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How Cannabis Affects Young Brains

Marijuana is the most used illicit drug used by adolescents in the United States, according to 2011 Monitoring the Future study. It’s also one of the few drugs that are increasing in popularity among teens. This isn’t new news, either. Marijuana has been the most used drug for nearly 40 years, and around 23% of high school seniors in the United States report using marijuana in the past month.

Over the past few decades, marijuana has become legal in 19 states, Washington, D.C., and Guam. So the term “illicit” drug may not apply for much longer.

Plus, there has been a lot more research about the potential medical and psychological benefits of marijuana use recently. Researchers believe that cannabis may reduce pain and nausea, help manage seizure disorders, and more. However, despite these potential benefits, research shows that marijuana use in children and teens has some damaging effects.

Cannabis and the Developing Brain

Does cannabis damage young brains? What are the effects of using marijuana as a teenager? Lots of people have these questions in regards to marijuana usage by young people.

At the moment, we don’t have a really clear idea of how marijuana affects the body. We need more studies before we get a clearer picture of all the effects of cannabis. However, the research that we do have points to cannabis use by teens being very problematic.

Cannabis has two big components, cannabidiol (CBD) and tetrahydrocannabinol (THC). CBD is known for its potential health benefits and its calming effects. THC is known for its psychoactive effects that cause a head “high.” Most recreational marijuana strains have high concentrations of THC that cause the user to get high.

Marijuana use has been shown to impair different functions like memory, attention, learning, and decision making. Research has also shown that heavy marijuana use in young people is associated with poor school performance, increased welfare dependence, increased unemployment, higher dropout rates, and overall lower life satisfaction. (Although it’s important to note that more studies need to be done before we can truly put all of the blame on cannabis. Researchers don’t know for sure if marijuana directly causes those outcomes, or if teens already struggling in different aspects of their life may use marijuana to help cope, or if they are affected by peer pressure to smoke weed.)

What Research Says About Teen Marijuana Use

One long-term study performed in New Zealand by psychologist Terrie Moffitt, Ph.D., and colleagues, showed some of the damage caused by early marijuana use.

The study followed 1,000 New Zealanders all born in 1972. The participants answered questions about their marijuana five different times between the ages of 18 and 38. They also participated in neuropsychological testing at 13 and 38. The findings from this study are worrisome - the team of scientists found that there was a prominent decline in IQ of about six points in persistent marijuana users. Although that may not seem like a lot, it’s comparable to the IQ point decrease caused by lead exposure.

There are many potential reasons for why adolescents may be susceptible to damage from marijuana use, and it’s mostly because, until the mid 20s, the brain is still developing. This is especially true for the frontal cortex - the part of the brain that is responsible for decision-making, personality, and planning. This physical immaturity in the brain can cause it to be more easily damaged by drug use early on.

Another study from 2013 found evidence of significant brain abnormalities and altered neural activity in persistent marijuana users.

Yet another study from 2013 found that heavy marijuana users, who reported smoking five of the previous seven days, and who had smoked more than 2,500 times in their lives, had damage to the white matter in their brains. White matter helps enable communication between neurons. Researchers found that those white matter changes correlated with higher impulsivity in people who began smoking before 16 years old.

Ultimately, research shows that cannabis use in adolescents may result in neurological changes and damage. Most states require people to be 21 or older before they can use marijuana recreationally, and that rule should certainly be followed.

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