fb pixel

The Science Behind Opiate Dependence: Drugs and the Brain

Table of Contents

science behind opiate dependence - drugs and the brain

Reviewed by Clare Waismann, RAS / SUDCC
With the advent of new medical technology, such as fine scanning of the brain through MRI, researchers have discovered the science behind opiate dependence and the particular mechanisms that lead to dependency. They have found that dependency actually has a biological cause. It is a treatable, predictable phenomenon of brain physiology that determines how you become dependent or struggle with overcoming it. In many ways, dependency has a great deal to do with body chemistry, although there certainly is a psychological component. However, this component is often not as great as people think.
To understand how opioids affect your brain, you need to understand how your brain works. Your brain is set up to reward certain behaviors with a release of chemicals that make you feel good. Medications and drugs short circuit this system and sometimes leave you searching out that feeling again and again. Dependency has many scientific reasons; exploring the science behind opiate dependence can help you get a handle on your condition.

Anatomy and Physiology of the Brain

Several brain cells, properly called neurons, make up the brain. They look like a circle with many tentacles protruding from them. The tentacle that is longer than the others is the axon. At the end of the axon is a group of deposits that hold brain chemicals or neurotransmitters.
When the neuron is excited or stimulated, it fires and releases these neurotransmitters from the end of the axon. They are secreted into a gap that exists between the current neuron and the next on the chain. The hair-like projections on the neuron, called dendrites, pick up these neurotransmitters, and that neuron becomes excited. It creates the release of neurotransmitters in the gap with the next neuron. In this way, the signal passes throughout the brain, down the spinal cord, and into the peripheral nerves.

How Drugs Affect the Brain

Medications act on the brain by influencing neurotransmitters. In some drugs, such as marijuana, the drug itself pretends to be a neurotransmitter and causes a pleasurable excitation of the neurons. Some medications keep the neurotransmitter in the gap longer or increase the amount of the neurotransmitter released. This causes a surge of excitement in the neurons, and they feel very good, very quickly.
Dopamine is the neurotransmitter most commonly manipulated by medications. Dopamine has many functions in the brain, and it is often integral in the movement of muscles and other processes. The most salient function this chemical performs is indicating pleasurable sensations. When you taste something sweet or gaze at a loved one, dopamine is released, and neurons are excited to make you feel good. With dependency creating drugs, the brain releases dopamine in large amounts, making you want that feeling all the time.

Scientific Reasons for Opiate Dependence

Since not everyone exposed to a drug becomes physically or psychologically dependent on it, some aberration of this reward system must exist in certain people to make them more susceptible. Science bears this out.
Some drugs help to multiply the number of dopamine receptors on the neurons, and this makes them give you a rush. However, those receptors don’t go away, and when they do not get the hit of the dopamine from the drug, it can induce cravings for that good feeling. It is a simple need for the receptors in your brain due to a chemical change brought about by the drug.
Another chemical in the brain, known as GABA, is responsible for stopping the flood of dopamine into the synaptic gap. It works as a virtual brake for the reward system and keeps you from getting too attached to that pleasurable feeling. In some people, this system does not work as well. Either you don’t have enough GABA, or it doesn’t work as it should.
In the end, the reasons for developing a dependency on a drug or medication are multifactorial. There is definitely a chemical and neurological reason why some people become addicted, and some do not. Also, social, psychological, and unknown factors influence why one person becomes dependent and another doesn’t. The important point to remember is that dependency is a treatable condition, and it has nothing to do with a person’s relative strength or weakness.


Drugs affect behavior and judgment because of the interaction with various chemicals and the pleasure center in the brain. The drug has such an impact on the brain that it becomes the priority, even over one’s health or family. Although there is an initial choice to take the drug, developing a physical or psychological addiction is not a choice. Instead, it is the result of regular drug use interacting with one’s social, biological and physiological makeup.
Next: Fighting The Stigma of Opioid Dependence

Reviewed by Clare Waismann, Registered Addiction Specialist (RAS), Substance Use Disorder Certified Counselor (SUDCC), founder of Waismann Method® Advanced Treatment for Opiate Dependence All topics for the Opiates.com blog are selected and written based on high standards of editorial quality, including cited sources. Articles are reviewed by Clare Waismann, RAS/SUDCC, and for accuracy, credibility, and relevancy to the audience. Clare Waismann is an authority and expert on opioid dependence, opioid use disorder, substance dependence, detoxification treatments, detox recovery, and other topics covered on Opiates.com. Some articles are additionally reviewed by one of Waismann Method’s specialists or third-party sources, depending on their field of expertise. For additional information and disclaimers regarding third-party sources and content for informational purposes only, please see our Terms of Service.

More To Explore

Suboxone Addiction and Its Impact on Families

Suboxone, a combination of buprenorphine and naloxone, has been widely used as a medication to treat opioid addiction. While its role in opioid replacement therapy is well-recognized, the potential...