The legalization of cannabis is increasing across the United States, for both recreational and medical use. This has resulted in a change in public opinion regarding the risks of cannabis use. This is particularly true for the current generation of older adults, which experiences a greater prevalence of cannabis use than previous members of this cohort. Due to decreased perception of risk and medical or emotional issues associated with old age, older adults increasingly use cannabis to cope with their psychiatric and medical symptoms. Current studies provide evidence of an association between using cannabis for medical symptoms and the development of a Cannabis Use Disorder (CUD). However, there is a lack of literature addressing the association between types of symptoms treated with medical marijuana and developing symptoms of CUD. This study developed a survey using the Cannabis Use Disorder Identification Test (CUDIT) and measures for motives and symptoms of cannabis use. This was done to evaluate the presence of CUD symptoms in older adults (ages 55+) who used cannabis in the past six months while owning a Medical Marijuana License (MML). Data preparation included an examination of outliers, multicollinearity, and data distributions. The primary analysis regressed cannabis use pathology onto psychiatric motives and physical motives. The results of this study suggest that those utilizing cannabis for anxiety symptoms experience more symptoms of a cannabis use disorder. At the same time, there was a negative association between using cannabis order for medical symptoms and developing cannabis use disorder symptoms. Additionally, there was no correlation between the amount of cannabis used and its use for physical symptoms.

Social control theory focuses on why some people do not commit deviant behaviours, such as illicit drug use. It proposes that bonding to conventional society constrains deviant conduct. In the book Causes of Delinquency, Hirschi distinguished four elements of social bonds: attachment, commitment, involvement, and belief. This study draws upon data from the 2012 Canadian Alcohol and Drug Monitor Survey to examine the effect of social control theory, specifically the element of attachment, on controlling cannabis use. This study also uses the element of attachment to interpret gender and rural/non-rural area differences in cannabis use. Two hypotheses are offered: (1) females are less likely to use cannabis than males because females have greater attachment to others; (2) rural residents are less likely to use cannabis than non-rural residents because rural residents have greater attachment to others. The research methods in the study are cross-tabulation analysis and binary logistic regression. The statistical analysis results support both hypotheses: females have a significantly lower rate of cannabis use than males and rural residents have a significantly lower rate of cannabis use than non-rural residents. Having greater attachment to others may be associated with a decreased rate of cannabis use. Policy and further research recommendations are made.

Risky sexual behavior (RSB) is the number one transmission method of HIV among adolescents. Reducing the rates of HIV among adolescents is of dire importance considering the rises in rates during the last several years. Minority adolescents are disproportionately affected by HIV, and a majority of the individuals living in Miami-Dade County (location of the proposed project) are minorities. RSB, externalizing disorders and cannabis use commonly occur together, such that both greater externalizing disorder symptoms and greater amounts of cannabis use have predicted engagement in more RSB. In addition, decision-making (a neurocognitive function) has found to be associated with cannabis use, externalizing disorders, and RSB. Little research has been conducted on these factors among adolescents. No study has evaluated externalizing disorders, cannabis use and decision-making together to determine the unique contribution of each factor to RSB among a sample of adolescents. The current study used the infrastructure and participants of an existing project examining how decision-making abilities and memory performance are impacted by cannabis use during adolescence. Structural equation modeling and multiple linear regression were used to analyze how externalizing disorders, cannabis use, and decision-making predict RSB. Results suggest that externalizing symptoms, cannabis use and some decision-making tasks predict RSB. Several interactions effects emerged between externalizing symptoms and decision-making tasks, cannabis use and decision-making tasks as well as externalizing symptoms and cannabis use to predict RSB. The results of the study will help future prevention and intervention efforts such that interventions can be tailored to address the areas that contribute the most to RSB among adolescents. Furthermore, cognitive skill building is one possible intervention that may be beneficial to adolescents with poorer decision-making performance.

As legalization of cannabis continues to spread across the United States, many question the public health implications. The term “cannabis” is often used to refer to anything that comes from the plant and can be used recreationally (to get high or alter one’s current state) or medically (to treat a medical condition). While previous research has primarily focused on the impact of recreational cannabis use, few studies have examined cognitive outcomes associated with medical cannabis (MC) use and the potential for development of problematic use in MC patients. Given important distinctions among recreational users and MC patients, it is likely that these distinct populations of cannabis consumers will experience differential cognitive effects and potential for problematic cannabis use. This dissertation is comprised of three studies. The first is a cross-sectional study that explores executive function and verbal learning and memory in recreational cannabis users relative to healthy controls who do not use cannabis, while also assessing whether cannabis use patterns (e.g., age of onset, urinary THC levels) influence findings. The second study is an observational, longitudinal study which examines executive function and memory, as well as changes in mood, anxiety, sleep, and quality of life in MC patients over 12 months of MC treatment relative to pre-MC treatment. In the third study, symptoms and behaviors associated with problematic cannabis use are examined in cohorts from study 1 and study 2. Specifically, scores on the Cannabis Use Disorder Identification Test – Revised (CUDIT-R) are assessed in MC patients over the course of treatment and also compared to a previously recruited cohort of recreational cannabis users; the validity of the CUDIT-R is also explored. Despite previous research, in the current study recreational users did not exhibit cognitive decrements relative to healthy controls. In MC patents, cognitive performance was stable over the course of 12 months of MC treatment relative to pre-MC treatment performance, and overall they reported improved ratings of mood, anxiety, sleep, and some aspects of quality of life. Although the CUDIT-R suggests MC patients’ average scores do not meet the threshold for possible cannabis use disorder, analyses revealed this measure is not valid and therefore not appropriate in MC patients. Although changes in cognition were not detected in recreational users or MC patients in the current studies, a number of methodological limitations (e.g., sample size and limited ability to adjust for confounding variables) must be considered as these factors likely affected study results. Future studies evaluating the impact of cannabis use will benefit from carefully considering the definition of cannabis itself, goal of use, product choice, and age of onset of use. Researchers and clinicians will also benefit from the development of screening tools specifically designed to assess cannabis use disorder in those who use cannabis for medical purposes.

Cannabis use is becoming increasingly prevalent in Canada and the United States, where legality and public perception have recently shifted to be more permissive of recreational use. Despite established negative health consequences associated with persistent use, there remains considerable debate in the scientific community surrounding the potentially harmful effects of cannabis use on human cognition. Evidence exists that heavy cannabis use predicts diminished performance within several neurocognitive domains and also predicts greater risk of having ADHD. Further evidence suggests that earlier age of first cannabis use strengthens these associations, however the findings in these literatures are mixed and in need of further delineation. This thesis sought to examine continuous associations among current cannabis use severity, age of first use, neuropsychological performance, and ADHD symptomatology. Two studies using large samples of community adults were conducted. Study 1 analyzed data from the Human Connectome Project, and examined performance on a battery of neuropsychological measures among young adults, and found recent use to be the strongest predictor of differences in episodic memory and processing speed, and CUD predicted lower fluid intelligence. Lifetime exposure to cannabis was not associated with any outcome measures. Study 2 examined similar associations in a sample of adults representative of the Hamilton community, and also included self-reported symptoms of ADHD. Study 2 found current cannabis use severity to be predictive of more impulsive reward preferences, and also of both hyperactive-impulsive and inattentive symptoms of ADHD. Both studies found a lack of support for the role of age of first cannabis use in differential cognitive performance, and also failed to find associations between cannabis involvement and several cognitive domains such as working memory, behavioural inhibition, executive function, and psychomotor dexterity. These findings challenge some of the current literature, and highlight the necessity of further investigation to better understand interrelationships among cannabis use, cognition, and ADHD. / Thesis / Master of Science (MSc) / It is unclear to what extent cannabis use effects mental functions such as memory, attention, and intelligence. The goal of this research was to investigate how recent and early-life cannabis use is related to these cognitive functions and real-life problems with attention and impulse control as seen in ADHD. Two studies were performed to investigate these relationships, and together found recent cannabis use rather than lifetime use to be predictive of performance on select cognitive abilities and ADHD symptoms. Age of first cannabis use and lifetime use were not associated with differences in cognition, suggesting that cannabis use in adolescence may not necessarily cause lasting detrimental changes. Rather, people who have symptoms of ADHD may be more likely to use cannabis earlier and in more problematic ways.

Lack of a brief empirically-verified screener for problematic and potentially problematic cannabis use has hampered implementation of a proactive opportunistic cannabis screening and early intervention (SEI) initiative in New Zealand. Addressing this instrumentation need was the primary aim of this thesis. This thesis also investigated the nature, prevalence, severity, and natural history of cannabis-related problems among a heterogeneous sample of 212 ‘at risk’ adolescent and adult users recruited from the community. In a 3-phase developmental design the CUPIT question candidates were first generated employing an Expert Panels methodology. The CUPIT structure, crosssectional, and longitudinal psychometric properties were then systematically tested, incorporating measures of cannabis-related pathology and DSM-IV/ICD-10 diagnoses of cannabis use disorders as criterion standard. High levels of cannabis consumption and related health and psychosocial problems reported portrayed a highly-disordered sample, most marked among adolescents. DSMIV/ICD-10 diagnoses were almost universal with no significant adolescent/adult differences in dependence symptoms count or severity. The two CUPIT subscales (Impaired Control, Problems) derived from principal components analyses exhibited good test-retest and internal consistency reliability and highly significant ability to discriminate diagnostic subgroups along the severity continuum (nonproblematic, risky, problematic use). At the 12-month follow-up, 194 adolescents and adults reported significantly increased cannabis consumption (adolescents), symptoms, and dependence severity. Baseline CUPIT subscale scores demonstrated highly significant longitudinal predictive utility for respondents’ diagnostic group membership, health and psychosocial problems, and significantly improved prediction of other measured outcomes in conjunction with age and gender. ROC analyses identified a CUPIT score of 12 to be the optimal cut-point for maximum sensitivity for both currently diagnosable cannabis use disorder and those ‘at risk’ in this sample. The empirical findings of this thesis research provide a compelling rationale for systematic implementation of opportunistic SEI among consumers of publicly-funded health and social services in New Zealand. Data confirmed that the vast majority of those needing help are unaware, or do not perceive, they need help. This thesis argues that, facilitated by the CUPIT, reliable proactive detection and appropriate intervention for early-stage cannabis use problems has potential for enormous cumulative impact on public health gains and the individual’s quality of life.

Cannabis use is considered a component cause of psychotic disorder interacting with genetic and environmental risk factors in increasing psychosis risk (Henquet et al., 2008). Recently, two cross-sectional and one prospective study provided evidence that cannabis use interacts additively with trauma to increase psychosis risk (Houston et al., 2008, Harley et al., 2010 and Konings et al., 2011). In an attempt at further replication, we examined prospective data from the German Early Developmental Stages of Psychopathology (EDSP) study (Wittchen et al., 1998b and Lieb et al., 2000).

The aim of this study was to explore the students’ use of and attitudes towards cannabis at Linnaeus University. Social psychology and gender perspective was used as theories to explain the use and attitudes among the students’ and how the use and attitudes could change through social influence. The study operates from a quantitative approach and is based on an online survey which includes answers from 126 respondents. The empirical result was coded in the computer program SPSS and has been analyzed through social psychology, gender perspective and against prior studies. The result shows that the majority of the respondents never had used cannabis and that the main reason for that is that the respondents are not interested to use cannabis. Among the respondents who used cannabis the last twelve months we found that the majority came in contact with cannabis through their friends the first time and that they most usually did consume cannabis together with friends. Finally we found that almost nine out of ten respondents experienced that they never got the information about Linnaeus University’s alcohol and drug policy at the introduction to their studies at the university.

Andelen ungdomar som inte uppfattar några större risker med cannabisbruk har ökat de senaste åren. Ungdomarnas uppfattning av riskerna med cannabisbruk påverkar huruvida de kommer att välja att avstå från eller bruka drogen. Syftet med denna uppsats har varit att se vilka risk- och skyddsfaktorer som påverkar ungdomars riskperception avseende cannabisbruk. Frågeställningarna har varit hur föräldrarna, skolan och vännerna påverkar riskperceptionen. Uppsatsen utgår från en subjektiv syn på riskperception som innebär att inte en faktor ensamt kan förklara om ungdomarna har en låg eller hög riskperception. För att analysera resultatet i uppsatsen har risk- och skyddsfaktorer, som har setts minska eller öka sannolikheten för ett cannabisbruk, använts. Det material som ligger till grund för uppsatsens undersökning är Centralförbundet för alkohol och narkotikas drogvaneundersökning från år 2010. Resultatet har tagits fram med hjälp av logistiska regressionsanalyser vilka visar hur starkt olika faktorer relateras till en låg riskperception även när hänsyn tas till andra faktorer. Flera faktorer kopplade till vännerna och föräldrarna har i resultatet visat sig ha ett statistiskt samband med ungdomarnas riskperception avseende cannabisbruk. Samtidigt fanns inget samband mellan skolan och riskperceptionen när föräldrarna och vänner togs med i beaktande. / The proportion of young people who do not perceive any major risks with cannabis use has increased in recent years. Adolescents' perception of the risks affects whether they will choose to use cannabis or not. The purpose of this essay has been to analyze risk and protective factors that influence young people's risk perception regarding cannabis use. The main questions have been how parents, school and friends affect risk perception. The essay is based on a subjective view of risk perception, which means that not a single factor alone can explain why the adolescent has a low or high risk perception. Risk and protective factors that have been observed to decrease or increase the likelihood of cannabis use have been used to analyze the result. The material that has been used in this essay is a survey conducted by the Centralförbundet för alkohol och narkotika year 2010 among Swedish teenagers. The result has been established by using logistic regression analyzes which shows how strongly different factors are related to a low risk perception even when other factors are taken into account. Several factors linked to friends and parents have proved to have a statistically association with adolescents risk perception regarding cannabis use, this while the school doesn’t.

Efforts to objectively inform cannabis discourses include research on the epidemiology of cannabis abuse and dependence disorders or, collectively, cannabis use disorder (CUD). For my dissertation I identified classes of individuals based on intraindividual CUD trajectory patterns and contrasted trajectory classes with respect to clinical characteristics of CUD, developmental risk factors, and psychosocial outcomes. Identifying differences between trajectory classes provides evidence for the validity of trajectory-based CUD constructs and informs the development of comprehensive models of CUD epidemiology and trajectory-specific intervention approaches. My dissertation used data from the Oregon Adolescent Depression Project, a prospective epidemiological study of the psychiatric and psychosocial functioning of a representative community-based sample randomly selected from nine high schools across western Oregon. Four waves of data collection occurred between mid-adolescence and early adulthood and included diagnostic interviews and self-report questionnaires. Onset and offset ages of all CUD episodes were recorded. The reference sample included 816 participants who completed all diagnostic interviews. A series of latent class growth models revealed three distinct CUD trajectory classes through age 30: (1) a persistent increasing risk class; (2) a maturing out class, marked by increasing risk through age 20 and then a decreasing risk through early adulthood; and (3) a stable low risk class. Rates of cannabis dependence were similar across the persistent increasing and the maturing out classes. Trajectory classes characterized by a history of CUD were associated with a variety of childhood risk factors and measures of psychosocial functioning during early adulthood. Participants who were male, had externalizing disorders, and had psychotic experiences during early adulthood discriminated between the persistent increasing and the maturing out classes. Future research based on more diverse samples is indicated, as are well-controlled tests of associations between risk factors, trajectory class membership, and psychosocial outcomes. A better understanding of these relationships will inform etiological theories of CUD and the development of effective intervention programs that target problematic cannabis use at specific developmental stages. Designing targeted versus undifferentiated interventions for those at greatest risk for adult psychosocial impairment could be a cost-effective way to mitigate the consequences of CUD.