Understanding the Chemical Effects of Cannabis on the Mind and Body

The video explores the chemical composition of cannabis and its effects on the body and mind. It discusses the two well-known active ingredients, cannabidiol (CBD) and tetrahydrocannabinol (THC), and how they interact with receptors in the brain. The video explains the process of smoking weed and how THC is quickly transferred into the bloodstream, leading to psychoactive effects. It also addresses the potential risks of marijuana use, including the impact on driving abilities and the potential for psychosis. The video concludes by discussing the historical context of cannabis and its complicated perception in society.

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Key Insights:

  • The cannabis plant has over 700 different strains, with CBD and THC being the most well-known active ingredients.
  • CBD has calming effects and is being tested for medical treatments, while THC is responsible for the psychoactive effects.
  • When smoking weed, THC enters the bloodstream through the lungs‘ alveoli, causing a rapid onset of the high.
  • Weed affects various parts of the brain, including the amygdala, basal ganglia, neocortex, and cerebellum, resulting in altered emotions, slower motor control, and delayed reflexes.
  • Driving under the influence of marijuana can be dangerous, as it impairs cognitive and motor functions.
  • There are hundreds of active components in cannabis, making it challenging to study its effects accurately.
  • Marijuana has a complex history, with medicinal use dating back to ancient times, but its criminalization began in the early 1900s.
  • Fear-mongering and misinformation have contributed to the negative perceptions and legal restrictions surrounding marijuana.
  • Marijuana can have both positive and negative effects on mental health, depending on individual factors and usage patterns.
  • While marijuana dependence is relatively common, addiction is less so and more likely in individuals with developing brains, such as teenagers.
  • Marijuana is neither a miracle drug nor a social menace; it’s important to evaluate it in a balanced and nuanced manner.


It takes a couple of attempts, but you manage to spark a lighter and hold it up steadily in front of your face to light up a joint. A familiar woody smell fills the room and drifts out of your window on the afternoon breeze.
You blink, steady yourself, inhale deeply, and feel your lungs fill up with warmth. But what happens next? Chemically speaking, biologically speaking, what is it about this little green plant that gets millions of people around the world to flock to it? How long has humanity been consuming it? And what exactly is it doing inside your body? Inside your mind?
To start, let’s have a look at the chemical composition of the cannabis plant itself rolled up in a joint in your hand. Native to Central and South Asia, the cannabis plant today is so popular it has now grown to be a global economy of its own. From small-scale rural farming operations all the way through to drug superlabs, including any number of illegal weed farms somewhere in the middle, experts believe that there are well over 700 different strains of cannabis currently on the market, and this number seems only set to increase. Being able to identify which strain of weed you have in your hand can be very easy when buying from a legal dispensary, but if you live in a country or a state where marijuana is still criminalized, being able to verify exactly what it is you’re smoking becomes much more difficult. Looking down at the green mossy balls in your hand, do you know where in the world it’s come from and what’s inside it? Let’s break it down a bit, or rather, grind it down.
You have likely heard of the two most well-known active ingredients in cannabis. These are cannabidiol and tetrahydrocannabinol, or as you probably know them, CBD and THC. Over the last ten years, in the West in particular, CBD has been championed as a potential medical breakthrough. It has been shown to have a calming effect on those with anxious dispositions and is currently being tested as a treatment for psychosis, sleep disorders, muscle spasticity, and more. You may have seen ads for CBD oil products popping up in your feed, claiming that it can solve a number of ailments. Research is ongoing; however, results do vary. In the case of curing cancer, for example, so far, there is no evidence to support that CBD has any kind of effect on the disease, despite what people on the internet may be saying. So you smoke CBD and get high, right? No. CBD is usually extracted as an oil and, on its own, will not get you high. But it is still psychoactive, meaning it alters your mental state, typically leaving you feeling more calm and mellow. The feeling of being high comes from the main active component in marijuana: THC. Typically found in much greater quantities than CBD, THC can have a powerful psychoactive effect. To see what that means in practice, let’s follow it as it enters the human body. Take in a deep breath of that joint and let the smoke fill your lungs. In this example, you’re going to be our test subject, and you will be smoking weed. Smoking is one of the most direct and quickest ways to get high. This is because the smoke from the burning marijuana contains high levels of THC. The smoke is then inhaled, filling your lungs. At this point, you may experience some irritation – manifesting in the iconic Smoker’s Cough – from introducing an alien substance into your lungs. This, however, is not unique to smoking weed, as you’re likely to see the same from people smoking or vaping conventional tobacco. The lungs are designed to quickly and efficiently transfer oxygen into the bloodstream when we breathe. Therefore, they have the capacity to take in large quantities of gas in one breath and get any number of elements or compounds from that gas into our bloodstream, and fast. The lungs aren’t just empty chambers; they are full of tiny little air pockets called alveoli. The average human adult has roughly 480 million alveoli in their lungs, constituting about 1500 miles of airways. That’s the equivalent of driving from Miami to New Hampshire for our American viewers or Madrid to Copenhagen for our European viewers. For everyone else, it’s roughly 13,636,363.6 bananas lying end to end. Anyway, back to your lungs. In each alveolus, the THC from the smoke is transferred directly into your bloodstream, which then carries it all over the body, including to the critical area: your brain. As a result, it often only takes a matter of seconds for the user to start to feel the psychoactive effects of what they’re smoking. So, let’s crack your head open and see what’s going on inside. Sorry, this might hurt a little. The THC and CBD bind themselves to receptors throughout your brain. The amygdala, for example, is responsible for anxiety, emotional responses, and fear. CBD dulls the activity in this part of the brain, but the THC component can stimulate it. While many users feel calmer having smoked weed, others can feel a heightened sense of paranoia and worry, particularly on the ‘comedown’ as the calming effects of the CBD wear off. Looking at other parts of the brain impacted by the CBD we have the basal ganglia, which is involved with motor control and planning, the neocortex which processes sensory information, and the cerebellum which is the center of motor control. All three of these areas are impacted by smoking weed, resulting in you feeling ‘slower’ in general. Reflexes are delayed, information takes more time to be processed, and motor functions and speech slow down. Driving under the influence of marijuana can be very dangerous as a result. One study in the UK found that fatal accidents are 1.65 times more likely to occur when the subject is under the influence of marijuana, while another study in Canada found that accidents could be up to four times as likely. Most countries have strict laws for driving under the influence of weed with zero tolerance policies, made stricter by the fact that it can take over 48 hours for weed to stop showing up on a blood test. If they’re testing your saliva, it can be up to 72 hours. Urine can be anywhere from 3 to 30 days, and it can even be tested in your hair follicles for up to 90 days. Fortunately, you won’t find many traffic cops that are plucking out your arm hairs for a routine traffic stop. However, it would be reductive to think that all that weed does is dull the brain. THC is a very active component that stimulates a lot of neural activity. Colors look brighter, sounds are louder, music sounds more rich and layered. Food often tastes better under the influence of THC, giving the subject the illusion that they’re really hungry. That’s right, this is why so many people using cannabis experience the famous “Munchies”, which is why having a stoner visit your home is potentially extremely dangerous to the state of your snack pantry and chip supply. Many people report having heightened imagination, being able to think outside of the box or come up with fresh and exciting ideas. Artists all throughout history have partaken in recreational drugs in an attempt to broaden their horizons. The dulling of a lot of negative sensations, such as feeling pain and anxiety, coupled with this stimulation from THC, results in feelings of euphoria. In short, you, our human test subject, have gotten high. But what does this high actually look like? Here’s where it gets really interesting. Let’s bandage your head up and take a look. So far, we have only focused on THC and CBD, but there are hundreds of active components within cannabis, which vary in quantity and intensity depending on which of the hundreds of strains the user is consuming. On top of that, there’s the method of consumption. While smoking or vaping gets the chemicals into the bloodstream quickly, the high only lasts around 3 hours or so. Many users instead take gummies or bake brownies and cookies. When weed is absorbed through the digestive system, it takes a significantly longer time to kick in, but when it does, the user can experience highs that go on for hours, even up to a day, as the digestive system slowly releases the chemicals into the bloodstream. All of this makes studying the effects of marijuana very difficult, as with almost any study, there are the caveats of which strain is being used, how the test subject is ingesting it, and who the test subject is. The human brain is an incredibly complex thing indeed. If you took a sample of the human brain that was the size of just one grain of sand, that sample would contain 100,000 neurons and 1 billion synapses. Now, multiply that by 860,000, and you’ve got a human brain, just like the one that’s sitting in your head, watching this video and feeling very smug about itself. Being able to quantify and measure exactly what is happening in an organ far more advanced and complicated than the computers we are studying it on has been a challenge in medical science for decades and will likely continue to be one for a very long time. While one individual might take one puff and spend the rest of the day feeling anxious; their elderly grandma might smoke a whole bowl and feel nothing but Zen. So, for nanna’s sake, is it dangerous? Well, on the whole, consuming marijuana is relatively harmless. As long as you aren’t driving, controlling heavy machinery, or performing open heart surgery, the risks of smoking the occasional joint with the right amount of weed in it are low. So why hasn’t it been legalized worldwide already? And why are there still skeptics out there, including in the scientific community? As is often the case with controversial topics, a lot of the conflict comes from political and cultural differences. To tell that whole story, we need to wind all the way back to China in 2800 BC, where we find the first recorded use of marijuana in history. Even that long ago, the cannabis plant was being used for medicinal purposes. Emperor Shen Nung, considered by many to be the grandfather of medicine, recorded the plant in his writings as being particularly useful. From that point, records of cannabis spread throughout India, Syria, Greece, and Rome. Various healing properties have been ascribed to it over the years, including cures for inflammation, depression, arthritis, and even asthma. Of course, most early medicine is notoriously rather unreliable – we’re looking at you, leeches and milk transfusions – but there has always clearly been something about this little green plant that’s captured the attention of doctors and pharmacologists throughout the centuries. Often, there is a grain of truth to the mythology that has sprung up around the drug. In Hinduism, for example, the God Shiva is given the title ‘lord of bhang’ because cannabis is his favorite food. For centuries, many Hindus believed that if you were suffering from a fever, it was the god’s hot breath of anger upon you. Rituals were conducted where you would be given a quantity of cannabis to consume so you would find favor with Shiva again, and your fever would pass. With modern Medical Science, we know that THC acts in the hypothalamus in the brain, reducing the body’s temperature and therefore counteracting fevers. So, where did it all go wrong for weed’s PR team? Why is it that many people in the West now include cannabis in the same conversation as crack cocaine and heroin, as opposed to paracetamol and penicillin? Well, medical marijuana was first introduced in the West in 1841 by William Brooke O’Shaughnessy, an Irish physician who had spent years studying all kinds of different medicines in India. But the real origins of the USA’s problem with marijuana began 200 years before that, in the Jamestown colony in 1605. Dissatisfied with the return on investment they were seeing, the English, and King James I in particular, demanded that the Colony change up the crop they produced to hemp, a plant within the cannabis family. The crop was a massive success and became key to the early expansion of the American colonial settlements. George Washington himself famously grew hemp as one of his three primary crops on Mount Vernon. The plant was used to manufacture ropes and fabrics, but following William Brooke O’Shaughnessy’s findings from India, Americans began to experiment with the plant’s medicinal properties. The USA was still in relative infancy, with many laws and prohibitions being established. Drug laws at the time involved labeling products as being poisons, which restricted them to being legal only if prescribed by a pharmacist. Even then, the debate about cannabis varied from state to state, with some issuing it with the poison status and others believing it was exempt from these rules. At the time, opium dens were rife across America, and alongside them, a number of hashish parlors popped up in which people would smoke various forms of hemp and cannabis. By 1880, these establishments were seen as quite fashionable, with many of the upper classes frequenting them. It’s estimated that there were roughly 500 such parlors in New York City alone. The laws needed to be strengthened further still. Fraud and corruption were rife in the drug industry, with many falsely labeling their products for the sake of profit. The tighter that these restrictions got, the more people looked for loopholes. The government and the newly established Food and Drug Administration were pulling in a different direction than a lot of the American public, who were looking to skirt prescriptions and drug laws in order to continue to get their highs. In the move to close these loopholes, cannabis was often grouped in with many of the much more addictive, much more harmful drugs that were plaguing the American population. The solution that the American government came to was a zero-tolerance policy on recreational drug use, including the Prohibition of alcohol and the criminalization of marijuana, which at the time they were spelling with an ‘H’. In 1971, President Nixon coined the term ‘war on drugs,’ where he declared drug abuse to be ‘Public Enemy number one’ of the American people. The approach was incarceration with an iron fist. Possession, distribution, and consumption of banned substances would result in jail time. It’s estimated that throughout its war on drugs, the USA spends roughly $51 billion annually on its endeavor to “clean up its streets.” To illustrate, with that money, the USA could give each Canadian citizen $1,416.67 per year just as a little thank you for being such lovely neighbors. Alternatively, they could give one lucky Canadian a dollar a minute for 97,032 years. A large amount of this campaign against drugs has involved a level of fear-mongering. There is a lot of false information swirling around the world about the negative effects that these drugs have. “It rots the brain and causes psychosis, it is a gateway drug to stronger and more dangerous highs, and it is highly addictive.” But is there truth to any of these claims? Let’s examine them one by one. Firstly, no, marijuana does not rot the brain. Rotting is the decay of dead organic material as bacteria and fungi consume it. That simply doesn’t happen. However, the link to psychosis is a much more contested field with evidence for both sides of the argument. Firstly, what is psychosis? It’s a term that is thrown around a lot, especially in the world of drug usage, but very rarely defined, meaning a lot of people attach their own fears, worries, and prejudices to the word. Psychosis is when someone loses contact with reality. The image of the world around them that their brain is painting does not match up with the objective reality surrounding them. The two main symptoms of psychosis are hallucinations and delusions, and it is important to know the difference between the two. A hallucination is when a person experiences something that isn’t actually happening. Most commonly, this takes the form of hearing voices that aren’t really there or sometimes seeing things that aren’t really there. In some cases, people have reported smelling, feeling, and tasting their hallucinations, too, such as tasting blood in their mouth despite there being none. A delusion, on the other hand, is more abstract. It could be the feeling that you’re being followed or that there is a conspiracy in your workplace to harm you. Delusional people are often highly susceptible to conspiracy theories, as often the paranoid messaging chimes with the fearful delusions their minds have already been generating. So, does marijuana cause psychosis? It’s complicated. Let’s go back to the chemicals active in your brain, we’re going to need to crack that skull open again. Sorry. THC is highly psychoactive; that is where the feeling of euphoria from being high comes from. While CBD can decrease the levels of panic and paranoia in the brain, it’s often present in much smaller quantities than THC, mainly as many cannabis farms compete with one another to grow stronger and stronger strains. Couple that with the fact that there are hundreds of active components within a cannabis plant, and it goes back to our earlier point about this being a challenging area of study. Therefore, many scientists rely on quite broad studies, taking large sample sizes of drug users and non-drug users and comparing the development of their brains over time, looking most notably at teenagers and young people. What they have found is there is often a link between heavy pot smoking and psychosis. There are cases of people living with schizophrenia and bipolar disorders where the heavy use of marijuana is linked to the onset of those symptoms. What has not been proven, however, is that weed was the cause. Most scientists believe that weed can, in some cases, accelerate the development of underlying psychotic disorders. The brain is a very complex and delicate thing. If somebody has an underlying psychotic condition, then the consumption of drugs that alter their state of mind and heighten activities within certain sections of the brain can naturally lead to an exacerbation of those symptoms. Schizophrenia is believed to affect one in 300 people, while bipolar disorder affects one in 100. While these are quite small percentages, they are not insignificant. THC does carry the risk of triggering a psychotic episode if you are genetically predisposed to having a psychotic condition. The chances are very low and won’t affect the majority of the population, but they are still there. Next, is it a gateway drug? The experience of a chemical buzz in the brain is a sensation that many of us try to chase in our lives. You get up and sing in a concert at your high school, and you get a rush from it. You do it a second time, and the high has worn off a bit. So you need a bigger crowd, and a bigger crowd, until suddenly you’re in a rock band on an arena tour. Chasing this type of bigger and better high is an experience we’re sure many of you are familiar with. Studies have shown that in a minority of cases, the same can happen with marijuana. Usage of the drug can prime the brain, ready for a more intense high, which it then craves. This sounds bad until you realize that the same thing happens with cigarettes and alcohol. Both of those demonstrate a similar connection to being ‘gateway drugs’ to harder substances as marijuana. So why are those not held up to the same level of scrutiny? One thing studies have shown is that there is a much more powerful ‘gateway drug’ out there: trauma. A difficult childhood, experiencing abuse, and going through acute pain and suffering are all far more likely to result in a person developing a dependence on hard substances. Weed is often a part of that journey, but in these cases, it seems to be a symptom more than the cause of the problem. But is it addictive? Let’s take a similar look at this question. You wake up one morning feeling tired, so you make yourself a cup of coffee. It clears away the fog, helps you focus on your job, and gives you a little endorphin rush from a good day’s work. So the next day, you do the same. And the next. And the next. Until one day, you’ve run out of coffee. You look in the jar, and it’s empty. A storm cloud gathers over your head. You go to work with a scowl, snap at your coworkers, have a headache by lunchtime, and come home feeling miserable. What’s happened here? Well, the human brain is incredibly flexible. Your brain has gotten so used to the influx of caffeine each day that it’s now rebalanced the chemicals inside itself to receive that caffeine boost. It’s ready and waiting. So when the boost doesn’t come, there is now a chemical imbalance. The same thing happens with weed. If you burn one down at 4:20, smoke weed everyday, your brain is going to be sitting there at 4:19 rubbing its metaphorical hands together in anticipation. Coming off weed now feels hard. You have cravings for it, feel irritated when you don’t have it, struggle to fall asleep, lose your appetite, and generally have a bad time… For about two weeks. Then, you are likely back to normal. That’s because what we’ve described here isn’t addiction, it’s dependence. It’s very common and can be broken fairly quickly. Up to 30% of weed smokers experience some level of dependence, and it can be overcome by just taking an extended break and giving your brain some rest. That said, there is a small risk of long-term addiction. People under the age of 18 have brains that are still developing. They are still growing and changing, adjusting to the world around them. Smoking weed regularly at this stage in your life could lead to your brain building itself around the expectation that it will be receiving those chemical hits every day. What may start as a dependence could grow to be much more deeply rooted and could result in a lifelong addiction. If there’s one thing you learn from this video, it’s that marijuana, much like life, is complicated. There may not always be a straight answer to every question. Anyone who tells you that something is totally amazing and has no downsides will always be lying. Even ice cream has downsides. What is important is looking at the big picture. Is weed the devil’s leaf that spells the end of society as we know it? No, of course not. But neither is it a miracle cure-all drug that everyone should take on a daily basis.