Brain Scans May Show How Marijuana Affects How We Think About Our Future
Dr. Kimberly Mercuri follows up on her cannabis study with Inverse.
Regular cannabis users might face challenges with episodic foresight or the ability to consider future behaviors, suggests a recent study, and its top researcher says neuroimaging techniques could help scientists learn more about the brains of weed enthusiasts.
Dr. Kimberly Mercuri, lead author of the study — published last month in the Journal of Psychopharmacology — says brain scans could offer more evidence and answers around the inability for marijuana users to possess “episodic foresight,” or “the ability to project oneself into the future and mentally simulate situations and outcomes.”
In her study, subjects were given future scenarios to consider, to see how regular cannabis use impacted their “ability to mentally travel” and imagine their personal future. Dr. Mercuri, of Australian Catholic University, tells Inverse that the scenarios given were “open to the participant’s imagination.”
We provided them with three cue words across two separate experimental conditions (six cue words in total). They were instructed to imagine three future-oriented events and three personally experienced past events based on these cue words, and provide as detailed a description as possible.
The cue words were birthday, vacation, bench, taxi, nightmare, and accident, Mercuri tells Inverse. The cue words didn’t have to be used in the actual description they provided, and subjects were provided a maximum of three minutes per description.
After these interviews, researchers determined this: compared to participants who didn’t use cannabis and participants who only used cannabis sparingly (less than once a week), regular users had difficultly imagining future scenarios.
The study looked at 57 cannabis users, 23 recreational and 34 who were more regular users, between the ages of 18 and 35 years, as well as 57 control subjects. Mercuri tells Inverse that that sample size is atually “quite large” for a clinical sample that’s been recruited through the community. She tells Inverse:
Substance using groups, generally, can be quite difficult to recruit to research projects, particularly those who are using at frequent levels. The sample we were able to assess would be considered a large sample for this type of research.
Also, the participants who generously volunteered their time to our study were recruited from the wider community, rather than drug-related services as we wanted to observe individuals who were functioning independently in the community, and also more likely to volunteer to treatment.
Now that Mercuri’s study has determined an association between regular cannabis use and the capacity for episodic foresight, more research may be needed to understand the issue.
It would also be useful to explore how this cognitive deficit is expressed behaviourally and whether/how it can impact therapeutic engagement.
Until further research — possibly including brain scans — about how marijuana affects future behaviors is done, Mercuri’s study alone may give us the best evidence of the association, and regular cannabis smokers will just have to decide for themselves whether they’ll heed the evidence.