Differences in those who prefer smoking cannabis to other consumption forms for mental health: what can be learned to promote safer methods of consumption?

Smoking cannabis in medical users is associated with exposure to harmful toxins. It is important to characterize cannabis-use profiles and risk-factors for medical cannabis users who smoke cannabis. 100 members of a medical cannabis dispensary with mental health concerns were interviewed in detail about their cannabis use. Forty seven percent of participants preferred smoking only, 18% preferred vaporizing, 25% preferred both smoking and vaping, and 10% preferred oral ingestion methods. Smokers differed from other users in multiple ways, including a greater preference for THC-dominant chemovars, and more frequent and greater amount of cannabis consumption. Smoking was also associated with greater rates of alcohol use disorder. These results may inform harm-reduction approaches to decrease the number of individuals smoking cannabis and use less harmful methods of medical cannabis ingestion.

Factors Associated with Problematic Cannabis Use in a Sample of Medical Cannabis Dispensary Users.

Background: With the recent legalization of cannabis for medical purposes in many countries, there has been an increased number of individuals using such products. While there is considerable evidence indicating that cannabis may have therapeutic effects for a range of different conditions, concerns remain about the risk of developing cannabis use disorders for those at risk, or patients without appropriate clinical guidance. The aim of the present study was to determine the prevalence of problematic cannabis use in a cohort of cannabis users who consumed the drug for medical purposes and to identify potential risk factors. Methods: One hundred individuals who self-identified as using cannabis to improve their mental health were recruited from a community dispensary. Extensive details were collected about subjects' patterns of cannabis use and reasons for use. All subjects completed a structured clinical interview with the Mini-International Neuropsychiatric Interview, while information about perceived stress, depressive symptoms, and somatic symptoms were recorded with the Perceived Stress Scale-10, Beck Depression Inventory, and the Patient Health Questionnaire-15. Results: Rates of problematic cannabis use were high, with 30% meeting the criteria. Only 10% of subjects reported medical cannabis use was recommended by their doctor. Significant risk factors for problematic use included earlier age of cannabis initiation, as well as self-reported use of cannabis products for depression. Conclusions: The prevalence of problematic cannabis use in the community dispensary was higher than expected. Specific risk factors for problematic cannabis use may represent important areas for future intervention to ensure safer consumption for medical purposes.

Differential effects of cannabis exposure during early versus later adolescence on the expression of psychosis in homeless and precariously housed adults.

Longitudinal studies of cannabis exposure during early adolescence in the general population frequently report an increased risk of subsequently developing psychotic symptoms or a psychotic illness. However, there is a dearth of knowledge about the effects of early cannabis exposure on psychosis in homeless and precariously housed adults, who represent a population afflicted with high rates of psychosis. The aim of the present study was to examine how early cannabis exposure (by age 15) compared to later first use (after age 15) affected the expression of adult psychosis in this population. Secondary measures of psychopathology, drug use, cognition and brain structure were also collected. 437 subjects were recruited from single room occupancy hotels in the urban setting of the Downtown Eastside of Vancouver, Canada. Psychiatric diagnoses were determined, and psychotic symptom severity was measured with the 5-factor PANSS. Participants completed a battery of neurocognitive tests, and brain structure was assessed using structural and diffusion tensor imaging MRI scans. Results indicated that early cannabis exposure was associated with an increased risk (OR = 1.09, p < .05) of developing substance induced psychosis, whereas later first use increased risk (OR = 2.19, p < .01) of developing schizophrenia or schizoaffective disorder. There was no group difference in neurocognitive function, although differences were observed in the lateral orbitofrontal cortex and white matter tract diffusivity. These findings indicate that early cannabis exposure in this population may increase the risk of developing drug associated psychoses, which could potentially be mediated in part through altered neurodevelopmental brain changes.

Characterization of mental health in cannabis dispensary users, using structured clinical interviews and standardized assessment instruments.

BACKGROUND: Cannabis is commonly used for its medical properties. In particular, cannabis is purported to have beneficial effects on a wide range of neuropsychiatric conditions. Studies assessing mental health in cannabis dispensary users typically evaluate symptoms using self-report check lists, which provide limited information about symptom severity, and whether subjects meet criteria for a psychiatric diagnosis. There is, therefore, a need for studies which assess mental health in dispensary users with standardized and well validated scientific instruments, such as those used in clinical drug trials. METHODS: One hundred medical cannabis users were recruited from a community dispensary. All subjects completed a structured clinical interview with the Mini-International Neuropsychiatric Interview (MINI). Subjects also completed the Perceived Stress Scale-10, PROMIS Fatigue Scale, PROMIS Sleep Disturbance Scale, Beck Depression Inventory, the Patient Health Questionnaire-15 and the Brief Pain Inventory. Details about cannabis use were also recorded. RESULTS: Lifetime prevalence of mental illness in this cohort was high, and a large proportion of subjects endorsed psychological symptoms. The proportion of subjects who met criteria for classification of a current psychiatric disorder was low for mood disorders, but high for anxiety disorders and substance abuse/dependence. Cannabis use differed between the main psychiatric conditions. CONCLUSIONS: The present results indicate that rates of mental illness may be high in medical cannabis dispensary users. Use of structured clinical assessments combined with standardized symptom severity questionnaires provide a feasible way to provide a more rigorous and detailed evaluation of conditions and symptoms in this population.