What do ducks like to smoke? Quack Cocaine! Drugs have been used by humans since ancient history, but they’re still subject of debates in many countries. Some consider them as a huge threat to society, while others see in them many benefits. But how do drugs work? Let’s explore what we know about drugs… To put it simply, drugs are any chemical compound that changes the normal behavior of the nervous system of an organism. Drugs can either be found naturally in plants and fungi or created synthetically. Some drugs are used for pleasure, while others are used to cure diseases. Most drugs affect neurotransmitters, either by directly imitating their effects or by indirectly changing their concentration. Because they have a molecular structure similar to neurotransmitters, they bound to the same receptors. The effects of the drug generally last a couple of hours, as the drug releases from the receptors and is destroyed by the body. However, some drugs like aspirin or Advil don’t affect neurotransmitters. Instead, these pain relievers prevent chemicals naturally produced by damaged cells from lowering the pain threshold of nociceptors. All drugs have a risk of causing death because of an overdose, the lethal dose depending on the mass of the animal. However, for certain animals, it is impossible to naturally overdose from some drugs, because they would need to eat a quantity of the drug larger than their stomach. Humans have found many ways to administrate drugs, each method affecting the body at a certain speed. The faster the drug goes into the bloodstream, the faster it reaches the nervous system and affects the body. The fastest way is intravenous injection with a syringe, closely followed by inhalation as the drug goes to the lungs and is quickly transferred to the bloodstream. Inhalation includes smoking with a fire, which releases not only the drug, but also other chemicals in the smoke, and vaping with a vape that heats the drug at a precise temperature, which only releases the drug. With these methods, drugs have an effect in less than a minute. Finally, ingestion takes more time (about 10 minutes) as the drug needs to be digested before going into the bloodstream. Ingestion includes swallowing food or pills and snorting powder, which is a little bit faster. Here are the most used drugs affecting human neurotransmitters: -A drink made from dried coffee beans, coffee contains caffeine, a natural insecticide produced by coffee plants. When ingested, caffeine bounds to adenosine’s receptors and thus prevents this neurotransmitter from doing its job, which is normally to slow down brain activity to allow the brain to rest at night. Caffeine also increases the release of adrenaline and dopamine, which makes the person energetic, happy and less tired. -There’s many types of alcohol, but all alcoholic beverages come from fermented plants. Indeed, beer comes from fermented grain mash, wine from fermented grapes, rum from fermented sugarcane, and vodka from fermented cereal grains or potatoes. Alcohol contains ethanol, a molecule that increases the release of GABA neurotransmitters when ingested, which makes the person focus on odd details and feel detached. Moreover, because it is highly flammable, ethanol can be used as fuel. -Dried tobacco leaves are used to make tobacco, which is present in pipes, cigars, cigarettes and now vapes and E-cigarettes. When heated, tobacco releases nicotine, a molecule known to increase the release of norepinephrine, dopamine and serotonin, which makes the person feel relaxed and alert at the same time. E-cigarettes work like vapes, but tobacco is replaced by a liquid solution composed of water, nicotine, flavourings and a base. However, the base used is different for each company, and not much is known about its effects on the human body. Moreover, many studies associate nicotine with cancer. -Marijuana comes from the cannabis plant. The resin of the plant is used to make hashish, while dried leaves and flower buds are used to make weed. Marijuana contains many cannabinoids, molecules that increase the release of dopamine and norepinephrine when ingested or inhaled. The major cannabinoid is tetrahydrocannabinol (or THC for short), a chemical that imitates anadamide, a neurotransmitter that is believed to play an important role in appetite, sleep and pain relief. This causes the person to feel relaxed and euphoric, but also hungry and sleepy. Furthermore, many reports show that it can cause anxiety. Despite this, some doctors believe that marijuana can have medical benefits, especially in the treatment of epilepsy, and studies are currently made to verify this. -Powerful chemicals are added to coca leaves to create cocaine. Powder cocaine is pure cocaine that can be snorted, while crack cocaine is cocaine plus a base and it can be smoked, because it has a lower melting point. When ingested, cocaine increases the release of dopamine and prevents this neurotransmitter from being reabsorbed. It thus creates an intense high and a feeling of euphoria. However, this highly addictive drug can cause restlessness, heart problems and mental problems such as extreme irritability, paranoia and delusional parasitosis the feeling that bugs are crawling under the skin, which leads to intense scratching. -Speed is a synthetic drug that contains amphetamine, a molecule that increases the release of dopamine and norepinephrine when ingested. This greatly stimulates the body and creates a feeling of happiness. In low doses, amphetamine is used to treat Attention Deficit Hyperactivity disorder (or ADHD for short), because people with this condition tend to lack dopamine and are constantly seeking stimulation. With the increase of dopamine release caused by amphetamine, they are less easily distracted. -Other chemicals are added to speed to create meth, a drug that contains methamphetamine. Powder meth can be snorted while crystal meth can be smoked. Diluted in water, meth can also be injected. Methamphetamine greatly increases the release of dopamine and norepinephrine and prevents these neurotransmitters from being reabsorbed. This is why it is a highly addictive drug. -Opium comes from dried poppy latex contained in the head of the flower. A drug that is smoked, opium contains different opioids, molecules that mimics the effects of endorphins. This creates a feeling of relaxation, pain relief, euphoria and happiness. The main opioids are morphine and codeine, two molecules widely used in medicine to kill pain in extreme cases. -Chemicals are added to morphine to create diamorphine (or heroin). Heroin is generally diluted in water and injected, but it can also be smoked or snorted. Highly addictive, diamorphine mimics endorphins and creates an intense feeling of relaxation for few minutes followed by a high that lasts hours. However, the intense relaxation can lead to serious heart problems and insufficient oxygenation, which can cause permanent damages to the brain. -MDMA is another synthetic drug that can be ingested. When it come with additives such as caffeine or amphetamine, it is called ecstasy. MDMA increases the release of norepinephrine, dopamine and serotonin, which creates an intense feeling of restlessness, happiness and sociability for a few hours. However, this can cause heart problems or mental problems such as depression, extreme irritability or fatigue. -Magic mushrooms are a type of fungus that contains psilocybin, a molecule that is decomposed into psilocin when ingested. It prevents serotonin from being reabsorbed and mimics the effects of this neurotransmitter. This creates hallucinations as the brain perceives things without any real stimulus. These hallucinations are mostly pleasant, but can sometimes be terrifying. Surprisingly, magic mushrooms are one of the least addictive drug that exist. -Chemicals are added to ergot, a parasite fungus that grows on rye, to create LSD. LSD contains ergine, a molecule that has very similar effects to magic mushrooms when ingested. So, although drugs can have many medical benefits in appropriate dosage, it’s important to remember that long term use of drug messes up the balance of neurotransmitters in the brain, which can be very dangerous. While waiting for new scientific studies on drugs to be published, we must remain careful with drug usage.