On this blog, we talk a lot about managing stress, other prevention methods, and the different kinds of prescription drug misuse. But it is also essential to know what happens to the brain when someone becomes addicted to prescription opioids or overdoses, as understanding the biology behind it can help us learn the reality of the harms of prescription drug misuse.
Before we get into this, however, we must learn how the brain functions on a day-to-day basis. Our brain is composed of millions of specialized cells called neurons which receive signals from each other. If a neuron receives enough signals, it releases a chemical substance called a neurotransmitter into the synapse, the area between itself and another neuron. When this neurotransmitter reaches the next neuron, it binds to receptors on the neuron’s surface, causing it to fire signals of its own. These signals continue down the neuron and reach many other neurons, allowing information to transfer between neurons in the brain and spinal cord and the nerves in the rest of the body. Meanwhile, other substances bring the neurotransmitter back to the neuron it was released from, stopping the signal.
So how do drugs alter this process? When drugs are taken, they can imitate the role of neurotransmitters by binding to neurons which activates them, causing the release of signals throughout the brain. Other drugs can cause neurons to release highly high, unnatural amounts of neurotransmitters, which will also cause many signals to travel throughout the brain. By imitating or causing the release of neurotransmitters, drugs influence the brain’s reward system by causing the release of the neurotransmitter dopamine. Usually, dopamine is involved in motor control, motivation, and the reinforcements and rewards we experience from performing actions. For example, when we find our new favorite flavor of ice cream, dopamine is released in the brain, so the behavior of eating this ice cream flavor is reinforced, making us more likely to remember this positive experience. However, because neurotransmitters also cause dopamine release, but on a much higher level, our brain associates these drugs with a positive feeling. Because of this, we are driven to continue abusing the drug to keep experiencing this feeling.
The impact does not end there, however. To adjust to such high levels of unnaturally released dopamine, the brain starts releasing much less dopamine in response to other actions. This means that a person abusing drugs will feel much less pleasure from activities that usually made them excited or happy, influencing them to continue taking drugs to experience this feeling again, unfortunately making the cycle worse. Drugs can also alter glutamate, another type of neurotransmitter, which influences our ability to learn. Because of these alterations, the brain will attempt to adjust by decreasing the amount of glutamate released, which can cause damage to cognitive functions. Drug use can also impair the operation of the brain’s pre-frontal cortex, which is essential to decision-making. This means that taking drugs can make it even harder for those abusing drugs to recognize the dangers of these actions. Finally, all of these alterations to the brain caused by drug use can cause the brain to adjust to the drugs’ are causing, meaning that the “pleasurable feeling” individuals experience from abusing the drug decreases with time. This encourages individuals to take higher and higher doses to achieve the same feeling as before.
The biology behind addiction demonstrates that addiction is not a conscious process. Therefore, the best way to prevent addiction is not taking drugs and taking prescription drugs responsibly if prescribed by a doctor.