Marijuana: science reveals its long-term effects on the brain
The use of marijuana is a widespread practice today , being one of the most consumed drugs.
While socially It has been seen as a soft drug comparable to alcohol and with relatively little risk in its use (in fact it has interesting properties that make it very useful at a medicinal level in different diseases and disorders), the frequent use of this drug can have relevant long-term negative effects, especially with regard to brain and its structure.
Of course, That does not mean it's a very dangerous drug comparable, for example, to heroin. However, the defense that has been made about the supposedly innocuous nature of its consumption is difficult to defend today, as we will see.
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What is marijuana?
Marijuana is one of the many ways in which cannabis is consumed , specifically the one that uses leaves and stems of the plant, chopped and crushed. This substance has psychoactive properties that are known since antiquity, having been used medicinally and recreationally since then by different peoples. Today, its consumption is widespread worldwide, especially for recreational and recreational purposes, and is even legalized in some places under certain conditions.
It is a substance whose initial effects are slightly stimulating and euphoric, to move to induce states of physical and mental relaxation. It causes a decrease in the level of tension and pain, increases the sensation of hunger and reduces and slows down the motor movement. It is also effective as an antiemetic and anticonvulsant.
The effects of this product are well known when it comes to the short term. But nevertheless, there is more discussion about its long-term effects of marijuana , with often contradictory results according to the type of study that has been carried out. In spite of this, today the evidence suggests that its habitual use causes that the health of the brain is worn away more than it should with the passage of time.
Long-term effects of marijuana
Although cannabis, especially in the form of marijuana, is a widely known substance, studies conducted on its effects have always been surrounded by a great controversy. A great deal of research has been done in this regard, in some cases with unclear results, on the results of their consumption. However, different investigations have shown that its consumption can cause long-term effects on the brain and behavior.
It is important to keep in mind that we are talking about cases in which consumption is carried out frequently over time. The effects in question depend on the age and the moment of neurodevelopment in which the consumption starts , as well as the time during which said consumption occurred.
1. Reduction of the orbitofrontal cortex
One of the results that the investigation has reflected is that the continued use of marijuana causes an obvious reduction in gray matter, especially in the orbitofrontal cortex . This also implies a lower long-term capacity to perform tasks that depend on this area, such as impulse control or planning.
2. Increase neuronal connectivity
In spite of the above, many habitual users of this substance present a behavior apparently normal after many years using marijuana. The reason for this is that according to other studies, despite the reduction of brain gray matter, the connectivity between the remaining neurons is increased , so that said loss is somewhat compensated.
That is, although under normal conditions an increase in the connectivity of the neurons would be good news, in this case is the result of many neurons dying , making those that remain must "work" more; It is a mechanism of the brain to try to replace the loss of thickness of the cortex. In addition, this increase in connections is decreasing as the consumption time increases.
3. Decreased performance and memory capacity
Different studies show that the habitual consumption of cannabis can produce in the long term a decrease in the intellectual capacity of the subjects, having a lower performance and results in different tests than in comparison with a non-consumer individual. However, in this type of cognitive skills many contradictory results have been found, which makes this phenomenon insignificant.
What there is solid evidence is that the use of marijuana produces long-term problems in various types of memory . For example, these alterations result in a greater difficulty of passing the contents of short-term memory into long-term memory.
It is important to note that these effects are especially noticeable in people who consume throughout their development process, ie adolescents, due to the structural modification of the brain that can lead to the consumption of cannabis. In already trained adults who begin to consume this decrease is less.
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4. Does it promote hippocampal neurogenesis?
One of the most popular positive effects of cannabis is the ability to promote formation of new neurons in the hippocampus , region of the brain that intervenes in the processing of memories. In fact, one of the medicinal applications of cannabis takes advantage of this factor and the fact that it allows to decrease the formation of beta-amyloid protein in order to contribute to the fight against certain disorders that cause a progressive degeneration of the hippocampus.
However, recently it has been seen that this occurs in the laboratory rats used to perform experiments, but not in humans: in our case, the birth of new hippocampal neurons is virtually non-existent in adults.
- Related article: "Hippocampus: functions and structure of the organ of memory"
5. It can produce psychotic outbreaks
Although it does not occur in all cases, some variants of cannabis can facilitate the appearance of psychotic outbreaks in people with genetic predisposition to them, especially when adolescent consumption begins. This is because the early consumption it hinders the correct neuronal maturation of the connection between prefrontal and limbic system, which it's it facilitates the appearance of hallucinations and makes it difficult to control and inhibit behavior. In some cases it may promote the expression of schizophrenia.
- Related article: "Research reveals why marijuana can cause schizophrenia"
6. Decrease in impulse control
Another effect observed and directly linked to the reduction of gray matter in the frontal cortex is the decrease in impulse control . The ability to inhibit behavior is linked to specific parts of that lobe, which is responsible for counteracting the power of the limbic system, related to emotions and the appearance of desires.
Bibliographic references:
- Colizzi, M., Iyegbe, C., Powell, J., Blasi, G., Bertolino, A., Murray, R. M. and Di Forti M. (2015). Interaction between DRD2 and AKT1 genetic variations on risk of psychosis in cannabis users: a case-control study. npj Schizophrenia 1, 15025 doi: 10.1038 / npjschz.2015.25.
- Dennis, C.V., Suh, L.S., Rodriguez, M.L., Kril, J.J. and Sutherland, G.T. (2016). Human adult neurogenesis across the ages: An immunohistochemical study. Neurophatology and Applied Neurobiology, 42 (7); pp. 621-638.
- Filbey, F. M .; Aslan, S .; Calhoun, V.D .; Spence, Jeffrey S .; Damaraju, E .; Caprihan, A. & Segall, J. (2014). Long-term effects of marijuana use on the brain. PNAS. vol. 11; 47 Center of BrainHealth. University of Texas
- Jiang, W .; Zhang, Y .; Xiao, L .; Van Cleemput, J. M .; Ji, S.P .; Bai, G. & Zhang, X. (2005). J.Clin.Invest. 115 (11); pp. 3104 - 3116.
- Volkow, N. D., Baler, R. D., Compton, W. M., Weiss, S. R. B. (2014). Adverse Health Effects of Marijuana Use. The New England Journal of Medicine, 370, pp. 2219-2227.
