A semi-naturalistic open-label study examining the effect of prescribed medical cannabis use on simulated driving performance.

BACKGROUND: Despite increasing medical cannabis use, research has yet to establish whether and to what extent products containing delta-9-tetrahydrocannabinol (THC) impact driving performance among patients. Stable doses of prescribed cannabinoid products during long-term treatment may alleviate clinical symptoms affecting cognitive and psychomotor performance. AIM: To examine the effects of open-label prescribed medical cannabis use on simulated driving performance among patients. METHODS: In a semi-naturalistic laboratory study, 40 adults (55% male) aged between 23 and 80 years, consumed their own prescribed medical cannabis product. Driving performance outcomes including standard deviation of lateral position (SDLP), the standard deviation of speed (SDS), mean speed and steering variability were evaluated using the Forum8 driving simulator at baseline (pre-dosing), 2.5 h and 5 -h (post-dosing). Perceived driving effort (PDE) was self-reported after each drive. Oral fluid and whole blood samples were collected at multiple timepoints and analysed for THC via liquid chromatography-mass spectrometry. RESULTS: A significant main effect of time was observed for mean speed (p = 0.014) and PDE (p = 0.020), with patients displaying modest stabilisation of vehicle control, increased adherence to speed limits and reductions in PDE post-dosing, relative to baseline. SDLP (p = 0.015) and PDE (p = 0.043) were elevated for those who consumed oil relative to flower-based products. Detectable THC concentrations were observed in oral fluid at 6-h post-dosing (range = 0-24 ng/mL). CONCLUSIONS: This semi-naturalistic study suggests that the consumption of medical cannabis containing THC (1.13-39.18 mg/dose) has a negligible impact on driving performance when used as prescribed.

Recreational Marijuana Legalization and Workplace Injuries Among Younger Workers.

This case-control study uses state-by-year workplace injury data to assess recreational marijuana legalization adoption and workplace injuries among younger workers aged 20 to 34 years.

The Puzzle of Marijuana Use and Forced Vital Capacity.

In study after study, marijuana use has been found to be associated with increased forced vital capacity (FVC). This is puzzling, because marijuana is commonly consumed by inhalation of its smoke, and smoke exposure of any kind is not generally considered a cause of increased FVC. Although this observation was first made decades ago, a satisfactory explanation remains elusive. In this review we survey the evidence supporting the relationship between marijuana use and increased FVC, discuss potential threats to validity when inferring causation, and, presupposing a possible causal relationship, pose two key questions. First, what are possible physiologic or pathophysiologic mechanisms by which marijuana use might increase FVC? Second, why might this effect be consistently observed with marijuana use but not with tobacco use? Explanations for the first question include lung and chest growth and remodeling from strenuous marijuana smoke inhalation and reductions in lung elastic recoil from marijuana smoke exposure. Explanations for the second include differences between marijuana and tobacco in smoke composition and patterns of consumption, such as smoking topography. Finally, the possibility that smoke, whether from marijuana or tobacco, might have nonmonotonic effects on FVC depending on the degree of exposure is explored. In synthesizing a curated breadth of epidemiologic and physiologic science, we leverage a perplexing observation to generate potential insights and avenues for further research into the biological effects of smoke, from marijuana or otherwise, on the respiratory system.

Birth outcomes following in utero co-exposure to tobacco and marijuana.

BACKGROUND: With recent changes in tobacco and marijuana use patterns, it becomes crucial to understand how the prenatal co-use of these substances impacts birth outcomes. The goal of this study was to examine the risk of adverse birth outcomes among infants born to women who used tobacco and marijuana concurrently throughout pregnancy compared to infants of women who used tobacco alone. METHODS: This study involved a retrospective chart review of pregnant women identified via self-report or biochemical testing who used tobacco products alone (N = 71) or tobacco and marijuana simultaneously (N = 127) at any point throughout pregnancy. Differences in birth outcomes between these groups, including APGAR (appearance, pulse, grimace, activity, and respiration) scores, respiratory distress, neonatal intensive care unit admission, intrauterine growth restriction, birth weight, birth length, head circumference, gestational age, and length of hospital stay, were analyzed using linear regression and odds ratio analysis. RESULTS: There were no significant differences in outcomes for infants of women who used tobacco and marijuana compared to infants of women who used tobacco alone during pregnancy. Rates of adverse birth outcomes were high among women who used tobacco compared to what would be expected in unexposed pregnancies. CONCLUSIONS: Tobacco and marijuana co-use during pregnancy was not associated with an additional risk of adverse birth outcomes compared to tobacco use alone. Women should be educated on potential risks of marijuana, and especially, tobacco use during pregnancy. These results will inform clinical recommendations for pregnant women using tobacco and marijuana, aiming to decrease preventable adverse outcomes for patients and infants.

Effects of cannabis smoking on the respiratory system: A state-of-the-art review.

The diminished perception of the health risks associated with the consumption of cannabis (marijuana) lead to a progressive increase in its inhalational use in many countries. Cannabis can be smoked through the use of joints, spliffs and blunts, and it can be vaporised with the use of hookah or e-cigarettes. Delta-9 tetrahydrocannabinol (THC) is the main psychoactive component of cannabis smoke but contains numerous other substances. While the recreational use of cannabis smoking has been legalised in several countries, its health consequences have been underestimated and undervalued. The purpose of this review is to critically review the impact of cannabis smoke on the respiratory system. Cannabis smoke irritates the bronchial tree and is strongly associated with symptoms of chronic bronchitis, with histological signs of airway inflammation and remodelling. Altered fungicidal and antibacterial activity of alveolar macrophages, with greater susceptibility to respiratory infections, is also reported. The association with invasive pulmonary aspergillosis in immunocompromised subjects is particularly concerning. Although cannabis has been shown to produce a rapid bronchodilator effect, its chronic use is associated with poor control of asthma by numerous studies. Cannabis smoking also represents a risk factor for the development of bullous lung disease, spontaneous pneumothorax and hypersensitivity pneumonitis. On the other hand, no association with the development of chronic obstructive pulmonary disease was found. Finally, a growing number of studies report an independent association of cannabis smoking with the development of lung cancer. In conclusion, unequivocal evidence established that cannabis smoking is harmful to the respiratory system. Cannabis smoking has a wide range of negative effects on respiratory symptoms in both healthy subjects and patients with chronic lung disease. Given that the most common and cheapest way of assumption of cannabis is by smoking, healthcare providers should be prepared to provide counselling on cannabis smoking cessation and inform the public and decision-makers.

Impairment of Endothelial Function by Aerosol From Marijuana Leaf Vaporizers.

BACKGROUND: Marijuana leaf vaporizers, which heat plant material and sublimate Δ-9-tetrahydrocannabinol without combustion, are popular alternatives to smoking cannabis that are generally perceived to be less harmful. We have shown that smoke from tobacco and marijuana, as well as aerosol from e-cigarettes and heated tobacco products, impair vascular endothelial function in rats measured as arterial flow-mediated dilation (FMD). METHODS AND RESULTS: We exposed 8 rats per group to aerosol generated by 2 vaporizer systems (Volcano and handheld Yocan) using marijuana with varying Δ-9-tetrahydrocannabinol levels, in a single pulsatile exposure session of 2 s/min over 5 minutes, and measured changes in FMD. To model secondhand exposure, we exposed rats for 1 minute to diluted aerosol approximating release of uninhaled Volcano aerosol into typical residential rooms. Exposure to aerosol from marijuana with and without cannabinoids impaired FMD by ≈50%. FMD was similarly impaired by aerosols from Yocan (237 °C), and from Volcano at both its standard temperature (185 °C) and the minimum sublimation temperature of Δ-9-tetrahydrocannabinol (157 °C), although the low-temperature aerosol condition did not effectively deliver Δ-9-tetrahydrocannabinol to the circulation. Modeled secondhand exposure based on diluted Volcano aerosol also impaired FMD. FMD was not affected in rats exposed to clean air or water vapor passed through the Volcano system. CONCLUSIONS: Acute direct exposure and modeled secondhand exposure to marijuana leaf vaporizer aerosol, regardless of cannabinoid concentration or aerosol generation temperature, impair endothelial function in rats comparably to marijuana smoke. Our findings indicate that use of leaf vaporizers is unlikely to reduce the vascular risk burden of smoking marijuana.

Association of self-reported use of cannabis for the purpose of improving physical, mental, and sleep health with problematic cannabis use risk.

BACKGROUND: Little is known about health-focused cannabis use purposes and their associations with risk for problematic cannabis use. This cross-sectional study examined three broad cannabis use purposes and association with risk for problematic use among young adult cannabis users who report using for > 1 health reasons. METHODS: Young adults completed an electronic survey as part of an ongoing study on substance use and health. Those who self-reported past 6-month use of ≥ 1 cannabis products-smoking, vaping, dabbing, eating, and blunts-were included in the analysis. Their purposes for use were coded into three categories: sleep, mental, and physical health. Problematic cannabis use (PCU) was measured with the three-level structure Cannabis Abuse Screening Test (CAST-3). Adjusted multivariable regression models were used to estimate use purposes associated with with problematic cannabis use at the p < 0.05 level. RESULTS: Participants (n = 954) were mostly female (63.94%) and Hispanic (54.93%). Mental health was the most endorsed reason (73.38%) for use among study sample. Among participants, 36.3% were classified as being at severe risk (CAST-3 score ≥ 8). There was a significant association between PCU risk and reporting cannabis use for physical health (p < 0.01), mental health, and sleep health (p < 0.01) purposes. Those who used cannabis for physical heath purposes had about four times the risk (adjusted relative risk ratio (aRRR) = 4.38, 95% CI = 3.06-6.69), those who used for mental health had about three times the risk (aRRR = 2.81, 95% CI = 1.86-4.72), and those who used for sleep health had almost two times the risk (aRRR = 1.83, 95% CI = 1.17-2.63) for severe PCU. CONCLUSION: All cannabis use purposes examined increased risk of problematic cannabis use. Physical health use purposes was associated with highest PCU risk. This study demonstrates the risk for cannabis use disorder associated with self-medicating with cannabis.

Casual Pot Use Is Harmful to Teens.

Study found similar risks among teens with and without cannabis use disorder.

Perceived risk of harm for different methods of cannabis consumption: A brief report.

BACKGROUND: Emerging adults' (EAs; ages 18-25) perceived risk of cannabis-related harms has decreased in recent decades, potentially contributing to their high prevalence of cannabis consumption. With the changing cannabis policy and product landscape, it is critical to understand perceived risk related to different consumption methods (e.g., smoking, dabbing). We examined differences in cannabis risk perceptions by method and consumption patterns. METHODS: EAs recruited from an emergency department (N=359, 71.3% female, 53.5% Black) completed assessments on individual characteristics, cannabis/other substance use, and perceived risk of cannabis-related harm for four different methods (smoking, vaping, dabbing, ingestion) and two use frequencies (occasional, regular). Analyses examined associations between variables of interest and three mutually exclusive groups: no cannabis use, smoking-only, and multiple/other methods. RESULTS: Forty-two percent of EAs reported no past 3-month cannabis use, 22.8% reported smoking only, and 35.1% reported consumption via multiple/other methods. Among all participants, the methods and frequency with the largest number of EAs endorsing any perceived risk from cannabis were dabbing and vaping cannabis regularly; smoking occasionally had the smallest number of EAs endorsing perceived risk. A greater proportion of EAs in the no use group viewed vaping cannabis regularly as having the most risk (63.6%), whereas the largest proportion of EAs in the smoking-only (64.6%) and multiple/other methods (47.2%) groups perceived dabbing regularly as having the most risk. CONCLUSIONS: This work shows that EAs vary in perceptions of risk across methods of cannabis use and can inform potential directions for public health and policy efforts.

Smoke Alarm.

As states relax their laws on cannabis, neuroscientist Yasmin Hurd is warning about the drug's dangers for the developing brain.

Change in marijuana use from adolescence to young adulthood and its relation to gestational alcohol and marijuana exposure.

INTRODUCTION: Many studies have examined changes in marijuana use across adolescence, but few have examined factors associated with transitions from adolescence to young adulthood. We examined prenatal exposures to alcohol and marijuana and adolescent risk and protective factors that best distinguished among abstinence, continuity, or cessation of marijuana use from 16 to 22 years. METHOD: Data were from the Maternal Health Practices and Child Development Project at the prenatal and 16- and 22-year follow-up phases. The offspring were of lower socioeconomic status with an average of 12.8 years of education at 22 years. Participants' frequency and quantity of marijuana use over the past year were used to determine change in use. A discriminant analysis was applied to distinguish among the identified groups. The risk factors considered included prenatal substance exposures and age 16 demographics, behavior, and home environment. RESULT: Four categories of transitions were defined based on marijuana use from 16 to 22 years: non-users (n = 193), stop/decrease (n = 81), continue at same level/increase (n = 125), and initiation after the 16-year phase (n = 122). The factors that best distinguished among these groups were peers' marijuana use, delinquency, caregivers' financial strain, prenatal exposure to alcohol and marijuana, and race. CONCLUSION: Prenatal alcohol and marijuana exposure were significantly related to transitions of marijuana use from adolescence to young adulthood, controlling for peers' use, behavior problems, and home environment. While gestational marijuana exposure was associated with early initiation/increasing use, alcohol exposure was related to later initiation. The findings emphasize the long-term effects of prenatal exposure to alcohol and marijuana.

Characteristics Associated With Cannabis Use Initiation by Late Childhood and Early Adolescence in the Adolescent Brain Cognitive Development (ABCD) Study.

This cohort study evaluates characteristics associated with early-onset cannabis use.

The association between reasons for first using cannabis, later pattern of use, and risk of first-episode psychosis: the EU-GEI case-control study.

BACKGROUND: While cannabis use is a well-established risk factor for psychosis, little is known about any association between reasons for first using cannabis (RFUC) and later patterns of use and risk of psychosis. METHODS: We used data from 11 sites of the multicentre European Gene-Environment Interaction (EU-GEI) case-control study. 558 first-episode psychosis patients (FEPp) and 567 population controls who had used cannabis and reported their RFUC.We ran logistic regressions to examine whether RFUC were associated with first-episode psychosis (FEP) case-control status. Path analysis then examined the relationship between RFUC, subsequent patterns of cannabis use, and case-control status. RESULTS: Controls (86.1%) and FEPp (75.63%) were most likely to report 'because of friends' as their most common RFUC. However, 20.1% of FEPp compared to 5.8% of controls reported: 'to feel better' as their RFUC (χ2 = 50.97; p < 0.001). RFUC 'to feel better' was associated with being a FEPp (OR 1.74; 95% CI 1.03-2.95) while RFUC 'with friends' was associated with being a control (OR 0.56; 95% CI 0.37-0.83). The path model indicated an association between RFUC 'to feel better' with heavy cannabis use and with FEPp-control status. CONCLUSIONS: Both FEPp and controls usually started using cannabis with their friends, but more patients than controls had begun to use 'to feel better'. People who reported their reason for first using cannabis to 'feel better' were more likely to progress to heavy use and develop a psychotic disorder than those reporting 'because of friends'.

Mechanisms of Injury in Adolescent Trauma Patients With a Positive Marijuana Screen.

BACKGROUND: Marijuana use among adolescents may have increased after its legalization in the United States. An association between violence and marijuana use in adults has been demonstrated in previous reports. We hypothesized that adolescent trauma patients presenting with a positive marijuana screen (pMS) are more likely to have been injured by gunfire or knives and will have more severe injuries overall, compared to patients with a negative marijuana screen (nMS). METHODS: The 2017 Trauma Quality Improvement Program database was queried for adolescent (13-17 years old) pMS patients and compared to adolescents who tested negative for all substance/alcohol. Patients with positive polysubstance/alcohol were excluded. RESULTS: From 8257 adolescent trauma patients, 2060 (24.9%) had a pMS with a higher rate of males in the pMS group (76.3% vs 64.3%, P < .001). The pMS group presented more frequently after gun (20.3% vs 7.9%, P < .001) or knife trauma (5.7% vs 3.0%, P < .001) and less frequently after falls (8.9% vs 15.6%, P < .001) and bicycle collisions (3.3% vs 4.8%, P = .002). The rate of serious thoracic injury (AIS ≥3) was higher for pMS patients (16.7% vs 12.0%, P < .001), and more pMS patients required emergent operation (14.9% vs 10.6%, P < .001). DISCUSSION: In our adolescent patient population, one quarter tested positive for marijuana. These patients are more likely to be injured by guns and/or knives suffering serious injuries, and often require immediate operative intervention. A marijuana cessation program for adolescents can help improve outcomes in this high-risk patient group.

Cannabis smoking, tobacco cigarette smoking, and adenomyosis risk.

OBJECTIVE: To investigate cannabis smoking and tobacco cigarette smoking in relation to adenomyosis risk. DESIGN: We used data from a case-control study of adenomyosis conducted among enrollees ages 18-59 years of an integrated health care system in Washington State. The case-control study used 2 control groups given the challenge of selecting noncases when cases are diagnosed by hysterectomy. SUBJECTS: Cases (n = 386) were enrollees with incident, pathology-confirmed adenomyosis diagnosed between April 1, 2001, and March 31, 2006. The 2 control groups comprised hysterectomy controls (n = 233) with pathology-confirmed absence of adenomyosis and population controls (n = 323) with an intact uterus selected randomly from the health care system population and frequency matched to cases on age. EXPOSURE: Detailed data on cannabis and tobacco cigarette smoking history were ascertained through in-person structured interviews, allowing estimation of joint-years of cannabis smoking and pack-years of tobacco cigarette smoking. MAIN OUTCOME MEASURES: Odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between cannabis smoking, tobacco cigarette smoking, and adenomyosis were estimated using multivariable unconditional logistic regression. Analyses were adjusted for age, reference year, menarche age, education, and pack-years of cigarette smoking (or joint-years of cannabis smoking). RESULTS: No association was observed between cannabis smoking history and adenomyosis risk. However, we did observe the suggestion of an association between ever tobacco cigarette smoking and adenomyosis risk, comparing cases to hysterectomy controls (OR, 1.3; 95% CI, 0.9-1.9) and population controls (OR, 1.2; 95% CI, 0.8-1.8). Our data suggested a 50% increased odds of adenomyosis with >15 pack-years of smoking (vs. never smoking), comparing cases to hysterectomy controls (OR, 1.5; 95% CI, 0.9-2.6; Ptrend=.135). The suggestion of a 40% increased adenomyosis odds was observed with smoking >5-15 pack-years (vs. never smoking), comparing cases to population controls (OR, 1.4; 95% CI, 0.8-2.4; Ptrend=0.136). CONCLUSION: In the first study of cannabis smoking and adenomyosis risk, no association was observed. However, our data suggested an increased odds of adenomyosis with history of tobacco cigarette smoking. Further research is warranted to replicate our results given the substantial morbidity with adenomyosis and frequency of cigarette smoking and recreational and medical cannabis use.