Marijuana Use in Young Adults

  • Posted at Apr 25, 2014
  • Written by Jesse Viner

All substances and behaviors that influence mood and cognition are potentially addictive. Throughout the world, the top three abused substances are nicotine, alcohol and cannabis. Often when individuals use one of these substances, they eventually migrate towards the use of all three.

Recently cannabis has gained significant social acceptance from the popular belief that it is benign with insignificant brain effects. It is also believed that cannabis is non-addicting. Both are false and significant popular misconceptions. Although the human brain naturally produces and uses cannabis-like molecules, current scientific data show that externally administered substances like marijuana influences behavior, they  also has a direct effect on brain functions.

In the US, data indicate that nicotine-use has decreased among college students, while cannabinoid-use has increased. In the light of these findings, we need to ask whether there are significant consequences for chronic cannabis-use. We also need to ask about the frequency of cannabis-use and the quantity of cannabis reaching the brain. In recent years, as cannabis’ quality has improved, there has been a significant increase in its potency. Marijuana’s psychoactive components have increased up to five fold, which increases their biological effect on the brain.

Moreover, as marijuana’s potency has increased, the age of first-time users has significantly decreased. Therefore, in light of emerging behavioral and imaging data that argue against recreational marijuana-use, the age-of-use becomes a significant issue. The data show that individuals, who routinely use marijuana, have significantly altered brain structures and functions with significant alterations in cognition and mood regulation. Relative to non-users, chronic marijuana-users generally underperform in memory and cognitive tasks; in addition chronic marijuana-users may develop significant mood deregulation that present as depression and anxiety. Current data are unclear about the duration of these effects. More alarming are data that argue that some chronic marijuana-users can develop psychosis that, in some cases, leads to significant psychiatric conditions such as schizophrenia spectrum disorder.

We need to ask who is vulnerable to such significant and potentially chronic conditions. Current data state that a subpopulation of individuals may be particularly vulnerable to marijuana-use. These individuals have been characterized as having an altered genetic makeup of certain brain molecules that regulate a neurotransmitter called dopamine. These brain molecules help eliminate dopamine after its release from brain neurons. Individuals with this genetic predisposition are more likely to develop psychosis and are potentially more vulnerable to developing chronic mental illness. In addition to genetic vulnerability, it appears that there is a well-defined window of vulnerability linked to age: Individuals, who engaged in heavy marijuana-use before 17, are five times more likely to abuse other substances later in life. Furthermore, these vulnerabilities indicate that marijuana-use may lead to future cognitive difficulties such as lower IQ and psychiatric symptoms later in life.

Many researchers would agree that pre-teen, teen, and young adult marijuana-use may be significantly detrimental to brain development and, consequently, to successful participation in life.  Emerging data shows that chronic marijuana-users performed poorly in school, often found themselves in conflict with the law, and did not progress, as expected, in developing their interests and careers. One proposed hypothesis states that marijuana-use leads to decreased motivation and decreased ability to focus, pay attention, form memories, and solve complex problems. It’s becoming clear that chronic marijuana-use impacts emotional as well as cognitive processes and affects structures such as the hippocampus–critical for memory formation and retrieval, the amygdala–a critical part of the emotional brain, and the frontal lobes–the executive brain.

Lastly, but not surprisingly, marijuana-use and the use of other substances such as nicotine and alcohol may significantly impair the academic performance of college students. As students learn to manage new challenges, college often becomes a significantly stressful time. Sometimes when faced with stressors, college students seek an easy solution and use substances that provide acute relief. Such behavior can undermine the educational process and prevent learning.  If one replaces hard work and natural modes of stress management for states of acute well-being, one will inevitably experience unfulfilled scholastic goals and potential psychiatric challenges.

This article was written by Dr. Lukasz Konopka.

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