Editor’s Note: Your Brain on Drugs has been updated for 2022. Since this article was first published in 2017, just five years ago, incredible advances have been made in understanding addiction and how it affects our loved ones and us. Marijuana is now legal for recreational use in many states, and psychedelics are being touted as a treatment for some mental illnesses.
The study of the human brain has made significant progress in recent years. This year, research has solidified the understanding of the brain’s role in regulating the immune system through molecular cues transmitted through cerebrospinal fluid1. Further insights were gained into the development of depression and diet, loneliness, and even Facebook activity. This has all been punctuated by years of pandemic-related depression and anxiety rates that a scientific brief by the WHO has estimated both jumped by 25%.
A more detailed understanding of the complexities of brain science helps us better understand how drugs work in the brain and their long-term implications for drug abuse and addiction on both the brain and the body. Knowing the effects of drugs on the brain can lead to more effective ways of reversing the damage.
Do You Remember “Your Brain on Drugs?”
It’s been over 30 years since this iconic ad campaign ran on the airwaves. Dramatically, the campaign compared the brain to an intact, raw egg. The brain on drugs was then shown to be a cracked egg in a frying pan. Of course, the message was strong and pointed, but at the time, we didn’t fully understand the working of the brain on drugs. It was a simplistic view of a highly complex mix of emotional, behavioral, and physical factors.
Today, we know much more, and the treatment protocols have changed dramatically. We know more about trauma and its effect on substance abuse and mental illness. We also know much more about the interplay between mental illness and substance abuse. In many ways, however, since this ad campaign first ran, we have taken some steps back, societally. With the advent of social media, we have seen a dramatic increase in depression and anxiety in adolescents and adults alike. We’ve also seen the progression of drug use, especially opioids, to epidemic proportions. And while fentanyl, the most potent opioid on the market, had been invented when this ad campaign started, it was not used and abused the way it is today, accounting for upwards of 60% of all opioid-related deaths as of 2017.
How Your Brain Works
Your brain is a complex organ that runs everything about you. Your thoughts, memories, ideas, and personality traits are housed in your brain. Your brain manages all of your physical functions — from climbing a mountain to the involuntary beating of your heart, with a chemical messaging system.
The brain works via physical structures that convey messages through brain chemicals. Sometimes, messages are sent from the body through the nervous system to the brain and back again. When you walk barefoot and step on a pebble, the pain sensation is transmitted to your brain, and your brain responds with a message to pick up your foot quickly.
Your brain uses neurotransmitters to send signals from cell to cell. There are several different types of cells in your brain with unique functions. Receptors read the messages from the neurotransmitters. Specialized receptors for each neurotransmitter fit together like a lock and key.
Information is managed by the type and number of available receptors in the brain, and the amount of the corresponding neurotransmitter produced. For a message to connect, the brain has to make the neurotransmitter sufficiently, and that brain chemical has to meet up with the right receptors. If the receptors are there but happen to be blocked, the message will not get through.
There are about 100 different neurotransmitters divided into three categories: Small molecules, neuropeptides, and others. Once released, a neurotransmitter is available for a short time. If it does not bind to a receptor, it’s gobbled up by enzymes or taken back into the neuron. Communication breakdown within the brain can result when these message chemicals are produced but not received.
One of the reasons neurotransmitters might not be received is that all the appropriate receptors are blocked. A receptor cannot take on a neurotransmitter if it is already engaged. Receptor cells can only connect with their intended neurotransmitters in a one-to-one relationship. Complex thoughts are handled with a combination of neurotransmitters. By adjusting the variables — the number of neurotransmitters produced, available receptor cells, and possible combinations of neurotransmitters — your brain can process complex thoughts, like emotions and abstract concepts.
With such significant responsibilities, your brain is a highly complex network of cells and chemicals that we continue to study fruitfully. While a lot of brain science is understood, several questions are still to be answered. Your complex brain is precious to life as we know it and warrants protecting.
Parts of Your Brain
The brain is divided into specific regions for ease of study and classification. Each part has a unique purpose, all of them working together harmoniously.
The largest part of the brain, the cerebrum, is responsible for most of the brain’s work. The cerebrum is divided into the left and right hemispheres, each containing the same subdivisions.
The frontal lobe spans the front part of the head. It is responsible for behavior, personality, creative thought, intellect, problem-solving, attention, smell, muscle movements, abstract thinking, judgment, physical reactions, and coordinated actions.
The parietal lobe sits directly behind the frontal lobe and is subdivided into the sensory and motor cortexes. The sensory cortex receives information about positioning, touch, and pain from the body. The motor cortex monitors and controls movement.
The temporal lobe is located near the temples on either side of the head. The right and left temporal lobes are connected with axons. Language, including speech and hearing, is the primary function of this lobe.
This small brain region handles some fundamental functions. The cerebellum is responsible for balance, coordination, and movement. Its procedures allow us to hold ourselves up and move our bodies.
The brain stem, the part of the brain that attaches to the spinal cord, manages essential life support functions. Heart rate, respiration, and blood pressure are all controlled by the brain stem.
There is some overlap in functioning among the regions of the brain. Certain more complex concepts, like language, are handled by coordination between different regions. This functional overlap can be good news when brain damage occurs due to an accident or illness. Certain brain functions can be rebuilt when they are lost.
How Drugs Do What They Do
No matter what type of drugs you use, whether they’re pills prescribed by a doctor or something you bought on the street, they eventually find their way to your brain. Smoking, swallowing, snorting, drinking, injecting, or any combination of these will all deliver drugs to your bloodstream, which moves them to your brain.
Since your brain manages all functioning and thoughts, it makes sense that a drug would have to travel to your brain to have any effect. Consider an over-the-counter cough suppressant that relaxes the cough reflex so that you can get some sleep. Your brain regulates that reflex, so the active ingredient in the cough medicine has to change the messages in your brain to be effective.
Once in your brain, drugs interfere with your normal brain chemistry to produce the desired effect. Because the brain is so complex, and our understanding of its functioning is not complete, drugs all have side effects. The cough suppressant reduces your cough and also makes you drowsy. Every drug you take has more than one effect on you.
Usually, drugs affect you both mentally and physically. For example, while alcohol reduces your inhibitions, it also depresses respiratory functions. Side effects can be a dangerous part of any drug since you’re not looking for or monitoring them. Most people tend to focus on the primary function of a drug and try to ignore the side effects.
Your Brain and Behavior
Your brain controls your behavior in many ways. A reflex response, for instance, results from some quick situational analysis in your central nervous system. Your brain makes you move your hand away from a hot stove to mitigate the burn’s damage to your skin.
Your brain also moves your muscles in response to various other cues, but most of these are simple thought patterns. Your brain adjusts your stride when you walk up and down an incline. It finds you a place to sit when you are tired and moves you to bed at the appropriate time in the evening. Psychologists group more complex behaviors as “executive behaviors,” which involve using emotional judgment to guide movements.
These are the eight executive behaviors governed by your brain and how their deficiency might affect the functioning of an otherwise healthy adult:
Task Initiation: Getting started with an activity
Self-monitoring: Evaluating your progress
Evaluating your progress is essential to maintaining a clear connection with your reality. A deficiency in this area would mean you could not catch your mistakes before someone else pointed them out to you. This could be a big problem if that someone else is your boss.
Organization: Keeping track of items and ideas
Flexible Thinking: Adjusting to unexpected circumstances
The inability to adjust to unexpected circumstances or accept new information would make it very difficult to learn anything. Once you develop a bad habit, it would also be challenging to alter your thinking to change that habit.
Impulse Control: Preceding actions with thought
This is a huge problem in addiction. When addiction takes hold of your brain, you tend to follow your impulses rather than reason. A lack of impulse control can result in risky behaviors and become very dangerous over time.
Working Memory: Holding onto the important information
Following a step-by-step procedure is a common ability in most adults. However, when your working memory is impaired, doing something as simple as remembering directions to a friend’s house can be difficult. Without a working memory, there is an increased risk of dangerous behavior. Not retaining basic flammability properties, for example, might lead you to set a burning cigarette down on top of the newspaper.
Emotional Control: Managing feelings
If you struggle to control your emotions, you may overreact or underreact in emotional situations. You might also act out of those overblown emotions and create unnecessary drama and pain. Addiction can cause a loss of emotional control because most people under the influence of drugs do not feel their emotions. When the drugs wear off, the emotional pain can be too much to process all at once. An addict will often act on those emotions until he can calm them with more drugs.
Prioritizing: Setting goals and making plans to meet them
The inability to prioritize and plan can make life somewhat chaotic. Not realizing what is most important, you may take action on something impulsively rather than applying your energy to necessary tasks. In the extreme, this could mean having a couple of drinks rather than being on time to pick your daughter up at school.
Your Brain’s Pleasure Center
Literature on drugs and addiction often mentions the pleasure center of the brain. Pleasure is not perceived in just one area of the brain. A reward system in the brain is made up of a group of interconnected glands and other structures, including many of the glands responsible for behavior. The pituitary gland is part of the reward system that circulates the feeling of pleasure throughout the body. Your brain’s reward system is designed to reinforce positive experiences to ensure you will repeat those actions. It’s like an internal conditioning mechanism that incentivizes essential functions and “good deeds” with pleasure.
Effects of Long-term Drug Use on Body and Brain
The human body has a tremendous ability to adapt to changing conditions. All of your vital functions can be measured within specific ranges. In other words, your body always seeks balance. When something becomes too high, adjustments are made to return to center.
Consider, then, a drug whose side effects include increased heart rate. When you put this drug in your system, your brain tries to lower your heart rate to make up for the difference and maintain your heart rate within the normal range. The more you use this drug; the more your brain has to compensate. Eventually, you may reach a level of drug abuse where it becomes impossible for your brain to counteract these effects.
In the meantime, your brain grows some new pathways to adjust your heart rate continually. It gets used to the presence of this drug and takes it as the new normal. With this drug as part of the equation, the new pathways begin to hardwire your brain to maintain your heart rate within a normal range.
When you stop using this drug, your brain goes into a spasm called withdrawal. It was accustomed to operating with the drugs, and suddenly the drugs are withheld. In this case, you may require medical intervention to maintain a reasonable heart rate while your brain readjusts to life without the drugs. It can be done, but it takes time. The more your brain’s hardwiring has changed, the longer it takes to grow new pathways to accommodate the new condition.
Heart rate is an excellent example because it’s vital to life, and most drugs affect it at some level. Many long-time drug users suffer damage to their hearts or other vital organs. Living with an elevated heart rate for an extended period has the effect of wearing out the muscle. When your heart doesn’t function within normal ranges, oxygen and nutrients do not circulate throughout your body correctly. Other vital organs cannot work optimally without their essential requirement.
Your brain continues to grow and change throughout your adult life. By adding drugs, you force certain changes in your brain that are not natural and can be dangerous. When the drugs add feel-good chemicals to your brain, it stops producing them naturally to maintain a normal balance. Eventually, new pathways grow based on the lack of natural feel-good chemicals.
A downward spiral can begin when negative thoughts become hardwired into your brain. The brain follows habits just like you do. Through repetition, it can develop a pattern of negative thoughts. The more it uses those thought pathways, the deeper they become. Eventually, growing new, more positive thought pathways can be very difficult.
How Your Brain Teaches You to Keep Taking Drugs
It’s clear that the brain is the central control for addiction, and drugs create that addiction when they are inserted into the complex messaging system. The most damage, in terms of addiction, is done in the brain’s reward system. The system is set up to encourage positive behavior. It provides an incentive to repeat actions that are important for survival. Procreation, for example, is required to continue our species, so sexual activity is rewarded with heightened pleasure responses. Eating is also necessary for survival, so good feelings are attached to that activity.
The idea of the reward system is to provide an incentive for repetition. When you do something good, the brain rewards you will get a feeling of pleasure. The pleasure should entice you to repeat that action. If you have a choice between two actions, you will usually repeat the one that gave you the most pleasure.
Drugs hijack this reward system and use it against you. When the drugs find their way into the reward system, they cause the brain to be flooded with dopamine or serotonin, two feel-good brain chemicals. The pleasure you get from this experience is remarkable because many drugs exponentially exceed your natural ability to produce feel-good chemicals. Even though the thinking part of your brain knows these drugs are harmful to your health and life, it’s difficult to override the extreme reward from your emotional brain. You begin to crave that intense pleasure again, but nothing else helps you achieve it.
Reversing the Damage After Long-term Use
Healing the damage caused by long-term drug abuse is a two-step process. First, the changes in brain structures and chemistry that perpetuate the addiction need to be reversed. As long as the brain works against recovery, we will fight a losing battle. The second step is to restore lost cognitive function.
There is evidence to suggest that dopamine receptors change in response when the brain is flooded with dopamine from drug abuse. These structural changes in the brain make it more difficult for the receptors to read naturally-produced dopamine, serotonin, or any other neurotransmitter being mimicked by the drugs. The new receptors are specifically adapted to the compounds in the drugs and don’t recognize their intended brain chemicals anymore. These changes help increase the tolerance for the drugs which, in turn, compels the user to increase the size and frequency of doses. They also strengthen the cravings between doses.
The brain is capable of healing itself given the right conditions. Scientists are working to create therapies that facilitate brain healing. Certainly, ending exposure to drugs is a start. Just like adding the drugs caused the brain to change and adapt, we can stimulate a re-adjustment by changing the conditions in the brain.
Of course, the key to this approach is to control cravings so the brain can remain drug-free. It’s also essential to provide medical support until the brain can maintain all vital functions again. During the detox period, the brain goes through a type of shock where it doesn’t know exactly what to do. It cannot continue on its current course but does not remember how it worked before the drugs.
Scientists have also discovered that the brain can work around damaged areas. This ability is referred to as “plasticity,” allowing the brain to continue to function even when thought pathways are damaged from cell death. The brain can grow new pathways and move its messages around a different route. The brain has tremendous flexibility this way.
Plasticity is like losing your right hand and learning to write with your left. Since many brain functions are spread out over different areas of the brain, it’s possible to build new language skills, for instance, when the original center of language has been destroyed. Brain cells are also capable of regeneration, so in time the losses can be minimized.
Although the amount of damage to the brain from long-term drug abuse can be extensive, the possibilities for healing always exist. The first step, of course, is to eliminate the drugs. Getting help for addiction as soon as possible will minimize the damage and speed up the healing.
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1Kisler, K., Zlokovic, B.V. How the brain regulates its own immune system. Nat Neurosci 25, 532–534 (2022). https://doi.org/10.1038/s41593-022-01066-w
From the JourneyPure team where we get to explore a wide variety of substance abuse- and mental health-related topics. With years of experience working alongside those suffering from substance abuse and mental health issues, we bring important messages with unparalleled knowledge of addiction, mental health problems, and the issues they cause.