Prevalence and risk factors of psychiatric symptoms and diagnoses before and during the COVID-19 pandemic: findings from the ELSA-Brasil COVID-19 mental health cohort.

BACKGROUND: There is mixed evidence on increasing rates of psychiatric disorders and symptoms during the coronavirus disease 2019 (COVID-19) pandemic in 2020. We evaluated pandemic-related psychopathology and psychiatry diagnoses and their determinants in the Brazilian Longitudinal Study of Health (ELSA-Brasil) São Paulo Research Center. METHODS: Between pre-pandemic ELSA-Brasil assessments in 2008-2010 (wave-1), 2012-2014 (wave-2), 2016-2018 (wave-3) and three pandemic assessments in 2020 (COVID-19 waves in May-July, July-September, and October-December), rates of common psychiatric symptoms, and depressive, anxiety, and common mental disorders (CMDs) were compared using the Clinical Interview Scheduled-Revised (CIS-R) and the Depression Anxiety Stress Scale-21 (DASS-21). Multivariable generalized linear models, adjusted by age, gender, educational level, and ethnicity identified variables associated with an elevated risk for mental disorders. RESULTS: In 2117 participants (mean age 62.3 years, 58.2% females), rates of CMDs and depressive disorders did not significantly change over time, oscillating from 23.5% to 21.1%, and 3.3% to 2.8%, respectively; whereas rate of anxiety disorders significantly decreased (2008-2010: 13.8%; 2016-2018: 9.8%; 2020: 8%). There was a decrease along three wave-COVID assessments for depression [ß = -0.37, 99.5% confidence interval (CI) -0.50 to -0.23], anxiety (ß = -0.37, 99.5% CI -0.48 to -0.26), and stress (ß = -0.48, 99.5% CI -0.64 to -0.33) symptoms (all ps < 0.001). Younger age, female sex, lower educational level, non-white ethnicity, and previous psychiatric disorders were associated with increased odds for psychiatric disorders, whereas self-evaluated good health and good quality of relationships with decreased risk. CONCLUSION: No consistent evidence of pandemic-related worsening psychopathology in our cohort was found. Indeed, psychiatric symptoms slightly decreased along 2020. Risk factors representing socioeconomic disadvantages were associated with increased odds of psychiatric disorders.

Children and adolescents' emotional problems during the COVID-19 pandemic in Brazil.

Brazil has been severely affected by the COVID-19 pandemic with one of the largest numbers of youth impacted by school closure globally. This longitudinal online survey assessed emotional problems in children and adolescents aged 5-17 years living in Brazil during the COVID-19 pandemic. Recruitment occurred between June to November 2020 and participants were invited for follow-up assessments every 15 days until June 2021. Participants were 5795 children and adolescents living across the country with mean age of 10.7 (SD 3.63) years at recruitment; 50.5% were boys and 69% of white ethnicity. Weighted prevalence rates of anxiety, depressive and total emotional symptoms at baseline were 29.7%, 36.1% and 36%, respectively. Longitudinal analysis included 3221 (55.6%) participants and revealed fluctuations in anxiety and depressive symptoms during one year follow-up, associated with periods of social mobility and mortality. Emotional problems significantly increased in July and September 2020 and decreased from December 2020 to February 2021 and then significantly increased in May 2021 relative to June 2020. Older age, feeling lonely, previous diagnosis of mental or neurodevelopmental disorder, previous exposure to traumatic events or psychological aggression, parental psychopathology, and sleeping less than 8/h a day were associated with increased rates of anxiety and depressive symptoms at baseline and over time. Food insecurity and less social contact with family and peers were associated with baseline anxiety and depressive symptoms, and lowest socio-economic strata, chronic disease requiring treatment and family members physically ill due to COVID-19 were associated with increasing rates over time. The pandemic severely affected youth, particularly those from vulnerable populations and in moments of increased mortality and decreased social mobility. Results underscore the need for allocation of resources to services and the continuous monitoring of mental health problems among children and adolescents.

Trajectories of common mental disorders symptoms before and during the COVID-19 pandemic: findings from the ELSA-Brasil COVID-19 Mental Health Cohort.

AIM: Evidence indicates most people were resilient to the impact of the COVID-19 pandemic on mental health. However, evidence also suggests the pandemic effect on mental health may be heterogeneous. Therefore, we aimed to identify groups of trajectories of common mental disorders' (CMD) symptoms assessed before (2017-19) and during the COVID-19 pandemic (2020-2021), and to investigate predictors of trajectories. METHODS: We assessed 2,705 participants of the ELSA-Brasil COVID-19 Mental Health Cohort study who reported Clinical Interview Scheduled-Revised (CIS-R) data in 2017-19 and Depression Anxiety Stress Scale-21 (DASS-21) data in May-July 2020, July-September 2020, October-December 2020, and April-June 2021. We used an equi-percentile approach to link the CIS-R total score in 2017-19 with the DASS-21 total score. Group-based trajectory modeling was used to identify CMD trajectories and adjusted multinomial logistic regression was used to investigate predictors of trajectories. RESULTS: Six groups of CMD symptoms trajectories were identified: low symptoms (17.6%), low-decreasing symptoms (13.7%), low-increasing symptoms (23.9%), moderate-decreasing symptoms (16.8%), low-increasing symptoms (23.3%), severe-decreasing symptoms (4.7%). The severe-decreasing trajectory was characterized by age < 60 years, female sex, low family income, sedentary behavior, previous mental disorders, and the experience of adverse events in life. LIMITATIONS: Pre-pandemic characteristics were associated with lack of response to assessments. Our occupational cohort sample is not representative. CONCLUSION: More than half of the sample presented low levels of CMD symptoms. Predictors of trajectories could be used to detect individuals at-risk for presenting CMD symptoms in the context of global adverse events.

Promoting mother-infant relationships and underlying neural correlates: Results from a randomized controlled trial of a home-visiting program for adolescent mothers in Brazil.

Poverty and teenage pregnancy are common in low-and-middle-income countries and can impede the development of healthy parent-child relationships. This study aimed to test whether a home-visiting intervention could improve early attachment relationships between adolescent mothers and their infants living in poverty in Brazil. Analyses were conducted on secondary outcomes from a randomized controlled trial (NCT0280718) testing the efficacy of a home-visiting program, Primeiros Laços, on adolescent mothers' health and parenting skills and their infants' development. Pregnant youth were randomized to intervention (n = 40) or care-as-usual (CAU, n = 40) from the first trimester of pregnancy until infants were aged 24 months. Mother-infant attachment was coded during a mother-infant interaction when the infants were aged 12 months. Electrophysiological correlates of social processing (mean amplitude of the Nc component) were measured while infants viewed facial images of the mother and a stranger at age 6 months. Infants in the intervention group were more securely attached and more involved with their mothers than those receiving CAU at 12 months. Smaller Nc amplitudes to the mother's face at 6 months were associated with better social behavior at 12 months. Our findings indicate that the Primeiros Laços Program is effective in enhancing the development of mother-infant attachment.

Risk factors for obsessive-compulsive symptoms. Follow-up of a community-based youth cohort.

Environmental factors are at least as important as genetic factors for the development of obsessive-compulsive symptoms (OCS), but the identification of such factors remain a research priority. Our study aimed to investigate the association between a broad scope of potential risk factors and OCS in a large community cohort of children and adolescents. We evaluated 1877 participants and their caregivers at baseline and after 3 years to assess various demographic, prenatal, perinatal, childhood adversity, and psychopathological factors. Mean age at baseline was 10.2 years (SD 1.9) and mean age at follow-up was 13.4 years (SD 1.9). Reports of OCS at baseline and follow-up were analyzed using latent variable models. At preliminary regression analysis, 15 parameters were significantly associated with higher OCS scores at follow-up. At subsequent regression analysis, we found that eight of these parameters remained significantly associated with higher follow-up OCS scores while being controlled by each other and by baseline OCS scores. The significant predictors of follow-up OCS were: lower socioeconomic status (p = 0.033); lower intelligence quotient (p = 0.013); lower age (p < 0.001); higher maternal stress level during pregnancy (p = 0.028); absence of breastfeeding (p = 0.017); parental baseline OCS (p = 0.038); youth baseline anxiety disorder (p = 0.023); and youth baseline OCS scores (p < 0.001). These findings may better inform clinicians and policymakers engaged in the mental health assessment and prevention in children and adolescents.

Is it time to change the gold standard of obsessive-compulsive disorder severity assessment? Factor structure of the Yale-Brown Obsessive-Compulsive Scale.

OBJECTIVES: The Yale-Brown Obsessive-Compulsive Scale has been considered the gold standard scale to assess obsessive-compulsive disorder severity. Previous studies using exploratory factor analysis and confirmatory factor analysis with this scale showed mixed findings in terms of factor structure and fit of models. Therefore, we used confirmatory factor analysis to compare different Yale-Brown Obsessive-Compulsive Scale models in a large sample aiming to identify the best model fit. METHODS: We assessed adult obsessive-compulsive disorder patients (n = 955) using three measures: Yale-Brown Obsessive-Compulsive Scale severity ratings, the Dimensional Yale-Brown Obsessive-Compulsive Scale and the clinical global impression scale. We tested all factor structures reported by previous studies to investigate which model best fitted the data: one-factor, two-factor, three-factor and their equivalent high-order solutions. We also investigated Yale-Brown Obsessive-Compulsive Scale items correlations with scores from the other measures of obsessive-compulsive disorder severity. RESULTS: Confirmatory factor analysis models presented mediocre to fair goodness-of-fit indexes. Severity items related to resistance to obsessions and compulsions presented low factor loadings. The model with the best fit indexes was a high-order model without obsessive-compulsive disorder resistance items. These items also presented small correlations with other obsessive-compulsive disorder severity measures. CONCLUSION: The obsessive-compulsive disorder field needs to discuss further improvements in the Yale-Brown Obsessive-Compulsive Scale and/or continue to search for better measures of obsessive-compulsive disorder severity.

Long-term outcome of children and adolescents with obsessive-compulsive disorder: a 7-9-year follow-up of a randomized clinical trial.

Pediatric obsessive-compulsive disorder (OCD) is an impairing disorder frequently associated with long-term persistence. Long-term follow-up studies that investigated psychopathological trajectories after initial treatment are scarce. The present study is a 7-9-year follow-up of a randomized clinical trial (RCT) that tested the efficacy of group cognitive-behavioral therapy (CBT) and sertraline for children with OCD (n = 40), and aimed to describe long-term outcomes of pediatric OCD and identify predictors of these outcomes. Thirty-five participants who were included in the original study were recruited for follow-up evaluations. Participants underwent a comprehensive assessment of demographic and clinical characteristics comprised of the Structured Clinical Interview for DSM Disorders (SCID) and/or Kiddie-Schedule of Affective Disorders and Schizophrenia Present-Lifetime (K-SADS-PL), and the Yale-Brown Obsessive-Compulsive Scale (YBOCS). Thirty-three participants had a complete psychiatric assessment at follow-up (mean age 21 years, SD 3.2; 65% male). At follow-up, 13 (39.4%) participants had an OCD diagnosis, 10 (30.3%) had a diagnosis of any mental disorder (excluding OCD), and 10 (30.3%) did not have any diagnosis of mental disorder. In total, 23 participants (69.7%) had at least one mental disorder (including OCD). Among those without OCD (n = 20), 60.6% had a mental disorder. The following characteristics at follow-up were associated with OCD diagnosis: YBOCS total score (p < 0.001), global functioning (p = 0.008), and presence of any anxiety disorder (p = 0.027). Being treated with GCBT or sertraline during the original RCT did not predict OCD at follow-up. New treatment strategies should consider the role of psychopathological trajectories using a dynamic approach to combine or change interventions to enhance prognosis.

Caudate volume differences among treatment responders, non-responders and controls in children with obsessive-compulsive disorder.

Treatment response in obsessive-compulsive disorder (OCD) is heterogeneous and the neurobiological underpinnings of such variability are unknown. To investigate this issue, we looked for differences in brain structures possibly associated with treatment response in children with OCD. 29 children with OCD (7-17 years) and 28 age-matched controls underwent structural magnetic resonance imaging. Patients then received treatment with fluoxetine or group cognitive-behavioral therapy during 14 weeks, and were classified as treatment responders or non-responders. The caudate nucleus, thalamus and orbitofrontal cortex were selected a priori, according to previous evidence of their association with OCD and its treatment. Gray matter (GM) volume comparisons between responders, non-responders and controls were performed, controlling for total GM volume. 17 patients were classified as responders. Differences among responders, non-responders and controls were found in both caudate nuclei (both p-values = 0.041), but after Bonferroni correction for multiple comparisons, these findings were non-significant. However, after excluding the effect of an outlier, findings were significant for the right caudate (p = 0.004). Pairwise comparisons showed larger caudate GM volume in responders versus non-responders and controls, bilaterally. The right caudate accounted for 20.2% of the variance in Y-BOCS changes after treatment in a linear regression model, with a positive correlation (p = 0.016). We present a possible neural substrate for treatment response in pediatric OCD, which is in line with previous evidence regarding the caudate nucleus. Considering the limitations, further research is needed to replicate this finding and elucidate the heterogeneity of treatment response in children with OCD (National Clinical Trials Registration Number: NCT01148316).

Prevalence and correlates of depression, anxiety, and stress in medical residents of a Brazilian academic health system.

BACKGROUND: Several studies correlate medical residency with the occurrence of mental health disorders, Burnout Syndrome and quality of life impairment. It has been demonstrated that mental health disorders increase medical errors and lead to less effective patient care. Considering such context, this study aimed to evaluate the prevalence of anxiety, depression, stress and to identify its correlates with Burnout Syndrome and quality of life in a sample of medical residents and fellow physicians of the largest Brazilian academic health system. METHODS: In 2017, 1648 participants were voluntarily and anonymously surveyed online about demographic characteristics, Burnout Syndrome, mental symptoms, and quality of life measured by validated questionnaires. Responses were captured through REDCap platform and multivariate statistical analyses were performed with STATA 15. RESULTS: A total of 606 (36.8%) residents/fellows physicians completed the survey. Depression symptoms were present in 19%, anxiety symptoms in 16% and stress symptoms in 17.7% of the sample. Burnout Syndrome was present in 63% of the sample. Multivariate analysis showed a statistical significant positive correlation between Burnout Syndrome and depression, anxiety and stress symptoms and a negative correlation between mental symptoms and quality of life scores. CONCLUSIONS: Mental health symptoms prevalence in this study is similar to other studies and their occurrence is positively correlated with Burnout Syndrome among medical residents/fellow physicians of the largest Brazilian academic health system. These results are relevant and must be confirmed by multicentric longitudinal studies. This study reinforces the importance of debating interventions to improve mental health among doctors in training.

The economic impact of subthreshold and clinical childhood mental disorders.

BACKGROUND: Mental disorders are common health problems associated with serious impairment and economic impact. AIMS: To estimate the costs of clinical and subthreshold mental disorders in a sample of Brazilian children. METHOD: The High Risk Cohort Study is a community study conducted in two major Brazilian cities. Subjects were 6-14 years old children being registered at school. From an initial pool of 9937 children, two subgroups were further investigated using a random-selection (n = 958) and high-risk group selection procedure (n = 1554), resulting in a sample of 2512 subjects. Mental disorder assessment was made using the Development and Well-Being Assessment. Costs for each child were estimated from the following components: mental health and social services use, school problems and parental loss of productivity. RESULTS: Child subthreshold and clinical mental disorders showed lifetime mean total cost of $1750.9 and $3141.2, respectively. National lifetime cost estimate was $9.9 billion for subthreshold mental disorders and $11.6 billion for clinical mental disorders (values in US$ purchasing power parity). CONCLUSIONS: This study provides evidence that child mental disorders have a great economic impact on society. There is an urgent need to plan an effective system of care with cost-effective programs of treatment and prevention to reduce economic burden.

The Gut Microbiome in the First One Thousand Days of Neurodevelopment: A Systematic Review from the Microbiome Perspective.

Evidence shows that the gut microbiome in early life is an essential modulator of physiological processes related to healthy brain development, as well as mental and neurodegenerative disorders. Here, we conduct a systematic review of gut microbiome assessments on infants (both healthy and with conditions that affect brain development) during the first thousand days of life, associated with neurodevelopmental outcomes, with the aim of investigating key microbiome players and mechanisms through which the gut microbiome affects the brain. Bacteroides and Bifidobacterium were associated with non-social fear behavior, duration of orientation, cognitive and motricity development, and neurotypical brain development. Lachnospiraceae, Streptococcus, and Faecalibacterium showed variable levels of influence on behavior and brain development. Few studies described mechanistic insights related to NAD salvage, aspartate and asparagine biosynthesis, methanogenesis, pathways involved in bile acid transformation, short-chain fatty acids production, and microbial virulence genes. Further studies associating species to gene pathways and robustness in data analysis and integration are required to elucidate the functional mechanisms underlying the role of microbiome-gut-brain axis in early brain development.

Incidence of Suicidal Ideation in a Civil Servants Cohort During the COVID-19 Pandemic in Brazil: Insights from the ELSA-Brasil Study.

OBJECTIVE: This study investigated the incidence of suicidal ideation and its associated risk factors in the São Paulo state of ELSA-Brasil cohort during the COVID-19 pandemic. METHODS: During a pre-pandemic ELSA-Brasil onsite assessment in 2016-2018 (wave 3) and a pandemic online assessment in May-July 2020 (wave COVID), we assessed suicidal ideation using the Clinical Interview Scheduled-Revised (CIS-R). Single and multi predictor logistic regressions were performed using sociodemographic characteristics, household finance impact during pandemic, presence of previous chronic diseases, alcohol abuse, adverse childhood experiences (ACE), living alone, and previous CMD as predictors. Suicidal ideation incidence was used as outcome. RESULTS: Out of 4191 participants of wave 3, 2117 (50.5%) answered wave COVID. There was a threefold increase in suicide ideation, from 34 (1.8%) to 104 (5.6%).In multiple predictor models, we found that previous CMD (OR 7.17; 95% CI 4.43 - 11.58) and ACE (OR 1.72; 95% CI 1.09 - 2.72) increased the odds of incident suicidal ideation. The sociodemographic predictors female sex, younger age and low income were significant risk factors only in the single predictor model. Conclusions These findings underscore the importance of monitoring and supporting individuals who suffered ACE and have a history of mental health disorders. This is especially critical in times of heightened societal stress, such as the COVID-19 pandemic. CONCLUSIONS: These findings underscore the importance of monitoring and supporting individuals who suffered ACE and have a history of mental health disorders. This is especially critical in times of heightened societal stress, such as the COVID-19 pandemic.

Influence of psychosocial risk factors on the trajectory of mental health problems from childhood to adolescence: a longitudinal study.

BACKGROUND: Longitudinal epidemiological studies involving child/adolescent mental health problems are scarce in developing countries, particularly in regions characterized by adverse living conditions. We examined the influence of psychosocial factors on the trajectory of child/adolescent mental health problems (CAMHP) over time. METHODS: A population-based sample of 6- to 13-year-olds with CAMHP was followed-up from 2002-2003 (Time 1/T1) to 2007-2008 (Time 2/T2), with 86 out of 124 eligible children/adolescents at T1 being reassessed at T2 (sample loss: 30.6%). OUTCOME: CAMHP at T2 according to the Child Behavior Checklist/CBCL's total problem scale. Psychosocial factors: T1 variables (child/adolescent's age, family socioeconomic status); trajectory of variables from T1 to T2 (child/adolescent exposure to severe physical punishment, mother exposure to severe physical marital violence, maternal anxiety/depression); and T2 variables (maternal education, child/adolescent's social support and pro-social activities). RESULTS: Multivariate analysis identified two risk factors for child/adolescent MHP at T2: aggravation of child/adolescent physical punishment and aggravation of maternal anxiety/depression. CONCLUSIONS: The current study shows the importance of considering child/adolescent physical punishment and maternal anxiety/depression in intervention models and mental health care policies.

Smartphone-assisted online brief cognitive behavioral therapy to treat maternal depression: findings of a randomized controlled trial.

OBJECTIVE: To test the efficacy of smartphone-assisted online brief cognitive behavioral therapy (b-CBT) to treat maternal depression compared to online brief CBT plus an active control app. METHODS: A randomized controlled trial was conducted. Assessments were performed at baseline (T0), midpoint (T1, week 4-5), post-treatment (T2, week 8), and follow-up (T3, 2-month postnatal follow-up) by blinded interviewers. The primary outcome was depression measured by the Edinburgh Postnatal Depression Scale (EPDS) at T2. We also assessed anxiety, stress, sleep quality, well-being, physical activity, treatment response, and offspring child behavior problems. RESULTS: Eighty-one participants were randomized to the intervention (n=37) or active control (n=44) groups. Seventy-one participants completed the post-treatment assessment or reported primary outcome data. No differences were found between the intervention and active control groups regarding maternal depression or other mental health outcomes. Overall, we found large within-group effect sizes, with 80% of the total sample responding to treatment. CONCLUSIONS: Our data showed no difference between the groups, suggesting that adding apps to psychotherapy treatment may not enhance treatment effects on prenatal depression. A within-groups analysis showed that most participants with depression responded to treatment; however, future studies are needed to confirm whether this effect is related to factors other than the intervention.

A pandemic toll in frail older adults: Higher odds of incident and persistent common mental disorders in the ELSA-Brasil COVID-19 mental health cohort.

INTRODUCTION: We aimed to investigate the association of frailty with persistent and incident common mental disorders (CMD) in older adults during the pandemic. METHODS: We included 706 older adults who participated in the onsite wave of the ELSA-Brasil study (2017-2019) and the online COVID-19 assessment (May-July 2020). CMD were assessed in both waves by the Clinical Interview Schedule-Revised. Frailty was defined according to the physical phenotype and Frailty Index in the 2017-2019 wave. Logistic regression was used to investigate the association of frailty with persistent and incident CMD, adjusted for sociodemographics. RESULTS: Frailty according to both definitions were associated with persistent CMD (Frailty Index: OR = 8.61, 95 % CI = 4.08-18.18; physical phenotype: OR = OR = 23.67, 95 % CI = 7.08-79.15), and incident CMD (Frailty Index: OR = 2.79, 95 % CI = 1.15-6.78; physical phenotype OR = 4.37, 95 % CI = 1.31-14.58). The exclusion of exhaustion (that overlaps with psychiatric symptoms) from the frailty constructs did not change the association between frailty and persistent CMD, although the associations with indent CMD were no longer significant. LIMITATIONS: Fluctuations in CMD status were not captured between both assessments. CONCLUSION: Frailty status before the COVID-19 outbreak was associated with higher odds of persistent and incident CMD in older adults during the pandemic first wave. Identifying individuals at higher risk of mental burden can help prioritize resources allocation and management.

Factor structure of the Dimensional Yale-Brown Obsessive-Compulsive Scale in a large sample of adults with obsessive-compulsive disorder.

OBJECTIVES: Although the Dimensional Yale-Brown Obsessive-Compulsive Scale (DY-BOCS) is a widely used instrument for assessing different obsessive-compulsive symptom dimensions, its factor structure has never been studied in a Brazilian population. Thus, we aimed to assess the goodness-of-fit indexes and factor loadings of two higher-order models of the DY-BOCS using confirmatory factor analysis (CFA) in a large obsessive-compulsive disorder (OCD) sample. METHODS: We tested two CFA models in a sample of 955 adults with OCD who had been assessed with the DY-BOCS in a cross-sectional multi-site study. The first model encompassed the symptom checklist (present or absent), whereas the second focused on items related to severity scores. RESULTS: Both models presented adequate goodness-of-fit indexes. The comparative fit index, Tucker-Lewis index, and omega were > 0.9, while the root mean square error of approximation was ≤ 0.06 for both models. Factor loadings for each item of each dimension are presented and discussed. CONCLUSION: Higher-order factor models showed adequate goodness-of-fit indexes, indicating that they appropriately measured OCD dimensions in this Brazilian population.

Brief internet-delivered cognitive-behavioural intervention for children and adolescents with symptoms of anxiety and depression during the COVID-19 pandemic: a randomised controlled trial protocol.

BACKGROUND: The COVID-19 pandemic has had major impacts in many different spheres, including mental health. Children and adolescents are especially vulnerable because their central nervous system is still in development and they have fewer coping resources than do adults. Increases in the prevalence of depressive and anxiety symptomatology have been reported worldwide. However, access to mental health care is limited, especially for the paediatric population and in low- and middle-income countries. Therefore, we developed a brief internet-delivered cognitive-behavioural intervention for children and adolescents with symptoms of anxiety and depression. The aim of this proposed study is to test the efficacy of the intervention. METHODS: We will conduct a two-arm, parallel randomised controlled trial involving children and adolescents (8-11 and 12-17 years of age, respectively) with symptoms of anxiety, depression or both, according to the 25-item Revised Child Anxiety and Depression Scale (t-score > 70). A total of 280 participants will be randomised to the intervention group or the active control group, in a 1:1 ratio. Those in the intervention group will receive five weekly sessions of cognitive-behavioural therapy via teleconference. The sessions will focus on stress responses, family communication, diaphragmatic breathing, emotions, anger management, behavioural activation and cognitive restructuring. Participants in both groups will have access to 15 videos covering the same topics. Participant-guardian pairs will be expected to attend the sessions (intervention group), watch the videos (control group) or both (intervention group only). A blinded assessor will collect data on symptoms of anxiety, depression and irritability, at baseline, at the end of the intervention and 30 days thereafter. Adolescents with access to a smartphone will also be invited to participate in an ecological momentary assessment of emotional problems in the week before and the week after the intervention, as well as in passive data collection from existing smartphone sensors throughout the study. DISCUSSION: Internet-delivered interventions play a major role in increasing access to mental health care. A brief, manualised, internet-delivered intervention might help children and adolescents with anxiety or depressive symptomatology, even outside the context of the COVID-19 pandemic. TRIAL REGISTRATION: ClinicalTrials.gov NCT05139433. Registered prospectively in November 2021. Minor amendments made in July 2022.