The most commonly used substances among adolescents are alcohol and marijuana. Nowadays, more people who smoke marijuana than tobacco. And, one valid reason for this increasing trend among adolescents is due to the belief that marijuana is relatively safer and less risky than tobacco.
Marijuana can be used in many ways, such as by smoking the dried plant in a rolled cigarette, pipe, or bong. Some use it by smoking liquid or wax marijuana in an electronic cigarette, or by eating baked goods or drinking beverages which contain hemp, and even by using oils and tinctures that are applied to the skin.
In Canada, about one in five adolescents use marijuana. The substance was recently legalized in the country, however, the need for a thorough investigation and further studies regarding its long-term consequences on the developing brain of adolescents arises.
At this stage, the adolescent brain is associated with maturation of cognitive functions such as decision-making, impulsivity control, and working memory — making it a very vulnerable period for brain development. This is also the time, wherein, the regulatory connection between regions of the cortex and emotional processing circuits are formed.
Canadian neuroscientists Patricia Conrod, Steven Laviolette, Iris Balodis, and Jibran Khokhar looked into the possible effects of marijuana use to the developing adolescent brain and their findings were featured at the 2019 Canadian Neuroscience Meeting in Toronto on May 25 of this year.
They studied the year-to-year changes happening in a sample of adolescents using alcohol and marijuana. Their study covered 5% of adolescents entering high school in 2012 and 2013 in the Greater Montreal region, which has a total of 3,826 7th grade students. During the 4-year duration, they assessed the students yearly for their alcohol and marijuana use, and their cognitive function was evaluated using computerized cognitive tests.
Researchers found out that use of alcohol and marijuana was linked to reduced cognitive function. This suggests that the use of these substances causes vulnerability.
As an example, marijuana was found out to be associated with impairments in working memory and inhibitory control, as well as deficits in memory recall and perceptual reasoning. Surprisingly, alcohol use was not linked to these impairments of cognitive function, which may suggest that the use of marijuana has more long-term consequences than alcohol use.
Dr. Steven Laviolett confirmed this finding in his study — which tackled about the active ingredient in marijuana having effects in rodent brain that resembles abnormalities observed in schizophrenia. He discovered that the active ingredient in marijuana also caused affective and cognitive defects, including deficits in social interactions, memory processing, and anxiety regulation.
Some studies about marijuana use say that the use of this particular substance during adolescence is associated with behavioral changes related to reward and motivation. Paradoxically, this use has both been suggested to increase motivation for other drug use and a potential “motivation syndrome” in which individuals are less willing to expend effort to receive a reward
To better understand the topic, Dr. Jibran Khokhar, from the University of Guelph, studied the effect of THC exposure — which is the active ingredient of marijuana — in adolescent rats on their adult behavior. He found out that there were changes in the connection between different regions of the brain, including those involved in encoding reward and motivation which suggests that marijuana exposure in rats can have long-term changes in the circuitry of the brain, which contributes to the behavioral changes observed after the exposure.
Overall, the findings of the study helped in understanding the association between the use of marijuana and the long-term changes in the brain, which can explain the behavioral changes in adolescents. These changes include impairments in working memory, self-control, and motivation. Fortunately, researchers found out that the changes are reversible through specific therapies.
Fundamentally, the brain is a very vital organ among humans since it can dictate the behavior and skills of a person. Therefore, we should be cautious when taking in substances that could potentially affect the development of this vital organ. Aside from the brain, there are studies which support the claim that alcohol and marijuana use could also affect other organs and bodily functions such as the liver and kidneys.