The effect of cannabidiol on simulated car driving performance: A randomised, double-blind, placebo-controlled, crossover, dose-ranging clinical trial protocol

Effects of cannabidiol on psychosocial stress, situational anxiety and nausea in a virtual reality environment: a protocol for a single-centre randomised clinical trial

INTRODUCTION

The non-intoxicating plant-derived cannabinoid, cannabidiol (CBD), has demonstrated therapeutic potential in a number of clinical conditions. Most successful clinical trials have used relatively high (≥300 mg) oral doses of CBD. Relatively few studies have investigated the efficacy of lower (<300 mg) oral doses, typical of those available in over-the-counter CBD products.

METHODS

We present a protocol for a randomised, double-blind, placebo-controlled, parallel-group clinical trial investigating the effects of a low oral dose (150 mg) of CBD on acute psychosocial stress, situational anxiety, motion sickness and cybersickness in healthy individuals. Participants (n=74) will receive 150 mg of CBD or a matched placebo 90 min before completing three virtual reality (VR) challenges (tasks) designed to induce transient stress and motion sickness: (a) a 15 min 'Public Speaking' task; (b) a 5 min 'Walk the Plank' task (above a sheer drop); and (c) a 5 min 'Rollercoaster Ride' task. The primary outcomes will be self-reported stress and nausea measured on 100 mm Visual Analogue Scales. Secondary outcomes will include salivary cortisol concentrations, skin conductance, heart rate and vomiting episodes (if any). Statistical analyses will test the hypothesis that CBD reduces nausea and attenuates subjective, endocrine and physiological responses to stress compared with placebo. This study will indicate whether low-dose oral CBD has positive effects in reducing acute psychosocial stress, situational anxiety, motion sickness and cybersickness.

ETHICS AND DISSEMINATION

The University of Sydney Human Research Ethics Committee has granted approval (2023/307, version 1.6, 16 February 2024). Study findings will be disseminated in a peer-reviewed journal and at academic conferences.

TRIAL REGISTRATION NUMBER

Australian New Zealand Clinical Trials Registry (ACTRN12623000872639).

[Cannabidiol (CBD): Analytical and toxicological aspects]

Cannabidiol (CBD) is a phytocannabinoid present in cannabis, obtained either by extraction from the plant or by synthesis. The latter has the advantage of being pure and contains few impurities, unlike CBD of plant origin. It is used by inhalation, ingestion or skin application. In France, the law stipulates that specialties containing CBD may contain up to 0.3% of tetrahydrocannabinol (THC), the psychoactive principle of cannabis. From an analytical point of view, it is therefore important to be able to quantify the two compounds as well as their metabolites in the various matrices that can be used clinically or forensically, in particular saliva and blood. The transformation of CBD into THC, which has long been suggested, appears to be an analytical artifact under certain conditions. CBD is not without toxicity, whether acute or chronic, as seems to attest to the serious adverse effects recorded by pharmacovigilance during the experiment currently being conducted in France by the Agence Nationale de Sécurité du Médicament et des Produits de Santé. Although CBD does not seem to modify driving abilities, driving a vehicle after consuming CBD containing up to 0.3% THC, and sometimes much more in products bought on the internet, can lead to a positive result in screening and confirmation tests by law enforcement agencies, whether salivary or blood tests, and therefore lead to a legal sanction.

Cognitive Safety Data from a Randomized, Double-Blind, Parallel-Group, Placebo-Controlled Phase IIb Study of the Effects of a Cannabidiol and Δ9-Tetrahydrocannabinol Drug on Parkinson's Disease-Related Motor Symptoms

BACKGROUND

Cannabis is increasingly available worldwide but its impact on cognition in Parkinson's disease (PD) is unknown.

OBJECTIVE

Present cognitive safety data from study of an oral high-dose cannabidiol (CBD; 100 mg) and low-dose Δ9-tetrahydocannabinol (THC; 3.3 mg) drug in PD.

METHODS

Randomized, double-blind, parallel-group, placebo-controlled study of a CBD/THC drug administered for 16.3 (SD: 4.2) days, with dosage escalating to twice per day. Neuropsychological tests were administered at baseline and 1-1½ hours after final dose; scores were analyzed with longitudinal regression models (alpha = 0.05). Cognitive adverse events were collected.

RESULTS

When adjusted for age and education, the CBD/THC group (n = 29) performed worse than the placebo group (n = 29) on Animal Verbal Fluency. Adverse cognitive events were reported at least twice as often by the CBD/THC than the placebo group.

CONCLUSION

Data suggest this CBD/THC drug has a small detrimental effect on cognition following acute/short-term use in PD. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

How long does a single oral dose of cannabidiol persist in plasma? Findings from three clinical trials

A growing number of clinical trials (CTs) are investigating the therapeutic potential of cannabidiol (CBD), a non-intoxicating phytocannabinoid found in Cannabis sativa. These CTs often use crossover experimental designs requiring 'washout' (clearance) periods. However, the length of time CBD persists in plasma (its 'window of detection') is unclear and could be significant. Indeed, the structurally related phytocannabinoid, Δ⁹ -tetrahydrocannabinol (THC), has a long window of detection in plasma. We investigated the extent to which CBD and its major metabolites persist in plasma. Data from three CTs that measured plasma cannabinoid concentrations ≥7 days after administering a single oral dose of CBD were pooled. The CBD doses were as follows: CT #1: 300 mg; CT #2: 200 mg (and 10 mg THC); and CT #3: 15, 300 and 1500 mg (one per treatment session). Thirty-two participants were included in the analysis, 17 of whom (from CT #3) provided repeated measures. Overall, 0% (15 mg), 60% (200 mg), 28% (300 mg) and 100% (1500 mg) of participants had detectable concentrations (i.e., >0.25 ng·ml^-1 ) of CBD in plasma ≥7 days post-treatment (some, several weeks post-treatment). A zero-inflated negative binomial mixed-effects regression analysis (R² _m  = 0.44; R² _c  = 0.73) predicted that, on average, a 13 day washout period would reduce plasma CBD concentrations to 'zero' (i.e., <0.25 ng·ml^-1 ) if a single oral dose of 300 mg was consumed. Higher doses require longer washout periods; concomitant medications may also affect clearance. In conclusion, CBD has a long window of detection in plasma. Crossover studies involving CBD should, therefore, be conducted with caution, particularly when higher doses and/or chronic dosing regimens are used.

Knowledge, experiences, and attitudes of Australian General Practitioners towards medicinal cannabis: a 2021-2022 survey

BACKGROUND

Medicinal cannabis (MC) products have been available on prescription in Australia for around six years. General practitioners (GPs) are at the forefront of MC prescribing and recent years have seen substantial increases in prescription numbers. This study examined the current knowledge, experiences, and attitudes of Australian GPs around MC. We also compared our findings to those of an earlier 2017 investigation.

METHOD

We conducted a cross-sectional study using a 42-item on-line questionnaire adapted from our earlier 2017 survey. The current survey was completed by GPs attending an on-line, multi-topic educational seminar. Australian GPs (n = 505) completed the survey between November 2021 and February 2022. Data were synthesised using descriptive statistics. MC 'prescribers' and 'non-prescribers' responses were compared using Pearson's χ2 tests.

RESULTS

While most GPs (85.3%) had received patient enquiries about MC during the last three months, only half (52.3%) felt comfortable discussing MC with patients. Around one fifth (21.8%) had prescribed a MC product. GPs strongly supported MC prescribing for palliative care, cancer pain, chemotherapy-induced nausea and vomiting, and epilepsy, more so than in our 2017 survey. Prescribing for mental health conditions (e.g., depression, anxiety) and insomnia received less support. Opioids, benzodiazepines, and chemotherapy drugs were rated as more hazardous than MC. GPs correctly endorsed concerns around Δ9-tetrahydrocannabinol-related driving impairment and drug-seeking behaviour. However, additional concerns endorsed around cannabidiol causing addiction and driving impairment do not agree with current evidence. Consistent with this, many GPs (66.9%) felt they had inadequate knowledge of MC.

CONCLUSION

Acceptance of MC as a treatment option has increased among Australian GPs since 2017. However, there is a clear need for improved training and education of GPs around cannabis-based medicines to provide increased numbers of skilled prescribers in the community.

Effects of cannabidiol on simulated driving and cognitive performance: A dose-ranging randomised controlled trial

BACKGROUND

Cannabidiol (CBD), a major cannabinoid of Cannabis sativa, is widely consumed in prescription and non-prescription products. While CBD is generally considered 'non-intoxicating', its effects on safety-sensitive tasks are still under scrutiny.

AIM

We investigated the effects of CBD on driving performance.

METHODS

Healthy adults (n = 17) completed four treatment sessions involving the oral administration of a placebo, or 15, 300 or 1500 mg CBD in a randomised, double-blind, crossover design. Simulated driving performance was assessed between ~45-75 and ~210-240 min post-treatment (Drives 1 and 2) using a two-part scenario with 'standard' and 'car following' (CF) components. The primary outcome was standard deviation of lateral position (SDLP), a well-established measure of vehicular control. Cognitive function, subjective experiences and plasma CBD concentrations were also measured. Non-inferiority analyses tested the hypothesis that CBD would not increase SDLP by more than a margin equivalent to a 0.05% blood alcohol concentration (Cohen's d_z = 0.50).

RESULTS

Non-inferiority was established during the standard component of Drive 1 and CF component of Drive 2 on all CBD treatments and during the standard component of Drive 2 on the 15 and 1500 mg treatments (95% CIs < 0.5). The remaining comparisons to placebo were inconclusive (the 95% CIs included 0 and 0.50). No dose of CBD impaired cognition or induced feelings of intoxication (ps > 0.05). CBD was unexpectedly found to persist in plasma for prolonged periods of time (e.g. >4 weeks at 1500 mg).

CONCLUSION

Acute, oral CBD treatment does not appear to induce feelings of intoxication and is unlikely to impair cognitive function or driving performance (Registration: ACTRN12619001552178).

Driving under the influence of drugs: Correlation between blood psychoactive drug concentrations and cognitive impairment. A narrative review taking into account forensic issues

Driving under the influence of alcohol has been shown to increase the risk of involvement in road traffic collisions (RTCs) however, less is known about the effects of illicit drugs, and a clear correlation between drug concentrations and RTC risk is still debated. The goal of this narrative review is to assess the current literature regarding the most detected psychoactive drugs in RTC (ethanol, amphetamines, cannabis, opioids and cocaine), in relation to driving performance. Evidence on impaired driving due to psychoactive substances, forensic issues relating to the assessment of the impact of drugs, blood cut-off values proposed to date as well as scientific basis for proposed legislative limits are discussed. At present there is no unequivocal evidence demonstrating a clear dose/concentration dependent impairment in many substances. Per se and zero tolerance approaches seem to have negative effect on drugged driving fatalities. However, the weight of these approaches needs further investigation.

Lower-Risk Cannabis Use Guidelines (LRCUG) for reducing health harms from non-medical cannabis use: A comprehensive evidence and recommendations update

BACKGROUND

Cannabis use is common, especially among young people, and is associated with risks for various health harms. Some jurisdictions have recently moved to legalization/regulation pursuing public health goals. Evidence-based 'Lower Risk Cannabis Use Guidelines' (LRCUG) and recommendations were previously developed to reduce modifiable risk factors of cannabis-related adverse health outcomes; related evidence has evolved substantially since. We aimed to review new scientific evidence and to develop comprehensively up-to-date LRCUG, including their recommendations, on this evidence basis.

METHODS

Targeted searches for literature (since 2016) on main risk factors for cannabis-related adverse health outcomes modifiable by the user-individual were conducted. Topical areas were informed by previous LRCUG content and expanded upon current evidence. Searches preferentially focused on systematic reviews, supplemented by key individual studies. The review results were evidence-graded, topically organized and narratively summarized; recommendations were developed through an iterative scientific expert consensus development process.

RESULTS

A substantial body of modifiable risk factors for cannabis use-related health harms were identified with varying evidence quality. Twelve substantive recommendation clusters and three precautionary statements were developed. In general, current evidence suggests that individuals can substantially reduce their risk for adverse health outcomes if they delay the onset of cannabis use until after adolescence, avoid the use of high-potency (THC) cannabis products and high-frequency/-intensity of use, and refrain from smoking-routes for administration. While young people are particularly vulnerable to cannabis-related harms, other sub-groups (e.g., pregnant women, drivers, older adults, those with co-morbidities) are advised to exercise particular caution with use-related risks. Legal/regulated cannabis products should be used where possible.

CONCLUSIONS

Cannabis use can result in adverse health outcomes, mostly among sub-groups with higher-risk use. Reducing the risk factors identified can help to reduce health harms from use. The LRCUG offer one targeted intervention component within a comprehensive public health approach for cannabis use. They require effective audience-tailoring and dissemination, regular updating as new evidence become available, and should be evaluated for their impact.

Mechanisms of cannabis impairment: Implications for modeling driving performance

Past research on cannabis has been limited in scope to THC potencies lower than legally available and efforts to integrate the effects into models of driving performance have not been attempted to date. The purpose of this systematic review is to understand the implications for modeling driving performance and describe future research needs. The risk of motor vehicle crashes increases 2-fold after smoking marijuana. Driving during acute cannabis intoxication impairs concentration, reaction time, along with a variety of other necessary driving-related skills. Changes to legislation in North America and abroad have led to an increase in cannabis' popularity. This has given rise to more potent strains, with higher THC concentrations than ever before. There is also rising usage of novel ingestion methods other than smoking, such as oral cannabis products (e.g., brownies, infused drinks, candies), vaping, and topicals. The PRISMA guidelines were followed to perform a systematic search of the PubMed database for peer-reviewed literature. Search terms were combined with keywords for driving performance: driving, performance, impairment. Grey literature was also reviewed, including congressional reports, committee reports, and roadside surveys. There is a large discrepancy between the types of cannabis products sold and what is researched. Almost all studies that used inhalation as the mode of ingestion with cannabis that is around 6% THC. This pales in comparison to the more potent strains being sold today which can exceed 20%. Which is to say nothing of extracts, which can contain 60% or more THC. Experimental protocol is another gap in research that needs to be filled. Methodologies that involve naturalistic (real world) driving environments, smoked rather than vaporized cannabis, and non-lab certified products introduce uncontrollable variables. When considering the available literature and the implications of modeling the impacts of cannabis on driving performance, two critical areas emerge that require additional research: The first is the role of cannabis potency. Second is the route of administration. Does the lower peak THC level result in smaller impacts on performance? How long does potential impairment last along the longer time-course associated with different pharmacokinetic profiles. It is critical for modeling efforts to understand the answers to these questions, accurately model the effects on driver performance, and by extension understand the risk to the public.

Orally administered cannabidiol does not produce false-positive tests for Δ9 -tetrahydrocannabinol on the Securetec DrugWipe® 5S or Dräger DrugTest® 5000

Many jurisdictions use point‐of‐collection (POC) oral fluid testing devices to identify driving under the influence of cannabis, indexed by the presence of Δ⁹‐tetrahydrocannabinol (THC), an intoxicating cannabinoid, in oral fluid. Although the use of the non‐intoxicating cannabinoid, cannabidiol (CBD), is not prohibited among drivers, it is unclear whether these devices can reliably distinguish between CBD and THC, which have similar chemical structures. This study determined whether orally administered CBD produces false‐positive tests for THC on standard, POC oral fluid testing devices. In a randomised, double‐blind, crossover design, healthy participants (n = 17) completed four treatment sessions involving the administration of either placebo or 15‐, 300‐ or 1500‐mg pure CBD in a high‐fat dietary supplement. Oral fluid was sampled, and the DrugWipe®‐5S (DW‐5S; 10 ng·ml⁻¹ THC cut‐off) and Drug Test® 5000 (DT5000; 10 ng·mL⁻¹ THC cut‐off) devices administered, at baseline (pretreatment) and ~20‐, ~145‐ and ~185‐min posttreatment. Oral fluid cannabinoid concentrations were measured using ultra‐high performance liquid chromatography–tandem mass spectrometry. Median (interquartile range [IQR]) oral fluid CBD concentrations were highest at ~20 min, quantified as 0.4 (6.0), 15.8 (41.6) and 167 (233) ng·ml⁻¹ on the 15‐, 300‐ and 1500‐mg CBD treatments, respectively. THC, cannabinol and cannabigerol were not detected in any samples. A total of 259 DW‐5S and 256 DT5000 tests were successfully completed, and no THC‐positive tests were observed. Orally administered CBD does not appear to produce false‐positive (or true‐positive) tests for THC on the DW‐5S and DT5000. The likelihood of an individual who is using a CBD (only) oral formulation being falsely accused of DUIC therefore appears low.