A study from Swinburne University suggests that medicinal cannabis produces little acute disruption to cognitive function in patients managing chronic health conditions.
Using a semi-naturalistic, open-label trial design, participants with a range of health conditions attended a single laboratory session where they self-administered a standard prescribed dose of medicinal cannabis according to the directions on their pharmacy label.
Cognitive performance was measured using the Cambridge Neuropsychological Test Automated Battery (CANTAB) and the Druid application, with assessments conducted both before and after self-administration.
The research team also tracked subjective drug effects at baseline and at one, two, and four hours post-dose, drawing on a series of self-reported measures covering feelings such as 'stoned', 'sedated', 'relaxed', 'comfortable', 'anxious', and 'confident'.
Among the 40 participants, 23 had been prescribed cannabis oil and 17 used vaporised flower. Chronic non-cancer pain was the most frequently reported condition, followed by sleep disorder and anxiety.
Over the course of the session, participants showed improved performance on the CANTAB Multitasking Test and the Rapid Visual Information Processing test. All other changes across cognitive performance measures were deemed "non-significant".
Flower vaporisation was associated with significantly stronger subjective experiences of feeling 'stoned' and 'sedated' compared to oil-based administration.
Lead researcher Dr Thomas Arkell said the results could indicate that patients develop tolerance over time, "akin to what we see with other psychoactive medications like anti-depressants and benzodiazepines".
He added: "It could also mean that patients experience some alleviation of their symptoms, such as pain, after using medical cannabis, which might lead to a normalisation of cognitive function."
The findings were published in the journal CNS Drugs.
