Bacteroides fragilis outer membrane vesicles preferentially activate innate immune receptors compared to their parent bacteria.

The release of bacterial membrane vesicles (BMVs) has become recognized as a key mechanism used by both pathogenic and commensal bacteria to activate innate immune responses in the host and mediate immunity. Outer membrane vesicles (OMVs) produced by Gram-negative bacteria can harbor various immunogenic cargo that includes proteins, nucleic acids and peptidoglycan, and the composition of OMVs strongly influences their ability to activate host innate immune receptors. Although various Gram-negative pathogens can produce OMVs that are enriched in immunogenic cargo compared to their parent bacteria, the ability of OMVs produced by commensal organisms to be enriched with immunostimulatory contents is only recently becoming known. In this study, we investigated the cargo associated with OMVs produced by the intestinal commensal Bacteroides fragilis and determined their ability to activate host innate immune receptors. Analysis of B. fragilis OMVs revealed that they packaged various biological cargo including proteins, DNA, RNA, lipopolysaccharides (LPS) and peptidoglycan, and that this cargo could be enriched in OMVs compared to their parent bacteria. We visualized the entry of B. fragilis OMVs into intestinal epithelial cells, in addition to the ability of B. fragilis OMVs to transport bacterial RNA and peptidoglycan cargo into Caco-2 epithelial cells. Using HEK-Blue reporter cell lines, we identified that B. fragilis OMVs could activate host Toll-like receptors (TLR)-2, TLR4, TLR7 and nucleotide-binding oligomerization domain-containing protein 1 (NOD1), whereas B. fragilis bacteria could only induce the activation of TLR2. Overall, our data demonstrates that B. fragilis OMVs activate a broader range of host innate immune receptors compared to their parent bacteria due to their enrichment of biological cargo and their ability to transport this cargo directly into host epithelial cells. These findings indicate that the secretion of OMVs by B. fragilis may facilitate immune crosstalk with host epithelial cells at the gastrointestinal surface and suggests that OMVs produced by commensal bacteria may preferentially activate host innate immune receptors at the mucosal gastrointestinal tract.

Correction: Gilmore et al. Association between Nightlife Goers' Likelihood of an Alcohol Use Disorder and Their Preferred Bar's Closing Time: A Cross-Sectional Observational Study in Perth, Australia. Int. J. Environ. Res. Public Health 2021, 18, 13040.

In the original publication [...].

Association between Bar Closing Time, Alcohol Use Disorders and Blood Alcohol Concentration: A Cross-Sectional Observational Study of Nightlife-Goers in Perth, Australia.

Introduction and aims: Associations between bar trading hours, a government lever for controlling alcohol availability, nightlife-goer intoxication levels and their likelihood of alcohol use disorder (AUD) have not been explored. We investigated whether: (i) participant AUD was associated with blood alcohol concentration (BAC); and, (ii) any association between AUD and BAC was moderated by participant preferred bar (i.e., venue spent most time at) closing time. Design and methods: A cross-sectional observational study using a sample of nightlife-goers who went out drinking in Perth, Western Australia, on weekends in 2015-16. Participants who reported alcohol use that night and spent most time in a bar (n = 667) completed street intercept surveys including AUDIT-C (n = 459) and provided a breath sample to estimate BAC (n = 651). We used gender-specific multinomial logistic regression models to explore associations between participant AUDIT-C score (1−4, lower risk; 5−7, hazardous; 8−12, active AUD), preferred bar type (standard vs. late closing time based on absence or presence of an extended trading permit) and BAC (male: 0−0.049, 0.05−0.099, ≥0.1 g/100 mL; female: 0−0.049, 0.05−0.079, ≥0.08 g/100 mL). Results: Males with active AUD (RR = 3.31; 95% CI 1.30−8.42; p = 0.01) and females with hazardous/active AUD (RR = 9.75; 95% CI 2.78−34.21; p < 0.001) were both more likely to have high-range BAC than their counterparts typically drinking at lower risk. We also found preferred bar type moderated the association between AUDIT-C score and BAC for some males but no females. Males with active AUD and high-range BAC were less likely to prefer late closing bars than males usually drinking at lower risk and high-range BAC (RR = 0.12; 95% CI 0.02−0.96; p = 0.046). Discussion and conclusions: Our study provides evidence of positive associations between AUD and acute intoxication among nightlife-goers and on the moderating effect of bar closing times among males.

Isolation and characterization of human embryonic stem cell-derived heart field-specific cardiomyocytes unravels new insights into their transcriptional and electrophysiological profiles.

AIMS: We prospectively isolate and characterize first and second heart field- and nodal-like cardiomyocytes using a double reporter line from human embryonic stem cells. Our double reporter line utilizes two important transcription factors in cardiac development, TBX5 and NKX2-5. TBX5 expression marks first heart field progenitors and cardiomyocytes while NKX2-5 is expressed in nearly all myocytes of the developing heart (excluding nodal cells). We address the shortcomings of prior work in the generation of heart field-specific cardiomyocytes from induced pluripotent stem cells and provide a comprehensive early developmental transcriptomic as well as electrophysiological analyses of these three populations. METHODS AND RESULTS: Transcriptional, immunocytochemical, and functional studies support the cellular identities of isolated populations based on the expression pattern of NKX2-5 and TBX5. Importantly, bulk and single-cell RNA sequencing analyses provide evidence of unique molecular signatures of isolated first and second heart field cardiomyocytes, as well as nodal-like cells. Extensive electrophysiological analyses reveal dominant atrial action potential phenotypes in first and second heart fields in alignment with our findings in single-cell RNA sequencing. Lastly, we identify two novel surface markers, POPDC2 and CORIN, that enable purification of cardiomyocytes and first heart field cardiomyocytes, respectively. CONCLUSIONS: We describe a high-yield approach for isolation and characterization of human embryonic stem cell-derived heart field-specific and nodal-like cardiomyocytes. Obtaining enriched populations of these different cardiomyocyte subtypes increases the resolution of gene expression profiling during early cardiogenesis, arrhythmia modelling, and drug screening. This paves the way for the development of effective stem cell therapy to treat diseases that affect specific regions of the heart- or chamber-specific congenital heart defects.

Disclosures of harming others during their most recent drinking session: Findings from a large national study of heavy-drinking adolescents.

INTRODUCTION: The extant Alcohol's Harms to Others (AHTO) literature is largely comprised of reports from victims. We investigated AHTO from perpetrators' perspectives, including how harms were associated with individual characteristics, and alcohol quantities consumed during the perpetration incident. METHODS: Participants (N = 2932) were 14-19 years old, recruited primarily through social media and screened as risky drinkers. They completed face-to-face (n = 594) or self-administered (n = 2338) surveys. They self-reported whether during their last risky drinking session (LRDS) they had perpetrated any verbal abuse, physical abuse or property damage. A multinomial logistic regression examined whether nine factors were associated with perpetrating zero, one or 2+ categories of AHTO. RESULTS: Eleven percent (n = 323) reported perpetrating at least one form of AHTO (7.5% verbal, 1.9% physical and 4.6% property). Perpetration of AHTO at LRDS was uniquely associated with: younger age, male gender, experiences of childhood physical punishment, greater perpetration incident-specific drinking, concurrent illicit drug use, and less frequent use of safety strategies while drinking in the past 12 months. Controlling for the other variables, an increase of six Australian standard drinks (60 g of alcohol) increased the odds of perpetration by 15% [95% confidence interval (CI) adjusted odds ratio (AOR) 1.08, 1.23], and an increase of 15 Australian standard drinks increased the odds by 42% (95% CI AOR 1.20, 1.69). DISCUSSION AND CONCLUSIONS: Individual characteristics, larger quantities of alcohol consumed, and a disinclination to practice harm reduction amplified risk of AHTO perpetration. This has implications for health promotion and risk prevention/reduction strategies.

Association between Nightlife Goers' Likelihood of an Alcohol Use Disorder and Their Preferred Bar's Closing Time: A Cross-Sectional Observational Study in Perth, Australia.

INTRODUCTION AND AIMS: Associations between longer-term alcohol-related conditions and licensed outlet trading hours are not well understood. We investigated the association between nightlife-goers' likelihood of an alcohol use disorder (AUD) and their preference for bars with special permits to remain open 'late' (i.e., spent more time there compared to any other venue) until 2 a.m. or 3 a.m. (Friday; Saturday) or midnight (Sunday) compared to bars with 'standard' closing times of midnight (Friday; Saturday) or 10 p.m. (Sunday). DESIGN AND METHODS: A cross-sectional observational study was conducted in four major nightlife areas of Perth, Australia, in 2015-2016. We conducted weekend street intercept surveys outside bars between 8 p.m. and 3 a.m. and screened participants who reported alcohol use prior to the survey and spent more time in a bar than any other venue type (n = 667) regarding their past year drinking pattern using AUDIT-C (n = 459). We used gender-specific logistic regression models to estimate associations between AUDIT-C categories (1-4, low risk; 5-7, hazardous; 8-12, active AUD) and preference for bars with different closing times (late vs. standard). RESULTS: A large proportion of participants were hazardous drinkers or had active AUD (83% males; 65% females), and over half preferred a late to a standard closing bar. We found evidence of a positive association between preference for late closing bars and hazardous drinking females (OR = 3.48; 95% CI 1.47-8.23; p = 0.01), but not for females with active AUD, male hazardous drinkers, nor males with active AUD. DISCUSSION AND CONCLUSIONS: Our study adds new evidence on associations between likelihood of AUD among nightlife-goers and trading hours. With increasing international relaxation of trading hours, evidence that late closing bars may be preferred by hazardous drinking females will be of concern to policymakers wanting to curb alcohol-related harms in the community.

Pathogenesis Mediated by Bacterial Membrane Vesicles.

The release of extracellular vesicles (EVs) is a process conserved across the three domains of life. Amongst prokaryotes, EVs produced by Gram-negative bacteria, termed outer membrane vesicles (OMVs), were identified more than 50 years ago and a wealth of literature exists regarding their biogenesis, composition and functions. OMVs have been implicated in benefiting numerous metabolic functions of their parent bacterium. Additionally, OMVs produced by pathogenic bacteria have been reported to contribute to pathology within the disease setting. By contrast, the release of EVs from Gram-positive bacteria, known as membrane vesicles (MVs), has only been widely accepted within the last decade. As such, there is a significant disproportion in knowledge regarding MVs compared to OMVs. Here we provide an overview of the literature regarding bacterial membrane vesicles (BMVs) produced by pathogenic and commensal bacteria. We highlight the mechanisms of BMV biogenesis and their roles in assisting bacterial survival, in addition to discussing their functions in promoting disease pathologies and their potential use as novel therapeutic strategies.

Immunomodulatory roles and novel applications of bacterial membrane vesicles.

Bacteria release extracellular vesicles (EVs) known as bacterial membrane vesicles (BMVs) during their normal growth. Gram-negative bacteria produce BMVs termed outer membrane vesicles (OMVs) that are composed of a range of biological cargo and facilitate numerous bacterial functions, including promoting pathogenesis and mediating disease in the host. By contrast, less is understood about BMVs produced by Gram-positive bacteria, which are referred to as membrane vesicles (MVs), however their contribution to mediating bacterial pathogenesis has recently become evident. In this review, we summarise the mechanisms whereby BMVs released by Gram-negative and Gram-positive bacteria are produced, in addition to discussing their key functions in promoting bacterial survival, mediating pathogenesis and modulating host immune responses. Furthermore, we discuss the mechanisms whereby BMVs produced by both commensal and pathogenic organisms can enter host cells and interact with innate immune receptors, in addition to how they modulate host innate and adaptive immunity to promote immunotolerance or drive the onset and progression of disease. Finally, we highlight current and emerging applications of BMVs in vaccine design, biotechnology and cancer therapeutics.

Psychometric Analysis of a Survey on Patient Safety Culture-Based Tool for Emergency Medical Services.

OBJECTIVE: Evaluating organizational safety culture is critical for high-stress, high-risk professions such as prehospital emergency medical services (EMS). The aim of the study was to evaluate the psychometric properties of a safety culture instrument for EMS, based on the Agency for Healthcare Research and Quality's widely used Surveys on Patient Safety Culture (SOPS). METHODS: The final EMS-adapted instrument consisted of 37 items covering 11 safety culture domains including 10 domains from existing SOPS instruments and one new domain for communication while en route to an emergency call. The analysis sample included 23,029 nationally certified EMS providers. Domain structure was evaluated on two separate halves of the data set through confirmatory factor analysis using a polychoric correlation matrix for ordinal data. The reliability and validity of each domain were evaluated using Cronbach α and Pearson correlation coefficients. RESULTS: The confirmatory factor analysis supported the 11-domain model. All items loaded above the 0.4 threshold (range = 0.508-0.984). Three composite domains exhibited factor variance below the 0.5 threshold: staffing (0.32), communication about incidents (0.26), and handoffs (0.26). Floor and ceiling effects were not detected. Inter-item consistency exceeded 0.6 for all subscales (α = 0.65-0.88). Predictive validity was supported as all domain composites were correlated with the outcome variables of overall safety rating (r = 0.44-0.72) and frequency of event reporting (r = 0.31-0.48). CONCLUSIONS: Overall, the EMS-adapted tool demonstrated adequate psychometric properties consistent with those of existing SOPS instruments. Additional research is needed to evaluate the instrument's performance at the agency level and its correlation with safety outcomes in the prehospital setting.

Safety first: Beliefs of older peers supplying alcohol to underage friends.

ISSUE ADDRESSED: Underage drinkers most commonly source alcohol from older peers. However, few studies have examined older peers' supply-related beliefs and motivations. METHODS: A sample of 270 risky drinkers aged 18-19 years were interviewed in Australia where the legal purchase age is 18. They were asked about their provision to underage friends, awareness of secondary supply legislation (intended to prohibit such supply) and 24 psycho-legal beliefs around supply. RESULTS: Half (49%) provided alcohol to a 16- to 17-year-old friend to drink at a party they were both attending at least twice a year. Three-quarters reported provision was okay so long as the recipient(s) were in a safe environment, and 46% reported "everyone gives alcohol to teenagers if they are in a safe environment." There was significantly higher agreement that "my friends would think I was mean if I did not give alcohol to a friend under the age of 18" (37%), compared to "my friends would think I was uncool if I did not give alcohol to a friend under the age of 18" (26%). Two thirds (69%) felt more responsible for an underage friend's safety if they provided the alcohol. A multivariate logistic regression revealed supply was more likely if the supplier: was aged 18 compared to 19 (95% CI OR: 1.57, 4.84), male (1.06, 3.27), of a higher SES quintile (1.08, 1.80) and believed alcohol supply to minors was morally acceptable (1.01, 1.33) and normal (1.04, 1.38). Knowledge of regulatory strategies (68%) designed to prevent supply to minors, and their perceived deterrent value did not significantly impact supply. CONCLUSIONS: Supply of alcohol to underage peers was perceived as morally and socially acceptable in a group of 18- to 19-year-old risky drinkers. SO WHAT?: Opportunities include harm reduction initiatives that prioritise caring responsibilities towards friends, as opposed to relying on external enforcement measures alone.

The Association between the Australian Alcopops Tax and National Chlamydia Rates among Young People-an Interrupted Time Series Analysis.

A national tax increase, which became known as the "alcopops tax", was introduced in Australia on the 27th April 2008 on ready-to-drink alcoholic beverages, which are consumed predominantly by young people. The affordability of alcohol has been identified as the strongest environmental driver of alcohol consumption, and alcohol consumption is a well-known risk factor in the spread of sexually transmitted infections via its association with sexual risk-taking. We conducted a study to investigate whether there was any association between the introduction of the tax and changes in national chlamydia rates: (i) notification rates (diagnoses per 100,000 population; primary outcome and standard approach in alcohol taxation studies), and (ii) test positivity rates (diagnoses per 100 tests; secondary outcome) among 15-24 and 25-34-year-olds, using interrupted time series analysis. Gender- and age-specific chlamydia trends among those 35 and older were applied as internal control series and gender- and age-specific consumer price index-adjusted per capita income trends were controlled for as independent variables. We hypothesised that the expected negative association between the tax and chlamydia notification rates might be masked due to increasing chlamydia test counts over the observation period (2000 to 2016). We hypothesised that the association between the tax and chlamydia test positivity rates would occur as an immediate level decrease, as a result of a decrease in alcohol consumption, which, in turn, would lead to a decrease in risky sexual behaviour and, hence, chlamydia transmission. None of the gender and age-specific population-based rates indicated a significant immediate or lagged association with the tax. However, we found an immediate decrease in test positivity rates for 25-34-year-old males (27% reduction-equivalent to 11,891 cases prevented post-tax) that remained detectable up to a lag of six months and a decrease at a lag of six months for 15-24-year-old males (31% reduction-equivalent to 16,615 cases prevented) following the tax. For no other gender or age combination did the change in test positivity rates reach significance. This study adds to the evidence base supporting the use of alcohol taxation to reduce health-related harms experienced by young people and offers a novel method for calculating sexually transmitted infection rates for policy evaluation.

Alcohol supply as a favour for a friend: Scenarios of alcohol supply to younger friends and siblings.

ISSUES ADDRESSED: Adolescents under the legal purchase age primarily source their alcohol through social networks. This study assessed the provision context from the perspective of both underage recipients and their suppliers who were older peers and siblings. METHODS: Interviewer-administered surveys were conducted with 590 risky-drinking (50 g alcohol per session, at least monthly) adolescents. Participants of legal purchase age (18- to 19-year-olds; n = 269) reported their provision to 16- to 17-year-olds under eight scenarios. Those aged 14-17 (n = 321) reported receipt of alcohol under the same scenarios plus two parental supply contexts. RESULTS: Purchase-age participants reported supply: to an underage friend (67%), an acquaintance (44%) or a sibling (16%) to drink at the same party; to a friend (43%) or sibling (20%) to take to another party (20%) and to a stranger near a bottle shop (5%). Supply to a friend at the same party was more likely if money was exchanged (60% vs 40%; P < 0.001). Almost all (98%) 14- to 17-year-olds reported receiving alcohol from an adult (including 36% from a parent for consumption away from the parent), with a similar pattern of receipt scenarios as those reported by the 18- to 19-year-olds. CONCLUSIONS: Provision of alcohol was more frequent with a friend than a sibling or stranger, in close environmental proximity, and if money was exchanged. SO WHAT?: As supply may be sensitive to monetary considerations, the incidence of underage receipt may be affected by community-wide pricing measures. Traditional alcohol availability regulations should be supplemented by strategies relating to the social nature of supply and demand.

Implications of Cardioprotective Assumptions for National Drinking Guidelines and Alcohol Harm Monitoring Systems.

The existence and potential level of cardioprotection from alcohol use is contested in alcohol studies. Assumptions regarding the risk relationship between alcohol use and ischaemic heart disease (IHD) are critical when providing advice for national drinking guidelines and for designing alcohol harm monitoring systems. We use three meta-analyses regarding alcohol use and IHD risk to investigate how varying assumptions lead to differential estimates of alcohol-attributable (AA) deaths and weighted relative risk (RR) functions, in Australia and Canada. Alcohol exposure and mortality data were acquired from administrative sources and AA fractions were calculated using the International Model of Alcohol Harms and Policies. We then customized a recent Global Burden of Disease (GBD) analysis to inform drinking guidelines internationally. Australians drink slightly more than Canadians, per person, but are also more likely to identify as lifetime abstainers. Cardioprotective scenarios resulted in substantial differences in estimates of net AA deaths in Australia (between 2933 and 4570) and Canada (between 5179 and 8024), using GBD risk functions for all other alcohol-related conditions. Country-specific weighted RR functions were analyzed to provide advice toward drinking guidelines: Minimum risk was achieved at or below alcohol use levels of 10 g/day ethanol, depending on scenario. Consumption levels resulting in 'no added' risk from drinking were found to be between 10 and 15 g/day, by country, gender, and scenario. These recommendations are lower than current guidelines in Australia, Canada, and some other high-income countries: These guidelines may be in need of downward revision.

From eye rolls to punches: experiences of harm from others' drinking among risky-drinking adolescents across Australia.

OBJECTIVES: Exploration of experience of harms due to another person's drinking within a demographic particularly vulnerable to these consequences. Importance of study: Largest sampling of young Australian risky drinkers, who are underrepresented in general population surveys. The range of harms due to others' drinking reported here is more comprehensive than documented elsewhere. STUDY TYPE: Cross-sectional self-report survey. METHODS: Participants were 14-19 years old and screened as being within the riskiest-drinking 25% for their age cohort. The convenience sample of 3465 was recruited primarily by social media advertising. Face-to-face interviews were conducted in all eight Australian capital cities (n = 596), supplemented by online surveys (n = 2869). Past 12-month experience of 13 harms due to others' drinking was assessed by age, gender and perpetrator. RESULTS: Females were more likely to experience seven harms, mainly characterised by fear and harassment, including being harassed or bothered at a party or some other private setting (41% vs 34% of males, p < 0.001), being given unwanted sexual attention (71% vs 47%, p < 0.001) and being put in fear (33% vs 20%, p < 0.001). Males were more likely to experience three harms, characterised by aggression: being yelled at, criticised or verbally abused (38% vs 33% of females, p = 0.002), being pushed or shoved (42% vs 28%, p < 0.001) and being physically hurt (17% vs 11%, p < 0.001). Teenagers of a legal alcohol-purchase age were more likely to experience harassment in public settings (49% vs 32-34%, p < 0.001) and unwanted sexual attention (66% vs 51-59%, p < 0.001) compared with younger teenagers. Seven of the harms studied were more likely (p < 0.01) to be perpetrated by people the respondents knew, and five (those associated with fear and aggression) were more likely to be perpetrated by strangers. CONCLUSION: Young people who are risky drinkers commonly experience multiple harms from others' drinking. Many of these alcohol harms to others are reported here for the first time, as previous studies of adolescent drinking have focused almost exclusively on the harms young people have experienced from their own drinking. This refocusing on the harms caused by the drinking of others may prompt greater community concern and concomitant calls for better alcohol regulation.

Treating alcohol-related liver disease from a public health perspective.

Herein, we describe the evolving landscape of alcohol-related liver disease (ALD) including the current global burden of disease and cost to working-aged people in terms of death and disability, in addition to the larger spectrum of alcohol-related heath complications and its wider impact on society. We further review the most effective and cost-effective public health policies at both a population and individual level. Currently, abstinence is the only effective treatment for ALD, and yet because the majority of ALD remains undetected in the community abstinence is initiated too late to prevent premature death in the majority of cases. We therefore hope that this review will help inform clinicians of the "public health treatment options" for ALD to encourage engagement with policy makers and promote community-based hepatology as a speciality, expanding our patient cohort to allow early detection, and thereby a reduction in the enormous morbidity and mortality associated with this disease.

A Pilot Study Investigating the Influence of Glucagon-Like Peptide-1 Receptor Single Nucleotide Polymorphisms on Gastric Emptying Rate in Caucasian Men.

Gastric emptying rate in humans is subject to large individual variability, but previous research on the influence of genetics is scarce. Variation in the glucagon-like peptide-1 receptor (GLP1R) gene is a plausible candidate gene to partially explain the high variance. This study aimed to investigate the influence of genetic variation in the GLP1R gene on gastric emptying rate of a glucose solution in humans. Forty eight healthy Caucasian males took part in this investigation. Gastric emptying rate of a 6% glucose solution was assessed using the 13C breath test method and a venous blood sample was obtained from each participant. Participants were genotyped for 27 Tag single nucleotide polymorphisms (SNPs) in the GLP1R locus using Sequenom MassARRAY iPLEX GOLD analysis and MALDI-TOF mass spectrometry. The time at which maximal emptying rate occurred (Tlag) was faster in participants with the CC genotype than in TT and TC genotypes for SNP rs742764: [median (quartiles) CC, 35 (30-36) min vs. TT, 43 (39-46) min, and TC, 41 (39-45) min; P < 0.01]. Tlag was also slower in participants with the AA genotype compared to the TT and TA genotypes for SNP rs2254336: [AA, 43 (39-49) min vs. TT, 36 (34-41) min, and TA, 39 (35-42) min; P < 0.05]. Analysis by phenotype also showed differences in half-emptying time (T12) and Tlag for SNPs rs9283907, rs2268657, and rs2254336. Several neighboring Tag SNPs within the GLP1R gene were found to be associated with gastric emptying rate, and should be further investigated.

Insomnia and Regulation of Sleep-Wake Cycle With Drugs Among Adolescent Risky Drinkers.

STUDY OBJECTIVES: We aimed to explore symptoms of insomnia in a group of youths characterized as engaging in risky drinking, their use of drugs as sleep/ wake aids, and the relationships between alcohol and other drug use and insomnia. METHODS: Face-to-face interviews were conducted with 596 Australian 14 to 19-year-olds identified as engaging in regular risky drinking. They completed the Insomnia Severity Index and were assessed for recent alcohol and other drug use, including drugs used specifically as sleep aids or to stay awake. Alcohol-related problems, emotional distress, self-control, and working outside of traditional hours were also assessed using validated scales. RESULTS: More than one-third of the study participants (36%) reported moderate to very severe sleep-onset insomnia, and 39% screened positive for clinical insomnia using adolescent criteria. Three-fourths used drugs in the past 2 weeks to regulate their sleep cycle (65% used stimulants to stay awake, mainly caffeine, and 32% used a depressant to get to sleep, mainly cannabis). Regression analyses showed that after controlling for variables such as sex, emotional distress, self-control, alcohol use problems, and past 6-month illicit or non-prescribed drug use, those who used drugs specifically to get to sleep or to stay awake were 2.0 (P < .001) and 1.7 (P = .02) times more likely to report clinical insomnia, respectively. CONCLUSIONS: Insomnia was commonly reported in this community sample of adolescents characterized as engaging in risky drinking. Those with symptoms of insomnia appeared to be managing their sleep-related symptoms through alcohol and other drug use, which may have further exacerbated their sleep issues.