Background:Mental disorders are leading contributors to disease burden among young people. Recent evidence suggests rising rates of these disorders, yet no recent national comparisons using diagnostic interviews have examined changes in individual disorder prevalence among Australian youth over time. This study provides current estimates of prevalence, patterns, severity, and profiles of mental disorders among Australians aged 16-24, comparing data from 2007 to 2020-2022. Methods:Data were drawn from the 2020-2022 National Study of Mental Health and Wellbeing (NSMHWB) and compared with the 2007 NSMHWB. A nationally representative sample of 16-24-year-olds completed the WMH-CIDI to assess 12-month DSM-IV mood, anxiety, and substance use disorders, along with measures of severity, comorbidity, suicidality and disability. Analyses were population-weighted and accounted for complex survey design. Temporal changes were examined using logistic and proportional odds regression. Findings:The 12-month prevalence of mental disorders increased from 23.4% in 2007 to 36.2% in 2020-2022 (OR 1.86, 95%CI 1.53-2.25). Mental disorders continue to be more common in females, but increases were also observed for males. Anxiety disorders nearly tripled (12.2% to 29.1%; OR 2.94, 95% CI 2.33-3.71), and mood disorders rose from 4.9% to 13.3% (OR 3.01, 95% CI 2.16-4.20), while substance use disorders declined (12.34% to 7.76%; OR 0.60, 95% CI 0.44-0.80). Comorbidity, severity, suicidal thoughts, psychological distress, and disability also rose, with one in five experiencing multiple disorders in 2020-2022. Interpretation:Mental disorders among Australian youth have increased markedly since 2007, with greater severity and functional impairment. Funding:The Australian National Health and Medical Research Council.

INTRODUCTION:As cannabis policies become more liberal, and products increasingly potent, it is important to monitor changes in rates of cannabis use and those at risk of harm. We used data from the largest national mental health survey in Australia to examine changes in prevalence, associations and comorbidity of past 12-month cannabis use and cannabis use disorder (CUD) from 2007 to 2020-22. METHODS:Data were drawn from the two most recent Australian National Surveys of Mental Health and Wellbeing (age range: 16-85): 2007 (n = 8841) and 2020-22 (n = 15,893). The prevalence of use and CUD were estimated and logistic regression was used to examine associations between individual characteristics and cannabis use outcomes, as well as changes in strength of association over time. RESULTS:Prevalence of recent cannabis use was stable from 2007 (6.7%, 95% CI 6.0%, 7.3%) to 2020-22 (6.7%, 95% CI 6.2%, 7.1%), as was CUD (1.0%, 95% CI 0.7%, 1.3%; 0.6%, 95% CI 0.4%, 0.8%). Respondents were significantly more likely to report CUD if they were younger (16-25 years), male, initiated cannabis use < 18 years, reported recent polysubstance use, exhibited other substance and mental disorders and had visited mental health services (OR 3.26-78.00). Compared to 2007, the association between younger age and CUD was stronger in 2020-22 (OR 2.39, 95% CI 1.20, 4.77), whereas the association between polysubstance use and CUD was weaker (OR 0.42, 95% CI 0.20, 0.91). DISCUSSION AND CONCLUSIONS:Findings suggest that population-level use and CUD may have remained stable over time, but young people may now be more vulnerable to developing CUD.

OBJECTIVES:We aimed to quantify inequalities in mental health service use in Australia and identify the sociodemographic, economic, and geographic factors associated with access. METHODS:We conducted a secondary analysis of the National Study of Mental Health and Wellbeing (NSMHWB, 2020-2022). We evaluated 12-month mental health service use before the survey among people who reported a mental disorder. We fitted multivariable logistic regression models adjusted for sociodemographic covariates and tested the joint (intersectional) effects of remoteness and socioeconomic area disadvantage on service use. Jackknife replicate weights accounted for the complex survey design. RESULTS:The study included 15,893 respondents (weighted population: 19,828,348). Lifetime prevalence of any mental health disorder was 42.9% (95% CI = [42.5, 43.3]), and 21.5% (95% CI = [20.7, 22.3]) reported symptoms in the past 12 months. Among those with a 12-month disorder, 45.2% (95% CI = [39.9, 50.5]) had accessed care, and 16.5% (95% CI = [15.8, 17.2]) reported using digital or telephone services. Service use was higher in university graduates and residents of advantaged areas and lower in remote/outer regional residents and the most disadvantaged quintiles. Intersectional analysis revealed compounded inequities, with the lowest service use observed among socioeconomically disadvantaged populations in remote areas and the highest among advantaged major-city residents. CONCLUSION:Substantial and intersecting inequalities exist in access to mental health services, with the lowest coverage among remote, socioeconomically disadvantaged, older, and male populations. Targeted, place-based strategies - including expanded outreach and tailored digital and community-based models - are needed to reduce unmet need and improve equity.

Background: Dating and relationship violence (DRV) is a pressing societal concern. Evidence-based prevention, delivered during adolescence, is urgently needed to disrupt harmful trajectories and promote healthy relationship behaviours. School-based consent and respectful relationship programs offer a promising avenue to deliver evidence-based education, build intra- and inter-personal skills, and shape healthy attitudes toward dating and relationships. However, no Australian programs have undergone rigorous evaluation to determine their efficacy. This paper presents the protocol of the respectED study, Australia’s first cluster randomised controlled trial (cRCT) to evaluate the efficacy of a school-based consent and respectful relationships program. Methods: A two-arm cRCT will be conducted among Year 9 and 10 students at secondary schools across Australia. Schools will be randomly assigned to either the intervention group (receive the respectED program) or the active control group (receive their regular health education). Students in both groups will be asked to complete three online self-report surveys over a 6-month period (baseline, post-intervention [~5-weeks post-baseline], and 6-months post-baseline) about their attitudes, knowledge and behaviours relating to adolescent dating and relationship violence. Students and teachers in the intervention group will also complete a brief evaluation of the respectEDprogram. Discussion: If found to be efficacious, respectED can be readily delivered to all Year 9 and 10 students in Australia, and will become an important tool in the nationwide effort to prevent DRV. Trial registration: This study is prospectively registered with the Australian and New Zealand Clinical Trials Registry (ACTRN 12625000483459p, http://www.anzctr.org.au/, registration date 20/05/2025).

PURPOSE:To determine the 2022 prevalence and co-occurrence of past 12-month mood (major depressive episode, bipolar), anxiety (generalized anxiety, social phobia), and substance use disorders (alcohol, cannabis, drug) among Canadians aged 15+, and to assess changes from 2012 to 2022. METHODS:Population-based data from the 2022 Mental Health and Access to Care Survey (n = 9861) and the 2012 Canadian Community Health Survey's Mental Health Component (n = 25,113) were analyzed. Mental disorders were assessed using the World Health Organization Composite International Diagnostic Interview. Multivariable multinomial regression examined demographic and clinical correlates, as well as changes over time, of mood/anxiety disorder(s) alone, SUD(s) alone, and concurrent disorders (mood/anxiety+SUD). Age (youth 15-24 vs adults 25+) and sex (females vs males) differences were explored through stratified analyses and interactions. RESULTS:In 2022, 16.4% met criteria for a mood (8.4%), anxiety (9.9%), or substance use (3.5%) disorders. Of those with at least one disorder, co-occurrence was common: 39.5% had 2+ disorders with 10.6% experiencing concurrent SUD and mood/anxiety disorders. Among those with an SUD, 48.9% had a concurrent mood/anxiety disorder, while 15.2% and 9.6% of those with a mood and anxiety disorders respectively had a concurrent SUD. Youth, unemployed individuals, and those with high distress or suicidality had elevated odds of concurrent disorders. Males had higher overall concurrent disorder prevalences, but among those with SUDs, concurrent disorders were higher among females. While the odds of SUD-alone declined, mood/anxiety and concurrent disorders doubled from 2012 to 2022. CONCLUSION:There is an urgent need for integrated mental health and substance use services, particularly for youth and females, who are disproportionately affected.

Purpose Preventing youth substance use and related harms is a global priority. Ecological momentary assessment (EMA) and ecological momentary interventions (EMIs), which assess and address substance use in real-time, may improve mechanistic understanding, screening, intervention in clinical care. This review synthesized EMA/EMI studies examining substance use among youth in clinical settings. Methods A systematic narrative review (PsychInfo, Medline Scopus) identified EMA/EMI studies assessing substance use in clinical samples of youth (mean/median age ≤ 25) across emergency, medical, mental health, and substance use treatment settings. Findings Of 12093 titles/abstracts and 2157 full texts, 43 studies of 24 unique protocols (15 observational, 9 intervention) were included. Alcohol (75%), cannabis (67%), and nicotine/tobacco (33%) were the most frequently studied substances. EMA protocols typically lasted 14 days with 4 daily prompts; 3 incorporated passive (bio)sensing. Studies included 270 momentary antecedents and 17 momentary consequences of substance use, organized into six domains: substance use, affect/cognitions, environmental context, social context, movement factors, and EMA compliance. Negative affect, contextual factors (e.g., evenings, weekends, friends), and prior substance use showed the most consistent associations with use, although findings were heterogeneous. Passive sensing approaches demonstrated strong predictive performance. Thirteen evaluated EMIs integrating real-time monitoring with feedback, goal-setting, and/or coping support reduced substance use harms. Conclusions EMA/EMI approaches show promise for understanding and addressing dynamic, context-dependents substance use processes among youth in clinical settings. While the evidence remains exploratory and methodologically heterogenous, findings suggest EMIs can deliver timely, individualized support. Future research should prioritize greater methodological transparency and rigor.

ObjectiveAs epidemiological patterns of cannabis use and internalizing problems evolve globally, it is critical to reassess their associations-particularly in the post-legalization and post-pandemic context.MethodsParticipants were assessed in the 2012 Canadian Community Health Survey's Mental Health Component (CCHS-MH; n = 25,113) and 2022 Mental Health and Access to Care Survey (MHACS; n = 9,861), two nationally representative cross-sectional epidemiologic surveys of Canadians aged 15+. Robust Poisson Regression analyses examined associations between frequency of cannabis use and past 12-month generalized anxiety disorder (GAD), major depressive episode (MDE), and suicidality assessed using the World Health Organization Composite International Diagnostic Interview.ResultsBetween 2012 and 2022, the prevalence of GAD, MDE, and cannabis use (any and 2+/week) approximately doubled, while suicidality remained unchanged in the full sample but increased by 44% among youth. Across all models, cannabis frequency was consistently associated with a higher prevalence of GAD, MDE, and suicidality in a frequency-dependent fashion. Additive interactions between year and cannabis on each of the outcomes demonstrated stronger associations in 2022 versus 2012. For example, from 2012 to 2022, those using cannabis 2+/week (relative to no use) had a: (1) prevalence ratio (PR) for GAD of 2.3 (95% CI, 1.6-3.4) increase to 4.5 (3.8-5.2); (2) PR for MDE of 3.0 (2.3-3.9) increase to 5.2 (4.6-5.7); and (3) PR for suicidality of 3.0 (2.1-4.0) increase to 5.4 (4.7-6.1). Select moderation effects indicated associations between cannabis and MDE or suicidality strengthened more among youth (15-24 vs. 25+), and associations with GAD strengthened more among females.ConclusionsCannabis use was consistently related to a higher prevalence of internalizing problems, and these associations strengthened between 2012 and 2022. Given continued escalations in co-occurring cannabis use and internalizing problems, greater investment in early identification, intervention, and access to integrated substance use and mental health treatment is needed.

PURPOSE:The epidemiological landscape of adolescent smoking, vaping, and emotional problems has drastically changed over the past two decades. Whether and why these problems co-occur remains unclear, though this understanding is crucial for global policy and prevention efforts. The nature of co-occurring problems may be influenced by different researcher decisions when defining, operationalizing, and modeling these relationships. This study uses multiverse analysis (also known as specification curve analysis or vibration of effects), which models all justifiable measurement and analytic specifications in a single sample, to unpack the impact of researcher decisions when modeling these relationships. METHODS:Multiverse analyses were done with 3,648 unique models using a longitudinal sample of 6,639 Australian adolescents (aged ∼14.7-15.7, 2021-2022). RESULTS:Consistent co-occurrence of smoking or vaping and emotional problems was seen across unadjusted or only demographic-adjusted cross-sectional models (100 %). However, the temporality of relationships, choice of confounders, and operationalization of emotional problems substantially impacted findings. Emotional problems appeared to lead to reports of past 6 month smoking more-so than the reverse (88 % vs. 9 % unadjusted/demographic-adjusted), depression-focused measures yielded more consistent associations with smoking or vaping than anxiety-focused, and certain confounders (i.e., conduct, ADHD, other substances) explained most of the associations between adolescent smoking or vaping and emotional problems. Decision related to missingness or binary versus continuous outcomes did not meaningfully impact findings. CONCLUSIONS:While adolescent smoking or vaping and emotional problems commonly co-occur, methodological choices regarding timing, definitions, and confounding significantly influence the perceived strength of these relationships. Hence, such nuances demand careful consideration when interpreting evidence for policy.

BACKGROUND AND AIMS:MDMA (3,4-methylenedioxymethamphetamine or "Ecstasy") is the fourth-most used illicit substance globally. While previous research found links between MDMA use and mental health outcomes, the direction and nature of this relationship remain unclear. This study assessed whether MDMA use in early adulthood increases the risk of anxiety or depression in mid-30s. DESIGN:A longitudinal, population-based study using doubly robust inverse probability treatment weighted regression analysis, a contemporary confounder adjustment technique, to examine the relationship between MDMA use in early adulthood (age 20-29) and subsequent anxiety or depression at age 35. SETTING:Victoria, Australia. PARTICIPANTS:Data were drawn from the Victorian Adolescent Health Cohort Study (VAHCS), which began in 1992 with a statewide representative sample of 1943 Year 9 students (aged 14-15) from 44 Victorian schools. This paper uses data collected from wave 2 to wave 10 (ages 15-35). MEASUREMENTS:Across waves 7-9 (ages 20-29), MDMA use was categorised as any use, persistent use (none, one wave, two or more waves) and frequent use (none, infrequent, frequent). Wave 10 (age 35) outcomes were 12-month diagnoses of major depressive disorder and anxiety disorders assessed using the Composite International Diagnostic Interview (CIDI). FINDINGS:There was little evidence linking any pattern of MDMA use in early adulthood with depressive disorders by the mid-30s; however, compared with non-MDMA users, the adjusted odds of an anxiety disorder were higher in those who reported past 12-month MDMA use [odds ratio (OR) = 1.73, 95% confidence interval (CI) = 1.12-2.68), persistent MDMA use at two or more waves (OR = 2.05, 95% CI = 1.07-3.94), as well as infrequent (OR = 2.11, 95% CI = 1.14-3.92) and frequent MDMA use (OR = 2.56, 95% CI = 1.15-5.71). CONCLUSIONS:MDMA use (3,4-methylenedioxymethamphetamine or "Ecstasy") in early adulthood appears to be associated with increased odds of anxiety disorders but not depressive disorder by the mid-30s.

The development of secure relationships between children and their adult carers, across the earliest years of life, emerges within a multifaceted and complex relational ecology. Here we present findings from a systematic scoping review designed to map the extent to which the relational ecology of child-caregiver relationships across early life (from conception to age 3 years) has been studied. A first phase of the review searched for studies that used applied social network analysis (SNA) to measure the relational ecology. A second phase extended the scope to studies of associations between individual elements of the relational ecology and the early child-caregiver relationship. Searches were conducted between February and September, 2023, rerun in March 2025and in total, yielded 11,226 articles for screening. We found no studies using SNA to investigate the relational ecology of early child-caregiver relationship development. We did, however, find 122 studies that examined individual predictors across the relational ecosystem of the early child-caregiver relationship. Most studies focused on the family microsystem and in particular the mother–child relationship. Few studies examined other aspects of the microsystem, or higher levels of the relational ecosystem (meso-, exo- or macrosystems). Our findings highlight that much of the broader relational ecology of early child relational health development continues to be neglected in observational research. Future research should consider using novel methods like SNA to capture and explain interconnections between relationships at all levels of the relational ecology of early child-caregiver relationship development.

BACKGROUND AND AIMS:The use of amphetamines (including amphetamine and methamphetamine) has been consistently associated with mental health difficulties; however, the direction of potential causal relationships has not yet been established. This study aimed to assess the direction relationships between illicit amphetamine use and mental health difficulties across adolescence and young adulthood. DESIGN:Observational study of four population-level cohorts participating in the Monitoring Illicit Substance Use (MISUse) Consortium. SETTING:Australia and New Zealand. PARTICIPANTS:A total of 7527 participants (51% female) were used: Christchurch Health and Development Study (n = 1056), Australian Temperament Project (n = 1644), Victorian Adolescent Health Cohort Study (n = 1943) and International Youth Development Study (n = 2884). MEASUREMENTS:Assessments were used to derive binary indicators of amphetamine use (≥monthly) and mental health difficulties during both adolescence (age 10-17 years) and young adulthood (age 18-30 years). FINDINGS:Associations were estimated as Risk Ratios (RRs) with 95% confidence internals (CIs) using G-computation procedures, while accounting for 15 potential confounding factors and interactions between exposure and both study cohort and participant sex. The risk of mental health difficulties in young adulthood was 21% greater (RR = 1.21, 95% CI = 1.04, 1.41) for those who reported monthly or more frequent amphetamine use in adolescence. The risk of monthly or higher amphetamine use in young adulthood was 19% greater (RR = 1.19, 95% CI = 0.99, 1.45) in those who reported mental health difficulties in adolescence. There was also some evidence to suggest that in males the strongest association was from amphetamine use to mental health difficulties (RR = 1.24, 95% CI = 0.95, 1.60), while in females the strongest association was from mental health difficulties to amphetamine use (RR = 1.33, 95% CI = 0.99, 1.78). CONCLUSIONS:There appears to be a bidirectional association between monthly or more frequent amphetamine use and mental health difficulties from adolescence to young adulthood.

Background Mental disorders have considerable impact on individual and societal well-being, with peak onset during adolescence. This study explored the relationship between neighbourhood socioeconomic status and internalising symptom progression during adolescence. Design Longitudinal data from 1556 adolescents was taken from the control group of a cluster-randomised controlled trial of school-based prevention program for mental health and substance use. Measures assessed internalising symptoms (SDQ) across six time points from 13 to 16 years and the Index of Relative Socioeconomic Advantage and Disadvantage (IRSAD) was used to measure participants’ neighbourhood socioeconomic status (SES) at baseline. Latent class growth analysis was used to estimate different internalising symptom trajectories among adolescents. Multinomial logistic regression explored the relationship between SES and internalising trajectory class, controlling for covariates. Results Four distinct trajectories of internalising symptoms were identified: Low stable (49 % of adolescents), Increasing (30.6 %), Decreasing (10 %), and High Increasing (10.2 %). Lower neighbourhood SES was associated with an increased likelihood of belonging to the High Increasing class relative to the Low Stable group. Additionally, female gender and baseline externalising symptoms were associated with an increased likelihood of belonging to all three elevated symptom trajectories compared to the low stable class, controlling for SES and other covariates. Conclusion The findings provide novel insight into the negative relationship between neighbourhood disadvantage on individual mental health trajectories, above and beyond individual factors, during adolescence. The findings have significant implications for social and economic policies.

AIMS:Prompt initial contact with a treatment provider is a critical first step in seeking help for a mental or substance use disorders (SUDs). The aim of the current study was to provide estimates of patterns and predictors of delay in making initial treatment contact based on the recently completed Australian National Survey of Mental Health and Wellbeing. METHODS:Data came a nationally representative epidemiological survey of n = 15,893 Australians. Measures included DSM-IV lifetime diagnoses of mood (MD), anxiety (AD) and SUDs; age of disorder onset; and age of first treatment contact. Correlates of treatment delay were examined. RESULTS:SUDs exhibited the lowest lifetime treatment rate (27%), compared to MD (94%) and ADs (85%). Individuals with AD experienced the longest delay in seeking treatment (Mdn = 11 years), followed by those with SUDs (Mdn = 8 years) and MDs (Mdn = 3 years). Females had higher odds of seeking treatment for MD and AD but lower odds for SUDs. Recent birth cohorts showed increased treatment seeking across disorders, and higher education was associated with increased treatment seeking for MD and AD. Age of onset, country of birth and co-occurring disorders had mixed associations with treatment seeking. CONCLUSIONS:The study reveals stark disparities in treatment-seeking behaviour and delays across mental and substance use disorders, with a pronounced underutilization of services for SUDs. Additionally, attention should be directed towards early intervention for individuals with earlier symptom onset, those from earlier cohorts and those with co-occurring SUDs.

BACKGROUND AND AIMS:Risky alcohol use in young adulthood is a significant public health concern. Understanding the predictors of risky drinking during this period is essential for prevention. This study aimed to measure the predictive accuracy of ensemble machine learning and identify the most important predictors of risky alcohol use in early adulthood. DESIGN AND SETTING:Secondary analysis of the Longitudinal Study of Australian Children, an Australian national longitudinal cohort study. PARTICIPANTS:A total of 4983 children, aged 4-5 years in 2004 (Wave 1), followed up for eight waves (to age 18/19 in 2018). MEASUREMENTS:Risky alcohol use was measured at age 18 and defined as more than 10 standard drinks per week, as per Australian National guidelines. Predictors from multiple domains-sociodemographic, adolescent substance use, adolescent mental health and behaviours, parental mental health and substance use, school factors, peer influences, parenting practices and parental stress-were included, measured from Wave 1 to 7. The SuperLearner package in R was used to test a series of models [regularised regression (LASSO, ridge and elastic net), random forest and kernel support vector machine (SVM)] using nested 10-fold cross-validation to identify the overall predictive ability of the model (measured by area under the curve; AUC) and the most important predictors of risky alcohol use across childhood and adolescence. Predictor importance was derived by normalising algorithm-specific scores per fold, weighting them by SuperLearner coefficients and aggregating across folds to rank predictors by mean weighted importance on a scale of 0 to 1 (higher scores indicating greater importance). FINDINGS:The ensemble model showed good prediction on the test set, with an AUC of 0.792, a slight improvement over any single algorithm (AUC = 0.783 for the best performing individual algorithm). The most important predictors were weekly drinking at the previous wave (mean weighted importance 0.999), lifetime cannabis use (0.446), lifetime parent financial stress (0.420), identifying as female (0.365), identifying as male (0.344; compared with a reference category of gender diverse), lifetime attention deficit hyperactivity disorder (0.248), pre-natal alcohol exposure (0.248), housing insecurity (0.243), religious involvement (0.238) and parent alcohol use problems (0.215). CONCLUSIONS:An ensemble learning approach appears to have good predictive ability of risky alcohol use among a contemporary cohort of young Australians. It underscores the complex interplay of individual, familial and social factors occurring across childhood and adolescence that influences risky alcohol use in early adulthood.

Purpose: Declining mental health has been observed in young people from across the globe since approximately 2010. One contributing factor may be the erosion of meaningful and supportive social connections. Fostering positive social connections and a focus on the social networks of young people could be a key strategy to enhance youth mental health and wellbeing. It is now well established that positive social connections benefit mental health. Social connections to peers and school communities become increasingly important during adolescence, a unique developmental window for prevention and a time in which peer influence increases. Key findings: While our understanding of the importance and utility of adolescent social connection to improve mental health is evolving, social network approaches and strengthening connections at school hold promise to improve youth mental health. We outline key evidence across two domains of social connection; the importance of peer connections and school connectedness. We also explore the application of Social Network Interventions (SNIs) as an emerging way to promote positive mental health and decrease key risk factors for poor mental health across youth social networks. Conclusion: Prevention strategies could target youth social connection as a transdiagnostic factor to improve youth mental health. This may take the form of interventions that leverage the importance of peers, create supportive social networks and environments, as well as the use of social network frameworks to develop an understanding of the mechanisms by which preventive interventions spread throughout different social networks.

In this article, we examine Australia's landmark decision to ban social media access for children under the age of 16, set to take effect in December 2025. While the legislation aims to protect young people from the harms of social media, including its impact on mental health and wellbeing, the evidence base underpinning the ban remains inconclusive, with most studies unable to establish causality. Drawing on parallels with adolescent alcohol prevention, we argue that prohibition alone is unlikely to be effective. Instead, we advocate for a harm minimisation approach that equips young people with digital literacy, resilience, and help-seeking skills. We highlight the essential roles of parents, schools, and adolescents in fostering safer social media use and call for inclusive, co-designed education initiatives.