Jillian Halladay

• Doctor of Philosophy
• Assistant Prof at McMaster University

Abstract Background: Depression, anxiety, and substance use disorders are leading causes of morbidity worldwide. The most commonly used illicit substance is cannabis and there is some evidence that the association between cannabis use and poor mental health is more pronounced among females compared with males. This analysis examines sex differences...

Background: With the recent legalization of nonmedical cannabis in Canada, it is important to document previous associations between cannabis use and major depressive episode and suicidal ideation, as well as the extent to which these associations have changed over time. Methods: This study uses pooled data from the 2002 and 2012 Canadian Commun...

Purpose: This systematic review summarizes and critically appraises the existing literature on brief interventions (BIs) for cannabis use among emerging adults. Methods: Eligible BIs were operationalized as 1-2 sessions focused exclusively on cannabis use for samples with mean ages between 15 and 30. Outcomes related to cannabis use, other subst...

Purpose This review characterizes empirically derived patterns of multiple (multi-) substance use among adolescents. A secondary objective was to examine the extent to which mental health symptomatology was included in the empirical analyses examining substance use patterns. Methods Eligible studies included those that used cluster-based approache...

Background To determine: (a) the feasibility and acceptability of administering a standardized electronic assessment of substance use and other mental health concerns to youth admitted to an inpatient psychiatric unit, and (b) the prevalence and clinical correlates of substance use in this sample. Methods The sample included 100 youth between the...

When comparing scores on psychological distress scales across people who use substances versus those who do not, it is essential that the psychometric characteristics of the measure across both groups are comparable. The current study investigated the presence of differential item functioning (DIF) in the Kessler 10 psychological distress scale (K1...

Background Adolescence is a critical period for preventing substance use and mental health concerns, often targeted through separate school-based programs. However, co-occurrence is common and is related to worse outcomes. This study explores prevention effects of leading school-based prevention programs on co-occurring alcohol use and psychologica...

Purpose: The co-occurrence of cannabis use and internalizing problems, such as depression and anxiety, during emerging adulthood (18-25 years) is well documented, but the directionality is unclear. This study investigates the bidirectional longitudinal relationships between cannabis use (frequency and consequences) and internalizing problems (depre...

Background The relationship between adolescent alcohol use and emotional problems remains unclear and contradictory. These inconsistencies may in part be due to differences in the measurement and operationalization of alcohol use and emotional problems across studies, as well as confounder selection and missing data decisions. This study explores t...

Background Few studies have examined the inter-relationships between teacher and student mental health. We aimed to examine associations between teacher distress and student mental health difficulties and if student perceptions of school safety moderate these associations. Method Data from 23,568 students in grades 6–12 and 1,478 teachers from 268...

Background Medication Treatment Satisfaction (M-TS) from the patients’ perspective is important for comprehensively evaluating the effect of medicines. The extent to which current patient-reported outcome measures (PROMs) for M-TS are valid, reliable, responsive, and interpretable remains unclear. To assess the measurement properties of existing PR...

Background Mental disorders are the leading cause of disease burden among youth. Effective prevention of mental disorders during adolescence is a critical public health strategy to reduce both individual and societal harms. Schools are an important setting for prevention; however, existing universal school-based mental health interventions have sho...

Importance: A growing number of jurisdictions have legalized recreational cannabis for adults, but most evaluations have used repeated cross-sectional designs, preventing examination of within-person and subgroup trajectories across legalization. Objective: To examine changes in cannabis use and misuse in the five years following legalization in Ca...

This study examines longitudinal behaviour change in six key lifestyle behaviours—sleep, physical activity (PA), sedentary recreational screen time, diet, alcohol use, and tobacco use—and associations with mental health in a large study of Australian adolescents. Change between baseline (Mage = 12.7, N = 6,639) and 3-year follow up (Mage = 15.7, N...

Background In recent years, psychological distress in Western countries has rapidly increased among older adolescents while alcohol use has declined, though little is known about younger adolescents. It is also unclear if and how these trends relate to co‐occurring alcohol use and distress. This study sought to examine temporal changes in the preva...

Across high-income countries, adolescent emotional concerns have been increasing in prevalence over the past two decades and it is unclear why this is occurring, including if and how substance use relates to these changing trends. On the other hand, substance use has been generally declining, and little is known about the role of emotional concerns...

Purpose Characterizing trends and correlates of adolescent psychological distress is important due to observed global increases over the last 20 years. Substance use is a commonly discussed correlate, though we lack an understanding about how co-occurrence of these concerns has been changing over time. Methods Data came from repeated, representati...

High rates of substance misuse during emerging adulthood (~17-25 years of age, also referred to as young adulthood) require developmentally appropriate clinical programs. This article outlines: 1) the development of an evidence-informed young adult outpatient substance use program that takes a biopsychosocial patient-centred approach to care; 2) a...

This study explored age, period, and cohort effects associated with trends in psychological distress and risky alcohol consumption. Data came from 108,536 Australians aged 14-79 years old from birth cohorts between 1925-2005, endorsing past year alcohol use in the 2004-2019 Australian National Drug Strategy Household Surveys. Risky alcohol consumpt...

Mental disorders have significant impact on the health and well-being of young people in Australia and worldwide. Intervention during adolescence is critical for reducing immediate harm and preventing the development of chronic mental disorders. This paper describes the protocol for a randomised controlled trial designed to evaluate the effectivene...

Objective: This work focuses on understanding quality of life and evaluating a brief quality of life measure in an outpatient emerging adult (17–25 years of age) substance use program. Method: Mixed methods were used including: (a) psychometric evaluation of the adapted MyLifeTracker (MLT) based on assessments completed four times throughout treatm...

Though mental health and substance use concerns often co-occur, few studies have characterized patterns of co-occurrence among adolescents in clinical settings. The current investigation identifies and characterizes these patterns among adolescents presenting to an outpatient mental health service in Ontario, Canada. Data come from cross-sectional...

Objective: The objective of this review is to provide an overview of the existing literature on psychosocial interventions aimed at addressing suicidality among adults in the context of an inpatient psychiatric admission. Introduction: For individuals admitted to a psychiatric inpatient unit, their risk of suicide in the period following dischar...

Background High rates of substance misuse during emerging adulthood require developmentally appropriate clinical programs. Objectives This work outlines the development of an evidence-informed emerging adult outpatient substance use program, quality improvement process and protocol, and 1-year program insights. Methods Literature reviews, program...

Objective: The development and evaluation of the Professor Hippo-on-Campus Student Mental Health Education Program, a mental health literacy intervention for post-secondary faculty and staff, is described. It includes 3-hour virtual, asynchronous e-modules and an optional 2-hour, synchronous workshop. Participants: All faculty and staff in a single...

Background While substance use and mental health symptoms commonly co-occur among adolescents, few population-level studies have examined profiles of co-occurrence to inform tailored prevention and early intervention. Methods A multilevel latent profile analysis was conducted on a representative sample of 11,994 students in 68 secondary schools to...

Objective: This study examined joint trends over time in associations between substance use (heavy drinking, cannabis, and cigarette smoking) and mental health concerns (depression, anxiety, and suicidal ideation) among US post-secondary students. Participants: Data came from 323,896 students participating in the Healthy Minds Study from 2009 to 20...

Background: Longitudinal research on COVID-19 impacts on drinking is scarce and largely restricted to comparing drinking levels before and after the introduction of COVID mitigation measures. This brief snapshot of behavior ignores the extended pre-COVID drinking trajectory, which may be decreasing increasing, or remaining stable over time. Behavio...

This paper describes the development and psychometric properties of a teacher version of the Ontario Child Health Study Emotional Behavioural Scales (OCHS-EBS-T) for dimensional measurement of six psychiatric disorders in elementary school-aged children based on DSM-5 criteria. Psychometric evaluation of the item and scale properties was conducted...

Background There are concerns that the coronavirus disease 2019 (COVID‐19) pandemic may increase drinking, but most accounts to date are cross‐sectional studies of self‐attributions about alcohol‐related impacts and the accuracy of those perceptions has not been investigated. The current study examined the correspondence between self‐attributions o...

Background There are significant concerns that the COVID‐19 pandemic may have negative effects on substance use and mental health, but most studies to date are cross‐sectional. In a sample of emerging adults, over a two‐week period during the pandemic, the current study examined: (1) changes in drinking‐related outcomes, depression, anxiety, and po...

Background: Participation in physical activity (PA) is a modifiable factor that contributes to academic success, yet the optimal dose (ie, frequency) and mechanisms underlying the effect require further exploration. Methods: Using data from 19,886 elementary and 11,238 secondary school students across Ontario, Canada, this study examined associa...

Objectives To quantify the strength of association between passive and active forms of screen time and adolescent major depressive episode and anxiety disorders.Methods Data from the 2014 Ontario Child Health Study, a representative sample of 2,320 adolescents aged 12–17 years in Ontario (mean age = 14.58, male = 50.7%) were used. Screen time was m...

Background Heavy episodic drinking (HED) is a major public health problem among emerging adults (individuals 18 to 25), but with considerable heterogeneity in concurrent substance use and psychopathology. The current study used latent profile analysis (LPA) to detect discrete subgroups of HED based on alcohol, other drug severity, and concurrent ps...

This study examined associations between teacher-student relationship quality at school and teachers' responsiveness to students' emotional concerns in a classroom and (a) students' intention to seek help at school for mental health concerns and (b) mental health-related service use. Data for analyses came from the School Mental Health Survey, a cr...

How does cannabis (marijuana) affect the developing brain, learning, and academic performance? Research tells us that the brain continues to develop through the teenage years into the mid-20s, and during this time the brain is especially sensitive to the effects of drugs like cannabis. This article will give an overview of the research on the short...

Psychiatric disorders and substance use disorders commonly co-occur and are major public health concerns given the morbidity and mortality associated with them. Globally, cannabis is among the most commonly used drugs, and cannabis use frequently begins in adolescence or emerging adulthood, both important periods of development and periods in which...

The legalization of recreational cannabis for adults who are 19 or older has prompted greater discussion about this substance in schools and in our communities. This increased discussion may result in more youth, parents/guardians and school staff approaching school mental health professionals (SMH professionals) with questions and disclosures abou...

Background: Heavy episodic drinking (HED) refers to alcohol consumption that exceeds the recommended threshold for a given episode and increases risk for diverse negative alcohol-related consequences. A pattern of weekly HED is most prevalent in emerging adults (i.e., age 18-25). However, rates of HED consistently decline in the mid to late twenti...

Abstract Health systems guidance (HSG) documents contain systematically developed statements or recommendations intended to address a health system challenge. The concept of HSG is fairly new and considerable effort has been undertaken to build tools to support the contextualization of recommendations. One example is the Appraisal of Guidelines for...

High levels of distress in post-secondary students, alongside the real or perceived barriers to accessing services, highlight the need for evidence-based, accessible, and brief interventions for students such as mindfulness-based interventions (MBIs). This systematic review and meta-analysis seeks to determine the effectiveness of MBIs for mental h...

Background: Rates of cannabis use are highest during emerging adulthood (age 18-25), with the prevalence of near daily and daily increasing among this age group. Emerging adults are clinically challenging in terms of harmful cannabis use due to perceptions of high rates of peer use, social acceptance, and low risk of harm. Brief interventions to i...

Background: With the impending legalization of recreational cannabis in Canada, it is important to examine the strength of association between cannabis use and common mental health concerns including depression, anxiety, and suicide and the extent to which these associations have changed over time. It is also important to examine the moderating eff...

Objectives Studies on brief interventions (BIs) for substance misuse among university students indicate their effectiveness for alcohol use, however, programs have rarely addressed cannabis use and comorbid mental health symptoms. This paper describes the development and implementation of a manualized single-session BI called PAUSE, based on motiva...

Background The authors updated a previously published systematic review to assess the effects of low-level laser therapy (LLLT) on reducing complications after the removal of impacted mandibular third molars. Types of Studies Reviewed The authors searched for randomized clinical trials in which the investigators evaluated the efficacy of LLLT comp...