Addiction: What

What Is Drug Addiction? [1]

“Addiction[2] is defined as a chronic, relapsing brain disease that is characterized by compulsive drug seeking and use, despite harmful consequences.”[3]  Some people think it is wrong to call an addiction or a severe substance use disorder a “disease” because they can’t catch it like a common cold.  However, they forget that they can’t ‘catch’ diabetes or heart disease or cancer and they most likely have no issue saying those conditions are diseases.   A disease is defined by the Oxford Dictionary as: “A disorder of structure or function in a human, animal, or plant, especially one that produces specific signs or symptoms or that affects a specific location and is not simply a direct result of physical injury.” With the significant changes in the brain that occur because of the substance, the brain clearly has a ‘disorder of structure.’

What is the Brain?

The brain is a complex nerve center that regulates everything we feel, think, and do. Neurons are the core component of the brain, and through neurons, information is transmitted via electrical and chemical signals.  

The areas of the brain include the Brain Stem, the Cerebral Cortex, and the Limbic System.  The brain stem controls much of our autonomic responses, such as breathing and heart rate.  For example, drink too much alcohol and it can ultimately affect the brain stem and a person can possibly die. 

The cerebral cortex has a number of areas that help us process our five senses, however, there is also the frontal cortex that provides our ability to plan, solve problems and importantly, make decisions.  The frontal cortex is not fully developed until into our mid-20’s.  This means when we ask a teen what he or she was thinking when the person did a certain risky act, in some ways, they weren’t thinking, meaning their frontal cortex is not fully developed.  It is the frontal cortex that considers the pros and cons of a certain action and to weigh the consequences. 

The limbic system has the reward system.  We are designed to feel pleasure such as when we are having a good meal.  Food, water, sex, and nurturing are aspects that are naturally rewarding, and ultimately those four items are important for the survival of our species.  When we do something that feels good or exciting, we are “rewarded” by the increase of dopamine. Thus, there is a desire to repeat that behavior and get that “reward” again.

The Brain’s System of Communication

As previously noted, messages in the brain are sent by chemical and electrical signals. Messages are sent by particular neurons, called neurotransmitters.  Other neurons receive the message and are called receptors.  The space between the neurotransmitter and the receptor is the synapse, and then the neurons that actually transmit between the neurotransmitter and the receptor are called transporters.

As an analogy, consider a ferry boat going back and forth between two docks.  One dock would be the neurotransmitter; the other dock would be the receptor and the river the synapse.  The ferry is the transporter.  The ferry picks up a load of vehicles and passengers on one side, crosses the river and discharges the load on the other side.  Throughout the day, that ferry continues going back and forth discharging its cargo from one side to the other.  That’s a very basic description of what is happening in the brain’s communication system.

Drugs Impact on the Brain

Drugs interfere with the brain’s communication, the way the neurons send and receive messages.   What drug is used can result in a different internal reaction. But ultimately, many drugs create an increase of dopamine, resulting in a reaction of pleasure.  But this reaction is not a normal reaction such as from eating a good meal; the drug actually causes an over stimulation.  In some situations, the amount of dopamine released because of the drug can be anywhere from 2 to 10 times greater than the four natural activities.  Whenever an activity causes the reward system to activate, the brain notes that activity and remembers it and teaches us to do it again and again to the point we can do that activity without even thinking about it. Drugs result in this same type of action, thus we learn to abuse drugs because the brain thinks it is a good thing. 

However, it is far from a good thing.  In time the brain recognizes that it is getting too much stimulation.  The brain is always trying to find balance.  Getting over stimulated requires the brain to reduce the amount of dopamine produced or it ‘shuts down’ some of the receptors. In other words, some of docks are closed and the ferry can no longer unload its cargo.  As the number of active receptors decreases, a person increases the amount of drugs used, or uses a more potent drug unsuccessfully trying to reach that first intense rush of pleasure.  With an increase of the drug, the brain then continues reducing the amount of dopamine or available receptors.  It becomes a virtual cycle.  Additionally, as the receptors decrease in number, normal life activities no longer bring pleasure.

During this time, the person’s frontal cortex is also “shutting down.” Remember that this is the part that provides a person’s decision making process.  The limbic system of the brain is demanding that a person use drugs to feel pleasure, and the frontal cortex is not stopping the action because its ability to provide ‘the brakes’ and recognize the dangerous consequences has been diminished.  As stated, a substance use disorder is defined by someone who compulsively uses the drug despite the possible harmful consequences which could include criminal charges or ultimately even death. From that person’s perception, it becomes more important to use the drug than to even breath.

When looking at brain scans (see sidebar) and comparing a normal brain’s activity to a person who is suffering a substance use disorder, the difference is obvious and dramatic.  It is almost like looking at a brain ‘and the lights are not on – no one is home.’

It is also critical to understand that once a person stops using, the brain does not heal quickly.  It takes time.  In the sidebar with the PET scan, it is possible to see that even after 3 months of non-use, there is still a long way for the brain to go to heal, and in fact, the brain may never heal completely.

Long Term Impact

Drug use can severely impact the brain and depending on the length of use and the drug used, it can also result in a person being conditioned to use drugs in order to feel normal.  It becomes a habit and as a habit, there are any number of activities that could trigger[4] a person to use again even if abstinent for years. Certain actions or things, or even some people may result in certain behavior.  For example, some people only smoke when in a bar – so going to a bar becomes the trigger. 

What this means is that a substance use disorder is a life-long disease.

For more information on the impact on the brain, read SAMHA's: Chronic Substance Use and Cognitive Effects on the Brain: An Introduction

Footnotes:

[1] Much of this content was obtained from Drug Abuse and Addiction, National Institute on Drug Abuse.  To read more or get more information on the research go to: https://www.drugabuse.gov/publications/drugs-brains-behavior-science-addiction/drugs-brain

[2] Addiction is more properly entitled substance use disorder.  See “Words Matter: Changing Our Language on ‘Addiction.’ ” 

[3] Drugs, Brains, and Behavior: The Science of Addiction, National Institute on Drug Abuse, obtained from: https://www.drugabuse.gov/publications/drugs-brains-behavior-science-addiction/drug-abuse-addiction

[4] A trigger is any action or item that brings back the thoughts and memories and ultimately initiates a desire to engage in the use.  That trigger is bringing up memories of the pleasure felt.  With proper treatment and continual effort, a person can overcome those triggers, but that takes time and learning—and even with the knowledge that an item is a trigger, a person may still succumb to the draw of the drug.  See Prevention and Relapse