Several avenues of investigation through which the 'labyrinths' of schizopsychotic diagnosis may be examined, are offered by the consideration of the 'beacons' of symptom-profiles and biomarkers. Neurodevelopmental issues and risk assessment, neurocognitive factors of predictive necessity, supersensitivity in neurotransmitter systems, the implications of prodromal expressions of the disorder, functional dysconnectivity arising from prefrontal to diverse regional patterns and circuits with a neurodevelopmental origin, and heritable gene characteristics are viewed against the backdrop of the schizophrenia spectrum disorders. The associations between adolescent-adult use of cannabis, on the one hand, and, alternatively, the prevalence of chromosomal abnormalities, e.g., GRIK4 and NPAS3, and mental retardation, on the other hand, with the symptom-profiles of schizopsychosis provide further evidence of emerging biomarkers of biological inheritance factors. The involvement of dopamine D1 and D2 receptors, particularly in prefrontal region, with regard to functional integrity of cognitive systems is reviewed. It would appear that considerations of these disorders imply that one essential hub around which much of the neuropathology revolves may be observed in the various expressions of the cognitive and structural insufficiency.

Internet Gaming Disorder (IGD) is included in the DSM-5 as a condition warranting more clinical research. Problematic gaming may increase when substance use is present (e.g. cigarette smoking, alcohol use; Raiff et al., 2012; Wartberg & Kammerl, 2020). However, little is known about the relation between cannabis use (CU) and IGD. Thus, the current study hypothesized that individuals engaging in increased CU will exhibit higher rates of IGD. Participants (N=114) were recruited from a rural southeastern university (M age=20.27, SD=4.15). Frequency of CU was measured as past month days with use, IGD was measured by the Video Game Dependency Scale (VGDS; Rehbein et al., 2010). Eleven percent of the sample met criteria for probable IGD. The average frequency of past month CU was 7.26 days (SD=10.88). An independent samples t-test compared frequency of past-month CU among individuals with or without probable IGD. Individuals with probable IGD had decreased CU (M =2.25, SD=5.72). Those without probable IGD had increased CU (M=7.70, SD=2.25), t(107)=2.72, p=.012, d= 0.246. Our results are contrary to previous study findings on the co-occurrence of IGD and substance use. Frequent video gaming may act as a protective factor against increased frequency of CU. Future research should expand on this understudied area and further investigate whether IGD is in fact a protective factor or if the relation found here is accounted for by another unmeasurable variable.

Posttraumatic stress disorder (PTSD) and substance use disorder (SUD) frequently co-occur. Comorbid PTSD+SUD confers heightened risk of other mental health concerns, suicidality, mortality, and functional impairment. Current treatments for comorbid PTSD+SUD show inconsistent results, highlighting the need for a more comprehensive understanding of the associations between PTSD and SUD symptoms. The current dissertation aimed to characterize the associations between PTSD and SUD using structural equation modelling among three different samples with differing clinical severity and presentation: (1) concurrent disorders sample with a high prevalence of PTSD; (2) an in-patient sample seeking treatment for PTSD; and (3) a subclinical sample of healthcare workers and public safety personnel. Data were extracted from multiple clinical databases across different studies to evaluate the associations between PTSD symptoms and alcohol/cannabis/substance use-related problems. Furthermore, the role of underlying mechanisms such as dissociation and emotion dysregulation, which are associated with both PTSD and SUD, were analyzed. All analyses used a structural equation modelling framework to represent the complex clinical presentation of comorbid PTSD+SUD analytically. A relatively consistent pattern of results was observed across the three samples. Global PTSD symptoms were significantly associated with cannabis-related problems, alcohol-related problems, and other illicit substance-related problems. Among PTSD symptoms, the reactivity symptom cluster (characterized by symptoms of hypervigilance, irritability, reckless behaviour, problems with concentration and sleep disturbances) was significantly associated with alcohol/cannabis/substance-related v problems across among the three samples. Furthermore, underlying mechanisms such as dissociation and emotion dysregulation significantly mediated the relations between PTSD symptoms and alcohol/cannabis/substance-related problems. Overall, the current results contribute to the limited literature examining the associations between PTSD and SUD symptoms. Lastly, the current results have important clinical implications for identifying efficacious treatment targets for comorbid PTSD+SUD. / Dissertation / Doctor of Philosophy (PhD) / Psychological distress following a traumatic event, known as traumatic stress, is often associated with problematic alcohol and/or substance use. The co-occurrence of these two confers a heightened risk of other mental health problems. As such, studying how these phenomena are associated with one another and what about each thing is more important to the association is important to understand. The purpose was to examine the connection between these phenomena among three different groups of people: two treatment-seeking groups and non-treatment seeking group one group. Traumatic stress was associated with problematic substance use in all three groups. In addition, other factors like mentally escaping from your body and having difficulties with regulating your emotions explained how traumatic stress and problematic substance use were connected to each other. These findings can help clinicians hone their treatment programs to better help individuals struggling with traumatic stress and problematic substance use.

Introduction: The homeostatic role of the endocannabinoid system (ECS) is mediated through the actions of endocannabinoids. Intake of exogenous cannabinoids found in Cannabis sativa alter the function of the ECS which may then impact other organ systems. Use of cannabis has been inconsistently linked to adverse cardiometabolic outcomes. Rates of cannabis use are high among patients with psychiatric conditions who are already at higher risk of cardiometabolic diseases when compared to the general population. Cannabis use patterns and cardiometabolic risk variables in this population need further study to clarify the links between use and outcomes. Methods: Patients with psychiatric conditions from the St. Joseph’s Healthcare Hamilton Hospital were enrolled into the Cannabis and Physical Health study. Sociodemographic data, medical history, cigarette use, and cannabis use patterns were collected. In addition, cardiometabolic profile data were collected including body mass index, blood pressure, lipids, and HbA1c. Multivariable regression analyses were conducted, and a Bonferroni correction applied. Results: This cross-sectional study enrolled 200 patients (female: n=86, 43.0%), 18 years of age and older. Among 79 cannabis users (female: n=34, 43.0%), the majority (n=53, 67.1%) consumed cannabis daily and had a diagnosis of a moderate cannabis use disorder (CUD; n=57, 72.2%, CUD score = 4.3 ± 3.4). Use of cannabis was initiated on average at 15.2 ± 3.5 years of age and used for an average of 13.5 ± 11.0 years. There was no association between cannabis use and cardiometabolic risk factors when adjusted for age, sex, psychiatric diagnosis, antipsychotic medication use, and cigarette smoking (P>0.006 for all outcomes). Conclusions: Our findings indicate that in this sample of patients with psychiatric diagnoses, patients who use cannabis had a similar cardiometabolic profile to non-users. Patterns of cannabis use highlight the importance of reducing cannabis consumption and preventing or slowing the progression of CUD in this population, as well as limiting adolescent exposure to cannabis. / Thesis / Master of Science (MSc) / The endocannabinoid system regulates several processes in the body via endocannabinoid signaling, and cannabinoids found in cannabis can change endocannabinoid system function. Cardiovascular events and changes in appetite have been noted with cannabis use, and this is especially important in some vulnerable populations at risk of increased cannabis use; one of these groups include patients with psychiatric conditions who tend to use cannabis but also already have an increased cardiometabolic risk. In this thesis, the relationship between cannabis use and cardiometabolic risk was examined in 200 patients, and patterns and determinants of cannabis use explored. Our results demonstrated that of the 79 cannabis users, most consumed cannabis daily, and had a moderate cannabis use disorder. On average, users began cannabis consumption at 15 years of age and for an average duration of 14 years. Moderate cannabis use was not related to cardiometabolic risk in these patients. Our data demonstrate the need to prevent or slow the progression of cannabis use disorder in these patients and the importance of reducing early exposure of adolescents to cannabis.

Background: Risk perception has been studied concerning the use of marijuana and it impacts the intention to use that specific substance. Aim: The aim was to study the association between the perceived risk of cannabis use and cannabis use among Swedish youth after controlling for gender, age, and education. The aim was also to study whether the association between the perceived risk of cannabis use and cannabis use was different according to gender. Method: The thesis project was based on data from the Flash Eurobarometer 330 - Youth Attitudes on Drugs. Results: When age and education were controlled for, both among Swedish youth and among male participants, the perceived risk had an association with cannabis use - higher risk perception entailed a lower use. Discussion: The association between the perceived risk of cannabis use and cannabis use appears to be due to the impact of risk perception on behaviour. Conclusion: By preserving the risk perception that Swedish youth have of cannabis, it may be possible to protect them from the potential harm that cannabis use cause.

Cannabis är den vanligaste illegala drogen bland unga vuxna i Sverige. Det är en omdebatterad drog, debatterna handlar ofta om huruvida cannabis effekter är negativa eller inte. Detta examensarbete undersöker om det finns skillnader i problemnivå inom olika livsområden beroende på grad av cannabisbruk. Examensarbetet är en kvantitativstudie som genom ett antal statistiska analyser jämför tre grupper av unga vuxna samt predicerar sannolikheten för vilka som löper störst risk att vara regelbundna cannabisanvändare. Resultatet tyder på att problemnivån ökar inom flera livsområden beroende på grad av cannabisbruk. Högre involvering i cannabisbruk är förknippat med högre problemnivå i psykisk hälsa, narkotikabruk, narkotikabrott samt hereditet för narkotika. Vidare visar resultatet att faktorer som att vara man, bo i storstad och hereditet för narkotika är riskfaktorer som kan predicera ett regelbundet cannabisbruk. Examensarbetets slutsatser ger stöd för att ökad cannabisinvolvering tycks medverka till missbruk av andra illegala droger och tycks ha negativ påverkanseffekt på psykisk hälsa samt att benägenhet till brottslighet snarare har att göra med selektion än med involvering i cannabisbruk. / Cannabis is the most commonly used illicit drug among young adults in Sweden. It is a controversial drug, the debates about cannabis are often about whether cannabis effects are negative or not. This thesis examines whether there are differences in the level of problems in different areas of life depending on the extent of cannabis use. The thesis is a quantitative study by a number of statistical analyzes comparing three groups of young adults, and predicts the probability of which ones are most likely to be regular cannabis users. The results suggest that in many areas of life the problem level is increasing, depending on the extent of cannabis use. Higher involvement in cannabis use is associated with problems of higher levels in mental health, drug use, drug and family history of narcotics. Furthermore, the results show that factors such as being male, living in a big city and family history of illicit drugs are risk factors that can predict a regular cannabis use. The findings of the thesis provide support for that increased cannabis involvement seems to contribute to the abuse of other illicit drugs and seem to have a negative impact on mental health, and at last that the tendency to commit crime has rather to do with personality factors than cannabis use.

Background. Various studies show that cannabis use alters attention and cognitive functioning in healthy humans and may contribute to development of schizophrenia or worsening of pre-existing psychosis. However, the impact of cannabis use on brain function in humans is not well understood. Schizophrenia is associated with a deficit in prepulse inhibition (PPI), the normal inhibition of the startle reflex by a non-startling stimulus (prepulse), presented before the startle stimulus at short time intervals (lead-time intervals). Such PPI deficit is thought to reflect a sensorimotor gating dysfunction in schizophrenia. PPI is also modulated by attention and PPI reduction in schizophrenia is observed when patients are asked to attend to, not ignore, the stimuli producing PPI. The aim of the current study was to investigate the association between self-reported chronic cannabis use and attentional modulation of PPI in healthy controls and in patients with schizophrenia. Furthermore, the association between cannabis use and other startle reflex modulators, including prepulse facilitation (PPF) of the startle reflex magnitude at long lead-time intervals, prepulse facilitation of the startle reflex onset latency and habituation of the startle reflex magnitude, were examined. Method. Auditory-evoked electromyographic signals were recorded from orbicularis oculi muscles in chronic cannabis users (29 healthy controls and 5 schizophrenia patients) and non-users (22 controls and 14 patients). The data for 36 participants (12 non-user controls, 16 healthy cannabis users, and eight non-user patients) were used in the final analyses and the patient data were used as a pilot study, because relatively few participants met the rigorous exclusionary criteria. Participants were instructed to attend to or to ignore either the startle stimuli alone (70 100 dB) or prepulse (70 dB) and startle stimuli (100 dB) separated by short lead-time intervals (20 200 ms) and long lead-time intervals (1600 ms). In order to ignore the auditory stimuli the participants played a visually guided hand-held computer game. A pilot study showed that the response component of playing the game had no effects on attentional modulation of the startle reflex magnitude and onset latency. Results. Relative to controls, cannabis use in healthy humans was associated with a reduction in PPI similar to that observed in schizophrenia while attending to stimuli, and with an attention-dependent dysfunction in the startle reflex magnitude habituation. While ignoring the stimuli there were no statistical differences in PPI between cannabis users and controls, although PPI in cannabis users tended to differ from that of the patients. The reduction in PPI in cannabis users was correlated with the increased duration of cannabis use, in years, but not with the concentration of cannabinoid metabolites in urine or with the recency of cannabis use in the preceding 24 hours. Furthermore, cannabis use was not associated with any differences in PPF, onset latency facilitation, and startle reflex magnitude in the absence of prepulses. The accuracy of self-reports of substance use was also investigated in this study and was found to be excellent. In addition, the study examined the validity of the substance use module of the diagnostic interview, CIDI-Auto 2.1, which was found to be acceptable for cannabis misuse diagnoses (abuse and/or dependence). Finally, cannabis dependence was found to be associated with more diagnoses of mental illness other than schizophrenia (mainly depression). Conclusions. The results of the current study suggest that chronic cannabis use is associated with schizophrenia-like deficit in PPI in otherwise healthy humans. This PPI reduction is associated with attentional impairment rather than a global sensorimotor gating deficit in healthy cannabis users.

Background: Substance use can have lifelong consequences for adolescents and the rates of substance use in Canadian adolescents are increasing. This is a serious public health issue which needs to be addressed. The purpose of this study is to determine the impact of public health unit (PHU) engagement in school-based substance use prevention programs on student substance use. Methods: Data was collected from the Cannabis, Obesity, Mental health, Physical activity, Alcohol use, Smoking and Sedentary behaviour (COMPASS) study over the 2018/19 data collection year. A multi-level logistic regression was used to analyze the associations between PHU engagement and student substance use. Results: The analyses found that 70% of schools had PHU engagement in substance use prevention programs. Overall, PHU engagement made no difference on student substance use. However, when PHU engagement was divided into five levels of engagement (with zero being no engagement and five being the highest level of engagement) it was found that students from schools where PHUs solved problems jointly (level two) had statistically significantly greater odds of binge drinking, alcohol use and cannabis use. Schools were also divided into low and high-use schools for each substance. It was found that students in low-use schools had statistically significantly greater odds of binge drinking, alcohol and cannabis use with some levels of PHU engagement and students from high-use schools had statistically significantly lower odds of cannabis and cigarette use with some levels of PHU engagement compared to a similar student from a school without PHU engagement. Conclusions: Our findings show that there is opportunity for greater PHU engagement with schools in substance use prevention programming. Furthermore, it is important that PHUs are working with schools to ensure school-based substance use prevention programs are evidence-based and tailored to the specific needs and risk-levels of the students. / Thesis / Master of Science in Nursing (MSN) / The purpose of this study is to determine the impact of public health unit (PHU) engagement in school-based substance use prevention programs on student substance use. Data for this study was collected from the Cannabis, Obesity, Mental health, Physical activity, Alcohol use, Smoking and Sedentary behaviour (COMPASS) study. The results show that 70% of schools had PHU engagement in substance use prevention programs. Across all schools, when PHUs and schools solved problems jointly an increase in student binge drinking, alcohol and cannabis use was found. When schools were divided into low and high-use schools, similar results were found when PHUs engaged with low-use schools whereas when PHUs engaged in high-use schools a reduced odds of student cannabis and cigarette use was found in some situations. These findings highlight the importance for PHUs to consider the specific needs and risk-levels of the students and schools they are engaging with.

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).

[pt] O uso de cannabis é um problema de saúde pública crescente, associado a diversos desfechos negativos. A identificação de fatores de risco é relevante para a prevenção, pois nem sempre tratamentos são eficazes. O abuso sexual infantil é considerado um forte preditor de uso e transtorno por uso de cannabis (TUC). Com a expansão da internet a violência sexual assumiu novos formatos, fazendo surgir um fenômeno contemporâneo denominado vitimização sexual on-line (VSO). Esta dissertação se dedicou ao aprofundamento do tema e realizou uma revisão narrativa com o objetivo de sintetizar o conceito de VSO e seus paralelos com abuso sexual off-line. Além disso, foi investigado exploratoriamentea VSO na infância e adolescência e suas associações com o uso de cannabis e TUC. Análises de regressão investigaram o efeito preditivo de VSO no uso de cannabis ao menos uma vez na vida e na idade do primeiro uso de cannabis. Mais de 70 por cento da amostra relatou ter sofrido VSO na infância e adolescência. Mulheres apresentaram quase o dobro de prevalência que os homens, com médias mais elevadas nas subescalas de insistência e ameaça. Minorias sexuais foram mais prevalentes que heterossexuais em todas as subescalas. A VSO foi capaz de prever significativamente o uso de cannabis pelo menos uma vez na vida e a idade do primeiro uso, mas somente a subescala de disseminação. Os resultados sugerem que VSO na infância e na adolescência é um fenômeno com alta prevalência, que pode estar associada ao uso de cannabis. Crianças e adolescentes merecem atenção especial porque utilizam a internet com maior freqüência, ficando expostos a riscos. Dessa maneira, é necessário pensar estratégias para prevenção de ocorrência de VSO e seusefeitos adversos. / [en] Cannabis use is a growing public health problem, associated with a variety of negative outcomes. The identification of risk factors is relevant for prevention, as treatments are not always effective. Child sexual abuse is considered a strong predictor of cannabis use and cannabis use disorder (CUD). With the expansion of the internet, sexual violence took on new formats, giving rise to a contemporary phenomenon called online sexual victimization (OSV). This dissertation was dedicated to deepening the theme and carried out a narrative review with the objective of synthesizing the concept of OSV and its parallels with offline sexual abuse. In addition, we exploratory investigated OSV in childhood and adolescence and its associations with cannabis use and CUD. Regression analyzes investigated the predictive effect of OSV on lifetime cannabis use and age of first cannabis use. More than 70 percent ofthe sample reported having suffered OSV in childhood and adolescence. Women had almost twice the prevalence of men, with higher means in the insistence and threat subescales. Sexual minorities were more prevalent than heterosexualin allsubscales. The OSV was able to significantly predict lifetime cannabis use and age atfirst use, but only the spread subscale. The results suggest that OSV in childhood and adolescence is a highly prevalent phenomenon that maybe associated with cannabis use. Children and teenagers deserv especial attention because they use the internet more frequently and are exposed to risks. Thus, it is necessary to think about strategies to prevent the occurence of OSV and its adverse effects.