The study of the human brain has made great progress in recent years. In 2015, for example, new discoveries were made in the link between the brain and the immune system, new details were revealed about how the brain changes as we age and new insights were gained into the development of depression and diet, loneliness and even Facebook activity.
A more detailed understanding of the complexities of brain science helps us better understand how drugs work in the brain, as well as their long-term implications of 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.
How Your Brain Works
Your brain is a complex organ that runs everything about you. Your thoughts, memories, and personality traits are all housed in your brain. Your brain manages all of your physical functions — from climbing a mountain to the involuntary beating of your heart. In addition, all of your ideas — both conscious and unconscious — originate in your brain.
The brain works via a series of physical structures that convey messages through brain chemicals. In some instances, messages are sent from the body through the nervous system to the brain and back again. When you are walking barefoot and step on a pebble, for example, the pain sensation is transmitted to your brain, and your brain responds with a message to pick up your foot quickly.
While your brain is handling pain responses, it’s also keeping your heart beating, regulating your body temperature and managing respiration. Your brain is the ultimate multitasker with some very important responsibilities, and it manages all of this with a chemical messaging system.
Your brain uses neurotransmitters to send signals from cell to cell. There are several different types of cells in your brain that have unique functions. Receptors read the messages from the neurotransmitters. There are specialized receptors for each of the different neurotransmitters which 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 produce the neurotransmitter in a sufficient quantity, 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 types of neurotransmitters divided into three categories: Small molecule, neuropeptides, and others. Once released, a neurotransmitter is available for a short time. If it does not bind to a receptor, it’s either gobbled up by enzymes or taken back into the neuron. A breakdown of communication 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. If a receptor is already engaged, it cannot take on a neurotransmitter. Receptor cells can only connect with their intended neurotransmitters, and only in a one-to-one relationship.
Complex thoughts are handled with a combination of neurotransmitters. By adjusting the variables — amount of neurotransmitter produced, number of available receptor cells and possible combinations of neurotransmitters — your brain is capable of processing complex thoughts, like emotions and abstract concepts.
With such great responsibilities, your brain is an extremely complex network of cells and chemicals that we continue to fruitfully study. While a lot of brain science is understood, there are still several questions to be answered.
Your complex brain is extremely precious to life as we know it, and warrants protecting.
Parts of Your Brain
For ease of study and classification, the brain is divided into certain regions. Each region has a unique purpose, and yet, they all work together harmoniously.
The largest part of the brain, the cerebrum is responsible for most of the work that the brain does. 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 and is responsible for behavior, personality, creative thought, intellect, problem-solving, attention, smell, muscle movements, abstract thinking, judgment, physical reactions, and coordinated movements.
The parietal lobe sits directly behind the frontal lobe and is subdivided into the sensory and motor cortexes. The sensory cortex receives information from the body about positioning, touch and pain. The motor cortex monitors and controls movement.
The temporal lobe is located on either side of the head near the temples. The right and left temporal lobes are connected with axons. Language is the primary function of this lobe, in addition to speech and hearing. There is a specialized area within the temporal lobe that’s believed to be important in processing language, but more study is needed to explain specifically how it works.
Vision is handled in the occipital lobe, located at the back of the head. Within the occipital lobe is a small area that specializes in facial expressions and understanding language.
This is a small region of the brain that handles some very basic functions. The cerebellum is responsible for balance, coordination, and movement. Its functions allow us to hold ourselves up and move in characteristically human ways.
A series of glands, the limbic system is located in the center of the brain. Emotions and hormonal responses come from this part of the brain. The limbic system includes four primary glands: Thalamus, hypothalamus, amygdala, and hippocampus.
The brain stem, the part of the brain that attaches to the spinal cord, manages basic life support functions. The 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 overlap in functioning can be good news when brain damage occurs, due to 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 to smoke, 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 in turn 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 you can get some sleep. That reflex is regulated by your brain, 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, as well. 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 mentally and physically. While alcohol reduces your inhibitions, it also depresses respiratory functions, for example. Side effects can be the more dangerous part of any drugs 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 a number of ways. A reflex response, for instance, is the result of some quick situational analysis in your central nervous system. Your brain makes you move your hand away from a hot stove to mitigate the damage of the burn 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 upstairs, or 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.
More complex behaviors are grouped together by psychologists as “executive behaviors,” and they involve using emotional judgment to guide movements. These are the eight executive behaviors governed by your brain and how their deficiency might affect functioning for an otherwise healthy adult:
Task Initiation: Getting started with an activity
Without the ability to initiate, people become stuck in their current condition. A deficiency in this area could keep someone from learning a new hobby or starting a new job. For smaller tasks, this can look like extreme procrastination.
Self-monitoring: Evaluating your progress
Evaluating your progress is essential to maintaining a clear connection with your own reality. A deficiency in this area would mean you were unable to 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
Some people are naturally more organized than others. A severe deficiency in organization could make it difficult to carry on a coherent conversation and would result in lots of wasted time looking for car keys.
Flexible Thinking: Adjusting to unexpected circumstances
The inability to accept new information would make it very difficult to learn anything. Once you develop a bad habit, it would also be difficult to change your thinking to change that habit.
Impulse Control: Preceding actions with thought
This is a huge problem in addiction. When addiction takes hold in your brain, you tend to follow your impulses rather than reason. A lack of impulse control can result in risky behaviors and can become very dangerous over time.
Working Memory: Holding onto important information
Following a step-by-step procedure is a common ability in most adults. When your working memory is impaired, however, doing something as simple as remembering the directions to a friend’s house can be difficult. Without a working memory, there is an increased risk of dangerous behavior. Not remembering 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 probably overreact 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 out 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 rather 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.
Although it is unclear exactly how the brain manages executive functions, it is possible to detect when the executive function system is not working. People with diagnosed mental disorders like attention deficit disorder, autism and obsessive-compulsive disorder (OCD) exhibit signs of impaired or under-developed executive functioning.
Recent studies have linked impaired executive functioning with a higher risk of addiction. Addiction can also erode your executive functioning capacity, making it more difficult to recover from addiction.
Your Brain’s Pleasure Center
Literature on drugs and addiction often mentions the pleasure center of the brain. In fact, pleasure is not perceived in just one area of the brain. There’s actually a reward system in the brain that’s 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 so you’ll repeat those actions. It’s like an internal conditioning mechanism that incentivizes “good deeds” with pleasure.
How Different Drugs Work on Your Brain
While all drugs work by getting into your brain and interfering with the chemical messaging system, each drug takes a slightly different path. There are a number of different ways a drug can disrupt the natural messaging system in your brain and create the intended effect.
Depressants are meant to have a calming effect and are used to reduce anxiety and induce relaxation. They slow down brain activity to eliminate racing thoughts, quick pulse, and rapid breathing. Some of the side effects of depressants are:
- Slurred speech
- Poor concentration
- Lack of coordination
Depressants work with the brain chemical GABA that slows down brain function. By binding to the GABA receptors, depressants increase GABA activity and thereby inhibit nerve transmissions. Depressants slow down brain activity, which affects all of the systems in the body. With the brain working more slowly, vital functions also slow down.
Some common depressants are:
Street names for depressants include:
- Sleeping pills
The medical uses for stimulants have changed in recent years. Historically, they were prescribed for a variety of disorders, including respiratory problems such as asthma, several neurological disorders, and even obesity. As the dangers of stimulant abuse and addiction became apparent, the medical uses for the substances were limited to narcolepsy, attention deficit disorder, and depression.
Popular prescription stimulants include:
Street names for stimulants include:
- Black beauties
- Vitamin R
- Kibbles and bits
- Truck drivers
The neurotransmitter associated with stimulants is dopamine, which is involved in pleasure, movement, and attention. When taken as prescribed, stimulants increase dopamine levels in the brain slowly until they reach a level that produces the desired effect. As recreational substances, stimulants raise dopamine levels quickly — much higher and faster than could ever be achieved naturally.
The sudden increase in dopamine, a feel-good brain chemical, produces a euphoric effect and increases the risk of addiction. By interfering with the reward system, large doses of stimulants can create intense cravings. Physical side effects can include:
- Increased heart rate
- Increased body temperature
- High blood pressure
- Decreased appetite
- Difficulty sleeping
Derived from opium, or synthesized to mimic certain substances found in opium, opioids were developed as pain relievers. They block pain by binding to certain receptor cells in the brain and central nervous system. With the opioids occupying the receptors, naturally occurring pain messages cannot get through.
Opioids send their own signals through those receptors that cause the brain to flood with dopamine, a feel-good chemical. The dopamine taps into the reward system in the brain and accelerates addiction. Meanwhile, breathing is slowed as part of the pain-dulling message. The biggest danger posed by opioid overdose is a cessation of breathing.
Common opioid pain relievers include:
Opioids are referred to by several different street names, including:
- Dream gun
- Black tar
- Midnight oil
Cannabis is the active ingredient in the hemp plant used for marijuana. The substance has also been replicated chemically in attempts to synthesize a drug with the same effects. Some people see synthetics as a more controlled, measured way of delivering the desired effects.
Cannabinoids produce a euphoric feeling and enhance sensory perception while creating irregular heartbeat, lack of focus and memory loss. Long believed to be rather harmless, cannabinoids have recently been more thoroughly studied. In the brain, marijuana and any other drug containing this compound kills cells, shrinks neurons and causes DNA fragmentation.
There are at least 85 different compounds that are considered cannabinoids and are naturally occurring in marijuana. Tetrahydrocannabinol (THC) and cannabidiol (CBD) are the two that producers concentrate on. THC has psychoactive properties, and CBD is believed to calm the nerves and also act as an anti-inflammatory. Commercially grown marijuana plants are designed to produce higher levels of these two compounds.
These drugs interact with the reward system in the brain. They increase dopamine activity, which is how they produce the euphoric feeling. Their actions in the reward system are similar to that of morphine or nicotine — two drugs known to be extremely addictive. Indeed, addiction seems to hinge primarily on the manipulation of dopamine in the reward system of the brain.
This class of drug is aptly named because it causes the user to hallucinate, hear sounds or see visions that are not real. Hallucinogens interfere with the brain messaging systems involved in sensory perception and send erroneous signals. They work mostly in the front part of the cerebrum where mood, cognition, and perceptions are processed.
Hallucinogens mimic serotonin, a neurotransmitter used to regulate appetite, digestion, sleep, sexual desire, memory, and mood, in order to bind with certain serotonin receptors. It is still unclear exactly how hallucinogens work, but research continues.
The effects of hallucinogens vary widely. Some users experience pleasant sensations and a deepened sense of understanding, while others have anxiety-ridden visions of terror. Hallucinogens also produce some of these side effects:
- Increased heart rate
- Increased body temperature
- High blood pressure
LSD is probably the most widely known hallucinogen. Some others include:
- Salvia divinorum
Here are some street names for hallucinogens:
- Big D
- Blue heaven
- Purple flats
- South parks
- Vodka acid
- Wedding bells
- Yellow dimples
What Happens When You Take Multiple Drugs at Once?
Polydrug abuse — taking more than one substance at a time — compounds the dangers. Drugs are hard to control, to begin with, but once they get into your brain, there are effects and side effects that you might not even be aware of. When you start combining drugs, the complications multiply.
Most drugs work on levels in your brain. Consider alcohol and blood alcohol content (BAC). When you drink alcohol, your BAC increases for a period of time. Eventually, the alcohol in your blood moves to your brain or is filtered out by your liver. Without a new supply of alcohol, your brain eventually clears and goes back to normal.
People who abuse alcohol tend to maintain a constant BAC, which becomes the new normal for their bodies. Because it is “normal,” they don’t realize that there’s alcohol in their bloodstream — even before they have their first drink of the day. When they add another drug on top of the alcohol, they’re in danger of overdosing without even realizing it.
Many drugs deliver too much of a good thing when it comes to their interaction with the reward system of the brain. Too much plus too much is scary dangerous. All of that pleasure sensation is just going to accelerate the addiction process that much faster. An overload of feel-good chemicals isn’t going to feel very good when it wears off. The subsequent low after the high-high could be deadly.
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 certain 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 the difference and maintain your heart 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.
But in the meantime, your brain grows some new pathways to continually adjust your heart rate. It gets used to the presence of this drug and takes it as the new normal. The new pathways begin to hardwire your brain for maintaining your heart rate within a normal range with this drug as part of the equation.
When you decide to detox and quit this drug use addiction, your brain goes into a spasm called withdrawal. It was used to operating with the drugs, and suddenly the drugs are withheld. 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 changes that have occurred over time to the hardwiring of your brain, the longer it takes to grow new pathways to accommodate the new condition.
Heart rate is a good example because it’s vital to life and because most drugs affect it at some level. Many long-time drug users suffer damage to their heart or other vital organs. Living with an elevated heart rate for a long period of time 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 properly. Other vital organs cannot work optimally without their basic requirement.
It’s similar to an engine running without gas and oil. The engine may still run without enough oil, but it’s sustaining damage that will eventually kill it. The same might be true if you watered down the gas to make it last longer. The engine might run, but it won’t run well and it will be damaged by the time it quits.
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 in order to try to maintain a normal balance. Eventually, new pathways grow based on the lack of natural feel-good chemicals.
When negative thoughts become hardwired into your brain, a downward spiral can begin. The brain follows habits just like you do. Through repetition, it can get in a groove, so to speak, of negative thoughts. The more it uses those thought pathways, the deeper they become. Eventually, it can be very difficult to grow new, more positive thought pathways.
Depression is a major problem for long-term drug users. Since their good moods have been artificially induced for so long, their brains are not prepared to produce pleasure and happiness on their own. The brain can heal and regain its ability for positive thinking, but the longer the drug use goes on, the harder it is to recover.
How Your Brain Teaches You to Keep Taking Drugs
Addiction is a complex concept that scientists continue to study and learn more about. 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 reward system of the brain. 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 for the continuation of our species, so sexual activity is rewarded with heightened pleasure responses. Eating is also necessary for survival, so there are good feelings attached to that activity, as well.
The whole idea of the reward system is to provide an incentive for repetition. When you do something good, the brain rewards you will a feeling of pleasure. The pleasure should entice you to repeat that action. If you have a choice between two actions, you are going to 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 exceed your natural ability to produce feel-good chemicals exponentially.
So your drug-taking behavior is rewarded by your brain and it feels good. Even though the thinking part of your brain knows these drugs are harmful to your health and your life, it’s difficult to override the extreme reward coming from your emotional brain. You begin to crave that extreme pleasure again, but nothing else helps you achieve it.
Drug Use and Mental Illness: Confusion in the Brain
There is a reciprocal connection between drug abuse and mental illness. For some people, mental illness precedes addiction. Self-medicating to escape the symptoms of mental illness in not an uncommon path to addiction. Mental illness often comes with emotional pain and confusion that can be mitigated temporarily with psychoactive drugs.
Self-medicating is never a good idea, however, for a number of reasons. Controlling or overcoming side effects without proper medical guidance is very difficult. In most cases, when drug addiction follows mental illness, the mental illness actually becomes worse.
Most mental illnesses have to do with abnormal brain chemistry. There is a lot going on in the brain, and just a small deviation in one or two neurons or neurotransmitters can change brain functioning. Adding drug abuse to the mix, which also changes brain chemistry, will just compound the problems in the long run.
Mental illnesses need to be professionally diagnosed and treated. In the presence of addiction, the mental illness cannot be properly assessed until the drugs are removed from the system. Brain chemistry is too complicated to diagnose in the presence of brain-altering substances.
Many substances of abuse actually make the addiction happen faster and more completely. By overstimulating the reward system in your brain, drugs create a stronger desire for increased pleasure than any natural occurrence. It is possible to become addicted to any happy experience, but it will take a long time. in the case of drugs that flood the brain with dopamine, the addiction comes very quickly because the brain is hardwired to want to repeat pleasant experiences, and the high you get from something like cocaine is exponentially more intense.
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 is working against recovery, we will be fighting a losing battle. The second step is to restore lost cognitive function.
There is evidence to suggest that, when the brain is flooded with dopamine from drug abuse, the dopamine receptors change in response. These structural changes that take place 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 that compels the user to increase size and frequency of doses. They also strengthen the cravings between doses. Essentially, this is the part of the brain where drug addiction is encouraged by the natural functioning of the brain.
The brain is capable of healing itself given the right conditions. Scientists are working to create therapies that facilitate brain healing. Certainly, ending the exposure to drugs is a start. Just like adding the drugs caused the brain to change and adapt, by changing the conditions in the brain, we can stimulate a re-adjustment.
The key to this approach, of course, is to control cravings so the brain can remain drug-free. It’s also important to provide medical support until the brain is capable of maintaining 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 it does not remember how it worked before the drugs.
Scientists have also discovered that the brain is capable of working around any damaged areas. This ability is referred to as “plasticity,” and it allows 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 actually has tremendous flexibility this way.
Plasticity is like losing your right hand in an accident 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 of 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 the healing.
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Chris Clancy is the in-house Content Manager for JourneyPure’s Digital Marketing team, where he gets to explore a wide variety of substance abuse- and mental health-related topics. He has more than 20 years’ experience as a journalist and researcher, with strong working knowledge of hospital systems, health insurance, content strategy, and public relations. He lives in Nashville with his wife and two kids.