Marijuana science > Scans reveal some of what weed really does in your brain, but science still misses the most important aspect

 

What weed really does to your brain, according to hundreds of thousands of scans

By 

Tracy Swartz

Published April 20, 2026

 Updated April 20, 2026, 6:38 a.m. ET

Marijana has been known to take a toll on the body.

It can irritate the lungs, damage blood vessels and accelerate heart rate. Not to mention the scromiting, the screaming — and vomiting! — that can accompany long-term, heavy use.

The brain also takes some hits.

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Over 52 million Americans are believed to smoke pot, which may be harming certain areas of their brain.

Jared Larson / NY Post

“From a brain imaging perspective, marijuana use is consistently associated with measurable changes in brain function,” Dr. Daniel Amen, founder of Amen Clinics, which has conducted hundreds of thousands of scans to measure blood flow and activity in patient brains, told The Post.

A study last year out of the University of Colorado, for example, linked chronic use to a decline in working memory, the brain’s ability to retain, process and use information immediately.

The other ways marijuana can drain your brain may blow your mind. Here’s a look at six of the potential puff-ects.

Coordination

The CDC estimates that 52.5 million Americans, or about 19% of the US population 12 and older, get high at least once a year. The legalization of cannabis in many states has increased access to grass, putting the ole noggin in the crosshairs.

“Marijuana users demonstrate widespread reductions in cerebral blood flow, particularly in regions critical for memory, coordination, emotion and executive function,” Amen said.

The main psychoactive compound of marijuana, THC, is the culprit here. It disrupts the brain’s cerebellum and basal ganglia, which are responsible for motor control, balance and coordination.

That could manifest as lane weaving while driving, body swaying due to instability and delayed reactions. These effects are most pronounced in the first hour after marijuana use and can last several hours.

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Research continues into the long-term effects of frequent marijuana use and brain function.

See Also

The real horrors of the ‘scromiting’ weed disorder plaguing ERs — from dwindling to 87 pounds to ‘nonstop puking’ for a week

Memory

THC also binds to receptors in the hippocampus, which plays a critical role in memory formation. It’s one of the brain regions most affected by weed, Amen noted.

“Cannabis users show significant hippocampal hypoperfusion, with studies demonstrating reductions of up to 13–17% compared to controls,” Amen said, referring to the sustained blood flow reduction to the hippocampus.

“This is clinically meaningful because the hippocampus is highly vulnerable to neurodegenerative processes and is essential for learning and memory consolidation,” he added.

In short, marijuana can disrupt the process of turning short-term memories into long-lasting ones.

Judgment

“The prefrontal cortex, responsible for judgment, impulse control and decision-making, shows reduced activation as well,” Amen said.

This can fuel smokers to seek out immediate rewards while overlooking long-term consequences, undermining their ability to assess risk and adapt to new information.

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Cannabis can significantly affect mental health, increasing the risk of schizophrenia, psychosis and addiction.

AndreaMonica – stock.adobe.com

Attention

Marijuana brings the smoke — and the brain fog.

Hash can make it harder to plan, organize, concentrate and multitask. Blame THC’s effect on the prefrontal cortex.

Sensory perception

Cannabis can intensify taste, sound, smell, vision and touch, making music feel more immersive and colors more vibrant, because THC activates brain regions linked to sensory processing.

On the flip side, marijuana can also dull night vision and slow glare recovery, making nighttime driving trickier.

Mental health

“The amygdala, which regulates emotional processing, demonstrates decreased activity in imaging studies,” Amen said.

“This may contribute to emotional blunting in some individuals, but cannabis use is also associated with increased rates of anxiety, paranoia and psychosis, particularly in high-frequency users or those with genetic vulnerability,” he noted.

Research shows that users are also at increased risk of mood changes, panic attacks, depression, addiction, schizophrenia and suicidal ideation.

Some of these brain changes may ease upon quitting marijuana. Research into the long-term effects of frequent use and neural recovery is ongoing.

“Findings suggest that marijuana use is associated with global reductions in brain function, rather than enhancement,” Amen said.

“While some individuals report short-term benefits, imaging data indicate potential negative effects on memory, coordination, emotional regulation and executive function — especially with chronic or heavy use.”

Science still hasn't figured out what I have been observing for 50 years:

Marijuana use stops the maturing process in most users

Because of this, marijuana is responsible for the dramatic drop in the birth rates in western societies - youth tend to remain in their teens emotionally right through their twenties and thirties as long as they continue using.

Emotionally immature youth don't want to raise children. 

Playing Russian Roulette with Your Sanity

Cannabis > The abuse of medical cannabis in Australia

 

‘Profits over patient safety’: Doctors face medicinal cannabis crackdown

Patients in emergency departments with cannabis-induced psychosis, consults lasting less than a minute and doctors who have issued more than 10,000 scripts in six months are among the cases that have prompted Australia’s healthcare watchdog to announce clearer guidelines for the booming medicinal cannabis industry. The Australian Health Practitioner Regulation Agency has released guidance for doctors prescribing medicinal cannabis products amid what it described as poor prescribing practice and surging patient demand.

The watchdog has been alarmed by the emergence of “vertically integrated” telehealth clinics, which both prescribe and dispense cannabis products and account for the vast majority of an estimated $500 million worth of sales each year. The regulator’s chief executive Jason Untersteiner said it would crack down on some practitioners with high rates of prescribing, including eight who had issued more than 10,000 scripts in six months, and one who has prescribed cannabis products more than 17,000 times. “Some business models that have emerged in this area rely on prescribing a single product or class of drug and use online questionnaires that coach patients to say ‘the right thing’ to justify prescribing medicinal cannabis,” Untersteiner said. “This raises the very real concern that some practitioners may be putting profits over patient safety.”

In Australia, GPs and qualified nurse practitioners can prescribe medicinal cannabis under a special access scheme set up after cannabis was legalised for medical use in 2016. Under the guidelines, GPs and nurses must only prescribe cannabis products after they have identified a therapeutic need, conducted a thorough assessment of their medical history and other medicines, and developed an exit strategy from the beginning.

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Another study misses the real reason for falling birth rates

 

Baby bust: Why the French want fewer children

– or none at all

Analysis

France

Long Europe’s baby-making champions, the French are increasingly aiming to have smaller families or no children at all, a trend driven by changing social norms, economic constraints and the concerns and aspirations of a younger generation.

Issued on: 10/07/2025 - 18:36

4 minReading time

By:

Barbara GABEL

France's traditionally resilient birth rate has dropped sharply in recent years, fuelling talk of the end of the country's “demographic exception”. © Joël Saget, AFP file photo

From her teenage years, Bettina Zourli knew she would be the “cool auntie” – but not a mother herself. It’s a choice she recalls having to justify time and time again.  

“People told me that I was bound to change my mind, that it was in the female nature to want children,” says the 31-year-old feminist writer and activist, whose Instagram account @jeneveuxpasdenfant ("I don’t want children") has more than 65,000 followers. 

Zourli's views on the matter are increasingly common in a country that used to stand out from its European neighbours for its high birth rate, but has recently fallen in line.

Last year, 12.2 percent of French people said they didn’t want to have children, more than twice the number from 2005, according to a study released on Wednesday by national demography institute INED. 

The figure is even higher in the 18-29 age group, roughly equivalent to “Gen Z”, with 15% percent of men and 13.3 percent of women saying they do not want to be parents. 

The shifting numbers are the latest indicator of changing attitudes to parenthood and the steady erosion of France’s so-called “demographic exception”. 

‘Changing social norms’ 

Zourli says it’s often hard to pinpoint a particular reason for not wanting children. 

“It’s just the absence of desire,” she says. “It’s more of an innate thing. You can’t explain why you don’t want kids.” 

According to the INED study, neither gender, nor standard of living, nor professional category alone can explain why a growing number of people say they have no desire for children. It points instead to how “attitudes and opinions” increasingly weigh in the balance. 

Here is the missing link that ties this all together - marijuana. Cannabis users have a tendency to stop maturing when they start using pot. Consequently, many never reach the level of maturity where they want to have children. Many remain emotionally adolescents well into adulthood.
Marijuana > The Astounding Effects it is Having on Civilization - No one is talking about

Didier Breton, a professor of demography at the University of Strasbourg and associate researcher at INED, cautions against reading the figures as evidence of a fading desire to have children.  

“It’s more a matter of changing social norms,” he says. “Twenty years ago, it was less acceptable for people to say they didn’t want children, particularly for women. Today, it’s easier to express such a choice.” 

Breton points to several possible motives for not wanting children, including the physical transformations associated with pregnancy, a refusal to accept the constraints of parenthood, and a desire to preserve one’s freedom and independence.  

“It’s about making life-defining choices, such as prioritising your career, travelling, or simply not reproducing the family model you’ve known,” he says. 

Gender inequality 

A 2021 survey of people who did not want children found that 86 percent cited the desire to devote themselves to “private life, relationships, friends and travel”. In second place, 71 percent of respondents said they didn’t identify with parenthood. 

The latter figure conceals a major gender gap, with 45 percent of women answering “not at all” against 29 percent for men – a discrepancy that is even wider among people aged under 30.  

“Gender inequality is a major factor in women’s stance on whether or not they want children,” says French sociologist Charlotte Debest, whose book “Elles vont finir seules avec leur chats” ("They will end up alone with their cats") will be published later this year.  

“The unequal division of domestic labour makes it harder for women to see themselves as mothers,” Debest explains. “Many women refuse to accept traditional models of the ‘good mother’ that persist to this day. Such models are out of step with the aspirations of many young women.”

Concern about climate change and the future of the planet is another major factor.  

In the 2021 survey, 63 percent of respondents cited environmental protection as a reason not to have children. The high percentage reflects both growing ecological awareness and a tendency to seek an ethical motive for remaining childless, argues Debest.  

Read moreThe French nationals going 'childfree' to save the planet

“Using the ecological argument gives social legitimacy to people who choose not to have children,” she explains. “Instead of just saying, ‘I don’t want children’, it’s a way to say you’re giving up on children for their own good.”  

She adds: “Of course, there are many childless people who are genuinely committed to environmental activism or concerned about the future of the planet.” 

The end of the three-child model 

Such concerns are fuelling a rapid drop in France’s fertility rate, which slumped to 1.62 children per woman last year, down from 2.02 in 2010, hitting its lowest level since the end of the First World War.

The steady decline in recent years has prompted President Emmanuel Macron to call for a “demographic rearmament” of the nation with new reforms making it easier for people to have children – which are yet to come into law.

According to the INED study, people who do want children are increasingly aiming for smaller families, largely because of economic constraints.  

Among women under 30, the desired number of children has fallen from an average of 2.5 in 2005 to 1.9 in 2024, the study found. 

“The high cost of living coupled with job and housing instability mean many people feel they simply cannot afford another child,” says Debest. “There is a new awareness of the cost of bringing up children.” 

Whereas 26 percent of French people said they wanted three children in 2005, the figure has now dropped to 15.5 percent.  

“We are witnessing the erosion of the three-child family model, which was once highly valued in France,” says Breton, for whom the model is “destined to disappear”.  

Zourli says she regularly receives Instagram messages from mothers wondering whether they should have a second child, and that many thank her for making them feel “less guilty”.  

“The societal pressure to have a nuclear family with a boy, a girl and their heterosexual parents remains strong,” she adds. “But it's being questioned more and more.” 

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