It’s no secret that using cannabis can cause short-term impairments in cognitive function, such as memory loss, slower reflexes and difficulty focusing.
But some side effects of marijuana use could last long after the initial “high” ends, especially when it comes to the brain’s higher levels of thinking, according to a newly published review of research in the journal Addiction.
The review, which evaluated studies on over 43,000 people, said the use of tetrahydrocannabinol — or THC — can have a negative impact on the brain’s ability to perform different executive functions.
Those include remembering important data, planning, organizing, problem-solving, decision making, and managing emotions and behavior.
“Notably, this diminished ability to learn, retain and retrieve verbal information may have repercussions for users’ occupational functioning, independent living and ability to navigate through their daily life adequately,” the review said.
Scientists aren’t yet sure if those effects can be reversed, and it’ll take more research to figure that out, according to Dr. Alexandre Dumais, one of the authors of the review and an associate clinical professor of psychiatry at the University of Montreal. Even with more research, the severity of negative effects might depend on the amount, frequency and years of marijuana use, CNN reported.
But what scientists can conclude, Dumais said, is that chronic marijuana use consistently affects the brains of adolescents and young adults.
“Thus far, the most consistent alterations produced by cannabis use, mostly its chronic use, during youth have been observed in the prefrontal cortex,” Dumais told CNN. “Such alterations may potentially lead to a long-term disruption of cognitive and executive functions.”
One of the analyses included in the review was based on six studies on young adults and cannabis use. That analysis “suggested an impaired capacity for chronic cannabis users to make appropriate behavioral decisions while switching between cognitive processes,” the review said.
Another analysis in the review evaluated 39 studies on young adult cannabis users who were an average age of 26. Those studies also concluded that young adults who are chronic cannabis users have a slightly worse ability to retain or manipulate information, as well as more difficulty remembering that information after a short delay.
Dumais said the findings imply that cannabis use might “lead to reduced educational attainment” in young adults and to issues like “poor work performance and dangerous driving” in adults, according to a news release on the findings.
“These consequences may be worse in regular and heavy users,” Dumais said.
The authors of the review note that more research is needed to fully understand the effects of marijuana on the brain, including the brain’s ability to recall memories or perform other cognitive functions.
But they warned others to proceed with caution when ingesting marijuana and to “understand the cognitive risks involved in using cannabis, especially to young people, whose brains are undergoing significant developmental changes,” according to the release.