aged 10-25 years. Meta-analyses generated summary odds ratio (OR) estimates.

REGISTRATION

PROSPERO CRD42018103973.

RESULTS

Nineteen studies representing 21 unique populations were included in the meta-analysis. Among studies reporting race/ethnicity, 79% of participants were of White/European descent. Seventeen studies were from high-income countries, with only two from an upper-middle-income country (China). Odds for first-onset depression were significantly greater for girls compared to boys (n = 13; OR = 1.78 [1.78, 2.28], p < 0.001) and for youth with other mental health problems at baseline (n = 4; OR = 3.20 [1.95, 5.23], p < 0.001). There were non-significant associations for negative family environment (n = 8; OR = 1.60 [0.82, 3.10], p = 0.16) and parental depression (n = 3; OR = 2.30 [0.73, 7.24], p = 0.16).

CONCLUSIONS

Most longitudinal studies do not report risk factors specifically for first-onset depression. Moreover, predictive data are limited to predominantly White populations in high-income countries. Future research must be more ethnically and geographically representative. Recommendations are provided for consistent and comprehensive reporting of study designs and analyses of risk factors for first-onset depression.

Detection of risk for future depression among adolescents: Stakeholder views of acceptability and feasibility in the United Kingdom

AIM

Depression is one of the most common mental illnesses globally and a leading cause of disability. It is often established by late adolescence and thus identifying which adolescents are most at risk is crucial to enable early intervention to prevent depression onset. We have previously developed a risk calculator to stratify which adolescents are at high risk of developing depression and in this study explore the views of stakeholders to ascertain the acceptability and feasibility of implementing such a tool in the UK.

METHODS

Semi-structured interviews were conducted with 60 UK-based stakeholders (12 healthcare workers, 12 social workers, 12 school workers, 12 policymakers and 12 parents). Interviews were audio-recorded and transcribed verbatim. Transcripts were analysed drawing on framework analysis techniques in NVivo 12.

RESULTS

Six overarching themes were identified: facilitators of acceptability; barriers to acceptability; role of stakeholders in implementing risk screening; feasibility of delivering the risk calculator in practice; barriers to implementation; and policy and system implications of using it in the current UK health and social care climate. The implementation of a depression risk calculator in the UK was seen as largely acceptable and feasible by most respondents. There was a strong emphasis on the utility of schools to implement this risk calculator, although it was recognized that training and support would be essential.

CONCLUSIONS

Stakeholders were generally positive about utilizing a tool to screen for risk of future depression among adolescents in the UK but raised important concerns which should be taken into account before implementation.

Identifying adolescents at risk for depression: Assessment of a global prediction model in the Great Smoky Mountains Study

The Identifying Depression Early in Adolescence Risk Score (IDEA-RS) has been externally assessed in samples from four continents, but North America is lacking. Our aim here was to evaluate the performance of the IDEA-RS in predicting future onset of Major Depressive Disorder (MDD) in an adolescent population-based sample in the United States of America - the Great Smoky Mountains Study (GSMS). We applied the intercept and weights of the original IDEA-RS model developed in Brazil to generate individual probabilities for each participant of the GSMS at age 15 (N = 1029). We then evaluated the performance of such predictions against the diagnosis of MDD at age 19 using simple, case-mix corrected and refitted models. Furthermore, we compared how prioritizing the information provided by parents or by adolescents affected performance. The IDEA-RS exhibited a C-statistic of 0.63 (95% CI 0.53-0.74) to predict MDD in the GSMS when applying uncorrected weights. Case-mix corrected and refitted models enhanced performance to 0.69 and 0.67, respectively. No significant difference was found in performance by prioritizing the reports of adolescents or their parents. The IDEA-RS was able to parse out adolescents at risk for a later onset of depression in the GSMS cohort with above chance discrimination. The IDEA-RS has now showed above-chance performance in five continents.

Exploring the role of immune pathways in the risk and development of depression in adolescence: Research protocol of the IDEA-FLAME study

Extensive research suggests a role for the innate immune system in the pathogenesis of depression, but most of the studies are conducted in adult populations, in high-income countries and mainly focus on the study of inflammatory proteins alone, which provides only a limited understanding of the immune pathways involved in the development of depression. The IDEA-FLAME study aims to identify immune phenotypes underlying increased risk of developing depression in adolescence in a middle-income country. To this end, we will perform deep-immunophenotyping of peripheral blood mononuclear cells and RNA genome-wide gene expression analyses in a longitudinal cohort of Brazilian adolescents stratified for depression risk. The project will involve the 3-year follow-up of an already recruited cohort of 150 Brazilian adolescents selected for risk/presence of depression on the basis of a composite risk score we developed using sociodemographic characteristics (50 adolescents with low-risk and 50 with high-risk of developing depression, and 50 adolescents with a current major depressive disorder). We will 1) test whether the risk group classification at baseline is associated with differences in immune cell frequency, phenotype and functional status, 2) test whether baseline immune markers (cytokines and immune cell markers) are associated with severity of depression at 3-year follow-up, and 3) identify changes in gene expression of immune pathways over the 3-year follow-up in adolescents with increased risk and presence of depression. Because of the exploratory nature of the study, the findings would need to be replicated in a separate and larger sample. Ultimately, this research will contribute to elucidating key immune therapeutic targets and inform the development of interventions to prevent onset of depression among adolescents.

Preventive strategies for adolescent depression: What are we missing? A focus on biomarkers

Adolescent depression is an important global issue with several unmet needs that still must be addressed and, to date, there are only few effective preventive strategies to reduce the burden of this disorder worldwide. In this mini-review, the evidence and potential ways to improve an early detection will be discussed as well as prompt interventions by focusing on a better understanding of the risks underlying the developing of adolescent depression from both a sociodemographic and a biological perspective.

Prediction models for child and adolescent mental health: A systematic review of methodology and reporting in recent research

BACKGROUND

There has been a rapid growth in the publication of new prediction models relevant to child and adolescent mental health. However, before their implementation into clinical services, it is necessary to appraise the quality of their methods and reporting. We conducted a systematic review of new prediction models in child and adolescent mental health, and examined their development and validation.

METHOD

We searched five databases for studies developing or validating multivariable prediction models for individuals aged 18 years old or younger from 1 January 2018 to 18 February 2021. Quality of reporting was assessed using the Transparent Reporting of a multivariable prediction models for Individual Prognosis Or Diagnosis checklist, and quality of methodology using items based on expert guidance and the PROBAST tool.

RESULTS

We identified 100 eligible studies: 41 developing a new prediction model, 48 validating an existing model and 11 that included both development and validation. Most publications (k = 75) reported a model discrimination measure, while 26 investigations reported calibration. Of 52 new prediction models, six (12%) were for suicidal outcomes, 18 (35%) for future diagnosis, five (10%) for child maltreatment. Other outcomes included violence, crime, and functional outcomes. Eleven new models (21%) were developed for use in high-risk populations. Of development studies, around a third were sufficiently statistically powered (k = 16%, 31%), while this was lower for validation investigations (k = 12, 25%). In terms of performance, the discrimination (as measured by the C-statistic) for new models ranged from 0.57 for a tool predicting ADHD diagnosis in an external validation sample to 0.99 for a machine learning model predicting foster care permanency.

CONCLUSIONS

Although some tools have recently been developed for child and adolescent mental health for prognosis and child maltreatment, none can be currently recommended for clinical practice due to a combination of methodological limitations and poor model performance. New work needs to use ensure sufficient sample sizes, representative samples, and testing of model calibration.

Development and external validation of a risk calculator to predict internalising symptoms among Ugandan youths affected by HIV

The aim of the study was to develop and externally validate a model to predict individualized risk of internalizing symptoms among AIDS-affected youths in low-resource settings in sub-Saharan Africa. Longitudinal data from 558 Ugandan adolescents orphaned by AIDS was used to develop our predictive model. Least Absolute Shrinkage and Selection Operator logistic regression was used to select the best subset of predictors using 10-fold cross-validation. External validation of the final model was conducted in a sample of 372 adolescents living with HIV in Uganda. Best predictors for internalizing symptoms were gender, family cohesion, social support, asset ownership, recent sexually transmitted infection (STI) diagnosis, physical health self-rating, and previous poor mental health; area under the curve (AUC)  = 72.2; 95% CI  = 67.9-76.5. For adolescents without history of internalizing symptoms, the AUC = 69.0, 95% CI = 63.4-74.6, and was best predicted by gender, drug use, social support, asset ownership, recent STI diagnosis, and physical health self-rating. Both models were well calibrated. External validation in adolescents living with HIV sample was similar, AUC = 69.7; 95% CI = 64.1-75.2. The model predicted internalizing symptoms among African AIDS-affected youth reasonably well and showed good generalizability. The model offers opportunities for the design of public health interventions addressing poor mental health among youth affected by HIV/AIDS.

Childhood exposure to ambient air pollution and predicting individual risk of depression onset in UK adolescents

Knowledge about early risk factors for major depressive disorder (MDD) is critical to identify those who are at high risk. A multivariable model to predict adolescents' individual risk of future MDD has recently been developed however its performance in a UK sample was far from perfect. Given the potential role of air pollution in the aetiology of depression, we investigate whether including childhood exposure to air pollution as an additional predictor in the risk prediction model improves the identification of UK adolescents who are at greatest risk for developing MDD. We used data from the Environmental Risk (E-Risk) Longitudinal Twin Study, a nationally representative UK birth cohort of 2232 children followed to age 18 with 93% retention. Annual exposure to four pollutants - nitrogen dioxide (NO₂), nitrogen oxides (NO_X), particulate matter <2.5 μm (PM_2.5) and <10 μm (PM₁₀) - were estimated at address-level when children were aged 10. MDD was assessed via interviews at age 18. The risk of developing MDD was elevated most for participants with the highest (top quartile) level of annual exposure to NO_X (adjusted OR = 1.43, 95% CI = 0.96-2.13) and PM_2.5 (adjusted OR = 1.35, 95% CI = 0.95-1.92). The separate inclusion of these ambient pollution estimates into the risk prediction model improved model specificity but reduced model sensitivity - resulting in minimal net improvement in model performance. Findings indicate a potential role for childhood ambient air pollution exposure in the development of adolescent MDD but suggest that inclusion of risk factors other than this may be important for improving the performance of the risk prediction model.

Identifying risk factors and detection strategies for adolescent depression in diverse global settings: A Delphi consensus study

BACKGROUND

Adolescence represents a vulnerable period for the onset of depression. Globally, there is a need to better understand risk factors for adolescent depression to inform policies for effective prevention initiatives.

METHODS

A Delphi consensus study was conducted on risk factors, early signs, and detection strategies for adolescent depression in global settings. Over 3 survey rounds, global experts formulated and ranked these variables for (1) specificity for adolescent depression and (2) feasibility of measurement (round 1, n=21 participants; rounds 2 and 3, n=17). We calculated Smith's salience index as a measure of consensus. Interviews were conducted with 10 participants to elicit qualitative reflections on the ranking results, and on the influence of cultural and contextual factors on depression risks.

RESULTS

Thirty-one risk factors for adolescent depression were generated. Panelists ranked three as highly specific and highly feasible to measure: family history of depression, exposure to bullying, and a negative family environment. Six were ranked as modestly specific and highly feasible: physical illness or disability, female sex, bereavement, trauma exposure, substance abuse, and low self-esteem. An additional 5 items were modestly specific and modestly feasible: social difficulties, academic stress, poverty, loss of family, and cognitive distortions. Five symptoms were at least modestly specific and feasible to measure: mood changes, loss of interest, social isolation, suicidality, and sleep changes. Schools were considered the most feasible place for screening.

LIMITATIONS

The participants were not representative of all countries and cultural regions.

CONCLUSIONS

This study offers a profile of risk factors developed and prioritized by experts to inform a research agenda for risk, identification and prevention of adolescent depression across global settings.

The Identifying Depression Early in Adolescence Risk Stratified Cohort (IDEA-RiSCo): Rationale, Methods, and Baseline Characteristics

Background: The characterization of adolescents at high risk for developing depression has traditionally relied on the presence or absence of single risk factors. More recently, the use of composite risk scores combining information from multiple variables has gained attention in prognostic research in the field of mental health. We previously developed a sociodemographic composite score to estimate the individual level probability of depression occurrence in adolescence, the Identifying Depression Early in Adolescence Risk Score (IDEA-RS). Objectives: In this report, we present the rationale, methods, and baseline characteristics of the Identifying Depression Early in Adolescence Risk Stratified Cohort (IDEA-RiSCo), a study designed for in-depth examination of multiple neurobiological, psychological, and environmental measures associated with the risk of developing and with the presence of depression in adolescence, with a focus on immune/inflammatory and neuroimaging markers. Methods: Using the IDEA-RS as a tool for risk stratification, we recruited a new sample of adolescents enriched for low (LR) and high (HR) depression risk, as well as a group of adolescents with a currently untreated major depressive episode (MDD). Methods for phenotypic, peripheral biological samples, and neuroimaging assessments are described, as well as baseline clinical characteristics of the IDEA-RiSCo sample. Results: A total of 7,720 adolescents aged 14-16 years were screened in public state schools in Porto Alegre, Brazil. We were able to identify individuals at low and high risk for developing depression in adolescence: in each group, 50 participants (25 boys, 25 girls) were included and successfully completed the detailed phenotypic assessment with ascertainment of risk/MDD status, blood and saliva collections, and magnetic resonance imaging (MRI) scans. Across a variety of measures of psychopathology and exposure to negative events, there was a clear pattern in which either the MDD group or both the HR and the MDD groups exhibited worse indicators in comparison to the LR group. Conclusion: The use of an empirically-derived composite score to stratify risk for developing depression represents a promising strategy to establish a risk-enriched cohort that will contribute to the understanding of the neurobiological correlates of risk and onset of depression in adolescence.

Predicting the risk of future depression among school-attending adolescents in Nigeria using a model developed in Brazil

Depression commonly emerges in adolescence and is a major public health issue in low- and middle-income countries where 90% of the world's adolescents live. Thus efforts to prevent depression onset are crucial in countries like Nigeria, where two-thirds of the population are aged under 24. Therefore, we tested the ability of a prediction model developed in Brazil to predict future depression in a Nigerian adolescent sample. Data were obtained from school students aged 14-16 years in Lagos, who were assessed in 2016 and 2019 for depression using a self-completed version of the Mini International Neuropsychiatric Interview for Children and Adolescents. Only the 1,928 students free of depression at baseline were included. Penalized logistic regression was used to predict individualized risk of developing depression at follow-up for each adolescent based on the 7 matching baseline sociodemographic predictors from the Brazilian model. Discrimination between adolescents who did and did not develop depression was better than chance (area under the curve = 0.62 (bootstrap-corrected 95% CI: 0.58-0.66). However, the model was not well-calibrated even after adjustment of the intercept, indicating poorer overall performance compared to the original Brazilian cohort. Updating the model with context-specific factors may improve prediction of depression in this setting.

Detection of risk for depression among adolescents in diverse global settings: protocol for the IDEA qualitative study in Brazil, Nepal, Nigeria and the UK

INTRODUCTION

Globally, depression is a leading cause of disability among adolescents, and suicide rates are increasing among youth. Treatment alone is insufficient to address the issue. Early identification and prevention efforts are necessary to reduce morbidity and mortality. The Identifying Depression Early in Adolescence (IDEA) consortium is developing risk detection strategies that incorporate biological, psychological and social factors that can be evaluated in diverse global populations. In addition to epidemiological and neuroscience research, the IDEA consortium is conducting a qualitative study to explore three domains of inquiry: (1) cultural heterogeneity of biopsychosocial risk factors and lived experience of adolescent depression in low-income and middle-income countries (LMIC); (2) the feasibility, acceptability and ethics of a risk calculator tool for adolescent depression that can be used in LMIC and high-income countries and (3) capacity for biological research into biomarkers for depression risk among adolescents in LMIC. This is a multisite qualitative study being conducted in Brazil, Nepal, Nigeria and the UK.

METHODS AND ANALYSIS

A systematic set of qualitative methods will be used in this study. The Delphi method, Theory of Change (ToC) workshops, key-informant interviews and focus group discussions will be used to elicit perspectives on the study topics from a broad range of stakeholders (adolescents, parents, policy-makers, teachers, health service providers, social workers and experts). Delphi panellists will participate in three survey rounds to generate consensus through facilitated feedback. Stakeholders will create ToC models via facilitated workshops in the LMIC sites. The framework approach will be used to analyse data from the study.

ETHICS AND DISSEMINATION

Ethical approvals were received from the Ethics Review Board of George Washington University and from site-specific institutions in Brazil, Nepal, Nigeria and the UK. The findings generated from this study will be reported in highly accessed, peer-reviewed, scientific and health policy journals.