Marijuana’s Effects on the Brain

Originally written by: Jennifer Taylor

Marijuana is a drug getting some new public relations spin. The drug has now been legalized for recreational use in Colorado and Washington and is legal for medicinal use in 19 states. In an April poll, more than half of American favored legalization of marijuana, a first in four decades of polling by Pew Research. Popular opinion makes marijuana seem like a harmless pastime and a medical wonder, but can your brain be harmed by using marijuana short-term or long-term? More times than not, people who frequently light up a joint often forget that marijuana has certain health risks. It’s time for everyone to take a second look at marijuana’s effects.


Short-Term Effects of Marijuana

Tetrahydrocannabinol (THC) is the active ingredient in marijuana. THC causes the brain to release dopamine, which  stimulates pleasure centers in the brain. The immediate effects include euphoria, relaxation and heightened perception for some people.  Marijuana use can increase appetite, which is why it may help cancer patients experiencing loss of appetite or nausea from treatment. Marijuana can impair the ability to form new memories and perform tasks that require balance and coordination.

Smoking marijuana regularly alters the normal blood flow to the brain, and studies show that this effect can last a month after smoking marijuana. Large doses of THC, even in the short term, can produce psychosis and hallucinations for some people.

Long-Term Effects of Marijuana

Many of marijuana’s effects on cognition are reversed when a person stops smoking. However, some people are more vulnerable to long-term effects and researchers cannot predict which users are more likely to experience them. But some long-term effects are more subtle and concern particular groups who use marijuana.

On Those Who Start as Teens. Although much of the research on marijuana is mixed, there is a consensus that those who start smoking as teens are more likely to develop more long-term problems. One study showed that people who started smoking as teens lost IQ points , which they did not regain those lost points when they stopped smoking as adults. Two studies linked teen marijuana use to psychotic symptoms, with both of them showing that teens with psychosis were more likely to smoke pot and teens who smoked pot were more likely to develop psychotic symptoms.

On Memory.  Several studies show that memory impairment linked to smoking marijuana reverses after it is stopped. But some long-term effects on memory are more subtle. THC affects how the brain processes information in the hippocampus, where memory formation occurs.  Changes there can interfere with the ability to learn new information or perform tasks related to memory. Prolonged marijuana use deprives the brain of its natural endocannabinoids and also affects blood flow, glucose metabolism and brain structure.

On Mental Illness. Marijuana use has been linked to several mental illnesses, including schizophrenia and psychosis. Schizophrenia includes deterioration in thinking and disturbed perceptions, which may be exacerbated by marijuana. The disconnect from reality of psychosis can increase the likelihood of dangerous behavior. Marijuana is also associated with depression and anxiety, but the cause and effect there is not established. People prone to depression may smoke marijuana or using marijuana may lead to depression. The THC in marijuana disrupts the brain’s natural endocannabinoids, which are part of mood regulation.

Marijuana Addiction

Many people believe that marijuana is not addictive. However, people who stop smoking it frequently experience withdrawal symptoms like anxiety, irritability, depression, cravings and insomnia. Research from the National Institute on Drug Abuse shows that about 9 percent of people who use marijuana will become addicted to it. The risk is even greater for those who started as teens. The addiction rate for people who use marijuana daily is between 25 and 50 percent.

Despite the calls for legalization everywhere, the risks of marijuana remain, especially for those who start as teens. If you’ve been using marijuana and feel that you have become addicted, you may need professional assistance to stop. Consider contacting a certified drug rehab facility to see what you can do to stop.


Jason Adams is an inbound marketing strategist at Lakeview Health Systems. He is dedicated to providing valuable content for friends, families and individuals who may be struggling with drug and alcohol related problems. Follow Jason on twitter @JasonSteelz.

2 thoughts on “Marijuana’s Effects on the Brain

  • July 20, 2013 at 11:46 am

    One does not need to see a pile of scientific literature on the evil effects of marijuana before one would believe the insightful facts shown by this author. In fact, the evil effects of marijuana are considered matters in public domain. If not, why have governments all over the world placed such material under strict check? Why have even some governments in the world gone the extra mile of applying the death penalty on anyone caught messing up with this material? Or are all the governments of the world, including the US, stupid by putting these checks. Come on, let’s not play the ostrich here! Marijuana is dangerous and it has remained so. Even the apparent relaxation on the ban against it use by some authorities still has a strong appendage of a caveat beyond which the law steps in again to clamp down on the user!

    Anybody who otherwise thinks that marijuana is safe does so at a risk to his health and his freedom because he could be violating any of these.

  • July 18, 2013 at 11:33 am

    Sources are not listed for this article. These claims made in this article have no legitimate studies to back up these claims. These are just opinions of this so called writer.


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