Heavy Marijuana Use ‘Shrinks’ the Brain but Increases Its Connectivity

There has been a many-years debate on the effects of pot smoking on the human health. Some say it is just a habitual pastime that does not cause any significant harm; others disagree and call marijuana a detrimental drug which corrupts the minds of the youth. New U.S. study shed some light on the impact of long-term use of marijuana on the brain.

Using magnetic resonance imaging (MRI), researchers from the University of Texas studiedthe brain activity in 48 adults who smoked marijuana three times a day on average. They were of various age range with the average of 28 years old and included both male and female volunteers. The control group consisted of 62 people who had never smoked marijuana.

As a result, the researchers found that those who smoked marijuana on a regular basis had a reduced volume of gray matter in the orbitofrontal cortex. This area of the brain is associated with impulse and emotion control, decision making and response for rewards.

However, taking a closer look at these results showed that marijuana use also increases the number of structural and functional connections between the different parts of the brain. This number tends to decrease after 6-8 years of heavy marijuana use, but even in this case, it exceeds that of non-smokers.

It seems that the brain is trying to compensate the decrease in gray matter volume by forming new connections with other regions. Apparently, pot smoking enhances the connectivity of the brain and its ability to form new neural connections.

Another interesting finding is that pot smokers had a lower IQ, which, however, was not associated with the mentioned changes in the brain structure.

“While our study does not conclusively address whether any or all of the brain changes are a direct consequence of marijuana use, these effects do suggest that these changes are related to age of onset and duration of use,” said co-author of the study Francesca Filbey.

Thus, the impact of marijuana use on the brain and the overall health remains a controversial topic, and more long-term research needs to be done to determine whether this habit is indeed as bad as they want us to believe. At the same time, the results of this and similar studies may not apply to all people since everyone is different. Not all marijuana users smoke it – some vaporize it, which is one of the healthiest ways to ingest the herb and avoid the negative effects of smoking.