According to a new study published this morning in JAMA Psychiatry, the effects of cannabis may not permanently damage brain function even in adolescents. In 2014 a study was published that suggested that marijuana consumption can negatively impair brain development in young adults, but this new study suggests something entirely different.
They study involved analyzing the cognitive effects of cannabis consumption on 2,152 regular consumers of the plant and 6,575 non cannabis consumers in 69 cross-sectional studies. For the first 72 hours, the non-cannabis consumers were much quicker mentally and scored higher. However, after 72 hours the cannabis smokers were on point again along with the participants that abstain from smoking marijuana.
Cobb Scott, an assistant professor of psychiatry at the Perelman School of Medicine at the University of Pennsylvania and a lead author of the study talked about some of the finding and what they could mean to the marijuana legalization movement.
“We looked at everything from learning and memory to different aspects of executive functioning such as abstraction ability,” Scott said. “And we basically showed that the largest effects — which was around a third of a standard deviation — was in the learning of new information and some aspects of executive functioning, memory and speed of processing.”
But when the researchers separated the studies based on length of abstinence from marijuana use, the difference in cognitive functioning between marijuana users and non-users was no longer apparent after 72 hours of marijuana abstinence. That could be an indication “that some of the effects found in previous studies may be due to the residual effects of cannabis or potentially from withdrawal effects in heavy cannabis users,” Scott said.
“There have been very important studies showing evidence for irreversible damage (from marijuana use), and so there needs to be more research in this area,” said Kevin Sabet, assistant adjunct professor at the Yale School of Medicine and president of the nonprofit Smart Approaches to Marijuana, who was not involved in the new study.
Undoubtedly, research should continue to be conducted on marijuana and its effects on the mind, in particular in adolescents. However, the findings do support the belief of many avid cannabis consumers that vehemently argue that there are no real negative health effects from cannabis consumption either short of long term.