Though past studies have associated cannabis (“marijuana”) use with poor memory and other cognitive issues, controversy over these findings remain largely due to one reason: it’s difficult to tell what may be resulting from the use and what may be the result of other lifestyle factors. A new study aims to solve this, offering a look at cognitive functioning in marijuana users independent of genetics and other potentially influencing issues.
It’s no secret that some regular cannabis users report poorer cognitive abilities over time, particularly when it comes to memory. Questions have remained over how much of this can be attributed to cannabis use itself rather than other potential factors, such as alcohol consumption, sleep quality, and even genetics.
The new study helps tease these factors apart by contrasting cannabis users with siblings who do not use the substance — and in doing so, the researchers say they’ve found a tight link between marijuana use and poorer cognitive functioning. The effects were particularly pronounced when it came to verbal memory, according to the study.
The negative effects were found in those who started using marijuana in adolescence and who reported frequent consumption of the drug; it’s unclear whether occasional use at older ages would have the same outcome.
Though additional research is necessary, the study notes that at least when it comes to the genes and environment the volunteers shared with siblings, those factors can’t explain the cognitive issues found in cannabis users.
Study lead author Jarrod M. Ellingson said:
More work needs to be done to determine how cannabis use is related to cognitive functioning and we hope that our study can help inform future study designs. These studies are particularly important because cannabis is becoming more potent and more accessible as states legalize its recreational use … Due to changes in the legality of recreational and medical cannabis and widespread access in many states, valid empirical data must be available to inform policy and public health decisions, including how cannabis use may affect the developing brain.