A recently published study out of Australia has suggested little next day impairment is experienced by insomnia patients using cannabis medicines containing THC at night as a sleep aid.
The release of the study, carried out by researchers primarily from Woolcock Institute of Medical Research at Macquarie University, is timely as Australian states grapple with the thorny issue of driving after taking legally prescribed cannabis medicines.
In Australia, with the exception of the state of Tasmania, it is illegal to drive with any detectable level of tetrahydrocannabinol (THC) in a driver’s system. This applies even if there is no impairment and the cannabis was legally prescribed. With THC detectable in some patients weeks after last consuming cannabis, it places patients in a difficult situation, limiting their mobility.
But the results of the study indicate that compared to placebo, a single oral dose of 10 mg THC combined with 200 mg of cannabidiol (CBD) taken the evening before does not notably impair ‘next day’ cognitive function or driving performance in adults with insomnia disorder who infrequently use cannabis.
For regular users, the risk of impairment could be even less as some tolerance may have been built up.
But the researchers state:
“Larger studies in patient populations are required to determine the effects of repeated dosing with THC (with or without CBD), and at higher doses of THC, on ‘next day’ function.”
In their study, twenty adults with an average age of 46.1 years and with physician-diagnosed insomnia participated. Outcome measures incorporated ‘next day’ performance on a battery of tests including cognitive and psychomotor function tasks, simulated driving performance, subjective drug effects, and mood.
Results of the study have been published in the journal Psychopharmacology.
On a related note, a controversial 18-month trial to gauge whether Victorians prescribed medicinal cannabis can drive safely will start soon. The trial will be carried out on a closed-circuit track that will mimic real-world driving conditions. But given results from the above and other studies has called into question whether such a trial – particularly one that will take so long – is really necessary.
Other studies have indicated patients using legally prescribed cannabis medicines, as prescribed, are safe to drive outside the impairment window, which can be reasonably short . However, impairment takes longer to appear and lasts significantly longer when using oral cannabis products compared to those inhaled.
