Definition matters: assessment of tolerance to the effects of alcohol in a prospective cohort study of emerging adults.

BACKGROUND AND AIMS: Tolerance to the effects of alcohol is an important element in the diagnosis of alcohol use disorders (AUD); however, there is ongoing debate about its utility in the diagnosis AUD in adolescents and young adults. This study aimed to refine the assessment of tolerance in young adults by testing different definitions of tolerance and their associations with longitudinal AUD outcomes. DESIGN: Prospective cohort study. SETTINGS: Australia. PARTICIPANTS: A contemporary cohort of emerging adults across Australia (n = 565, mean age = 18.9, range = 18-21 at baseline). MEASUREMENTS: Clinician-administered Structured Clinical Interview for DSM-IV Research Version (SCID-IV-RV) assessed for AUD criteria across five interviews, at 6-month intervals over 2.5 years. Tolerance definitions were operationalized using survey-type response (yes/no), clinician judgement (SCID-IV-RV), different initial drinking quantity and percentage increase thresholds and average heavy consumption metrics. AUD persistence was operationalized by the number of times AUD was present across the 2.5-year study period (n = 491), and new-onset AUD was operationalized as any new incidence of AUD during the follow-up period (n = 461). FINDINGS: The (i) SCID-IV-RV clinician judgement [odds ratio (OR) = 2.50, P = 0.005], (ii) an initial drinking quantity threshold of four to five drinks and 50% minimum increase (OR = 2.48, P = 0.007) and (iii) 50% increase only (OR = 2.40, P = 0.005) were the tolerance definitions more strongly associated with any new onset of AUD throughout the four follow-up time-points than other definitions. However, these definitions were not associated with persistent AUD (Ps > 0.05). Average heavy consumption definitions of tolerance were most strongly associated with persistent AUD (OR = 6.66, P = 0.001; OR = 4.65, P = 0.004) but not associated with new-onset AUD (Ps > 0.05). CONCLUSIONS: Initial drink and percentage change thresholds appear to improve the efficacy of change-based tolerance as an indicator for new-onset alcohol use disorder diagnosis in self-report surveys of young adults. When predicting persistent alcohol use disorder, average heavy consumption-based indicators appear to be a better way to measure tolerance than self-reported change-based definitions.

DSM-5 and ICD-11 alcohol use disorder criteria in young adult regular drinkers: Lifetime prevalence and age of onset.

BACKGROUND: Alcohol Use Disorder (AUD) is a significant contributor to global disease burden. AUD has a relatively early onset during young adulthood (Teesson et al., 2010). However, compared to AUD in adults, we have relatively little understanding of AUD in adolescents and emerging adults. METHODS: The RADAR study is a prospective cohort study designed to investigate the emergence of AUD in community-dwelling adolescents and emerging adults across Australia (age range = 18-21 at baseline). At 6 monthly intervals over 2.5 years, participants were interviewed regarding alcohol consumption and alcohol use disorder criteria by clinical psychologists using the SCID-IV-RV. This paper reports the baseline findings of the RADAR cohort. RESULTS: Proportions of lifetime criteria endorsement among regular drinkers varied considerably. Tolerance was the most endorsed criterion (50.3%), followed by Social Problems (10.4%) and Larger/Longer (9.0%). The median age of onset for most individual AUD criteria was 18 years of age. 18.4% of our cohort met DSM-5 AUD diagnosis in their lifetime to date, and 16.8% met ICD-11 dependence. When removing Tolerance from the AUD criteria, DSM-5 AUD lifetime prevalence reduced to 11.0%, and ICD-11 AUD lifetime prevalence fell to 7.1% in our cohort. CONCLUSIONS: Variable rates of criteria endorsement likely reflect both true differences in the experience of AUD criteria and methodological challenges in the assessment of AUD in an emerging adult age group. High rates of tolerance to the effects of alcohol, and relatively low rates of drinking larger/longer than intended are discussed considering methodological challenges in assessing these criteria in young adults.

Trends in cannabis use and attitudes toward legalization and use among Australians from 2001-2016: an age-period-cohort analysis.

BACKGROUND AND AIMS: Changes in cannabis legalization and availability in Australia necessitate monitoring use and attitudes. We estimated age-period-cohort effects of past-year cannabis use and attitudes toward criminalization and legalization. DESIGN: Analysis of six waves of the Australian National Drug Strategy Household Survey (NDSHS) every 3 years (2001-2016). SETTING AND PARTICIPANTS: The study was nationally representative of Australian households using multistage random sampling, totaling 145 168 respondents 18-79 years old. Data were collected using telephone, face-to-face, and drop-and-collect. Sample sizes per analysis varied based on data availability (~107 000-127 000 per model). MEASUREMENTS: Six waves of data for past-year cannabis use (by sex and education), attitudes toward criminalization and legalization. FINDINGS: Past-year cannabis use decreased in young adults ages 18-35 from 2001-2016 (25.1%-18.6%) and increased in middle adults ages 36-55 (8.6%-10.1%) and older adults ages 56-79 (0.6%-3.0%). We observed a positive period effect and negative cohort effect for recent cohorts for past-year use (e.g. 1955 cohort had 1.41 (95% CI: [1.11, 1.70]) increased log odds vs. 1998 cohort had -2.86 (95% CI: [-3.17, -2.55]) increased log odds) compared with the mean across years. Results were consistent by sex and varied by education. We observed a negative period effect for criminalization favorability (0.14 (95% CI: [0.003, 0.28]) increased log odds in 2001 vs. -0.31 (95% CI: [-0.45, -0.17]) increased log odds in 2016) and positive cohort effect for recent cohorts. Last, we observed a positive period effect for legalization support (-0.03 (95% CI: [-0.20, 0.14]) increased log odds in 2001 vs. 0.38 (95% CI: [0.22, 0.55]) increased log odds in 2016) and negative cohort effect for recent cohorts. CONCLUSION: Cannabis use appears to be increasing in Australia among adults over 35, while decreasing among adolescents and young adults. Legalization support also appears to have been increasing since 2007, signaling discordance between use and attitudes among adolescents and young adults, and potentially predicting increases in use over time.

Changes in cannabis potency and first-time admissions to drug treatment: a 16-year study in the Netherlands.

BACKGROUND: The number of people entering specialist drug treatment for cannabis problems has increased considerably in recent years. The reasons for this are unclear, but rising cannabis potency could be a contributing factor. METHODS: Cannabis potency data were obtained from an ongoing monitoring programme in the Netherlands. We analysed concentrations of δ-9-tetrahydrocannabinol (THC) from the most popular variety of domestic herbal cannabis sold in each retail outlet (2000-2015). Mixed effects linear regression models examined time-dependent associations between THC and first-time cannabis admissions to specialist drug treatment. Candidate time lags were 0-10 years, based on normative European drug treatment data. RESULTS: THC increased from a mean (95% CI) of 8.62 (7.97-9.27) to 20.38 (19.09-21.67) from 2000 to 2004 and then decreased to 15.31 (14.24-16.38) in 2015. First-time cannabis admissions (per 100 000 inhabitants) rose from 7.08 to 26.36 from 2000 to 2010, and then decreased to 19.82 in 2015. THC was positively associated with treatment entry at lags of 0-9 years, with the strongest association at 5 years, b = 0.370 (0.317-0.424), p < 0.0001. After adjusting for age, sex and non-cannabis drug treatment admissions, these positive associations were attenuated but remained statistically significant at lags of 5-7 years and were again strongest at 5 years, b = 0.082 (0.052-0.111), p < 0.0001. CONCLUSIONS: In this 16-year observational study, we found positive time-dependent associations between changes in cannabis potency and first-time cannabis admissions to drug treatment. These associations are biologically plausible, but their strength after adjustment suggests that other factors are also important.

RADAR study: protocol for an observational cohort study to identify early warning signals on the pathways to alcohol use disorder.

INTRODUCTION: Harmful alcohol consumption, particularly alcohol use disorder (AUD), is a worldwide health priority, contributing substantially to global morbidity and mortality. The peak age of onset of AUD is 18-24, thus a deeper understanding of the young adult experience is vital if we are to identify modifiable risk factors and intervene early in the developmental course of this disabling disorder. Critical unanswered questions include: How soon after drinking initiation do AUD symptoms begin to emerge? Which symptoms come first? Do the symptoms unfold in a predictable pattern? In what ways do the emerging symptoms interact with individual, peer, family and environmental risk factors to impact on the transition to disorder? METHODS AND ANALYSIS: The proposed RADAR study will examine the prospective development of AUD symptoms over the young adulthood (18-24) years. We will capitalise on an existing cohort of 1911 community-based adolescents who were recruited at age 13 and have completed a baseline and five annual follow-up assessments as part of an observational cohort study. We will interview these adolescents every 6 months between the ages of 19 and 23 to derive monthly histories of both alcohol use and AUD symptomatology, along with a comprehensive battery of risk and protective factor scales hypothesised to predict the emergence and course of AUD. The results of this study will inform the natural history of AUD and will be used to identify specific targets for prevention and early intervention of AUD. ETHICS AND DISSEMINATION: Ethical approval has already been granted for the study (UNSW HREC 10144). We will disseminate the results of the study through published manuscripts, conferences and seminar presentations. Data used in published manuscripts will be made available through a suitable online repository (eg, Dryad-datadryad.org).

Evidence for Sex Convergence in Prevalence of Cannabis Use: A Systematic Review and Meta-Regression.

OBJECTIVE: Generally, cannabis use has been more prevalent in men than in women. However, emerging evidence suggests that the prevalence of cannabis use is converging among males and females from recent cohorts. This study aimed to systematically summarize published literature on birth cohort changes in male-to-female ratios in prevalence of cannabis use. METHOD: Twenty-two studies with a median sample size of 85,052 were identified for inclusion. Data were collected between 1979 and 2010, representing birth cohorts from 1936 to 1999. For quantitative synthesis, male-to-female ratios in prevalence of any cannabis use were calculated for all 5-year birth cohorts available, generating 348 separate ratios among birth cohorts from 1941 to 1995 in 30 countries. Random-effects meta-analyses generated pooled sex ratios, stratified by 5-year birth cohorts. RESULTS: Of the 22 included studies, 10 reported some evidence of sex convergence in cannabis use among more recent cohorts. Quantitative synthesis found that the ratio of cannabis use prevalence in males and females decreased significantly from 2.0 among cohorts born in 1941 to 1.3 among those born in 1995. CONCLUSIONS: Findings support the narrowing sex gap in the prevalence of cannabis use. Results are concordant with a broader literature demonstrating sex convergence in prevalence of other substance use, particularly alcohol use and related harms. Both young women and men should be the target of prevention and early intervention efforts. Future research in more diverse global settings, especially in low- and middle-income countries, would enhance the international scope of the findings.

A prospective study of the substance use and mental health outcomes of young adult former and current cannabis users.

INTRODUCTION AND AIMS: The extent to which young adult former cannabis users fare better than infrequent users is unclear. We investigated the association between cannabis use status at age 23 and substance use and mental health outcomes at age 27. DESIGN AND METHODS: Data were from the 20+ year cohort of the PATH Through Life Study. Lifetime cannabis users (n = 1410) at age 23 were classified as former/occasional/regular users. Multivariable logistic regression was used to estimate the association between cannabis use status at age 23 and six outcomes assessed at age 27. RESULTS: Compared with occasional cannabis users: (i) former users had odds of subsequent tobacco use [odds ratio (OR) = 0.67, 95% confidence interval (CI) 0.52-0.85], illicit drug use (cannabis, OR = 0.22, 95% CI 0.17-0.28; other illicit drugs, OR = 0.29, 95% CI 0.22-0.39) and mental health impairment (OR = 0.71, 95% CI 0.55-0.92) that were 29-78% lower; and (ii) regular users had odds of subsequent frequent alcohol use (OR = 2.34, 95% CI 0.67-1.34), tobacco use (OR = 3.67, 95% CI 2.54-5.30), cannabis use (OR = 11.73, 95% CI 6.81-20.21) and dependence symptoms (OR = 12.60, 95% CI 8.38-18.94), and other illicit drug use (OR = 2.95, 95% CI 2.07-4.21) that were 2-13 times greater. Associations attenuated after covariate adjustment, and most remained significant. DISCUSSION AND CONCLUSIONS: Clear associations exist between cannabis use status in young adulthood and subsequent mental health and substance use. While early intervention remains important to prevent regular cannabis use and the associated harms, experimentation with cannabis use in the years leading into young adulthood may not necessarily determine an immutable pathway to mental health problems and illicit substance use. [Silins E, Swift W, Slade T, Toson B, Rodgers B, Hutchinson DM. A prospective study of the substance use and mental health outcomes of young adult former and current cannabis users. Drug Alcohol Rev 2017;00:000-000].

First examination of varying health outcomes of the chronically homeless according to Housing First configuration.

OBJECTIVE: To determine whether two Housing First configurations (scattered site [SS] versus congregated site [CS]) are associated with different health-related outcomes. METHODS: This ecological study employed a longitudinal, quantitative design to compare the outcomes from 63 individuals (SS: n=37; CS: n=26) in Sydney, Australia, over 12 months. RESULTS: Both configurations showed similar improvements in quality of life and psychological distress. While recent use of substances remained stable across the two configurations over time, a marginally greater increase in the proportion of CS individuals injecting more than weekly was found. For health service utilisation, CS participants had notably higher service utilisation rates for mental health specialists and the emergency department for mental health reasons at follow-up than SS participants. CONCLUSION: Preliminary evidence of differential injecting and health service utilisation outcomes between configurations emerged within this small-scale study over the 12-month period. Implications for public health: Given the rapid expansion of both SS and CS Housing First configurations across Western countries and the indications from this initial study that outcomes may differ according to configuration, there remains a need for robust evaluative evidence on the efficacy of various supported housing models on long-term individual outcomes.

Birth cohort trends in the global epidemiology of alcohol use and alcohol-related harms in men and women: systematic review and metaregression.

OBJECTIVE: Historically, alcohol use and related harms are more prevalent in men than in women. However, emerging evidence suggests the epidemiology of alcohol use is changing in younger cohorts. The current study aimed to systematically summarise published literature on birth cohort changes in male-to-female ratios in indicators of alcohol use and related harms. METHODS: We identified 68 studies that met inclusion criteria. We calculated male-to-female ratios for 3 broad categories of alcohol use and harms (any alcohol use, problematic alcohol use and alcohol-related harms) stratified by 5-year birth cohorts ranging from 1891 to 2001, generating 1568 sex ratios. Random-effects meta-analyses produced pooled sex ratios within these 3 categories separately for each birth cohort. FINDINGS: There was a linear decrease over time in the sex ratio for all 3 categories of alcohol use and related harms. Among those born in the early 1900s, males were 2.2 (95% CI 1.9 to 2.5) times more likely than females to consume alcohol, 3.0 (95% CI 1.5 to 6.0) times more likely to drink alcohol in ways suggestive of problematic use and 3.6 (95% CI 0.4 to 30.3) times more likely to experience alcohol-related harms. Among cohorts born in the late 1900s, males were 1.1 (95% CI 1.1 to 1.2) times more likely than females to consume alcohol, 1.2 (95% CI 1.1 to 1.4) times more likely to drink alcohol in ways suggestive of problematic use and 1.3 (95% CI 1.2 to 1.3) times more likely to experience alcohol-related harms. CONCLUSIONS: Findings confirm the closing male-female gap in indicators of alcohol use and related harms. The closing male-female gap is most evident among young adults, highlighting the importance of prospectively tracking young male and female cohorts as they age into their 30s, 40s and beyond.

Adolescent Predictors of a Typology of DSM-5 Alcohol Use Disorder Symptoms in Young Adults Derived by Latent Class Analysis Using Data From an Australian Cohort Study.

OBJECTIVE: There is little research examining alcohol use disorder (AUD) symptoms (based on criteria from the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition [DSM-5]) in young adulthood. We assessed symptom structure at 24 years using latent class analysis (LCA), examining relationships between class membership and (a) concurrent alcohol use and DSM-5 AUD severity and (b) adolescent risk factors. METHOD: A stratified, random sample of 1,943 adolescents ages 14-15 years was recruited from 44 secondary schools in Victoria, Australia, and interviewed during adolescence and young adulthood. We report findings on drinkers who completed the AUD module (N = 1,268; 51% male). RESULTS: Data clearly fit a three-class, dimensional model, comprising "mild symptoms" (63.2%), "moderate symptoms" (32.2%), and "severe symptoms" (4.6%) classes. Class membership was validated by concurrent drinking patterns and in reasonable agreement with DSM-5 AUD severity categories. Relative to mild symptoms class membership, moderate symptoms class membership increased odds of adolescent alcohol problems (odds ratio [OR] = 2.0, 95% CI [1.2, 3.5]) and persisting anxiety/depression symptoms (OR = 1.9, 95% CI [1.2, 3.1]). Daily smoking (OR = 2.6, 95% CI [1.1, 5.9]), persisting anxiety/ depression symptoms (OR = 2.5, 95% CI [1.3, 5.0]), and antisocial behavior (OR = 3.2, 95% CI [1.5, 6.8]) increased odds of severe symptoms class membership. Adolescent daily smoking (OR = 0.3, 95% CI [0.11, 0.81]) and antisocial behavior (OR = 0.3, 95% CI [0.14, 0.64]) were less likely among members of the moderate symptoms class, relative to the severe symptoms class. CONCLUSIONS: We found support for a dimensional AUD typology like that in DSM-5. Young adults with more severe AUD symptoms had a different adolescent risk profile than those in the low and moderate classes. These findings provide a focus for preventive intervention in adolescence to limit the severity of AUDs in young adulthood.

Understanding trends in Australian alcohol consumption-an age-period-cohort model.

AIMS: To decompose Australian trends in alcohol consumption into their age, period (survey year) and cohort (birth year/generation) components. In particular, we aimed to test whether recent declines in overall consumption have been influenced by reductions in drinking among recently born cohorts. DESIGN: Seven cross-sectional waves of the Australian National Drug Strategy Household Survey (1995-2013). Age, period and cohort effects were estimated using a linear and logistic cross-classified random-effects models (CCREMs). SETTING: Australia PARTICIPANTS: A total of 124 440 Australians (69 193 females and 55 257 males), aged 14-79 years. MEASUREMENTS: Whether or not respondents consumed alcohol in the 12 months prior to the survey and, for those who did, the estimated volume of pure alcohol consumed, derived using standard quantity-frequency survey questions. FINDINGS: Controlling for age and period effects, there was significant variation in drinking participation and drinking volume by birth cohort. In particular, male cohorts born between the 1965 and 1974 and female cohorts born between 1955 and 1974 reported higher rates of drinking participation (P < 0.05), while the most recent cohorts (born in the 1990s) had lower rates of participation (P < 0.01). Among drinkers, the most recently born cohort also had sharply lower average consumption volumes than older cohorts for both men and women (P < 0.01). CONCLUSION: Recent birth cohorts (born between 1995 and 1999) in Australia report significantly lower rates of both drinking participation and drinking volume than previous cohorts, controlling for their age distribution and overall changes in population drinking. These findings suggest that the recent decline in alcohol consumption in Australia has been driven by declines in drinking among these recently born cohorts. These trends are consistent with international shifts in youth drinking.

Associations of Housing First Configuration and Crime and Social Connectedness Among Persons With Chronic Homelessness Histories.

OBJECTIVE: This study compared changes in criminal justice contact, quality of life, and social connectedness over a 12-month follow-up period between participants in two Housing First configurations (scattered site [SS] and congregate site [CS]). METHODS: A longitudinal, quantitative design was utilized for this ecological study. Changes in individual outcomes over time were compared for SS and CS participants who completed both baseline and 12-month follow-up surveys (N=63). RESULTS: The number of contacts with various types of criminal justice system channels differed significantly between SS and CS participants, decreasing significantly among SS participants and increasing significantly among CS participants. The two groups did not differ on quality-of-life outcomes or social-connectedness measures, with the exception of case management engagement, whereby a greater proportion of SS participants disengaged from this service over time compared with CS participants. At follow-up, significant within-group changes over time emerged, with increased boredom reported among SS participants, whereas CS participants reported improvements in social relationships, with fewer reporting losing their temper. CONCLUSIONS: The findings supported the notion that the Housing First approach has the potential to significantly improve the lives of persons who have experienced chronic homelessness, a traditionally marginalized and vulnerable group. Over time, this may result in a reduction in the use of acute services, thereby reducing societal costs. The challenge remains to identify the suitability of particular configurations of housing and support and how service delivery can optimize individual outcomes so positive outcomes are maintained in the longer term.

Does the social context of early alcohol use affect risky drinking in adolescents? Prospective cohort study.

BACKGROUND: There are limited longitudinal data on the associations between different social contexts of alcohol use and risky adolescent drinking. METHODS: Australian prospective longitudinal cohort of 1943 adolescents with 6 assessment waves at ages 14-17 years. Drinkers were asked where and how frequently they drank. Contexts were: at home with family, at home alone, at a party with friends, in a park/car, or at a bar/nightclub. The outcomes were prevalence and incidence of risky drinking (≥5 standard drinks (10g alcohol) on a day, past week) and very risky drinking (>20 standard drinks for males and >11 for females) in early (waves 1-2) and late (waves 3-6) adolescence. RESULTS: Forty-four percent (95 % CI: 41-46 %) reported past-week risky drinking on at least one wave during adolescence (waves 1-6). Drinking at a party was the most common repeated drinking context in early adolescence (28 %, 95 % CI 26-30 %); 15 % reported drinking repeatedly (3+ times) with their family in early adolescence (95 % CI: 14-17 %). For all contexts (including drinking with family), drinking 3+ times in a given context was associated with increased the risk of risky drinking in later adolescence. These effects remained apparent after adjustment for potential confounders (e.g. for drinking with family, adjusted RR 1.9; 95 % CI: 1.5-2.4). Similar patterns were observed for very risky drinking. CONCLUSIONS: Our results suggest that consumption with family does not protect against risky drinking. Furthermore, parents who wish to minimise high risk drinking by their adolescent children might also limit their children's opportunities to consume alcohol in unsupervised settings.

A place to call home: study protocol for a longitudinal, mixed methods evaluation of two housing first adaptations in Sydney, Australia.

BACKGROUND: This protocol describes a study evaluating two 'Housing First' programs, Platform 70 and Common Ground, presently being implemented in the inner-city region of Sydney, Australia. The Housing First approach prioritises housing individuals who are homeless in standard lease agreement tenancies as rapidly as possible to lock in the benefits from long-term accommodation, even where the person may not be seen as 'housing ready'. METHODS/DESIGN: The longitudinal, mixed methods evaluation utilises both quantitative and qualitative data collected at baseline and 12-month follow-up time points. For the quantitative component, clients of each program were invited to complete client surveys that reported on several factors associated with chronic homelessness and were hypothesised to improve under stable housing, including physical and mental health status and treatment rates, quality of life, substance use patterns, and contact with the health and criminal justice systems. Semi-structured interviews with clients and stakeholders comprised the qualitative component and focused on individual experiences with, and perceptions of, the two programs. In addition, program data on housing stability, rental subsidies and support levels provided to clients by agencies was collected and will be used in conjunction with the client survey data to undertake an economic evaluation of the two programs. DISCUSSION: This study will systematically evaluate the efficacy of a scatter site model (Platform 70) and a congregated model (Common Ground) of the Housing First approach; an examination that has not yet been made either in Australia or internationally. A clear strength of the study is its timing. It was designed and implemented as the programs in question themselves were introduced. Moreover, the programs were introduced when the Australian Government, with State and Territory support, began a more focused, coordinated response to homelessness and funded rapid expansion of innovative homelessness programs across the country, including Common Ground supportive housing developments.

Multiply disadvantaged: Health and service utilisation factors faced by homeless injecting drug consumers in Australia.

INTRODUCTION AND AIMS: Homelessness status is strongly correlated with higher rates of substance use. Few studies, however, examine the complex relationship between housing status and substance use in people who inject drugs (PWID). This study extends previous research by comparing the physical and mental health status and service utilisation rates between stably housed and homeless PWID. DESIGN AND METHODS: A cross-sectional sample of 923 PWID were recruited for the 2012 Illicit Drug Reporting System. Multivariate models were generated addressing associations between homelessness and the domains of demographics; substance use; and health status, service utilisation and criminal justice system contact, with significant correlates entered into a final multivariate model. RESULTS: Two-thirds of the PWID sample were male. The median age was 39 years and 16% identified as Indigenous. Almost one-quarter (23%) reported that they were homeless. Homeless PWID were significantly more likely to be unemployed [adjusted odds ratio (AOR) 2.83, 95% confidence interval (CI) 1.26, 6.34], inject in public (AOR 2.01, 95% CI 1.38, 3.18), have poorer mental health (AOR 0.98, 95% CI 0.97, 1.00), report schizophrenia (AOR 2.31, 95% CI 1.16, 4.60) and have a prison history (AOR 1.53, 95% CI 1.05, 2.21) than stably housed PWID. DISCUSSION AND CONCLUSIONS: Findings highlight the challenge of mental health problems for homeless PWID. Our results demonstrate that further research that evaluates outcomes of housing programs accommodating PWID, particularly those with comorbid mental health disorders, is warranted. Results also emphasise the need to better utilise integrated models of outreach care that co-manage housing and mental health needs.

Young adult sequelae of adolescent cannabis use: an integrative analysis.

BACKGROUND: Debate continues about the consequences of adolescent cannabis use. Existing data are limited in statistical power to examine rarer outcomes and less common, heavier patterns of cannabis use than those already investigated; furthermore, evidence has a piecemeal approach to reporting of young adult sequelae. We aimed to provide a broad picture of the psychosocial sequelae of adolescent cannabis use. METHODS: We integrated participant-level data from three large, long-running longitudinal studies from Australia and New Zealand: the Australian Temperament Project, the Christchurch Health and Development Study, and the Victorian Adolescent Health Cohort Study. We investigated the association between the maximum frequency of cannabis use before age 17 years (never, less than monthly, monthly or more, weekly or more, or daily) and seven developmental outcomes assessed up to age 30 years (high-school completion, attainment of university degree, cannabis dependence, use of other illicit drugs, suicide attempt, depression, and welfare dependence). The number of participants varied by outcome (N=2537 to N=3765). FINDINGS: We recorded clear and consistent associations and dose-response relations between the frequency of adolescent cannabis use and all adverse young adult outcomes. After covariate adjustment, compared with individuals who had never used cannabis, those who were daily users before age 17 years had clear reductions in the odds of high-school completion (adjusted odds ratio 0·37, 95% CI 0·20-0·66) and degree attainment (0·38, 0·22-0·66), and substantially increased odds of later cannabis dependence (17·95, 9·44-34·12), use of other illicit drugs (7·80, 4·46-13·63), and suicide attempt (6·83, 2·04-22·90). INTERPRETATION: Adverse sequelae of adolescent cannabis use are wide ranging and extend into young adulthood. Prevention or delay of cannabis use in adolescence is likely to have broad health and social benefits. Efforts to reform cannabis legislation should be carefully assessed to ensure they reduce adolescent cannabis use and prevent potentially adverse developmental effects. FUNDING: Australian Government National Health and Medical Research Council.

The persistence of adolescent binge drinking into adulthood: findings from a 15-year prospective cohort study.

OBJECTIVES: To examine the prevalence of binge drinking in adolescence and its persistence into adulthood in an Australian cohort. DESIGN: 15-year prospective cohort study. SETTING: Victoria, Australia. PARTICIPANTS: 1943 adolescents were recruited from secondary schools at age 14-15 years. PRIMARY OUTCOME MEASURES: Levels of past-week 'binge' drinking (5+ standard drinks on a day, each 10 g alcohol) and 'heavy binge' drinking (20+ standard drinks on a day for males, 11+ for females) were assessed during six adolescent waves, and across three adult waves up to age 29 years. RESULTS: Half of the males (52%) and a third of the females (34%) reported past-week adolescent binge drinking. 90% of male and 70% of female adolescent-onset binge drinkers continued to binge in young adulthood; 70% of males and 48% of females who were not adolescent-onset binge drinkers reported young adult binge drinking. Past-week heavy bingeing was less common in adolescence than adulthood. Overall, 35% of the sample (95% CI 33% to 38%) reported past-week binge drinking in adolescence and young adulthood and one-third (33%; 30% to 35%) first reported binge drinking in young adulthood; only 7% of the sample (6-8%) had binge drinking in adolescence but not young adulthood. 'Heavy binge' drinking occurred in adolescence and young adulthood for 9% (8% to 10%); 8% (7% to 10%) reported it in adolescence but no longer in young adulthood; and 24% (22% to 26%) began 'heavy binge' drinking in young adulthood. Among adolescent binge drinkers (n=821), young adult binge and heavy binge drinking were predicted by being male, adolescent antisocial behaviour and adverse consequences of drinking in adolescence. CONCLUSIONS: Binge alcohol use is common and persistent among young Australians. Efforts to prevent the onset of binge drinking during adolescence may substantially reduce harmful patterns of alcohol use in young adulthood.

Factors associated with variability and stability of cannabis use in young adulthood.

BACKGROUND: This study investigated the factors associated with initiating cannabis use, reverting to cannabis use and remaining a cannabis user in young adulthood. This is an important area of research as the risk for cannabis initiation is extending beyond adolescence and opportunities to influence cannabis use pathways can emerge throughout the life-course. METHODS: A large, community-based sample was followed prospectively. Data from two successive waves (mean age 23 years and 27 years respectively) of the Path Through Life Study (PATH) were analysed (n=2045). The longitudinal design enabled change in cannabis use in young adulthood to be predicted based on factors assessed approximately four years prior. RESULTS: An environment of licit drug use was strongly associated with initiating cannabis use (tobacco: OR=4.98, 95%CI: 2.31-10.76) and reverting to cannabis use in young adulthood (alcohol: OR=2.13, 95%CI: 1.42-3.19). Greater fun seeking was found to orientate people towards initiating cannabis use in young adulthood (OR=1.17, 95%CI: 1.04-1.30). Higher psychoticism increased the odds of remaining a cannabis user (OR=1.19, 95%CI: 1.07-1.33). Religious involvement was protective of cannabis initiation (OR=0.89, 95%CI: 0.83-0.95). Early childhood factors did not influence the pattern of cannabis use in young adulthood. CONCLUSIONS: The findings make an important contribution to the development of prevention and intervention strategies for young adults by drawing attention to specific areas of risk and protection.

Analysis of cannabis seizures in NSW, Australia: cannabis potency and cannabinoid profile.

Recent analysis of the cannabinoid content of cannabis plants suggests a shift towards use of high potency plant material with high levels of Δ(9)-tetrahydrocannabinol (THC) and low levels of other phytocannabinoids, particularly cannabidiol (CBD). Use of this type of cannabis is thought by some to predispose to greater adverse outcomes on mental health and fewer therapeutic benefits. Australia has one of the highest per capita rates of cannabis use in the world yet there has been no previous systematic analysis of the cannabis being used. In the present study we examined the cannabinoid content of 206 cannabis samples that had been confiscated by police from recreational users holding 15 g of cannabis or less, under the New South Wales "Cannabis Cautioning" scheme. A further 26 "Known Provenance" samples were analysed that had been seized by police from larger indoor or outdoor cultivation sites rather than from street level users. An HPLC method was used to determine the content of 9 cannabinoids: THC, CBD, cannabigerol (CBG), and their plant-based carboxylic acid precursors THC-A, CBD-A and CBG-A, as well as cannabichromene (CBC), cannabinol (CBN) and tetrahydrocannabivarin (THC-V). The "Cannabis Cautioning" samples showed high mean THC content (THC+THC-A = 14.88%) and low mean CBD content (CBD+CBD-A = 0.14%). A modest level of CBG was detected (CBG+CBG-A = 1.18%) and very low levels of CBC, CBN and THC-V (<0.1%). "Known Provenance" samples showed no significant differences in THC content between those seized from indoor versus outdoor cultivation sites. The present analysis echoes trends reported in other countries towards the use of high potency cannabis with very low CBD content. The implications for public health outcomes and harm reduction strategies are discussed.