Prescribed Medical Cannabis Does Not Impair Driving Performance, Study Finds

A new study conducted by researchers at Swinburne University of Technology has found that prescribed medical cannabis does not impair driving performance when used as directed for chronic health conditions. The study, published in the Journal of Psychopharmacology, assessed the driving ability of 40 patients who used medical cannabis for various conditions, such as chronic pain, epilepsy, and multiple sclerosis.

Medical cannabis is a treatment option for patients who suffer from chronic and debilitating health conditions that do not respond well to conventional medications. Medical cannabis can provide relief from symptoms such as pain, spasms, seizures, and nausea, and improve the quality of life of patients.

However, medical cannabis also raises concerns about its effects on driving performance and safety, as cannabis can impair cognitive and motor functions, such as reaction time, attention, and coordination. Cannabis can also affect the perception of speed, distance, and time, and increase the risk of accidents and injuries.

Therefore, it is important to understand how medical cannabis affects driving performance, and to provide clear and evidence-based guidelines for patients who use medical cannabis and drive.

Medical Cannabis and Driving: A Simulated Study

The study by Swinburne researchers aimed to investigate the effects of prescribed medical cannabis on simulated driving performance among patients who use medical cannabis for chronic health conditions. The study was an open-label, within-subjects, placebo-controlled, randomized clinical trial, which means that the participants received both their prescribed medication and a placebo (an inactive substance) in different sessions, and their driving performance was compared.

The participants were 40 patients who had been using medical cannabis for at least three months, with a range of chronic health conditions, such as chronic pain, epilepsy, multiple sclerosis, and post-traumatic stress disorder. The participants had their driving ability assessed in a simulator before and after consuming a standard dose of their prescribed medication or a placebo. The driving simulator consisted of a 100-kilometer highway drive, with a single task (following a lead vehicle) and a dual task (following a lead vehicle and responding to traffic signs) condition.

The study measured the driving performance of the participants using two main indicators: the standard deviation of lateral position (SDLP), which reflects the ability to maintain a steady position in the lane, and the mean speed (MS), which reflects the ability to adjust the speed according to the traffic conditions.

The study also measured the subjective effects of the medication, such as the feeling of being high, relaxed, or impaired, and the self-reported perception of driving ability, such as the confidence and effort required to drive.

Medical Cannabis and Driving: A Negligible Effect

The results of the study showed that prescribed medical cannabis had a negligible effect on simulated driving performance when used as directed for chronic health conditions. The study found that:

• There was no significant difference in SDLP or MS between the medication and placebo conditions, which means that medical cannabis did not impair the ability to maintain a steady position in the lane or adjust the speed according to the traffic conditions.
• There was no significant difference in SDLP or MS between the single task and dual task conditions, which means that medical cannabis did not impair the ability to handle multiple tasks while driving.
• There was no significant difference in SDLP or MS between the baseline (before consumption) and post-consumption assessments, which means that medical cannabis did not impair the driving performance over time.
• There was no significant correlation between the subjective effects of the medication and the driving performance, which means that the feeling of being high, relaxed, or impaired did not reflect the actual driving ability.
• There was no significant correlation between the self-reported perception of driving ability and the driving performance, which means that the confidence and effort required to drive did not reflect the actual driving ability.

The study concluded that prescribed medical cannabis, when used as directed for chronic health conditions, had a negligible effect on simulated driving performance, and did not impair the driving ability of the patients.

Medical Cannabis and Driving: A Cautionary Note

The study by Swinburne researchers is the first to examine the effects of prescribed medical cannabis on simulated driving performance among patients who use medical cannabis for chronic health conditions. The study provides valuable information and insights for patients, clinicians, and policymakers, and contributes to the growing evidence on the safety and effectiveness of medical cannabis treatment.

However, the study also has some limitations and implications that need to be considered and addressed, such as:

• The study involved a relatively small sample size and a specific population of patients who use medical cannabis for chronic health conditions. The results may not apply to other patients who use medical cannabis for different conditions, or to recreational cannabis users who may consume higher doses or different strains of cannabis.
• The study used a simulated driving task, which may not reflect the real-world driving conditions and challenges, such as traffic, weather, distractions, and emergencies. The study also did not measure the effects of medical cannabis on other driving-related skills, such as hazard perception, decision making, and risk taking.
• The study did not account for the potential interactions of medical cannabis with other medications or substances, such as alcohol, opioids, or benzodiazepines, which may have additive or synergistic effects on driving performance and safety.
• The study did not assess the long-term effects of medical cannabis on driving performance and safety, such as the residual or cumulative effects of chronic cannabis use, or the effects of cannabis withdrawal or tolerance.

Therefore, the study cautions that the findings should not be interpreted as a green light for patients who use medical cannabis to drive without any concern or restriction. The study recommends that patients who use medical cannabis should consult their clinicians and follow their advice on the appropriate dosage, timing, and mode of consumption of medical cannabis, and on the potential effects and risks of medical cannabis on driving performance and safety. The study also recommends that patients who use medical cannabis should monitor their own driving ability and behavior, and avoid driving if they feel impaired or unsafe.

For more information on the study and the research on medical cannabis and driving, visit scimex.org.