14 DAY TRIAL // A team of researchers from the Northwestern University and Massachusetts General Hospital/Harvard Medical School say that teens and young adults who start to smoke marijuana early on are at a higher risk of displayed structural changes in particular areas of the brain. The correlation was found to hold even after experts accounted for a variety of other factors that may have influenced the result.
Two brain areas in particular were found to exhibit the most significant changes, the team said. One of them is involved in controlling emotion, while the other plays a key role in underlying motivation Young adults who smoked marijuana at least once per week displayed variations in shape and size in these two brain areas, as opposed to healthy control subjects.
While the effects of heavy pot smoking on the human brain are relatively well understood, not the same can be said about the long-term consequences of consuming either low or moderate amounts of marijuana. The new investigation, led by scientists Jodi Gilman, PhD, Anne Blood, PhD, and Hans Breiter, MD sought to address this issue, PsychCentral reports.
In a paper published in the latest issue of the esteemed Journal of Neuroscience, the team urges the international scientific community to conduct additional research in this grey area, in order to fully understand how the human brain changes due to early exposure to the active ingredient in marijuana, tetrahydrocannabinol (THC). Nearly 19 million people in the United States use pot frequently.
This figure was compiled by the US National Survey on Drug Use and Mental Health. In a recent report, the organization has shown that marijuana abuse can impair memory, learning, attention, and motivation, to name but a few. Unfortunately, the recent discovery supports previous conclusions derived from animal studies, which have shown similar changes in the brains of rats from THC use.
“This study suggests that even light to moderate recreational marijuana use can cause changes in brain anatomy. These observations are particularly interesting because previous studies have focused primarily on the brains of heavy marijuana smokers, and have largely ignored the brains of casual users,” says study coauthor Carl Lupica, PhD.
For this research, scientists scanned the brains of young adults aged from 18 to 25 using a Magnetic Resonance Imaging (MRI) machine. The data were then compared to scans collected from young adults who reported no marijuana use. The nucleus accumbens, which processes data related to rewards, and the amygdala, which processes emotions and fear, were found to have peculiar dimensions.
Both structures were larger than normal, and displayed significant variations in shape and inner structure. “This study raises a strong challenge to the idea that casual marijuana use isn’t associated with bad consequences,” Breiter comments.