Drugs and the Brain









Remember that iconic television commercial that started airing in 1980s from the Partnership for a Drug-Free America where the guy holds up an egg, and says, “This is your brain.” Then the camera shows a frying pan where he says, “This is drugs.” Then he dramatically cracks the egg and puts it in the frying pan where it instantly starts to sizzle and fry and says, “This is your brain on drugs.” Watching it now, it seems super corny. Everyone says addiction isn’t a choice and it changes the chemistry of your brain (or “cooks” it), but how exactly? How can it change your brain so that the desire to seek out and do drugs is stronger than wanting to spend time with your family? Care for your children? Work? Go to school? Have the basics such as food and shelter? Understanding what exactly occurs in the brain from substance use will help answer some of these questions. We will also talk about how each drug impacts the brain and body, too. Buckle up…

The brain is a SUPER complex organ, despite only weighing three pounds. It is mission control for your body. It regulates everything from your body’s basic functions to shaping your thoughts, emotions, and behaviors. It is a communications center that consists of billions of neurons, or nerve cells, that allow you to interpret and respond to everything you experience. There are many parts to the brain that work together to make all of this happen. But let’s focus on the three main parts that are affected by drug use, specifically the limbic system.







The Brain Stem

The brain stem controls basic functions that are critical to life, such as heart rate, breathing, and sleeping. These are automatic and we don’t have to think about doing them. Our body can just do what it needs to. BUT when you introduce a chemical, such as a drug, it can cause some serious and sometimes deadly problems. The introduction of this foreign substance can cause your heart rate to slow down or speed up, depending on the drug. It can increase your blood pressure. It can suppress, or even stop, your breathing. Drugs wreak havoc on this part of your body and that is where those physical/health side effects of drugs come from.

The Limbic System

The limbic system controls the reward circuit of the brain. This is where dopamine comes into play. When you eat, sleep, exercise, meditate, listen to your favorite music, or do anything else that brings you joy and happiness, your brain releases dopamine. Dopamine makes you feel good. That feeling of goodness, or reward for that specific activity, is also transmitted to the amygdala and the hippocampus, which record a memory of that feeling associated to that activity. You learn to repeat those activities (conditioning) so you experience that dopamine release again.

So what does drug use do to this system? Here is where it starts to transform and reprogram your brain. When drugs or alcohol are used, they activate the same dopamine process in the survival center, or limbic system. But drugs cause the brain to release 2 – 10 times the amount of dopamine! It is an immediate release and it can even last longer than dopamine released by activities such as eating, traveling, etc. When use is repeated over and over again, the substance takes over that part of the brain, so that it thinks that the primary need for survival is the drug. The dopamine high experienced from using the drug becomes greater than the dopamine high experienced from eating, sleeping, exercising, having shelter, etc. (Remember, it is stronger and lasts longer.) Over time, more and more of the drug is needed to experience the dopamine high or the same level of reward, or feeling of pleasure (tolerance). Continued drug use only further damages this part of the brain.

Knowing this about the limbic system and dopamine process might help you understand how so many people on drugs can lose everything – their house, family, car, job, etc. – but still seek out drugs. It has reprogrammed this center of their brain to get more out of a dopamine high from doing drugs than from other activities. And it isn’t a process that is easily reversed. They can’t just quit, because they face withdrawal symptoms. Brain scans have shown that once in recovery, the limbic system and cortex can get better. But it takes a supportive team to see the addict through to recovery, and even long after. It is the reason why things like triggers are still an issue for those years into the recovery phase, because the brain has been conditioned from the drug use.

The Frontal Cortex

This part of our brain separates us from other animals, because this is where decision-making and impulse control happen. This part of the brain is tied to the limbic system processes, which is discussed above.

Now that you understand the basics of how drugs generally affect the brain, lets break it down to specifics, drug by drug.

Cigarettes and Tobacco, E-cigarettes

When nicotine is absorbed into the bloodstream, it stimulates the adrenal glands to release the hormone epinephrine, or adrenaline. Epinephrine stimulates the central nervous system and increases blood pressure, breathing, and heart rate. Similar to other drugs like cocaine and heroin, nicotine activates the brain’s reward system and increases levels of dopamine. Dopamine reinforces rewarding behaviors. Other chemicals in tobacco smoke may also enhance nicotine’s effects on the brain.


Cocaine increases the levels of dopamine in the brain’s reward system. Normally, the dopamine would recycle back into the cell that released it, which shuts off the signal between nerve cells. With cocaine, it prevents dopamine from being recycled. Instead, large amounts build up in the space between two nerve cells, which stops their normal communication. This flood of dopamine in the brain’s reward system reinforces drug-taking behaviors because eventually, it adapts to the excess of dopamine caused by cocaine use. In other words, it becomes the normal state after repeated use. This causes tolerance, and people will take stronger or more frequent doses to feel the same high and to get relief from withdrawal symptoms.


Fentanyl has the same effect as other opioid drugs like heroin and morphine. Fentanyl binds to the body’s opioid receptors, which are found in the parts of the brain that control pain and emotions. When the opioid drugs bind to these receptors, they increase dopamine levels in the brain’s reward system, which produces a state of euphoria and relaxation.


Hallucinogens work in part by temporarily disrupting communication between brain chemical systems throughout the brain and spinal cord. It interferes with the action of the brain chemical serotonin, which regulates mood, sensory perception, sleep, hunger, body temperature, sexual behavior, and muscle control. Some hallucinogens interfere with the action of the brain chemical glutamate, which regulates pain perception, responses to the environment, emotion, and learning and memory. The short-term general effects of hallucinogens can include increased heart rate, nausea, intensified feelings and sensory experiences, and changes in sense of time. There are some hallucinogens that have specific short-term effects such as increased blood pressure, breathing rate, body temperature, loss of appetite, dry mouth, sleep problems, mixed senses (such as “hearing” colors), spiritual experiences, feelings of relaxation or detachment, uncoordinated movements, excessive sweating, panic, paranoia, and psychosis. Long-term effects could possibly include speech problems, memory loss, weight loss, anxiety, depression and/or suicidal thoughts. There are some rare long-term effects such as persistent psychosis and flashbacks.


Heroin can activate neurons because their chemical structure mimics that of a natural neurotransmitter. It “fools” receptors and allows the drug to attach onto and activate the neurons, which leads to abnormal messages being transmitted through the network. Heroin enters the brain rapidly. It then binds to opioid receptors on cells located in many areas of the brain, especially those involved in feelings of pain and please, and that control heart rate, sleeping, and breathing. Short-term effects include a “rush” of pleasure or euphoria, dry mouth, warm flushing of the skin, heavy feelings in the arms and legs, nausea, vomiting, severe itching, clouded mental functioning, and nodding off. Long-term effects can include insomnia, collapsed veins for those who inject it, damaged tissue inside the nose for those who snort it, infection of the heart lining and valves, abscesses, constipation, stomach cramping, liver and kidney disease, lung complications, and mental disorders.


Inhalants impact the central nervous system and slow down brain activity. The short-term effects are similar to alcohol, and include slurred or distorted speech, lack of coordination, euphoria, and dizziness. People may also feel light-headed or have hallucinations or delusions. With repeated use, people can feel less self-conscious and less in control of their body.


The effects of kratom on the brain are similar to both opioids and stimulants. There are two compounds in kratom leaves, called mitragynine and 7-a-hydroxymitragynine, that interact with the opioid receptors in the brain to produce sedation, pleasure, and decreased pain. Mitragynine also interacts with other receptors that produces stimulant effects. If taken in small amounts, it gives users increased energy, sociability, and alertness instead of sedation. However, it can also have dangerous side effects, which may include nausea, itching, sweating, dry mouth, constipation, increased urination, loss of appetite, seizures, and hallucinations. Psychosis has also been reported by some users.


Marijuana can activate neurons because their chemical structure mimics that of a natural neurotransmitter, like heroin can. It “fools” receptors and allows the drugs to attach onto and activate the neurons, which leads to abnormal messages being transmitted through the network. THC quickly goes from the lungs to the bloodstream, where it carries the chemical to the brain and other organs in the body. The body absorbs THC more slowly when eaten, and effects are usually felt after 30 minutes to 1 hour. THC acts on specific brain cell receptors that ordinarily react to natural THC-like chemicals. These chemicals play a role in normal brain development and function. Marijuana over-activates parts of the brain that contain the highest number of these receptors, which causes the high the people feel and causes altered senses, altered sense of time, changes in mood, impaired body movement, difficulty with thinking or problem-solving, impaired memory, hallucinations (high doses), delusions (high doses), and psychosis (high doses). Marijuana does affect brain development. When used as a teenager, it may impair thinking, memory, and learning functions and how the brain builds connections between the areas necessary for these functions.


Methamphetamine increases the amount of the natural chemical dopamine in the brain. It releases dopamine quickly, so it strongly reinforces drug-taking behavior making the user want to repeat their experience. Short-term effects are similar to those of other stimulants, such as cocaine or amphetamines. They include increased wakefulness and physical activity, decreased appetite, faster breathing, rapid and/or irregular heartbeat, and increased blood pressure and body temperature.

MDMA (Ecstasy/Molly)

MDMA increases the activity of these three brain chemicals (effects can last for 3 – 6 hours):

  • Dopamine: increased energy/activity and acts in the reward system to reinforce behaviors
  • Norepinephrine: increases heart rate and blood pressure
  • Serotonin: impacts mood, appetite, sleep, and other functions; it also triggers hormones that affect sexual arousal and trust; the release of large amounts of serotonin likely causes the emotional closeness, elevated mood, and empathy felt by those who use MDMA.
Synthetic Cannabinoids (K2/Spice)

These act on the same brain cell receptors as THC. However, each batch is different, so it can produce different health effects and can be unpredictable as well as dangerous. Some effects reported by users include elevated mood, relaxation, altered perception, psychosis, extreme anxiety, confusion, paranoia, and hallucinations. Other health effects include rapid heart rate, vomiting, violent behavior, and suicidal thoughts. They can also raise blood pressure and cause reduced blood supply to the heart, as well as kidney damage and seizures.

Synthetic Cathinones (“Bath Salts”)

These are chemically similar to drugs like amphetamines, cocaine, and MDMA. It impacts the brain like cocaine does, but it is 10 times more powerful. Effects can include paranoia, hallucinations, increased friendliness, increased sex drive, panic attacks, and excited delirium. Other health effects include raised heart rate, blood pressure, chest pain, dehydration, breakdown of skeletal muscle tissues, and kidney failure.

To sum things up, here is a great video to go over how drugs hijack the brain. Hopefully this article has given you a little more insight into addiction and how drugs have the ability to reprogram the brain, making it hard for addicts to “just quit.” Until next week!