New research provides evidence that regular cannabis use is associated with impairments in episodic foresight, meaning the capacity to envision the future. The findings, which appear in the Journal of Psychopharmacology, suggest that cannabis can impair the ability to mentally travel into one’s personal future.

“I have always been interested in the psychology behind problem behaviours. When I began my post-graduate studies I did not have a specific lean to any particular type of behaviour but knew I wanted to explore possible underpinnings for maladaptive functioning presented in clinical groups that I would eventually work with,” said study author Kimberly Mercuri of Australian Catholic University.

“I was fascinated by substance dependence because despite so many negative outcomes (psychological, physical, behavioural, and cognitive), many individuals were able to function relatively well on the day-to-day. However in saying this, I also observed many barriers impeding on this clinical group’s ability to function at more adaptive levels, seek treatment, and achieve treatment gains.

“As a clinician, as well as a researcher, I wanted to explore a potential barrier for this population, with a hope to better inform treatment delivery,” Mercuri said.

The study compared 57 cannabis users (aged 18 to 35 years) to 57 matched control subjects. The researchers measured episodic foresight using the Autobiographical Interview task, which requires participants to respond to a cue word by either describing a personally experienced event from their past or thinking up a novel future event.

Regular cannabis users — who reported smoking cannabis at least three times per week — displayed difficulties imagining novel future scenarios, compared to participants who didn’t use cannabis and participants who used cannabis less than once a week.

“The findings indicate that with regular cannabis use the ability to mentally time travel is negatively impacted; relative to people who have never used the drug and those who use it infrequently,” Mercuri told PsyPost.

“I guess the take home message is that there is growing evidence for possible cognitive deterioration with regular use which in turn can hinder the simplest of day-to-day tasks as the capacity to recall and imagine the self plays important roles other cognitive process (e.g decision making, goal setting).”

“Also, this deficit is not isolated to cannabis users, with another paper of ours indicating a significant impairment in future thinking observed in long-term opiate users,” Mercuri noted.

“Hopefully the average person may be able to develop some compassion for substance users who display maladaptive patterns in functioning (which admittingly can be frustrating to observe) as the reason behind their behaviour may be due to more complex neurological functions.”

Even though infrequent cannabis users didn’t show impairments in episodic foresight, that doesn’t mean infrequent cannabis use does not have consequences.

“The findings should not be interpreted in way that recreational drug use is safe, as any level of drug use poses potential risks,” Mercuri said.

There are several things future research could address.

“More research is needed to better understand the neurological underpinnings of this observed deficit as well as the exact functional implications of the observed future thinking deficit,” Mercuri explained.

“It is also very difficult to delineate the effects of other drugs. However interestingly, the deficit is observed in other drug-dependent groups (i.e. opiate users), so future research could explore whether this impairment extends to other substances.”

“Also, although limitations in future thinking may provide some explanation for functional difficulties observed in substance-dependent groups, it does not excuse an inappropriate behaviour,” Mercuri added.

The study, “Episodic foresight deficits in regular, but not recreational, cannabis users“, was authored by Kimberly Mercuri, Gill Terrett, Julie D Henry, H. Valerie Curran, Morgan Elliott, and Peter G Rendell.