The human brain is the most complex organ in the body.
Having an understanding of how it works helps us to understand how drug addiction is a brain disease because drugs affect the brain’s pathological and biological processes. Almost all drugs affect the chemical neurotransmitters, blocking natural receptors and preventing natural neuronal messages from getting through.
Just as different parts of the body are responsible for different actions, the same goes for the brain. Different parts of the brain are responsible for coordinating and performing different functions in the body, everything from breathing, to emotions, to heart regulation. Drugs can alter any of these life-sustaining functions. Some of the areas in the brain that are most affected by drug abuse are:
The cerebral cortex – The cerebral cortex is divided into different areas that control specific functions. Some areas process the information from our senses, and the frontal cortex is the “thinking” part of our brain. This is the area that processes solving problems, making decisions, planning, and in general, thinking.
The brain stem- The brain stem controls vital functions such as breathing, heart rate, and sleeping.
The limbic system – This is the brain’s reward circuit. It controls and regulates our ability to feel pleasure, which is a life sustaining property because if we did not get pleasure from eating or having sex, we would cease to exist. This is the part of the brain that is activated by drugs. When drugs release the dopamine, or “feel good” receptor, it trains the brain to keep on doing it so it can keep feeling pleasure. The problem begins to occur when the drug is taken so often that the brain builds a tolerance to it and can no longer feel pleasure on its own, eventually “needing” the drug just to feel “normal”.
Our brains are huge communication centers.
Neurons, or nerve cells, pass information back and forth not only throughout the brain, but also throughout the spinal cord and the nerves in the rest of our body. This is the networking of all we feel, think, and do. Neurotransmitters are carried between neurons and attach to a specialized site on a receiving receptor. The transporters (the brain’s chemical recyclers) transport these neurotransmitters, shutting off the signal between the neurons.
When drugs are put into the system, they interfere with the tender communication system going on within all of the neurons and transmitters within the brain. They can activate neurons because similar chemical structures allow them to attach to and activate neurons. They may mimic the brain’s natural chemicals, but what they are really doing is killing them off, sending abnormal messages to the body, therefore leading not only to addiction, but also to death.
The most dangers presented with drugs and the brain is that drugs target the brain’s reward system, leading the brain, and therefore the body, to want and need more and more, overdosing it with dopamine. This is why once someone stops taking drugs, they may feel depressed; their body needs to readjust to dopamine working naturally once again. Chronic over exposure to drugs can change the chemical balance in the brain.
The National Institute on Drug Abuse. Effects of Drug Abuse on the Brain. Retrieved February, 2016.