Thomas Arkell

• Doctor of Philosophy
• The University of Sydney

Importance Cannabis use has been associated with increased crash risk, but the effect of cannabidiol (CBD) on driving is unclear. Objective To determine the driving impairment caused by vaporized cannabis containing Δ⁹-tetrahydrocannabinol (THC) and CBD. Design, Setting, and Participants A double-blind, within-participants, randomized clinical tr...

Introduction Prescribed medicinal cannabis (MC) is an increasingly common prescription in Australia for treating pain, anxiety, and sleep disorders. Prescribed MC products generally contain tetrahydrocannabinol (THC) and/or cannabidiol (CBD) in a variety of dose levels and forms. It is unclear whether THC and CBD products are used by patients with...

Evidence for acute amphetamine effects on behavioural impulsivity in healthy populations remains elusive and, at times, mixed. This review collates and reviews the clinical literature on the acute effects of amphetamines on measures of behavioural impulsivity in healthy adults. Randomised and placebo-controlled clinical trials that assessed behavio...

Some evidence suggests that males and females may differ in their responses to acute cannabis effects, including subjective drug effects and behavioural effects, and cannabinoid pharmacokinetics. This is significant given current changes to cannabis-related policies and, in consequence, increased cannabis accessibility. The present study combines d...

Blood and oral fluid Δ⁹-tetrahydrocannabinol (THC) concentrations are often used to identify cannabis-impaired drivers. We used meta-analytic techniques to characterise the relationships between biomarkers of cannabis use, subjective intoxication, and impairment of driving and driving-related cognitive skills. Twenty-eight publications and 822 driv...

Background: Medical cannabis use is increasingly common in Australia. Patients and physicians need to be aware of the important implications that such use may have for driving. Objective: The aim of this article is to briefly review the scientific evidence regarding cannabis and driving impairment and discuss current legal issues affecting patie...

In Reply Our recent investigation¹ about the effects of CBD and THC on driving offers relevant insights for research and policy. This study confirmed previous findings from on-road and driving simulator studies² showing that THC produces modest but clinically relevant driving impairment similar to that seen in drivers with a blood alcohol concentra...

Objective Many jurisdictions use per se limits to define cannabis-impaired driving. Previous studies, however, suggest that THC concentrations in biological matrices do not reliably reflect cannabis dose and are poorly correlated with magnitude of driving impairment. Here, we first review a range of concerns associated with per se limits for THC. W...

The increasing legal availability of cannabis has important implications for road safety. This systematic review characterised the acute effects of Δ⁹-THC on driving performance and driving-related cognitive skills, with a particular focus on the duration of Δ⁹-THC-induced impairment. Eighty publications and 1534 outcomes were reviewed. Several mea...

Sleep disturbance is a common symptom encountered by cannabis-dependent individuals abstaining from cannabis use. In the present study, we investigated the effect of daily aerobic cycling exercise versus control stretching on sleep quality during inpatient cannabis withdrawal in treatment-seeking dependent cannabis users. The protocol incorporated...

As the use of cannabis for medical purposes becomes increasingly prevalent, driving under the influence of cannabis (DUIC) is emerging as a major public health issue. Understanding current behaviours, attitudes and perceptions around DUIC in medical cannabis users is an important first step in addressing this issue. Here we present the results from...

Objective Interest in the use of cannabidiol (CBD) is increasing worldwide as its therapeutic effects are established and legal restrictions moderated. Unlike Δ⁹‐tetrahydrocannabinol (Δ⁹‐THC), CBD does not appear to cause cognitive or psychomotor impairment. However, further assessment of its effects on cognitively demanding day‐to‐day activities,...

Background: In 2016, the Australian federal government passed legislation enabling a range of cannabis-based products to be prescribed to patients by registered healthcare professionals. An online survey conducted immediately prior to these legislative changes found that the vast majority of respondents at the time were illicitly sourcing cannabis...

Background : In 2016 the Australian federal government passed legislation enabling a range of cannabis-based products to be prescribed to patients by registered healthcare professionals. An online survey conducted immediately prior to these legislative changes found that the vast majority of respondents at the time were illicitly sourcing cannabis...

Background: In 2016 the Australian federal government passed legislation enabling a range of cannabis-based products to be prescribed to patients by registered healthcare professionals. An online survey conducted immediately prior to these legislative changes found that the vast majority of respondents at the time were illicitly sourcing cannabis p...

Background The main psychoactive component of cannabis, delta-9-tetrahydrocannabinol (THC), can impair driving performance. Cannabidiol (CBD), a non-intoxicating cannabis component, is thought to mitigate certain adverse effects of THC. It is possible then that cannabis containing equivalent CBD and THC will differentially affect driving and cognit...

Point‐of‐collection testing (POCT) for Δ9‐tetrahydrocannabinol (THC) in oral fluid is increasingly used to detect driving under the influence of cannabis (DUIC). However, previous studies have questioned the reliability and accuracy of two commonly used POCT devices, the Securetec DrugWipe® 5s (DW5s) and Dräger DrugTest® 5000 (DT5000). In the curre...

Background and aims Cannabis withdrawal is thought to be a major contributor to relapse to cannabis use and is now included in the DSM-5. Aerobic exercise relieves withdrawal symptoms from tobacco and other drugs, but has yet to be tested in cannabis users. Methods A prospective, single blind, parallel-group RCT comparing daily aerobic exercise to...