A recent study published in the journal CNS Drugs has revealed that prescribed medical cannabis may not have a significant impact on cognitive function among patients with chronic health conditions. This finding will likely come as a relief to long-term cannabis patients who have been concerned about potential neurological drawbacks of the drug.
The study involved 40 participants in Australia who consumed a single dose of medical marijuana in a laboratory setting, following the instructions on the product label. The participants were then tested on various neuropsychological metrics, including multitasking, pattern recognition memory, reaction time, rapid visual information processing, and spatial working memory. They were also surveyed on their subjective experience.
Surprisingly, the study found no evidence for impaired cognitive function when comparing baseline scores with post-treatment scores. This finding contradicts previous research that has shown that non-medical or recreational cannabis use can impair cognitive functions. However, two systematic reviews published in the last year have suggested that regular and consistent use of medical cannabis for chronic health concerns may have minimal impact on cognitive function.
The researchers did find some differences in effects between participants who consumed cannabis flower and those who used concentrates. Participants who self-administered flower reported feeling more stoned and sedated one hour after consumption compared to those who self-administered oil. Additionally, participants who consumed flower reported feeling more confident than those who consumed oil, although this difference was only statistically significant at the 4-hour mark.
It’s important to note that cannabis tolerance increases with long-term use. A separate study mentioned in the report found that occasional users who were given a dose of THC exhibited significant alterations in reward circuitry and impaired performance on a sustained attention task. However, chronic cannabis users administered the same dose of THC did not exhibit these neurometabolic alterations or performance decrements, despite reporting increased intoxication.
The report emphasizes the importance of stable dosing with THC for potential mitigation of impairment. Gradual dose titration up to the point of effective symptom relief is crucial. The report advises patients to consider potential impairment, especially early on and after any increase in dosages. Safety-sensitive tasks, such as driving, are not recommended until patients are taking a stable dose of THC and should be temporarily avoided following any increase in dose.
One limitation of the study was the lack of a placebo, which made it difficult to determine whether any residual impairment was due to medical cannabis use. Participants were also not screened for other drugs prior to the trial. Additionally, the controlled use of medical cannabis in the study may not match real-world usage patterns. Patients typically use medical cannabis in the evening before sleeping, and these findings may not apply to patients who are just starting treatment or changing dose/product type.
While the long-term effects of cannabis use are still being studied, recent research has shown that some fears about its neurological impact may be overblown. For instance, a study published in April found that cancer patients reported improved clarity of thought and pain management when using medical marijuana. Another study found that regular marijuana use over a two-year period did not trigger early onset of psychosis symptoms in teens and young adults at risk.
Contrary to claims that marijuana causes mental illness, a study published by the American Medical Association (AMA) found no statistically significant increase in psychosis-related diagnoses in states that have legalized marijuana compared to those that criminalize it.
Overall, this study provides some reassurance for long-term cannabis patients with chronic health conditions who have been concerned about potential cognitive impairment. However, further research is needed to fully understand the long-term effects of medical cannabis use on cognitive function in different patient populations.
