A new study has found that cannabis use in both recreational and chronic users can lead to persistent and severe acute cognitive impairments that may continue well beyond the period of intoxication.
The systematic review of 10 papers and more than 43,00 participants, led by Canadian reseaxjmtzywrchers and published Wednesday in the scientific journal Addiction, found that cannabis intoxication can produce small to moderate cognitive impairments in areas such as decision making, suppressing inappropriate responses, and the overall time needed to complete a mental task.
The review also found that the ability to remember what one reads or hears, as well as learning through reading and listening, were also impacted.
"These acute impairments accord with documented residual effects, suggesting that the detrimental effects of cannabis persist beyond acute intake," the study’s authors wrote.
According to the World Health Organization, cannabis is the third most commonly used psychoactive substance in the world, after alcohol and nicotine.
In 2013, an estimated 181.8 million people globally aged 15-64 used cannabis for non-medical purposes, according to the WHO, with the highest rates of cannabis use reported among adolescents and young adults.
According to researchers, meta-analyses were included in the review if they examined the effects of cannabis use on any neurocognitive domain and involved healthy individuals from the general population.
The study’s authors note they did not restrict the search to a specific cognitive impairment or a certain age group in order to "obtain a better overview of results."
Study co-author Alexandre Dumais, associate clinical professor of psychiatry at the Université de Montréal, said in a press release that the findings suggest that the "damaging effects of cannabis" begin while it is being consumed, but can continue after that period.
"Our study enabled us to highlight several areas of cognition impaired by cannabis use, including problems concentrating and difficulties remembering and learning, which may have considerable impact on users’ daily lives," Dumais said in the release.
Dumais noted that "numerous cognitive domains" are impacted by cannabis use, with the most notably being executive functions, verbal learning and memory, and processing speed.
However, the review notes that these change based on people’s age and when they began using cannabis.
"Cannabis use in youth may consequently lead to reduced educational attainment, and, in adults, to poor work performance and dangerous driving. These consequences may be worse in regular and heavy users," Dumais said.
With recent changes in the legalization of cannabis around the world, the study’s authors report that the public perceptions of its safety and acceptability are also changing.
Because of this, researchers say it is important to understand the "cognitive risks" involved in using cannabis, especially for young people, whose brains are "undergoing significant developmental changes."
To help mitigate the cognitive risks of cannabis use, researchers say health professionals should be informed of the potential risks and screen their patients for "problematic use." The study’s authors said it may also be helpful to implement cognitive remediation programs in more severe cannabis users to try to improve cognition.
As youths remain "particularly susceptible to the effects of cannabis," the study’s authors say school settings should also put in place prevention and intervention measures to educate students on cannabis use and discourage them from using the substance in a chronic manner.
Despite the findings, the study’s authors say more research is needed to examine whether the cognitive deficits shown in performance-based tasks are also expressed in daily life, such as forgetting to carry through intended tasks, academic difficulties or work-related errors and car accidents.
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Cannabis is seen in this file photo. (Pexels/Kindel Media)
