This is a huge question to answer in a blog post but I’ll give it my best try.
Let’s start with the brain as a whole and move into the more minute details of the subject.
The base of the brain (brain stem) is often referred to as the “reptile brain.” I like to call it the “croc brain,” but basically this is the part of your brain that is keeping you alive. It controls all the automatic body functions like breathing and heart rate.
Although, this isn’t the biggest part of the brain, it is the strongest from one perspective. It has the capability to override the other two parts of the human brain, which would be the limbic brain (emotions/connections), and the cerebral cortex or “frontal brain” (critical thinking and cognitive processing).
Croc Brain (keeps you alive)
Limbic Brain (emotions and connection)
Front Brain (thinking/reasoning)
Your brain likes balance and will readily adapt to changes it encounters by compensating in order to maintain this balance. So, if you dump a bunch of chemicals into your body, your brain will compensate for them. The human brain is so adaptive, that over time it will get used to compensating and will put the whole process on autopilot. For example, if you drink every day after work at 5:00, your brain will learn the pattern and will release the chemicals it needs to balance the presence of alcohol at 5:00 every day, whether you drink or not. When this happens, you will likely experience craving.
At this stage, your brain will signal to you that it “needs” alcohol because it is using it in its current balancing plan. Your “croc brain” will then kick itself into gear to make sure this balancing act goes as planned because it is the survival part of your brain and a balanced brain is key to survival. The “croc brain” can take control of the limbic and frontal brains in its effort to get what the overall system “needs” for survival.
Think of it like a pirate taking control of a ship. The pirate will use the crew (in this case limbic and frontal cortex) to get whatever it needs. Have you ever seen Captain Phillips with Tom Hanks???
BUT… Just like a sneaky pirate, addiction knows how to strike when you are vulnerable. You see, it is not just the “chemical reactions” that cause addiction. When a person is feeling depressed and anxious they generally don’t feel very connected to others. This is because the limbic system is not regulated enough for connection to take place.
In the case of anxiety, the limbic system is too heated up (or overactive), and in the case of depression it can be underactive. You need a pretty stable limbic system to form connections. Situations that make the limbic system unstable prevent you from forming connections. If someone was shooting at you, making besties would probably not be at the top of your mind’s priorities!
When we aren’t very connected to others, or when we have suffered an unexpected loss of some kind (losing a loved one, divorce, losing a job, etc…), or if you have a history of trauma, you will likely have a diminished capacity to connect to others.
Humans aren’t made to live without connection because we are a fragile species and need other humans to survive. In essence, you can be “starving for connection.” It is like being emotionally malnourished.
The combination of this vulnerable brain state in combination with the presence of a regular source of added chemicals IS VERY HIGH RISK FOR FORMING A SUBSTANCE USE DISORDER. You begin to attach to the substance instead of a person. The more you do this, the more it keeps the “croc brain” in control, and the less ability you have to feel connected to others.