♪ ♪ ♪ ♪ NARRATOR: Cannabis.

A multi-billion dollar industry is moving from the illicit market into our daily lives, creating a stark divide.

KASSANDRA FREDERIQUE: In a country where people are talking about its medical use, someone gets arrested for cannabis every 58 seconds.

♪ ♪ NARRATOR: A plant demonized to arrest millions now marketed as a medicine.

EVELYN NUSSENBAUM: My son had a devastating form of epilepsy, and a cannabis compound gave him a life.

NARRATOR: How does the vast array of chemicals in cannabis engage a mysterious system in our bodies?

YASMIN HURD: The cannabinoid receptor is the most abundant receptor in the brain.

MATTHEW HILL: How a single system can influence so many biological processes is surprising.

♪ ♪ NARRATOR: Will regular-- even daily-- use cure us or hurt us?

PAUL DEBASSIO: If someone were to tell me that I was dependent on marijuana, I would have said no way, absolutely not.

NARRATOR: Smoked, dabbed, vaped, and eaten, today's cannabis is hyper-potent, and far from understood.

ZIVA COOPER: These products are coming online much faster than we can actually research them.

NARRATOR: As federal law blocks science, an unintended public health experiment is underway.

CHINAZO CUNNINGHAM: Really the questions are for what conditions is it beneficial and for what conditions is it harmful?

It's not black and white and it's complicated.

NARRATOR: What's the right dose?

Who should use cannabis?

Who shouldn't?

STACI GRUBER: It's a highly contentious subject, but it's not about your personal thoughts or feelings.

What does the data tell us?

What does the science tell us?

Truth through science.

We should know the answers.

NARRATOR: "The Cannabis Question," right now on "NOVA."

♪ ♪ ♪ ♪ NARRATOR: More than 80 years after America ended one type of prohibition, it's ending another.

The majority of people now live in a state where cannabis is legal.

As a multi-billion-dollar industry rises, our country is at a crossroads.

♪ ♪ HILL: Cannabis is genuinely one of the most fascinating discussion topics I've ever seen because of how emotionally polarizing it is amongst people.

And it's very strange because the entire field of cannabis science is very poorly developed.

There's not been a lot of research and there's a lot of things that we don't understand.

And yet, what we have in society is groups of people that very fervently believe it is this panacea that can cure any disease that exists, or it's the devil's grass, and it's going to cause the downfall of society, not recognizing that the reality of cannabis is somewhere in the middle.

♪ ♪ (birds chirping) ♪ ♪ NARRATOR: Americans everywhere are turning to cannabis, seeking relief from a wide range of ailments, including veterans, like Sean Worsley, who uses cannabis to treat his post-traumatic stress disorder caused by combat in Iraq.

SEAN WORSLEY: Our sole purpose was to clear the routes for supply convoys that came through, looking for roadside bombs that were on the route.

(explosion) I was on a mission and we rode over a hole that was in the center of the road and unfortunately it was an IED that went off.

(explosion) (overlapping shouting) Knocking me unconscious, and when I woke up, medic was in my face, asking me was I okay, could I hear him.

(shouting) ♪ ♪ NARRATOR: After his tour, Sean struggled with a traumatic brain injury and disturbing symptoms caused by PTSD.

WORSLEY: For me it's paranoia, insomnia, seeing things that aren't necessarily there-- "shadow people," as they call them-- night terrors, dreams, but these nightmares were very realistic.

(gunshot fires) If I was shot in the dream, I would wake up grabbing my chest because I felt the pain.

NARRATOR: Sean's medications for PTSD had troubling side effects, so he got a medical cannabis card.

RYAN VANDREY: Cannabis at a low dose can help reduce anxiety, relax someone.

And individuals who have PTSD that newly initiate cannabis use report it being life-changing.

So, I can sleep for the first time in two years, and I can go to the grocery store without being so intense and on edge.

That's why individuals with PTSD heavily gravitate towards cannabis use.

NARRATOR: For thousands of years, humans have cultivated cannabis for its fiber, seeds, and medicinal properties.

Ancient Hindu texts claim it was brought by the god Shiva for the pleasure of humanity.

♪ ♪ The plant contains over 400 chemicals, including cannabinoids, which are most abundant in the resin glands of budding female plants.

♪ ♪ In the 1960s, Israeli scientist Raphael Mechoulam isolated THC, the psychoactive cannabinoid that makes users feel high.

♪ ♪ The discovery launched a new chapter in neuroscience.

DANIELE PIOMELLI: Cannabis opened a window into the functioning of our body, completely unexpected window.

Because what was discovered was that THC binds to receptors in the brain and outside the brain, and when it does so, when it binds to these receptors, the cells now behave differently.

♪ ♪ NARRATOR: Cannabinoid receptors, named after cannabis, are found on nearly every organ in the body.

They bind with our own cannabis-like molecules, called endocannabinoids, which regulate functions like sleep, cognition, memory, and mood.

♪ ♪ Unlike other brain chemicals, they travel backwards, across the synapse, where they control the release of most neurotransmitters.

♪ ♪ GRUBER: One of the most amazing things that happened was the discovery of the endocannabinoid system.

Every mammal has one.

And this is a system of chemicals and receptors throughout the brain and body.

And really the primary goal of the endocannabinoid system is homeostasis-- keeping things in balance.

♪ ♪ NARRATOR: At Mount Sinai Hospital, neuroscientist Yasmin Hurd remembers the first time she looked for cannabinoid receptors in the human brain, seen here in vivid red, orange, and yellow colors.

The cannabinoid receptor is the most abundant receptor in the brain.

When we looked at where these receptors were expressed, they're expressed in brain regions relevant for motor coordination, cognition, memory, emotional regulation, reward.

All of these brain areas are key to so many normal behaviors, obviously, but also psychiatric disorders as well.

A key role of the endocannabinoid system is to manage stress.

In fact, the first endocannabinoid found in our body was given a Sanskrit name, anandamide, meaning "bliss."

HILL: In response to stress, our body mobilizes an endocannabinoid signal.

And so, if something aversive happens to us and we suddenly see a threat in front of us, our body kind of goes into a high alert mode and we shoot up.

Once we've been removed from that threat, though, our body needs to turn that stress response back off.

And what we have learned is that this burst of endocannabinoids that occurs in response to stress is really critical for that recovery phase.

NARRATOR: Scientists suspect this signal goes awry in people with PTSD, and that's why THC, which mimics our own endocannabinoids, might help.

VANDREY: And so, when you look at individuals that have PTSD and use cannabis, in short-term trials, you see very beneficial outcomes.

But if all they do is use cannabis and they don't engage in other behavior therapies to help work through their trauma, they're not treating the root cause of the disorder.

And it's important to recognize that THC at higher doses increases anxiety.

CUNNINGHAM: Cannabis is not a miracle, nothing is a miracle.

And so really the questions are for what conditions is it beneficial and for what conditions is it harmful, and for whom is it beneficial and for whom is it harmful?

So, it's shades of gray.

It's not black and white, and it's complicated.

♪ ♪ NARRATOR: In 1996, cannabis was legalized in California for medical use.

But federally, it remains a Schedule One drug, like heroin, making research difficult, and leaving patients like Elizabeth Pinkham on their own.

To cope with her cancer treatments, Elizabeth has turned to cannabis.

ELIZABETH PINKHAM: When you go through chemotherapy, there are side effects that can be... like nauseousness.

You may have loss of appetite, you may have difficulty sleeping.

So I was looking for something that wasn't another big, heavy-duty pharmaceutical.

NARRATOR: On display, one can find cannabis-infused teas, sodas, candies, bath salts, psychoactive body washes, and flower, with THC, that can ease nausea when smoked.

PINKHAM: The effects are pretty immediate.

I've definitely gotten my appetite back a little bit more.

It also helps with neuropathy, which is like the numbness in your fingers and your toes.

This is super medicinal.

You see how, like, dark and dense that is?

Mm-hmm.

That's indicating more of the indica family.

Good for the body, good for pain.

STEVE D'ANGELO: My staff needs to do the best that they can to try and guide people to the products that are going to serve them the best.

But my staff, they're not trained doctors, and really we should have cannabis medicine being taught in every single medical school across the United States.

And that's not happening now because of federal law.

It's really a voter-approved quote-unquote "medicine," so people say, "Oh, there's medical cannabis that's approved."

It has not been, it has not gone through FDA rigorous research process.

And that's what's critical for medicine.

PINKHAM: I think it would be great if there was a bit more science behind this.

But I think in the meantime you have to do what works for you, and you have to figure this out as you go.

♪ ♪ NARRATOR: But it's challenging.

Scientists aren't sure whether cannabis sativa, indica, and ruderalis are distinct species.

Most cultivars grown today are hybrids.

They have distinct chemicals called terpenes, which create flavors and smells.

And in addition to THC, the plant contains over 100 other cannabinoids.

One, called CBD, is flooding the market.

COOPER: One in seven adults in the United States are using CBD.

You see CBD everywhere, you see it in the pet stores, you see it at Bed Bath and Beyond, at Whole Foods.

And so there's a multi-billion-dollar industry that's built on this plant and there are all these different hypotheses of what these different chemicals can do to help us.

But these products are coming online much faster than we can actually research them.

♪ ♪ NARRATOR: Despite CBD's availability today, it took a group of determined parents to bring it to market.

One quest began in Palo Alto, California, where Stanford neuroscientist Catherine Jacobson set out to treat her son Ben's epilepsy.

♪ ♪ CATHERINE JACOBSON: Watching your child have a seizure is really, really scary.

It's awful, right?

It's awful because you know that brain damage is happening.

The kids get scared, they get confused.

And with uncontrolled epilepsy, we all live with this fear that they're going to die.

(gasping) NARRATOR: About a third of epilepsy patients don't respond to medications.

Catherine knew the longer Ben's seizures continued, the less likely they'd be controlled.

Could you have just given him medicine?

MAN: Mm-hmm.

NARRATOR: And she was not alone.

In Berkeley, California, her friends Fred Vogelstein and Evelyn Nussenbaum also felt powerless to control their son Sam's epilepsy.

♪ ♪ FRED VOGELSTEIN: I mean the thing about seizures that most people don't realize is that they're dozens of different kinds.

So, the kind of seizures that most people know about are the grand mal seizures where you just lie on the ground and, like, start flopping.

The other seizure that a lot of people know about are staring spells.

Sam had a version of those seizures because he would go unconscious for, like, 15 seconds.

NUSSENBAUM: When anyone has a seizure, you could compare it to an electrical storm, or an overtaxed electrical grid.

We all have electricity in our brains.

And when someone has a seizure, the electricity becomes irregular.

FRED VOGELSTEIN: Every single drug we tried didn't control the seizures, and some of them had pretty nasty side effects.

NUSSENBAUM: One time he had hallucinations and thought he had holes in his skin and there were bugs crawling out of them.

I thought we were going to have to take him to the psych ward.

VOGELSTEIN: And then there were all the medicines that made him a zombie.

NARRATOR: Then, they stumbled across research suggesting cannabis might quell seizures.

JACOBSON: I knew nothing about cannabis, but I did some research and I found out that obviously there are many different chemicals in cannabis, the two most prominent are CBD and THC.

We know that THC makes people high.

CBD doesn't do that.

And so, my preference was of course to try CBD first.

NARRATOR: CBD doesn't bind to cannabinoid receptors directly, but it's presence seems to reduce the impact of THC.

♪ ♪ It also increases levels of anandamide, our bliss molecule, and interacts with receptors like serotonin, which affect our mood.

Yet in 2011, it was hard to find extracts high in CBD.

JACOBSON: And so we would get these vials and sometimes they would work a little bit and then the next vial wouldn't work.

So, after probably six to eight months of doing this and seeing no benefit to Ben, I just said, look, I'm going to make my own.

(machine whirring) NUSSENBAUM: When Sam first took Catherine Jacobson's CBD tincture, it was clear as day, his seizures were going down immediately.

Unfortunately, Catherine only had enough for five days.

And so we had this incredible five-day stretch.

And then we ran out.

♪ ♪ NARRATOR: CBD also helped Catherine's son, Ben.

But her next batch of tinctures were too weak to use.

Drug companies get a lot of abuse for their marketing tactics.

But the one thing that they do really, really well, is they make every pill exactly the same.

It's sanitized, it's quality controlled.

And I wanted that for my son.

♪ ♪ NARRATOR: Then, they heard about an English company called GW Pharmaceuticals, with greenhouses full of cannabis, and labs that could make chemically pure drugs.

♪ ♪ Since CBD was illegal in the U.S., Sam's family flew to London for treatment while Ben's family waited.

(plane engines roar) After four days of taking GW's CBD, Sam's seizures dropped from 68 to six per day.

♪ ♪ On the eighth day of treatment, he only had three.

NUSSENBAUM: It worked and it worked fast.

But the other thing about him improving was that I saw this child that I hadn't seen since he was four years old and started having seizures, except now he was 11 and he was clever and funny and wanted to ride a zip line over London.

♪ ♪ NARRATOR: Sam is now seizure-free.

His story led to clinical trials, and in 2018, FDA approval of the first CBD drug, called Epidiolex.

In certain types of epilepsy, it can reduce seizures by some 40%.

Sam is now in college.

♪ ♪ But since seizures cause brain damage... Is that a seizure?

NARRATOR: ...for Ben, help came too late.

Okay, okay, hey.

I have no idea whether Epidiolex given at six months would have changed the course of his disease.

I feel like it has reduced the severity of the most severe kinds of seizures he has, so I feel like it helps.

But Epidiolex is not a miracle drug.

It's a tool in the toolbox, just like every other anti-seizure drug.

You try it, if it doesn't work, you stop it.

If it works, then, you know, it changes your life.

♪ ♪ One of the things that's like super important about a drug like Epidiolex is that for the first time, you've got a drug that's derived from cannabis that is completely legitimate for mainstream medicine to study.

And we're only beginning to see where that can lead.

♪ ♪ Scores of clinical trials are now underway, including at U.C.

San Diego's Center for Medicinal Cannabis Research.

Look at each dot until it explodes.

NARRATOR: 14-year-old Braylon has severe autism.

RESEARCHER: Okay, look with your eyes, look right here.

NARRATOR: His parents are hoping CBD might help.

Good job.

DORIS TRAUNER: Braylon is a very sweet boy who has a great personality.

He gets extremely anxious if he doesn't know what's going to happen.

And if something happens that he didn't expect, he can be very difficult to manage.

I'll just go home.

KEVIN PULLEY: I want you to get up, please.

Uh-uh.

No, thank you.

KEVIN PULLEY: We wanted to see what can be done to try to curb that behavior.

He was hitting, being kind of violent.

LETITIA PULLEY: And I'd never forget one therapist told me you want to get a handle on it because it affects his learning.

If you can't control the behavior, it's going to be hard for him to focus in class.

♪ ♪ NARRATOR: Children who have autism have different brainwave patterns than children who don't.

♪ ♪ TRAUNER: There is something different about the way the brain develops that causes children to have tremendous difficulty with social interactions, with social communication.

And it appears that one of the problems may be a type of sensory overload.

RESEARCHER: There you go, yeah.

Touch my finger and then touch your nose.

NARRATOR: To find out if Epidiolex might treat severe autism, Trauner is running a double-blind clinical trial.

Keep them out, and close your eyes.

NARRATOR: Over two eight-week sessions, children will take either CBD or a placebo, and researchers will use a battery of tests to see if the drug helps.

(overlapping chatter) NARRATOR: To study CBD's impact on the brain, in another part of the trial, Alysson Muotri will work with human skin cells.

♪ ♪ That's because skin cells can be converted back into master builder cells, and then coaxed to develop as brain cells do, forming networks of neurons.

♪ ♪ ALYSSON MUOTRI: These brain cells, they will actually self-arrange and form what we call a brain organoid.

And as they mature over time, they start to become more and more electrically active.

NARRATOR: That activity is captured by electrodes placed beneath the cluster of brain cells.

When their neurons fire, they create electrical signaling comparable to a developing brain.

♪ ♪ Next, the brain cells are treated with different doses of CBD to see if the drug has any impact.

♪ ♪ One of the biggest surprise that we see is that by adding CBD in the culture, we actually silence or quiet the activity of these brain cells over time.

This is not permanent.

We can wash it out, CBD, from the system, and we see that the brain is able to restore electrical activity.

So what are you going to do in the morning?

Wake up.

Wake up.

Wash up.

Wash up.

NARRATOR: But will CBD calm excess neuronal activity in the brains of children with autism?

Momma, car.

Yes, we're gonna drive... NARRATOR: The study is still blinded, but Braylon's parents are certain CBD helped him in phase one of the trial.

(overlapping indistinct chatter) KEVIN PULLEY: It was dramatic.

It was like night and day.

So, I could be wrong, but, you know, I... we both saw the difference.

All right... LETITIA: Focus... LETITIA PULLEY (voiceover): Having eight weeks of really no hitting, no perseveration and things like that was wonderful.

KEVIN PULLEY: And then when we went on the second half of the trial, he was back to his normal self.

So, I'm hopeful the first round was the CBD.

Here, I need you to take this, take your medicine.

TRAUNER: What we are hearing from the parents is pretty remarkable.

And we don't know whether they were on placebo or CBD.

But it's really important to get good data that demonstrates whether CBD is effective and whether it's safe, because we're talking about long-term treatment.

♪ ♪ NARRATOR: Treatment that uses hundreds of milligrams of Epidiolex.

Not the small amounts of CBD you can buy in a dispensary.

HILL: As little as four percent and maybe as great as 20% of the CBD that you consume orally actually gets into your body.

And so, it seems like you need to take around about 100 milligrams of CBD oil orally for there to even really be a signal in your bloodstream that you have CBD on board.

HURD: Most of the products being sold are like ten and 20 milligrams.

And some people say that they benefit from that.

And even if it's a placebo effect, I'm actually fine with it.

But what I'm worried about is that the CBD that they're taking has other chemicals.

NARRATOR: Generally, only products in legal states that contain THC, not CBD, are regulated.

Before they can be sold, they must be tested in licensed labs for potency and contaminates like pesticides, molds, and heavy metals.

Using untested cannabis is dangerous.

But when it comes to assessing risk, a key factor is your age, because the endocannabinoid system, which cannabis targets, changes over our lifespan.

♪ ♪ PIOMELLI: As we grow from being a fetus into becoming an adolescent, eventually an adult and an elderly person, the endocannabinoid system follows us and, at each of these stages of our life, serves a slightly different purpose.

♪ ♪ NARRATOR: During adolescence, our natural endocannabinoids reach their highest levels, as the brain rapidly changes.

It's also a time when many first try cannabis.

♪ ♪ PIOMELLI: So when one consumes THC, you're basically indiscriminately activating all your cannabinoid receptors in your entire body and the entire brain.

HURD: So, THC, it's like a hammer on all of these receptors.

Our natural endogenous cannabinoids are never these hammers.

NARRATOR: To understand the impact of cannabis, clinical psychologist Joanna Jacobus has scanned over 1,000 teenage brains to search for differences between those who use the drug and those who don't.

♪ ♪ Today, she is evaluating Angel, who has smoked cannabis at least once a week for the past year and is curious to learn about its impact.

♪ ♪ All I needed to really hear is, like, "Hey, do you want an MRI of your brain?"

"Yes!"

Like that... to me, that's like really cool.

I know it's nerdy, but, like, the substance you're doing, you don't get to see what it does to your brain.

♪ ♪ NARRATOR: Using functional magnetic resonance imaging, Jacobus can study brain structures that are critical for healthy development in young adults.

♪ ♪ The brain is rapidly changing from infancy through childhood, adolescence, into young adulthood.

Two types of tissue are rapidly changing that support cognitive development.

So, gray matter contains the cell bodies and makes up the cerebral cortex.

So, the outermost lining of the brain.

And white matter allows gray matter regions to communicate quickly and efficiently.

♪ ♪ NARRATOR: During the teenage years, white matter increases and grey matter diminishes, as weaker neural connections are eliminated and new ones formed to make the brain more efficient.

♪ ♪ Jacobus has found that teen cannabis users have a thicker cerebral cortex, suggesting that this pruning of synapses has been disrupted.

JACOBUS: Now I'm going to read the same list again.

NARRATOR: And it's not just physical brain changes.

I want you to tell me... NARRATOR: Thousands of cognitive tests reveal that teens who use cannabis regularly struggle more on learning and memory tasks than those who don't.

Bowl, dinner, mug...

It made me realize that memory is probably the biggest thing that impacts me with cannabis.

But definitely if I stop for a little bit, I have a feeling that, like, it would be easy to remember those things.

♪ ♪ NARRATOR: Research shows after a period of abstinence, cognitive performance can bounce back.

And the brain changes?

Other studies link them to alcohol, or genetic and environmental influences.

ARPANA AGRAWAL: It is possible that cannabis itself is not the culprit.

That these differences that we see in the brain are preexisting and that they come before a child ever picks up their first joint.

Go ahead and release your breath.

NARRATOR: To unravel the role of drugs, genes, and the environment, over 11,000 children are being tracked through their teenage years in the Adolescent Brain Cognitive Development Study.

And would you say that's definitely a no, kind of no... NARRATOR: N.I.H.

researchers will evaluate the children's physical and mental health, academic achievement, and drug use with tests of saliva and hair.

♪ ♪ So far, few of the children have tried cannabis, but there is data from surveys about their parents' use.

One of the things that we are most interested in was prenatal exposures, and we saw that there were a fair number of mothers in the study-- just like what we're seeing in the general population-- that used cannabis during their pregnancy.

CYNTHIA ROGERS: And we were able to look and see, among those children whose moms used cannabis during pregnancy, did we see any difference in their developmental outcomes?

And one questionnaire that really stood out to us was the psychosis-like experiences assessment.

And although you couldn't see anything or anyone, did you suddenly start to feel that an invisible energy, creature, or some person was around you?

Uh, yeah.

RESEARCHER: Yeah, okay, and did that bother you?

Uh, no.

Not so much.

AGRAWAL: And this data set gave us an opportunity to roll back the tape to a period of time in an individual's life where they're being exposed at a time when their brain is exquisitely vulnerable.

Did you start to worry at times that your mind was trying to trick you or wasn't working right?

Uh, yeah.

Okay.

RYAN BOGDAN: So, among kids who were exposed to cannabis following their mother's knowledge of their pregnancy, they experienced more psychotic-like experiences, they experienced more depression and anxiety-like behavior, they're breaking more rules, they have more attentional thought problems.

♪ ♪ NARRATOR: Psychotic-like experiences are also associated with an increased risk for mental illnesses like schizophrenia and depression.

♪ ♪ ROGERS: We know that the use of cannabis during pregnancy is increasing.

We've seen advertisements online, social media, targeting women saying this is something that's safe for you to use during pregnancy for things like nausea or insomnia.

And these women are not trying to harm their babies, they're just trying to get through what can be a challenging time.

As you know, we're interested in looking at... NARRATOR: Rogers and Agrawal are now scanning 250 babies to see if brains exposed to cannabis during pregnancy are different from brains that were not.

ROGERS: THC crosses the placenta.

So, we know the baby's brain is exposed to it.

We also know that the receptors in the brain that THC binds to develop very early during pregnancy.

The endocannabinoid system is critical for hard wiring of the brain during development.

So, if cannabis comes on board while the endocannabinoid system is regulating neural circuits that are laid down, how the cells communicate as they're being developed, obviously, it can have an impact on that.

And that is the thing that is critical for people to understand, cannabis is not a benign drug.

♪ ♪ NARRATOR: While scientists worry about the risks, most agree that far greater harm has come from criminalizing cannabis, starting in 1937.

The treasury department intends to pursue the despicable, dope-pedaling vulture... NARRATOR: Harry Anslinger, head of the Bureau of Narcotics, stoked racism towards Mexican immigrants by demonizing their word for cannabis, marijuana, and claiming "the evil weed" corrupted users.

NEWSREEL NARRATOR: Debauchery, violence, murder, suicide.

(woman screaming) If you look at the way that they talked about marijuana, part of the strategy was to make cannabis something that wasn't acceptable, make it foreign, and create the hysteria to put laws in place that control a group of people that were not white and push forward a narrative that the government is keeping us safe.

NARRATOR: In the 1970s, Richard Nixon ignored an expert panel recommending decriminalization and declared a "war on drugs."

Soon drugs would become the key reason for being arrested in the U.S. Do you mind if we search the car?

NARRATOR: Since 2000, over 14 million people have been arrested, and some 40,000 Americans are now behind bars for cannabis-- mainly for possession charges.

FREDERIQUE: Someone gets arrested for cannabis every 58 seconds.

In a country where we are now legalizing cannabis, people are talking about its medical use, in the midst of COVID-19, it is an essential service, cannabis is one of the driving forces fueling mass incarceration in this country and it is disproportionately targeting poor people and communities of color.

In every single state in the United States, whether cannabis is legal or not, Black people are arrested for cannabis-related offenses more than white people.

(sirens wailing) FREDERIQUE: Despite the fact that all government data shows that usage is equal across races.

NARRATOR: Although many Americans believe the war on cannabis is over, for Black people especially, like Sean and Eboni Worsley, it's a war that's still going on.

♪ ♪ To manage his post-traumatic stress, Sean had gotten a medical cannabis card in Arizona.

But as he and Eboni began a cross-country trip to see family, they would drive through states where cannabis is illegal and racial profiling common.

♪ ♪ EBONI WORSLEY: We needed gas.

We have no idea, especially in a place you are not familiar with, when is the next place you're gonna be able to stop for gas?

SEAN WORSLEY: I get out of the car.

As I'm walking away, a vehicle pulls in front of my wife's car and it is a police vehicle.

EBONI WORSLEY: And all of a sudden, I am approached by an officer.

It startled me, when I looked up and he's like, you know, "Where are you heading?"

and I'm like, "We're heading to North Carolina."

And then he began speaking to my husband, who is outside of the vehicle.

SEAN WORSLEY: He asked me about any weed being in the vehicle and I just was honest and I told him, "Sir, you know, I am a medical "cannabis patient from Arizona and I do have my cannabis, but it's zipped up and it's in the trunk."

At that point, he puts me in handcuffs and proceeds to search the vehicle.

I give him my IDs, and he said, "Hmm, well you won't need these where you're going."

NARRATOR: The officer found a third of an ounce of medical cannabis.

LEAH NELSON: He charged them as severely as he could with possession for other than personal use, and that was because Sean had with him a grinder and he had rolling papers, and he had a scale.

All of those things were recommended by his doctor.

If you smoke marijuana medically, it's not uncommon for a doctor to tell you to use a scale so you know how much you are smoking.

♪ ♪ NARRATOR: Eboni and Sean spent six days in jail before getting a hearing.

At the Pickens County Courthouse, they were charged with multiple felonies.

♪ ♪ After struggling to pay a bondsman and impound fees for the car, the couple returned to Arizona.

♪ ♪ EBONI WORSLEY: The fines and the fees became astronomical.

By the time we made it back to Arizona, we literally couldn't afford to pay our rent or bills, and we ended up evicted.

We were homeless.

NARRATOR: Under stress, Sean had a stroke.

Eventually, Eboni's charges were dropped, but due to prior minor convictions, Sean was sentenced to five years and put on probation.

NELSON: Probation requires a stable address, it requires you to pay money, and one of the conditions of Sean's probation is that he needed to get drug treatment.

And the V.A.

looks at him and says, "You have a medical marijuana card, man, "We're not going to treat you.

You don't qualify because you don't have a drug problem."

♪ ♪ SEAN WORSLEY: Probation and parole, they're just traps to send you right back, to keep you in their grasp.

You want to lock me up for not having a job, you want to lock me up for not having a place to stay.

How am I supposed to get these things if I can't get a job because you have me labeled as a felon?

♪ ♪ NARRATOR: In March 2020, Sean was extradited to Alabama to serve the remainder of his sentence behind bars.

CUNNINGHAM: I see the harms of the war on drugs every single day in all of my patients' lives.

It is so clear.

There's not a single family that I know that doesn't have some member who's been arrested or incarcerated.

And what I see is that what happens in society, the arrests, the incarceration, the poverty, dramatically affects people's health, their lives, their quality of life.

NARRATOR: As criminalization destroys lives, at the same time, the cannabis wellness industry is thriving.

One entrepreneur is Eugene Monroe, a former football player who believes cannabis can help address chronic pain.

EUGENE MONROE: Playing in the NFL was a lifelong dream.

I love the sport.

That explosive power... to propel my body and essentially flatten people.

(players grunting) Each time that happens, each time your brain rattles in your skull, you pay a price.

The job creates a need for pain relief inherently, so I was given a lot of opioid drugs, which would let you go into a game with acute injuries and perform because you don't feel bad.

I was taking my oxycodone just as prescribed, and saw my daughter walking down the hallway and didn't recognize her.

And I realized that they were causing a serious issue, and I stopped taking them.

And that's the point where I decided that cannabis is a better option.

♪ ♪ Cannabis didn't just allow me to cut back on opioids, it allowed me to eliminate all pharmaceutical drugs.

♪ ♪ It hasn't cured my injuries, but what it did for me was alleviate my pain, so I felt motivated to go in the gym and work out and take care of my body.

CUNNINGHAM: We know that cannabis leads to less pain and it alters people's ability to tolerate the pain.

It affects the immune system and reduces inflammation.

It's certainly safer than other medications that we've been using for decades.

NARRATOR: Monroe is now a partner and consultant for one of the nation's largest cannabis companies.

Yet, while many praise the benefits of cannabis, some scientists warn there are risks, especially for those who use it daily.

About nine percent of users will develop a cannabis addiction.

One is Paul.

DEBASSIO: I was in my junior year of high school and it was a 400 freestyle relay.

The last leg of the race, always you go just as hard as humanly possible.

And as I came up from the flip turn and I snapped my head up, I just felt this twinge just right in between my shoulder blades, and it just killed me.

But it wasn't until I went into college that it became a recurring detrimental thing.

And I started using cannabis to alleviate a lot of the pain and to help me sleep at night, because I could never get a full night's rest.

♪ ♪ NARRATOR: Cannabis seemed to cure Paul's insomnia.

DEBASSIO: I loved how calming it was.

I'd have the best night of sleep that I've ever had in my life.

And I said, "This is amazing."

NORA VOLKOW: It would be fantastic if we have a drug that could actually calm you when you need it, that makes you feel groovy, more social, and there's no negative consequences.

It would be extraordinary, but that's not the case.

Biology basically adapts to stimuli that you give.

NARRATOR: Cannabis is less addictive and safer than tobacco, heroin, cocaine, and alcohol, which kill hundreds of thousands each year.

But, you can take too much.

We're seeing an increase in the number of people that end up in emergency departments with a full-blown psychosis because of the high content THC.

Dependence can impair memory, mood, and motivation.

Paul didn't know he had a problem until he needed a drug test for a job.

♪ ♪ DEBASSIO: And so I quit cold turkey, and almost immediately I noticed a big change in my mood.

They get irritable, they get aggressive, and they can feel depressed.

DEBASSIO: There were stretches of weeks that I slept for maybe two to three hours a night, every night.

And that was all I could get.

DEEPAK CYRIL D'SOUZA: We looked at sleep architecture and what we found was that when people quit using marijuana, slow wave sleep, which is the kind of sleep that makes you feel rested the next morning, was significantly disrupted.

♪ ♪ Okay, hi, Paul, how are you?

Good morning.

NARRATOR: In a new clinical trial, Deepak D'Souza hopes to harness the endocannabinoid system to prevent cannabis withdrawal.

I need to observe you take the medication.

So let's just go through that.

NARRATOR: When the brain is repeatedly flooded with THC, it reduces the number of cannabinoid receptors.

Once a person is dependent on cannabis, abruptly quitting triggers withdrawal.

To replace THC, D'Souza is testing a drug that increases our own cannabis-like molecule, anandamide.

There was a two-week period where I was taking either the placebo or the study medication and still smoking at the same time.

And then I had to quit cold turkey.

And the day that I quit, I thought that there was no way I was going to sleep that night.

♪ ♪ I had no issues.

It was very, very easy.

I'll never forget that first night that I was able to sleep after, after not smoking.

I, I woke up the next day in absolute shock and awe.

Paul doesn't know if he got the study drug.

But an earlier trial showed that it helped people quit.

And PET scans reveal that after cannabis is stopped, the brain's own cannabinoid receptors come back.

♪ ♪ HURD: Our endocannabinoid system is really powerful.

And that's why we shouldn't really play with it that much.

A drug may be fine for one person, but it isn't for everyone.

Dose matters.

When you take it during development matters.

We need to really understand what these drugs do to the brain, even if they will, and I do believe have some medicinal benefits.

♪ ♪ NARRATOR: So what does the future hold for cannabis as a medicine?

Moving on to the sky walker OG.

NARRATOR: To find out, Staci Gruber is following adults who buy cannabis from dispensaries to treat a range of ailments.

This is fantastic for the afternoon.

Chronic pain is the number one condition.

Anxiety is probably number two.

PTSD, difficulties with sleep.

And we have patients who come to us and say, "You know, I use these types of products for this problem."

And then we go, "Hmm, we should look at that."

How's the anxiety?

In all honesty, how is it?

Things are going really good.

I'm really busy, I'm taking three classes.

NARRATOR: Two years of clinical and psychological tests show patients improving.

Wow, so that's a decided change.

Yes.

Reduced symptoms of pain, reduced anxiety, improved sleep, and improvements across the board on a number of different cognitive tasks that require executive function.

The question is why?

It may very well be that the restorative sleep that people are starting to get once they find something that works for them is the key to the improvement.

♪ ♪ I think this was the most important document.

NARRATOR: Back in Alabama, Leah Nelson is working with Eboni Worsley to get her husband Sean paroled.

NELSON: Alabama's war on cannabis has failed.

People like Sean, and particularly Black men, are paying this horrific price for doing something that is already legal in states where half of Americans live.

♪ ♪ (laughter) NARRATOR: In November 2020, Sean was released from prison and placed on parole.

It's time to go.

You ready?

SEAN WORSLEY (voiceover): It was scary being inside.

It rocked me to the core.

It was probably one of the most difficult things I've had to do.

♪ ♪ I would pick going back to war before going back to prison.

Most definitely.

♪ ♪ EBONI WORSLEY: It set us back so far.

It's supposed to help rehabilitate individuals.

Instead, it's putting us in positions where we need so much more mental help.

We need much more financial help, we need so much more than we needed before.

♪ ♪ FREDERIQUE: It is past time for us to end the war on drugs.

We need to legalize cannabis.

We need to be pumping money into research to actually learn more about this substance.

This moment is about building new responses to drugs that are based in science and that are based in the rights of people.

NARRATOR: There are still many questions to answer.

Should cannabis be marketed as candy?

Should the THC potency of products have limits?

♪ ♪ From reducing harms, to expunging convictions and ensuring equity, getting legalization right is as complicated as the plant itself.

GRUBER: Cannabis is not one thing.

Our recreational consumers have a different goal for using cannabis than our medical patients.

Our medical patients say, "I'm not looking necessarily to change how I feel.

I just want to address this set of symptoms."

But we have frighteningly little data on the long-term effects of medical cannabis use.

The plant is comprised of over 400 compounds-- 400.

If people turn to it, we should know the answers.

♪ ♪ ♪ ♪ ALOK PATEL: Discover the science behind the news with the "NOVA Now" podcast.

Listen at pbs.org/novanowpodcast or wherever you find your favorite podcasts.

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