Introduction Australia’s medicinal cannabis framework has been increasingly used and commercialised. This study aimed to estimate the proportions of different motives (medical-only, recreational-only and dual-use [concurrent medical and recreational use]) of cannabis use among Australian adults, and the conditions for which cannabis was used. Method Cross-sectional data (N=3042) from the 2023 International Cannabis Policy Study (ICPS) measured Australians’ cannabis use and whether it was for medical, recreational, or dual use motives. Health conditions treated with cannabis were also reported. We estimated proportions of cannabis use motive type and conducted multinomial and logistic regressions using post-stratification sample weighted data to investigate predictors of motive type and condition used. Results Among all respondents, 86.3% reported no cannabis use, 1.9% reported medical-only cannabis use, 6.7% reported recreational-only use and 5.0% reported dual-use. The most frequently cited indications were anxiety (64%), pain (53%) and depression (52%). Dual-use compared to medical-only was associated with use for sleep, depression, and post-traumatic stress disorder. Use for pain was more likely among older adults (56+ years, RRR=3.52, 95% CI: 1.28-9.66) compared to people aged 16-25. Use for anxiety was more likely among females compared to males (RRR=2.27, 95% CI: 1.31-3.94) and less likely in older adults compared to other age groups (RRR=0.21, 95% CI: 0.08-0.60). Discussion The findings suggest cannabis is commonly used to treat conditions for which high-quality evidence of efficacy is lacking. The frequent use of cannabis for pain and anxiety contradicts guidance from peak medical bodies, underscoring the need for better regulatory and educational responses in Australia.

Importance:Australia is leading the world in efforts to reduce tobacco use by implementing high cigarette taxes and restrictive regulations on nicotine vaping products. However, concerns have emerged that these policies may unintentionally drive the expansion of illicit tobacco and vaping markets, potentially undermining public health gains. Objectives:To assess spatial and temporal changes in total nicotine, tobacco-derived nicotine, and illicit tobacco use across Australian regions of different remoteness from 2017 to 2023. Design, Setting, and Participants:This longitudinal, cross-sectional wastewater study was performed from April 2017 to April 2023. Wastewater samples were collected from as many as 55 wastewater treatment plants (WWTPs) in Australia, including 3 remoteness levels: major cities, inner regional, and outer regional to remote areas. The selected WWTPs serve more than 50% of the Australian population. Main Outcomes and Measures:Nicotine metabolites (cotinine and hydroxycotinine) and the tobacco-specific alkaloid (anabasine) were analyzed in wastewater samples using a validated liquid-chromatography tandem mass spectrometry method. Total nicotine and tobacco-derived nicotine consumption were back-estimated. Illicit tobacco use was identified in combination with the tobacco sales data. Results:Wastewater samples collected across Australia, representing 14 million people, were analyzed for back-estimation. Total nicotine consumption declined fastest in outer regional to remote areas (-2.2% annually; 95% CI, -3.2% to -1.1%), followed by inner regional areas (-1.4% annually; 95% CI, -2.1% to -0.8%), and remained stable in major cities. By comparison, tobacco-derived nicotine consumption decreased faster in major cities (-5.0% annually; 95% CI, -8.3% to -1.9%) and inner regional areas (-9.8% annually; 95% CI, -12.5% to -7.3%) than in the outer regional to remote areas (-2.3% annually; 95% CI, -6.0% to 1.8%). Illicit tobacco use was estimated to have increased from 1350 to 3400 tons from 2017 to 2023. Conclusions and Relevance:In this cross-sectional study of wastewater surveillance in Australia, different trends of tobacco use were observed across regions, accompanied by increasing use of illicit tobacco and vaping products. These findings provide evidence for future tobacco and vaping control policies. Ongoing wastewater monitoring is essential for evaluating new tobacco and vaping product control measures implemented in 2024.

BACKGROUND:Australia has adopted two policies that the World Health Organization (WHO) recommends as best practice for tobacco control: it has steeply increased tobacco taxes since 2010 and only allowed access to nicotine vapes for medical use. ARGUMENT:The rate of decline in tobacco smoking in Australia has slowed in the past decade but may have recently increased. At least half of all tobacco cigarettes and most vapes in Australia are now purchased from an illicit market that exceeds the size of the combined Australian illicit markets for cannabis, cocaine, heroin and ecstasy (MDMA). An estimated $7 billion in tobacco excise and arson attacks on tobacco retailers have prompted large increases in law enforcement funding. Based on the experience from other illicit markets, increased enforcement will at best limit sales but at likely enormous social and economic cost and, specific to nicotine, constraining access to vapes and thus potentially leading to more smoking. New Zealand, which allows vapes to be sold as consumer products under public health-oriented regulations, has shown a faster decline in the prevalence of cigarette smoking than Australia. It also has high tobacco taxes but a much smaller illicit tobacco market. CONCLUSIONS:Punitive taxes on cigarettes and restricted access to lower-risk nicotine products have diverted Australians who use nicotine into illicit markets and may also have increased cigarette smoking among young people. Australia should allow easier consumer access to less harmful alternative nicotine products to help bring the illicit tobacco and nicotine markets under better control.

BACKGROUND:We know little about the extent psychedelic substances are consumed therapeutically and/or discussed with medical professionals despite renewed global interest in these substances. METHODS:We examined self-reported responses from the 2023 International Cannabis Policy Study (ICPS) in repeated cross-sectional surveys in Canada, the United States, Australia, and New Zealand. The survey included questions on lifetime, past year, and past month use of psilocybin, LSD, MDMA, and ketamine. It inquired about respondents' discussions with medical professionals, their self-reported medical use, and related adverse events. We estimate the mean proportion rate for each of these using logistic regression methods that adjust for demographics, country, and sampling weights. FINDINGS:Estimated results suggest nineteen per cent of all ICPS respondents reported lifetime use of one of the four substances. Psilocybin was the most commonly estimated to be used in one's lifetime and in the past year, followed by LSD and MDMA. Estimated prevalences of ever using psilocybin were higher among respondents from Canada (16.3%, CI: 15.6-16.9%) than the USA (13.0%, CI: 12.3-13.6%) and New Zealand (12.1%, CI: 10.4-13.8%). Estimated rates of psilocybin ever use in Australia were significantly lower (7.8%, CI: 6.8-8.8%). An estimated 10-20% of respondents who report ever-use of a psychedelic asked their medical provider about medical use, and over a third who had used in the past year reported experiencing an adverse health effect. Estimated rates of past month use were low for all countries. INTERPRETATION:Consumer interest in therapeutic use of psilocybin, MDMA, LSD, and ketamine has surpassed the pace of clinical trials and therapeutic use provisions. These provisions do not necessarily equate to patient access and dual use motivations are not uncommon. Access via nonregulated pathways and self-initiated use in the absence of medical supervision may influence the proportion of individuals who experience adverse events.

INTRODUCTION:Although research has documented the rapid rise in youth disposable E-cigarette use, understanding of the distinct characteristics and behaviors of youth who use these devices remains limited. METHODS:This cross-sectional study analyzed data from the 2023 National Youth Tobacco Survey, a nationally representative survey of U.S. students Grades 6-12 (N=22,069). Analyses were conducted in 2025. Participants were classified into 6 mutually exclusive groups on the basis of their current tobacco product use: predominantly disposable E-cigarettes and no cigarettes, predominantly nondisposable E-cigarettes and no cigarettes, cigarettes only, concurrent use of cigarettes with disposable E-cigarettes, concurrent use of cigarettes with nondisposable E-cigarettes, or no use. Measures included E-cigarette use patterns, nicotine dependence indicators, exposure to E-cigarette content on social media, social norms, and psychological distress. Weighted analyses and multinomial logistic regression were performed. RESULTS:Youth who predominantly used disposable E-cigarettes reported significantly higher rates of nicotine-containing product use (81.9% vs 49.6%) and fruit flavor preference than those who use nondisposable E-cigarettes. Those who predominantly used disposable E-cigarettes without cigarettes reported fewer smoking peers but similar numbers of E-cigarette-using peers than those who use cigarettes and E-cigarettes concurrently. Getting high from nicotine was more commonly reported than flavor availability as a motivation across all E-cigarette use groups. Relative to nonuse, predominant disposable E-cigarette use without cigarettes was significantly associated with daily social media exposure (RRR=2.1), peer E-cigarette use (RRR=1.2), home E-cigarette exposure (RRR=1.2), and severe psychological distress (RRR=2.3). Concurrent use of cigarettes and E-cigarettes showed the strongest associations with dependence indicators and social exposure across multiple domains. CONCLUSIONS:Youth who predominantly used disposable E-cigarettes were characterized by nicotine-seeking behavior and social media influence, whereas those who concurrently used cigarettes and disposable E-cigarettes showed elevated risk indicators across multiple domains. Prevention strategies should be differentiated to address the specific risk profiles of groups with different use patterns.

Triangulating complementary data sources can provide a more complete picture of population-level opioid use trends, both spatially and temporally. This study aimed to evaluate trends in fentanyl and oxycodone use in Australia from 2018 to 2022 using two data sources: Pharmaceutical Benefits Scheme (PBS) dispensing data and wastewater-based epidemiology (WBE), and to assess their agreement. Wastewater samples from 57 wastewater treatment plants, covering all Australian states and territories, were analyzed for biomarkers of fentanyl and oxycodone to estimate consumption. PBS claims were also converted to consumption and spatially mapped to wastewater catchments, enabling site, state, and national comparisons with WBE data. Spatially, PBS and WBE estimates showed better alignment for fentanyl than for oxycodone at both the site and state/territory levels. Temporally, there were strong correlations between PBS and WBE data for both opioids, particularly for fentanyl. PBS and WBE trends had similar decreasing rates of use of the two opioids over time. Fentanyl consumption decreased by 0.29 mg/day/1000 people per year according to PBS data, and by 0.31 mg/day/1000 people per year based on WBE estimates. Corresponding values for oxycodone were 15.36 mg/day/1000 people and 16.85 mg/day/1000 people. By integrating these complementary data sets, our study provides strong evidence of the declining trend of fentanyl and oxycodone use in Australia after stricter prescription regulation. WBE and dispensing data provide a powerful framework for comprehensive opioid monitoring to inform targeted public health interventions.

The growing emergence of new psychoactive substances (NPS) challenges traditional approaches to drug monitoring, highlighting a need for innovative surveillance strategies. We explored the potential to better understand the NPS market in Australia by combining wastewater analysis with toxicosurveillance programs. Focussing on a time of year of likely higher NPS and drug use, influent wastewater samples were collected from four Australian states (South Australia, Victoria, Queensland, and New South Wales) over the New Year period from 2019-2020 to 2024-2025. Clinical samples presenting between 15 December and 15 January each period from the toxicosurveillance systems Emerging Drugs Network of Australia (including Western Australia, South Australia, and Queensland), Emerging Drugs Network of Australia Victoria (Victoria) and Prescription, Recreational and Illicit Substance Evaluation-PRISE (New South Wales) were extracted. In total, 294 wastewater and 117 clinical samples were included in this work. A total of 46 individual NPS were found in both datasets. This included: 21 only in wastewater, 36 only in clinical, and 12 in both. Overall, 743 instances of NPS were found in all wastewater samples and 171 in clinical data. In wastewater samples, N, N-dimethylpentylone (54%), mitragynine (52%), and bromazolam (45%) were the most frequently detected. In the clinical samples, the most common were bromazolam (44%) and clonazolam (21%). Overall, synthetic cathinones and plant-based compounds were more prevalent in wastewater, and synthetic opioids and benzodiazepines in clinical samples. Differences in detected NPS classes illustrate the complementary nature of these surveillance systems. Higher wastewater concentrations may indicate broader use and lower acute harm than drugs identified clinically. Integrating these datasets with additional sources such as surveys, coronial records, police seizures, and drug-checking services can strengthen NPS monitoring.

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.

Australia's mental health system is under increasing pressure as demand for the assessment and treatment of attention-deficit/hyperactivity disorder grows. Many people face long wait times, high out-of-pocket costs and limited specialist capacity. This encourages faster assessments, increasing the risk of misdiagnosis and avoidable downstream demand. The policy response has been to improve access and relieve specialist bottlenecks by expanding the role of general practitioners. Assessment for attention-deficit/hyperactivity disorder requires time-intensive clinical evaluation, including careful consideration of developmental history, collateral information and differential diagnoses. Making an attention-deficit/hyperactivity disorder diagnosis in adulthood adds complexity given the need for retrospective assessment to support childhood onset, limitations in the availability of collateral information and the impact of life events on executive functioning. Without dedicated time and training, general practitioners may struggle to maintain consistent diagnostic quality and appropriate prescribing at scale. There is already limited delivery of guideline-recommended multimodal care for Australians experiencing attention-deficit/hyperactivity disorder. Medications reduce core symptoms for many people, but sustained functional improvement typically requires psychoeducation, skill-based therapies, coaching and family, school or workplace interventions. Reform should pursue both access and quality by clarifying guideline advice for difficult adult diagnoses, introducing higher Medicare rebates for longer assessment appointments, linking any general practitioner role expansion to structured training and shared-care support, and funding scalable multimodal attention-deficit/hyperactivity disorder care through multidisciplinary clinics, group-based programmes, workforce upskilling, and national digital psychoeducation and self-management supports.

Cannabis use often begins in adolescence and young adulthood, when anxiety, depression, psychosis, and bipolar disorder typically first develop. Young people aged in their mid-teens to mid-twenties who engage in daily cannabis use and develop a cannabis use disorder have a higher prevalence of these mental disorders. We assessed the coherence of evidence from epidemiological, genetic, experimental, and preclinical studies to assess relationships between daily cannabis use and the increased incidence, prevalence, and persistence of psychosis, bipolar disorder, anxiety, depression, and suicidal behaviours. We found credible evidence that daily cannabis use is a contributory cause of psychosis. There were fewer high quality epidemiological and genetic studies of bipolar disorder. The role of cannabis use in depression, anxiety, and suicidality was less certain because associations were modest and could reflect self-medication, shared risk factors, or bidirectional relationships. A high priority should be given to developing effective interventions for cannabis use disorders in people with mental disorders.

Canada has been experiencing a public health crisis of high levels of overdose deaths mainly from toxic, synthetic opioids (e.g., fentanyl) drugs for more than a decade. While a wide range of prevention and treatment interventions to reduce overdose risk have been scaled up, drug overdose death levels have overall increased - reflecting similar US-based trends - before abruptly decreasing since 2023. These developments raise the crucial question: What factors have been driving the recent decreases in drug overdose deaths? We considered North America-based studies/data that examined potential supply-related factors. Emerging data suggest that while drug user-oriented prevention and treatment interventions have averted substantial numbers of overdose deaths, recent decreases in deaths appear to be associated mainly with changes in the global supply dynamics of toxic drugs, possibly related to intensified source control efforts (e.g., on fentanyl precursors) in China. Available data plausibly suggest that these changes may have affected both the composition and/or potency of illicit synthetic opioids available for consumption, and thereby reduced the population-based risks for and burden of overdose fatalities from exposure. While requiring further examination, these developments raise important questions about effective health-oriented overdose prevention measures and policy that are independent of unpredictable global drug supply dynamics.

Cannabis policies vary from strict prohibition to commercialised legalisation and are rapidly evolving worldwide. Here, we reviewed evidence for associations between international cannabis policy changes from 2000-25 and cannabis use, cannabis use disorder, and other psychiatric disorders. Commercialised legal markets for non-medical use in Canada and the USA were associated with increased prevalence of cannabis use and cannabis use disorder in adults and increases in cannabis potency since legalisation. There was no consistent evidence for associations between policy change and the prevalence or incidence of psychotic disorders. Commercialised legalisation was associated with an increase in hospital admissions for psychosis, and for psychotic disorders comorbid with cannabis use disorder. Poorly regulated legal access to medical cannabis, in the absence of efficacy and safety data, could increase risk of harm. Policies that limit commercialisation, such as strictly regulated legalisation of medical or non-medical supply, were not as strongly associated with cannabis use or psychiatric disorders, but long-term evaluation is needed. There was little evidence that decriminalisation of non-medical cannabis in Europe, Africa, Oceania, and Asia was associated with cannabis use or psychiatric disorders.

BACKGROUND:Mental disorders and substance use disorders (SUDs) are among the leading reasons for which the medical use of cannabinoids has been approved, but their efficacy and safety in treating these conditions is yet to be established. We conducted a systematic review and meta-analysis of randomised controlled trials (RCTs) testing the efficacy and safety of cannabinoids as the primary treatment for mental disorders or SUDs. METHODS:We searched Ovid MEDLINE, PsychINFO, Cochrane Central Register of Controlled Clinical Trials, Cochrane Database of Systematic Reviews, and Embase for peer-reviewed articles published between Jan 1, 1980, and May 13, 2025, evaluating the efficacy of cannabinoids in reducing or treating mental disorders and SUDs as the primary indication. Primary outcomes were remission of disorder or reduction in disorder symptoms. Safety was assessed via synthesis of all-cause and serious adverse events, which was used to calculate the number needed to treat to harm (NNTH). Two independent reviewers screened all studies and performed data extraction. Evidence was synthesised as odds ratios (ORs) for dichotomous measures and standardised mean differences (SMDs) for continuous measures, via random-effects meta-analysis in Review Manager, version 5.4. Risk of bias was assessed using the Cochrane Collaboration Risk of Bias 2.0 tool. We evaluated the quality of the primary outcomes using the GRADE framework. The study was registered with PROSPERO (CRD42023392718). FINDINGS:54 trials were identified for inclusion (2477 participants; 1713 [69%] males, 764 [31%] females; median age 33·3 years [IQR 28·1-38·05; ethnicity data not available). 24 (44%) of these trials had a high risk of bias, and the certainty of evidence for most outcomes was low. Our meta-analysis revealed that a combination of cannabidiol and delta-9-tetrahydrocannabinol reduced cannabis withdrawal symptoms (SMD -0·29, 95% CI -0·57 to -0·02) and weekly grams of cannabis use (-1·00, -1·69 to -0·30) among those with cannabis use disorder, and a reduction in tic severity among those with tic or Tourette's Syndrome (-0·68, -1·03 to -0·34) compared with placebo. Any cannabinoid type led to an increase in sleep time as recorded by an electronic device (0·54, 0·14 to 0·95) and sleep diary (0·55, 0·01 to 1·09) among those with insomnia. There was a reduction in autistic traits (-0·36, -0·66 to -0·07) among those with autism spectrum disorder. Cannabinoids led to an increase in cocaine craving among those with cocaine use disorder (0·69, 0·22 to 1·15) compared with placebo. There were no significant effects on outcomes associated with anxiety, anorexia nervosa, psychotic disorders, post-traumatic stress disorder, and opioid use disorder. There were insufficient data to meta-analyse studies of ADHD, bipolar disorder, obsessive-compulsive disorder, and tobacco use disorder. There was an absence of RCT evidence for the treatment of depression. Meta-analysis revealed higher odds of all-cause adverse events (OR 1·75, 95% CI 1·25 to 2·46) among those using cannabis versus control group (NNTH=7) but no higher odds of serious adverse events or study withdrawal. INTERPRETATION:There was some evidence that cannabinoids can reduce symptoms of cannabis use disorder, insomnia, tic or Tourette's syndrome, and autism spectrum disorder, but the quality of this evidence was generally low. Cannabinoids were associated with a greater risk of any adverse events but not of serious adverse events. Overall, there is a crucial need for more high-quality research. Given the scarcity of evidence, the routine use of cannabinoids for the treatment of mental disorders and SUDs is currently rarely justified. FUNDING:The National Health and Medical Research Council.