Both legal and illicit drugs may affect the ability of the brain to learn. There are three ways in which drugs affect memory. They first prevent learning by impairing the brain's ability to store information. Secondly, they cause distortions of reality that have such a powerful effect that they are stored and are either recalled as good or bad experiences. Third, there is slight evidence that shows small amounts of chemicals can actually increase learning. The most common effect of several common drugs is to suppress learning (Rankin, 1975).
Merriam Webster defines 'drug' as "a substance intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease, 2) a substance other than food intended to affect the structure or function of the body and 3) often an illegal substance that causes addiction, habituation, or a marked change in consciousness" (Merriam Webster, 2009). In accordance with Webster's first definition, there are a few drugs that which alter the functions of our body and brain in a positive and necessary manner.
Aspirin
Aspirin is one of the most common over the counter drugs. It is in a group of drugs known as salicylates. It works by reducing fever, and inflammation. Aspirin often treats mild to moderate pain. It can also be used to prevent heart attacks, strokes and chest pain when under a physicians care. Side effects that may occur include nausea, swelling, and blood in stool or ringing in your ears. It is able to reduce fever and inflammation by attaching itself to an enzyme called cylooxygenase-2. This enzyme then makes chemicals called prostaglandins which send signals to the brain to tell it that there is pain in a certain area where damage to cells has occurred. It also creates a cushion around the damaged cells to prevent further damage which causes inflammation. When aspirin is attached the enzyme, it does not produce as many prostaglandins causing the brain to not register as much pain in that area which then reduces inflammation (Orwell, 2009).
Ritalin
Ritalin is a stimulant medication prescribed to treat attention deficit hyperactivity disorder. Its success is based on its ability to "fine-tune the functioning of neurons in the prefrontal cortex- a brain region involved in attention, decision making and impulse control" (Science Daily, 2008). By increasing dopamine levels in the brain, the user is given a feeling similar to a "high" in order to better help him/her focus on the task at hand. It also lessons the firing of neurons not associated with the task so to prevent the brain from becoming distracted and increasing the brains ability to transmit a clear signal.
Ritalin has not been proven to be effective for children under the age of six years old. Ritalin use must be closely monitored since long term use can have significant side effects such as decreased appetite, vomiting, nervousness, insomnia, an increase in blood pressure, heart palpitations, dependence and depression upon withdrawal (Science Daily, 2008).
Penicillin
Penicillin is an antibiotic that destroys bacteria by attacking the cell well. It inactivates an enzyme called transpeptidase that is responsible for linking bacterial cell walls. Once the cell wall construction is ceased the bacteria dies. Despite high levels of penicillin in the blood, low concentrations of this drug are found in cerebrospinal fluid which implies that penicillin is blocked from entering the brain.
This is because of the blood-brain barrier. The brain is protected by a thin barrier that prevents certain toxic substances in the blood from reaching the brain. The blood-brain barrier "has transport systems that move substances the brain needs across the barrier to brain tissue" (Goldman, 2007). The cells that form the capillary walls in the brain are tightly sealed. Capillaries are small blood vessels where nutrients and oxygen are exchanged between the blood and tissues. This barrier limits the types of substances that can pass into the brain. Penicillin as well as many chemotherapy drugs, and most proteins cannot pass into the brain, unlike substances such as alcohol, caffeine, and nicotine that pass into the brain freely (Goldman, 2007).
Caffeine
Caffeine can be found in coffee, tea, chocolate and cola soft drinks. It can also be found in some medications. It is naturally produced in the leaves and seeds of many plants. It can also be made artificially and is sometimes added to other foods. Caffeine is a stimulant. Stimulants are drugs that cause a sense of energy, alertness and well being that users find pleasurable. Simultaneously, the user will experience increased heart rate and blood pressure as well as dilation of the respiratory passages in the lungs. At low to moderate doses people will feel an increased alertness and ability to concentrate, while higher doses may result in nervousness and agitation. Some symptoms of overdose may include tremors, nausea, vomiting, irregular or rapid heart beat and confusion. Since caffeine is a stimulant, when it's combined with other medications it can increase their effect (Kuhn… et all, 1998).
In addition to these symptoms, caffeine affects the brain. At moderate doses about 200 milligrams which is equal to about two cups of coffee, electroencephalograph (EEG) studies indicate that the brain is aroused. Higher doses of 500 milligrams increase heart rate and breathing. When these centers are activated blood vessels in the brain are narrowed. Dependence on caffeine can develop and when users try to stop they generally suffer from fatigue and headaches.
In small children, toxic effects may be observed with consumption of 800 milligrams for a 50 pound child which is equivalent to 4 Caffeine pills or 7 cups of coffee. Although most parents do not let their children drink coffee, some don't realize the how much caffeine their children drink through soft drinks. Children should not consume more that 45 milligrams which is about the same amount found in a 12 oz cup of soda or a chocolate bar. It is necessary to limit the amount of caffeine that is consumed by children for other reasons, notably the high amounts of sugar in soda drinks. Because caffeine is a diuretic, it can contribute to dehydration which effects learning. Below is a chart with information about the amount of caffeine in common drinks, chocolate and pain relievers.
(The Nemours Foundation, 2009)
Lesson 6 - How does caffeine affect you?
Objective: Students learn more about how a drug, caffeine, affects their body.
Materials
Preparation: Before beginning this investigation, be sure to have permission forms signed by parents or guardians for the students to drink either a caffeinated or caffeine-free soft drink. Those students who do not have permission can participate in the investigation by drinking water, thereby providing a comparison or second control for the activity. Several days prior to conducting this activity decide which students will be in which group. Tell students which group they will be a part of if you are asking them to bring a can of soft drink to class. Approximately half of the class should be assigned to each group.
Introduction: Caffeine is a mild stimulant contained in coffee and some soft drinks. People often report that mild doses of caffeine increase their alertness and their ability to concentrate. Higher doses can cause a person to feel jittery or nervous. High doses can cause sleeplessness.
Procedure:
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1) Teach students how to find their pulse, count their heartbeats, and calculate their resting heart rate. A student can find his or her pulse most easily by pressing two fingers against the artery in the neck or on the inside of the wrist. It is easiest to count for 15 seconds and then multiply that number by four to obtain the resting heart rate for one minute. Students should repeat the process several times until they get a consistent resting heart rate. . Students should record their data on chart paper.
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2) Students can work in pairs. Distribute cans of the appropriate soft drink, one to each student. Instruct students to then drink their beverage. Students will then track their heartbeat in a table by taking their pulse 5 minutes after drinking the beverage, 15 minutes later and finally 45 minutes after drinking the beverage. This is because caffeine concentration is at its highest, 15-45 minutes after ingestion.
Closure: When all the students have filled in their data tables and calculated the difference between their resting heart rate and their heart rate after drinking a soft drink, discuss their findings by asking
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Did your heart rate go up, down, or stay the same after you drank a caffeinated
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soft drink?
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If you drank a caffeine-free soft drink, how did your heart rate change?
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What happened if you drank water?
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On average, most students will see their heart rate go up after drinking the caffeinated soft drink 15- 45 minutes following ingestion. (National Institute of Health, 2000).
Nicotine
Unlike caffeine, as soon as nicotine enters the body, through the lungs, it immediately travels through the bloodstream to the brain where it is then delivered to the rest of the body. Nicotine is a chemical found in tobacco. Tobacco is a plant that can be smoked in cigarettes, pipes or cigars. It is also found in smokeless tobacco. Nicotine is a specific type of stimulant that increases attention, concentration and possible memory. It is reported that it sometimes has a calming or anti-anxiety affect. Nicotine stimulates the heart and circulation. When combined with other drugs it can cause problems with heart rate and blood pressure as well as reduce the amount of oxygen-carrying capacity in the blood. Combinations of these types of drugs can cause heart attacks. Nicotine and other poisonous chemicals found in tobacco can cause heart disease and cancer. Overdose from nicotine, although rare is possible. Such symptoms would include tremors and convulsions that could paralyze muscles need for breathing. Other effects include dizziness, weakness and nausea. Nicotine is very harmful for women who are pregnant because it reaches the fetus and can cause permanent damage (Kuhn… et all, 1998).
Nicotine affects the brain by stimulating receptors that are widely distributed on nerve cells throughout the brain. Nicotine excites nerves cells which increases signaling from cell to cell. Some studies have shown that it increases the brain activity in regions associated with memory as well as physical movement, but he detrimental effects are far worse (Kuhn… et all, 1998).
When tobacco is smoked, nicotine is absorbed by the lungs and quickly moved into the bloodstream, where it is circulated throughout the brain. Nicotine reaches the brain within 8 seconds after someone inhales tobacco smoke. Nicotine can also enter the bloodstream through the mucous membranes that line the mouth, nose and even through the skin.
Nicotine affects the entire body. Nicotine acts directly on the heart to change heart rate and blood pressure. It also acts on the nerves that control respiration to change breathing patterns. In high concentrations, nicotine is deadly. The nicotine molecule is shaped like a neurotransmitter called acetylcholine. Acetylcholine and its receptors are involved in many functions, including muscle movement, breathing, heart rate, learning, and memory. They also cause the release of other neurotransmitters and hormones that affect your mood, appetite and memory. When nicotine gets into the brain, it attaches to acetylcholine receptors and mimics the actions of acetylcholine (National Institute on Drug Abuse, 2009).
Nicotine activates areas of the brain that are involved in producing feelings of pleasure and reward. Nicotine raises the levels of a neurotransmitter called dopamine in the parts of the brain that produce these feelings. Dopamine is the same neurotransmitter that is involved in addictions to other drugs such as cocaine and heroin (National Institute on Drug Abuse, 2009).
Alcohol
Alcohol is a hypnotic sedative. When alcohol is first consumed, most people feel pleasure or relaxation. After about an hour some become talkative but quickly turns drowsy as the alcohol is eliminated from the body. Some want to keep the feeling of pleasure so they continue to drink. People can become very sick and even die when too much alcohol is consumed too fast. After someone has fallen asleep, the alcohol consumed prior to losing consciousness will continue to be absorbed by the body. The amount of alcohol in their blood can reach dangerous levels and the person can die in their sleep. If a person becomes unconscious and vomits, their airway may become blocked which can cause them to suffocate and die. A person's body type can determine how the alcohol is distributed throughout the body. A heavier person would show a lower blood alcohol level in their blood but retains the alcohol longer than a leaner person. Both the alcohol concentration as well as the presence or absence of food will influence the effects of alcohol (Kuhn… et all, 1998).
Once alcohol has been absorbed and distributed, it has many effects on the brain and behavior. Alcohol changes the neurons' membrane and opens the potassium and chloride channels at synapse. It temporarily quiets the brain by reducing worry and tension. It can even suppress a panic attack until the level of alcohol begins to decline. This then causes an over stimulation of brain mechanisms. This over excited brain can then cause anxiety, sleeplessness delirium tremens and epileptic seizures. Alcohol also affects the dopamine, norepinephrine, and serotonin neurotransmitter systems in the brain (Dupont, 1997). Because alcohol is a depressant, it first affects the higher functions of the brain including self observation and self criticism. Anger and irritability is often released after only a small amount of alcohol. In higher doses, alcohol; produces a lack of coordination and upsets the digestive process. Alcohol triggers the brains' vomiting mechanism and irritates the lining of the stomach. Alcohol can cause amnesia.
Ecstasy
Ecstasy also referred to as methylenedioxymethamphetamine (MDMA.) It typically produces drowsiness, a loss of inhibition and a distortion of sense, time and distance. It often intensifies a persons' mood from euphoria to anxiety. "Users often claim they feel uniquely connected to the world and an unusual muscular restlessness" (Dupont, 1997).
After effects like exhaustion, depression, fatigue nausea and numbness is a reflection of long term serotonin deficiencies in the users' brain. Ecstasy affects many of the brain neurotransmitter systems at the synapse, by its ability to increase levels of dopamine, norepinephrine and serotonin (Kuhn… et all, 1998). It's the increase of serotonin levels at the synapse that causes a unique positive feeling of empathy and a decrease in aggression. The range of neurotoxicity is based on how long and how much it has been used.
Marijuana
Marijuana is a green, brown, or gray mixture of dried, shredded leaves, stems, seeds, and flowers of the hemp plant. Marijuana first relaxes a person and then elevates their mood. This period is followed by drowsiness and sedation. Marijuana impairs judgment, coordination and increases the heart rate. THC (delta-9-tetrahydrocannabinol), is the main active chemical in marijuana as well as more than 400 other chemicals. Marijuana's effects on the user depend on the amount of THC it contains. Heavy or daily use of marijuana affects the parts of the brain that control memory, attention, and learning. It inhibits memory formation and the ability to store these memories due to its profound damage to the hippocampus (National Institute on Drug Abuse, 2009).
Lesson 7- Marijuana Activity 1
Objectives: The student will understand the effects of marijuana on the brain structures that control the five senses, emotions, memory, and judgment.
The student will use knowledge of brain-behavior relationships to determine the possible effects of marijuana on the ability to perform certain tasks and occupations.
Activity: Review the way marijuana use affects brain regions and structures that control the five senses, heart rate, emotions, memory, and judgment. Students will then randomly select (for example, draw from a hat) an occupation and be asked to act out, in front of the class, how marijuana use might specifically affect the performance of a person in that occupation. (airline pilot, professional basketball player, doctor, truck driver, construction worker, waiter/ waitress, politician.) Students will identify the brain regions and structures affected by marijuana use, and describe the link between these structures and behavior (National Institute on Drug Abuse, 2009).
Lesson 8- Marijuana Activity Two
Objective: The student will understand how marijuana interferes with information transfer and short-term memory.
Activity: Read aloud a list of 20 words to the class; then ask the students to write down as many words as they can remember. Next, have several students, stand in pairs around the room and carry on loud conversations while you read another list of 20 words to the remainder of the class. Ask students once again to write down as many of the words as they can remember. Compare the performance of the two trials. Tell the students that, like the disruptive pairs of students, marijuana interferes with normal information transfer and memory. Students will then identify the areas of the brain and structures responsible for these functions and will be reminded that marijuana alters neurotransmission in these areas. Students can also search the Internet and other sources for more research into the effects of marijuana on information transfer and memory, and then prepare a brief report summarizing their findings (National Institute on Drug Abuse, 2009).
Heroin
Heroin is in the drug class, opiate. People who inject opiates experience a rush of pleasure then enter a dreamy state and have little sensitivity to pain where all cares are forgotten. Some side effects include slowed breathing, constipation and pinpoint pupils. Opiates elicit their effects by activating opiate receptors that are widely distributed throughout the brain and body. When it reaches the brain, it activates the opiate receptors and produces an effect that correlates with the area of the brain involved. Two important effects produced by opiates, such as morphine, are pleasure and pain relief. The brain also produces substances known as endorphins that activate the opiate receptors. Endorphins are involved in respiration, nausea, vomiting, pain modulation, and hormonal regulation.
Opiates activate the brain's reward system. When a person injects, sniffs, or orally ingests heroin, it travels to the brain through the bloodstream. Heroin then activates opiate receptors in the brain which results in feelings of reward or pleasure (National Institute on Drug Abuse, 2009).
Opiates also act on the respiratory center in the brainstem. This causes a decrease in breathing rate. Excessive amounts of an opiate, like heroin, can cause the respiratory centers to shut down breathing. When someone overdoses on heroin, it is the action of heroin in the brainstem respiratory centers that can cause the person to stop breathing and die (National Institute on Drug Abuse, 2009).
Cocaine
Cocaine is considered a stimulant. It immediately causes a surge of energy and alertness, by stimulation of the nervous system. This results in increased heart rate, blood pressure and dilation of the breathing tubes in your lungs. It also causes an intense feeling of euphoria (Kuhn… et all, 1998).
Cocaine changes brain function by changing the way nerve cells communicate. One of the neurotransmitters affected by cocaine is dopamine. Once dopamine has attached to a nerve cell's receptor and caused a change in the cell, it's pumped back to the neuron that released it. But cocaine blocks the pump, called the dopamine transporter. Dopamine then builds up in the gap (synapse) between neurons. Dopamine will continue to affect a nerve cell after it should have stopped. Cocaine also causes the body's blood vessels to become narrow and constricts the flow of blood. The heart is then forced to work harder to pump blood through the body. The heart can even temporarily lose its natural rhythm, called fibrillation. Many of cocaine's effects on the heart are actually caused by cocaine's impact on the brain (Kuhn… et all, 1998).
Initially, cocaine may make someone feel pleasure. Later it can damage the ability to feel pleasure. Long-term cocaine use may reduce the amount of dopamine or the number of dopamine receptors in the brain. Nerve cells, then must have cocaine to communicate properly. Without the drug, the brain can not send enough dopamine into the receptors to create the feeling of pleasure (Kuhn… et all, 1998).
Steroids
Anabolic steroids are artificial versions of the hormone testosterone. The body's testosterone production is controlled by a group of nerve cells at the base of the brain, in the hypothalamus. The hypothalamus helps control appetite, blood pressure, moods, and reproductive ability. While steroids are used to increase physical strength, they inhibit the immune system making you more susceptible to sickness. The ultimate problem lies in the mental damage that they create. Anabolic steroids can change the messages the hypothalamus sends to the body and can disrupt normal hormone function. They can also lead to liver damage or cancer. They can also permanently stop bones from growing. This means that a young steroid user may not grow to be his or her full adult height (National Institute on Drug Abuse, 2009).
Anabolic steroids also affect the part of the brain that influences mood, memory and learning. They cause feelings of irritability and depression. Often steroids will cause aggressive behavior. The effect may wear off, but it has long term consequences on the developing brain. This outward aggression is correlated with inner changes in the brain. This is because the neurotransmitter levels in the brain's aggression control region are activated. Neuroscientists have found that steroid use as a teenager can cause serious behavioral changes well into adulthood (American Psychological Association, 2009).
