New research has revealed that young people who casually smoke marijuana could cause permanent changes to areas of the brain associated with emotion and motivation.
The study, conducted by researchers from Northwestern University's medical school, Massachusetts General Hospital and Harvard Medical School, will be published on Wednesday in the Journal of Neuroscience, Reuters reported this week.
These findings are unlike any other marijuana-related studies that examined habitual pot smokers - they demonstrated a direct link between the number of times people smoked per week and irregularities in the brain.
"What we're seeing is changes in people who are 18 to 25 in core brain regions that you never, ever want to fool around with," one of the study's authors, Dr. Hans Beiter, told Reuters.
Beiter, who works as a professor of psychiatry and behavioral sciences at Northwestern, said he and his colleagues noted key shifts of the nucleus accumbens and nucleus amygala throughout their research. These two areas of the brain control emotion and motivation.
People who smoked anywhere between one to seven joints per week had different volume, shape and density in those regions of the brain. Beiter said more research is necessary to pinpoint exactly what brain function differences could show up in the future. He told Reuters it's unclear at this point whether young people who steer clear of marijuana can reverse changes in the brain.
"Our hypothesis from this early work is that these changes may be an early sign of what later becomes amotivation, where people aren't focused on their goals," he said.
There has been other research on the various ways alcohol modifies the brain, Beiter added, and it's apparent that the changes marijuana makes differ from those brought on by consumption of spirits.
The National Institute on Drug Abuse and the White House Office of National Drug Policy co-funded the study, which comes just months after Colorado and Washington state have legalized its recreational use, Reuters reported.
