How Does Marijuana Affect A Teenager’s Brain


The researchers performed brain scans on 92 adolescents aged 14 years. Half of the young people admitted they had already tried marijuana or hashish. The other half had not yet had such an experience. At the same time, both groups were selected to exclude the effect of alcohol and smoking on the research results.

To study the brains of teenagers, scientists used so-called voxel morphometry, when magnetic resonance imaging (MRI) can evaluate the parameters of individual brain regions.

It turned out that adolescents who tried marijuana (which you can smoke at only once or twice increased the gray matter in volume. The changes affected the part of the brain where the cannabinoid receptors that respond to drugs in cannabis are located. In particular, the increase was recorded in two areas of the brain: the hippocampus, which is involved in the formation of memory and orientation in space, and the almond body, which is associated with a sense of fear. 

Grey matter is the center of our nervous system.

Doctors call the gray matter the bodies of neurons and leading areas of the central nervous system. These areas of the brain control muscle activity and are also responsible for vision, hearing, speech, memory and expression of emotions. The white matter, on the contrary, consists mainly of channels of information transmission. These are the nerve fibers and axons that transmit nerve impulses.

The white and gray matter of the brain got its name because of the different coloring of these tissues when placed in formalin. This solution is used by scientists to conserve and disinfect biological preparations containing protein.

Scientists do not study teenagers who smoke weed

Scientists have not yet determined what effect grey matter increase – positive or negative – has. They are cautious about the interpretation of the data obtained. One thing is certain: among adolescents who use cannabis regularly, doctors observe an increased number of anxiety disorders.

From 30 to 40 percent of teenagers from developed countries such as Germany and the United States have tried weed by the time they finish high school. Medics suggest that even a short acquaintance with cannabis has a long-term effect on the nervous system. It is difficult to speak about these effects in detail, because scientists practically do not conduct research on teenagers who smoke marijuana regularly. The subject is usually adults who have been using cannabis for many years. 

The authors of the publication believe that their research is particularly relevant, because the legal status of cannabis is constantly being reviewed, and the perceived risks of smoking it for teenagers in the public mind are constantly being reduced. Further research should show whether marijuana is harmless for the still unformed brain of teenagers.

However, the same can be said about all psychoactive products, including tobacco and alcohol: the earlier a person starts using them and the more often he or she does it, the greater the risk of addiction and the risks associated with the product itself. Marijuana is a psychoactive product that is usually consumed by youth who inhale its smoke. It provides immediate insight into two major risks: mental health effects and long-term lung toxic effects (especially when smoking marijuana with tobacco).

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