Brooke Manning

Background and objectives Cannabinoid treatments are commonly used for sleep conditions, but the direct sedating effects of daytime treatment consumption and indirect effects on night-time sleep are unclear. This study measures the direct effects of low-dose cannabinoid treatments on daytime sleepiness and potential indirect night-time sleep effects in healthy adult, novice cannabis users. Methods Using a double-blind, randomised, placebo-controlled cross-over design, participants were orally administered a standardised dose of 1 mL oil containing THC:CBD ratios of either 1:1, 1:16 or a placebo over five weekly in-lab visits. Daytime sleepiness was measured at 40, 135 and 265 min post-dosing using the Karolinska Sleepiness Scale (KSS). Indirect night-time sleep effects on total sleep time (TST), sleep-onset latency (SOL), and number of awakenings after onset were measured using daily wrist-actigraphy and sleep-diary entries during the 7-day washout period between treatments. Results Final analyses (N = 20) showed subjective sleepiness (KSS score) significantly increased (mean difference = 1.9, SE 0.25) from 40 min to 265 min post-treatment (p < 0.001). No significant differences were observed between treatments for KSS. Indirect sleep measures (TST, SOL, number of awakenings) showed no differences between treatments or over time (all p > 0.05). Conclusion Daytime consumption of low-dose cannabinoid oils did not induce direct sleepiness or indirect night-time effects post-dosing among adults. Future studies would benefit from exploring pharmacokinetics and the possibility of treatment amplification of daytime fatigue, mood and cognitive changes to assist the development of therapeutic guidelines for safe daytime medical cannabis use. ANCTR Trial Registration Number ACTRN12622001539729, 13 December 2022, prospectively registered.

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.

Driving is a critical everyday task necessitating the rapid and seamless integration of dynamic visually derived information to guide neurobehaviour. Biological markers are frequently employed to detect Δ9‐tetrahydrocannabinol (THC) consumption among drivers during roadside tests, despite not necessarily indicating impairment. Characterising THC‐specific alterations to oculomotor behaviour may offer a more sensitive measure for indexing drug‐related impairment, necessitating discrimination between acute THC effects, chronic use and potential tolerance effects. The present review aims to synthesise current evidence on the acute and chronic effects of THC on driving‐relevant oculomotor behaviour. The review was prospectively registered (10.17605/OSF.IO/A4H9W), and Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines informed reporting standards. Overall, 20 included articles comprising 12 experimental acute dosing trials, 5 cross‐sectional chronic use studies and 3 roadside epidemiological studies examined the effects of cannabis/THC on oculomotor parameters including saccadic activity gaze behaviour, nystagmus, smooth pursuit and eyelid/blink characteristics. Acute THC consumption selectively impacts oculomotor control, notably increasing saccadic latency and inaccuracy and impairing inhibitory control. Chronic cannabis users, especially those with early age of use onset, display enduring oculomotor deficits that affect visual scanning efficiency. The presence of eyelid tremors appears to be a reliable indicator of cannabis consumption while remaining distinct from direct impairment associated with visual attention and motor control. Cannabis selectively influences oculomotor activity relevant to driving, highlighting the role of cannabinoid systems in these processes. Defining cannabis/THC‐specific changes in oculomotor control may enhance the precision of roadside impairment assessments and vehicle safety systems to detect drug‐related impairment and assess driving fitness.

Background and objectives Medical cannabis use is increasing in Australia and other jurisdictions, yet little is known about the effects of medical cannabis on cognitive function. Findings from studies of non-medical (‘recreational’) cannabis may not be applicable to patients using prescribed medical cannabis to manage a health condition. Methods In this semi-naturalistic, open-label trial, patients with various health conditions attended a single laboratory session in which they self-administered a standard dose of prescribed medical cannabis as per instructions on the pharmacy label. We assessed cognitive performance using the Cambridge Neuropsychological Test Automated Battery (CANTAB) and Druid application (app) prior to and following (CANTAB: + 3 h; Druid: + 3 and 5.5 h) medical cannabis self-administration. We also assessed subjective drug effects prior to and following (1, 2 and 4 h) medical cannabis self-administration using a range of 0–10 cm visual analogue scales (‘stoned’, ‘sedated’, ‘relaxed’, ‘comfortable’, ‘anxious’ and ‘confident’). Data were analyzed using linear fixed-effect models. Results Participants (N = 40; 22 females) were prescribed a range of products including orally administered oils (n = 23) and flower for vaporization (n = 17). Participants had a mean (standard deviation [SD]) age of 41.38 (12.66) years and had been using medical cannabis for a mean (SD) of 10.18 (8.73) months. Chronic non-cancer pain was the most common indication for medical cannabis use (n = 20), followed by sleep disorder (n = 18) and anxiety (n = 11). The mean (SD) delta-9-tetrahydrocannabinol (THC)/cannabidiol (CBD) dose administered by participants was 9.61 (8.52) mg/9.15 (10.11) mg among those using an oil, and 37.00 (24.53) mg/0.38 (1.58) mg among those who vaporized flower, respectively. Participants’ performance improved over time on the CANTAB Multitasking Test and Rapid Visual Information Processing test (both p-values 0.05). Vaporization of flower was associated with significantly stronger subjective feelings of ‘stoned’ and ‘sedated’ relative to oils (both p < 0.001). Conclusions These findings suggest that prescribed medical cannabis may have minimal acute impact on cognitive function among patients with chronic health conditions, although larger and controlled trials are needed.

Background: Medicinal cannabis products containing Δ9-tetrahydrocannabinol (THC) are increasingly accessible. Yet, policy guidelines regarding fitness to drive are lacking, and cannabinoid-specific indexations of impairment are underdeveloped. Aims: To determine the impact of a standardised 1 mL sublingual dose of CannEpil ^® , a medicinal cannabis oil containing 100 mg cannabidiol (CBD) and 5 mg THC on simulated driving performance, relative to placebo and whether variations in vehicle control can be indexed by ocular activity. Methods: A double-blind, within-subjects, randomised, placebo-controlled, crossover trial assessed 31 healthy fully licensed drivers (15 male, 16 female) aged between 21 and 58 years ( M = 38.0, SD = 10.78). Standard deviation of lateral position (SDLP), standard deviation of speed (SDS) and steering variability were assessed over time and as a function of treatment during a 40 min simulated drive, with oculomotor parameters assessed simultaneously. Oral fluid and plasma were collected at 30 min and 2.5 h. Results: CannEpil did not significantly alter SDLP across the full drive, although increased SDLP was observed between 20 and 30 min ( p < 0.05). CannEpil increased SDS across the full drive ( p < 0.05), with variance greatest at 20–30 min ( p < 0.001). CannEpil increased fixation duration ( p < 0.05), blink rate (trend p = 0.051) and decreased blink duration ( p < 0.001) during driving. No significant correlations were observed between biological matrices and performance outcomes. Conclusions: CannEpil impairs select aspects of vehicle control (speed and weaving) over time. Alterations to ocular behaviour suggest that eye tracking may assist in determining cannabis-related driver impairment or intoxication. Australian and New Zealand Clinician Trials Registry, https://anzctr.org.au(ACTRN12619000932167) .