Recent Research

Predictors of Substance Use Among Young Adults Transitioning Away from High School

Young adulthood has been shown to be a time of increased substance use. Yet, not enough is known about which factors contribute to initiation and progression of substance use among young adults specifically during the transition year away from high school. Objectives: A narrative review was undertaken to increase understanding of the predictors of changes in use of tobacco, alcohol, cannabis, other illicit drugs, and mental health problems among young adults during the transition period after high school. Methods: A review of academic literature examining predictors of the use of tobacco, alcohol and cannabis, and co-morbidities (e.g., co-occurring substance use and/or mental health issues) among young adults transitioning from high school to post-secondary education or the workforce. Results: Twenty six studies were included in the review. The majority of the studies (19) examined substance use during the transition from high school to post-secondary settings. Seven studies examined substance use in post-secondary settings. The studies consistently found that substance use increases among young adults as they transition away from high school. During the transition away from high school, common predictors of substance use include substance use in high school, and peer influence. Common predictors of substance use in post-secondary education include previous substance use, peer influence, psychological factors and mental health issues. Conclusions/Importance: Further research on social contextual influences on substance use, mental health issues, gender differences and availability of substances during the transition period is needed to inform the development of new preventive interventions for this age group.

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The prevalence of tobacco use comorbidities in Canada

OBJECTIVES: Tobacco use co-morbidities, including co-occurring tobacco use, substance use and mental health problems, are a serious public health issue that has implications for treatment and policy. However, not enough is known about the prevalence of various types of tobacco use co-morbidities among the Canadian population. The purpose of this study was to increase understanding of the extent of this issue through an examination of prevalence and correlates of tobacco use co-morbidities in Canada.

METHODS: We undertook a series of comprehensive secondary analyses of population survey data from the Canadian Community Health Survey (CCHS) and the Canadian Alcohol and Drug Monitoring Survey (CADUMS). Data were analyzed for 123,846 individuals from the CCHS and 13,581 individuals from the CADUMS. Substance use and mental health variables were compared by smoking status, with chi-square tests. Multivariate logistic regression models were fit to quantify the association between smoking, substance use and mental health issues, adjusting for age, sex, and family income.

RESULTS: Prevalence of problematic alcohol and illicit drug use was significantly higher among current smokers than non-smokers. Co-morbid mental health problems were also elevated among current smokers, and co-morbidities varied by age and gender. While smokers of all ages and genders were more likely to report problematic substance use and poor mental health, the effect of smoking status was significantly larger among youth.

CONCLUSION: Smoking in Canada is associated with problematic use of alcohol and illicit drugs, as well as co-morbid mental health problems. Youth tobacco use co-morbidities are at a concerning level, especially among young female smokers. More research on this issue in the Canadian context is needed, as well as the development of integrated interventions tailored to treat smokers with co-morbidities, particularly youth.

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Kirst, M., Chaiton, M., Mecredy, G. The prevalence of tobacco use comorbidities in Canada. Canadian Journal of Public Health. 2013. 104(3):e210-e215.

The Co‐Use of Tobacco and Cannabis Among Adolescents Over a 30‐Year Period


This study explores the patterns of use and co-use of tobacco and cannabis among Ontario adolescents over 3 decades and if characteristics of co-users and single substance users have changed.


Co-use trends for 1981-2011 were analyzed using the Centre for Addiction and Mental Health Ontario Student Drug Use and Health Survey, which includes 38,331 students in grades 7, 9, and 11. A co-user was defined as someone reporting daily tobacco and/or cannabis use in the past month. Trends over time (by gender and academic performance) were analyzed with logistic regression.


The prevalence of tobacco-only use, cannabis-only use, and co-use fluctuated considerably. During 1981-1993, there were more tobacco-only users than co-users and cannabis-only users; since 1993 the prevalence of tobacco use has decreased dramatically. Co-use prevalence peaked at 12% (95% confidence interval: 9, 15) in 1999, when prevalence of overall use of both substances was highest. In 2011, 92% of tobacco users also used cannabis, up from 16% in 1991.


In 2011 nearly all students who smoke tobacco daily also use cannabis. Non-regular use of either substance is highest now compared with the past 3 decades. Contemporary tobacco and cannabis co-users are significantly different than past users. Youth prevention programs should understand the changing context of cannabis and tobacco among youth.

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Citation: Webster, L. Chaiton, M. Kirst., M. The co-use of tobacco and cannabis among adolescents over a thirty year period. Journal of School Health. 2014 Mar;84(3):151-9

Suicidal Thoughts and Attempts Among Street-involved Youth

There is a considerably higher suicide rate among homeless or street-involved youth compared to the general youth population. New research by Frederick et al. (2012) looks at this discrepancy by examining variables associated with both suicidal thoughts and attempts among 150 homeless or street-involved youth in Toronto, Canada. Their results underscore the negative impacts of depression, self-harm, bullying, and on-street discrimination in relation to suicidal ideation and attempts.

Tyler J Frederick; Maritt Kirst; Patricia G Erickson (2012). Suicide attempts and suicidal ideation among street-involved youth in Toronto. Advances in Mental Health: Vol. 11, Substance Use and Mental Health, pp. 8-17. doi: 10.5172/jamh.2012.11.1.8 (abstract)

Concurrent Smoking and Drinking Among College Students

Cigarette smoking and drinking commonly co-occur in college students, yet few studies have examined the factors that influence concurrent use in this population. A recent study by Witkiewitz et al. (2012) used a 21-day electronic diary of US college students to examine event-level associations between smoking and drinking in the students’ natural environment. They found that students drank more while smoking and smoked three times as many cigarettes during drinking episodes. Further, being with others at a party or bar, as well as increased stress, were associated with increased odds of smoking while drinking. Social settings and stress are key factors to consider for future prevention and intervention efforts in this population.

Witkiewitz K, Desai SA, Steckler G, Jackson KM, Bowen S, Leigh BC, et al. Concurrent drinking and smoking among college students: An event-level analysis. Psychol Addict Behav 2012, 26(3):649-54 (abstract)

Drinking and Smoking at a Young Age Lead to Cannabis Use in Early Adulthood

A recently published study by Behrendt et al. (2012) examined the association between age at first alcohol and tobacco use, and cannabis use in early adulthood. They found that those individuals who began drinking alcohol at a younger age were more likely to smoke cannabis in early adulthood. Further, individuals who began smoking tobacco at a younger age were more likely to begin smoking cannabis at a young age as well. These findings suggest that the early onset of both alcohol and tobacco use have direct implications for cannabis use later in life.

Behrendt S, Beesdo-Baum K, Hofler M, Perkonigg A, Buhringer G, Lieb R et al. The relevance of age at first alcohol and nicotine use for initiation of cannabis use and progression to cannabis use disorders. Drug and Alcohol Dependence 2012, 123(1-3):48-56 (abstract)

Neighbourhood Cohesion Associated with Levels of Alcohol, Cannabis and Tobacco Use

A recent study by Lin et al. (2012) looked at how one’s neighbourhood can have an effect on substance use. Specifically, they explored the association between perceived neighbourhood cohesion and alcohol, cannabis, and tobacco use. They found that individuals who perceived their neighbourhood as more cohesive had higher annual frequency of alcohol consumption, but lower consumption on a typical drinking occasion. Higher perceived cohesion was also associated with a decrease in the probability of tobacco and cannabis use and of the amounts consumed. Further, area-level census aggregated neighbourhood cohesion exerted an additional effect on the frequency of tobacco and cannabis consumption over-and-above individual perceptions of cohesion.

Lin EY, Witten K, Casswell S, You RQ. Neighbourhood matters: Perceptions of neighbourhood cohesiveness and associations with alcohol, cannabis and tobacco. Drug and Alcohol Review 2012, 31(4):402-412 (abstract)

Smokers Who Quit are Less Likely to Suffer from Major Depression

In a recent study by Khaled et al (2012), the authors explored the association between smoking and major depression. They examined 12-year risk of major depression among persistent heavy smokers, as compared to former heavy smokers, using data from the National Population Health Survey (NPHS) in Canada. The authors found that current heavy smokers were over three times more likely than former heavy smokers to experience an episode of major depression, even after accounting for differences in age, sex, and stress. Further, former heavy smokers became increasingly less likely to suffer from major depression the longer they were abstinent from smoking, pointing to the benefits of smoking cessation maintenance.

Khaled SM, Bulloch AG, Williams JV, Hill JC, Lavorato DH, Patten SB. Persistent heavy smoking as risk factor for major depression (MD) incidence – evidence from a longitudinal Canadian cohort of the National Population Health Survey. J Psychiatr Res 2012, 46(4):436-443 (abstract)

Delusional-like Experiences More Common Among Users of Tobacco, Alcohol, and Cannabis

A recent study by Saha et al. (2011) explored the association between delusional-like experiences (DLE) and three commonly used substances – tobacco, alcohol, and cannabis. With respect to tobacco use, compared to nonusers, DLE were more common in those who smoked daily, began smoking before the age of 16, and smoked heavily (>22 cigarettes per day). DLE were also more common among both cannabis and alcohol users, and were most prominent among early onset users. The authors conclude that the influences of these three substances on psychosis-related outcomes warrants closer scrutiny in longitudinal prospective studies.

Saha S, Scott JG, Varghese D, Degenhardt L, Slade T, and McGrath JJ. The association between delusional-like experiences, and tobacco, alcohol or cannabis use: a nationwide population based survey. BMC Psychiatry 2011,11:202 (abstract)

Marijuana Use Prevalent Among Smokers

A recent study by Ramo and Prochaska (2012) examined past-month marijuana use, as well as the co-use of marijuana and tobacco, among young adult smokers in a national US sample. More than half (53%) of their sample reported past month marijuana use, with a median use of 18 out of the past 30 days. Further, co-use of tobacco and marijuana occurred on nearly half (46%) of the days on which either substance was used, and was more frequent among daily versus nondaily smokers. The authors conclude that cessation treatments for young adult smokers should broaden intervention targets to include marijuana.

Ramo DE and Prochaska JJ. Prevalence and co-use of marijuana among young adult cigarette smokers: An anonymous online national survey. Addiction Science & Clinical Practice 2012,7:5 (abstract)