Marijuana is known to be a relatively harmless drug, but researchers are learning more about the effects it may have on the brain.
Marijuana use may pose an increased risk of psychosis, the scrambled neuron signals and changes in the brain’s reward system, and some other effects. The biggest risk associated with the use of marijuana is the increased risk of psychosis. For those who use marijuana during their teenage years, there may be an increased risk of an IQ drop.
It’s safe to say that people who smoke marijuana, especially during their teenage years, are more likely to have IQ drop later in life.
In this article, we look at 7 ways marijuana may affect the brain.
How marijuana affects the brain
Here is how marijuana affects the brain:
- Marijuana and psychosis
- Marijuana effect on brain size, connectivity
- Marijuana effects on IQ
- Marijuana effects on the brain’s reward system
- Marijuana effects on munchies and the brain
- Marijuana causes noisy neuron
- Weed affects a teenager’s brain
1. Marijuana and psychosis
Several studies have linked the use of marijuana with a higher risk of psychosis, which is a medical term that applies to symptoms that involve losing touch with the real world, such as paranoia or hallucinations. For instance, researchers in an analysis published in the journal Schizophrenia Bulletin in 2016, looked at previous studies of 67,000 people.
They discovered that people in the study who used the most marijuana were more likely to be diagnosed with a psychotic mental-health condition, like schizophrenia than people who had never used marijuana.
Another review published in the journal Biological Psychiatry in April 2016 also discovered a link between cannabis use and an increased risk of psychosis. Evidence from epidemiology studies provides strong enough evidence to let the people know that cannabis use can increase psychotic disorders risk.
2. Marijuana effects on brain size, connectivity
The research suggested that using marijuana for many years may be linked to changes in brain size. A November 2014 study published in the journal Proceedings of the National Academy of Sciences, researchers analyzed 48 adults who use marijuana at least three times a day, for an average of 8 or 9 years and 62 people who didn’t use marijuana.
The people who had been smoking pot daily for at least 4 years had a smaller volume of gray matter in a region of the brain known as the orbitofrontal cortex, which previous research had linked to addiction.
3. Marijuana effects on IQ
The research suggested that teens that smoke marijuana (pot) may be more likely to experience a drop in IQ when they are older. In a study of over 1000 people in New Zealand, researchers administered IQ tests to the participants twice: when they were 13-year, and when they were 38. The researchers also asked the participants about their drug use throughout the period of study.
Around 5% of the teens in the study had been using pot when they were teens. Those who smoked pot at least 4 times a week and continued to use it throughout their lives experienced an IQ drop of 8 points, on average by the end of the study.
It is not clear why pot has negative effects on the IQ of people, but it could be that teens are more vulnerable to pot’s effect on brain chemistry.
4. Marijuana effects on the brain’s reward system
It has been discovered that the brain of people that smoked marijuana for several years may respond to certain rewards differently, compared with the brains of people who don’t use marijuana.
In a study, researchers wanted to see whether the brains of 59 chronic pot users would respond differently to photos of objects used for smoking pot than they did to the photo of objects considered to be “natural rewards,” such as their favourite fruits.
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The researchers found that study participants who had on average smoked marijuana for 12 years, exhibited greater activity in the brain’s reward system when they were shown photos of objects that they used for smoking marijuana (such as a joint or a pipe) than when they were shown the photos of their favourite fruits.
The people in the control group who didn’t smoke marijuana didn’t show greater activity in this brain region when they were shown marijuana-related objects.
This study shows that marijuana disrupts the natural reward circuitry of the brain, making marijuana highly important to those who use it heavily.
5. Marijuana effects on munchies and the brain
Marijuana may affect the brain’s neurons that are normally responsible for suppressing appetite and this effect may explain why people often get hungry after smoking pot.
In a 2015 study, scientists stimulated the appetite of mice by manipulating the same cellular pathway as the one that mediates pot’s effects on the brain, and they observed what was going on in the brain of mice during the experiment.
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The researchers expected that the neurons that typically suppress appetite would be turned off by their efforts to stimulate the rodent’s appetites. But it turns out that those neurons were actually activated because they had switched to releasing chemicals that promote hunger.
The researchers noted that it isn’t clear whether it would work the same way in people. But it’s been suggested that using marijuana makes people hungry
According to researchers, the finding could point to the way to treat the loss of weight and appetite that some cancer patients experience while undergoing treatments.
6. Marijuana causes noisy neurons
THC is the main compound in marijuana and research suggests that it may increase the level of neural noise or random neural activity in the brain.
In a study published in the journal Biological Psychiatry in 2015, researchers measured the levels of the random neural activity in 24 people under two conditions: after they had been given pure THC, and after they had been given placebo.
The scientists found that the people showed greater levels of neural noise after receiving the THC, compared with their levels after taking the placebo.
At doses roughly equivalent to half or a single joint containing THC, people experienced psychosis-like effects and increased neural noise in. The findings suggest that psychosis-like symptoms experienced by the people after smoking weed may be related o this neural noise.
7. Weed and the teenage brain
Weed or marijuana may affect teenage brains in a different way to adult brains. However, two studies showed that the effect may not be the same for every user, as it may depend on individual factors like genetics.
In one of the studies, scientists found that marijuana didn’t lead to small brain size in teens, in contrast with previous findings that had suggested that the drug does cause the brain sizes of teens to reduce.
However, the study found that, in teenage boys that are genetically susceptible to schizophrenia, weed might alter their brain development in potentially negative ways over time. The researchers in that study also looked at the teenage boys’ brains when they were 15, and when they were almost 19.
Scientists found that the boys who smoked weed and carried genes linked to an increased schizophrenia risk experienced thinning in their brain’s cortex – over the 4-year study.
The bottom line
Marijuana may affect the brain in many ways that is why pot smokers are advised to do it moderately if they can’t abstain completely. If you need help to stop smoking completely, see a specialist for help.
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