The Effects of Opioids on the Brain -

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Editor Daniel Callahan MSW, CAP
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The Effects of Opioids on the Brain

The Effects of Opioids on the Brain

The brain is the most complex organ in the human body, and it’s in charge of how our bodies work. The beautiful part about brains is that they grow and adapt to different circumstances. The ability of the mind to change and repair itself — neuroplasticity — is an extraordinary and lasting process.

Brain governs all our habits, which is why sometimes they are difficult to overcome once they’ve cut a trail through our mind so many times. Even the practice of slouching at your workstation can be challenging to get rid of if you’ve done it for a more extended period.

When you look at the brain that way, it becomes easier to understand why bad habits form. And one of the most brain-damaging habits someone could have is undoubtedly drug abuse. The recent opioid abuse crisis in America is claiming more victims, and scientists are racing to figure out exactly how opioids affect our brains. There are plenty of things to learn about how addiction works — let’s have a look at what scientists know so far.

How Does the Brain Respond to Opioids?

The main thing to remember about brain’s reaction to opioids is that we’ve all experienced it — even those who have never used or abused opioids. For example, whenever you exert yourself in a fun physical activity, the endorphins your body makes help you feel good. Positive triggers such as food can activate the same reward circuits in the brain that opioids affect. Of course, there are specific subtle individual differences in reaction to pleasure, but this is how our brains are wired to work.

Enter opioids, with a much stronger effect that simultaneously stimulates the brain and dissolves its resistance. Opioids act at the beginning of the pleasure pathway which releases dopamine.  However, opioids do provide not only pleasure but also affect parts of our brain that can increase drug cravings as a result. Furthermore, frequent use of opioids decreases our capability to think through and solve problems, as well as push the brain’s reward system out of balance.

How Do Opioids Alter the Brain?

There are four main parts of the brain that opioids target and effect. The first is the previously mentioned brain reward pathway — the various regions of the brain containing neurons that release dopamine. Opioids stimulate dopamine release, signaling to the brain that this action causes pleasure and should be repeated in the future.

The second target is the amygdala, the part of our brain in charge of emotional and reward processing. It’s a small, almond-shaped part of the brain governed by the prefrontal cortex. Opioids disrupt the functioning of the amygdala and its projecting signals to the prefrontal cortex which regulates our reward-seeking behavior. With the check of the prefrontal cortex gone, that reward-seeking behavior takes over, increasing our drug craving. It has been proven that opioid addicts lose gray matter in the amygdala over time, and the prefrontal cortex can lose volume permanently as well.

Then we have the dendritic spines, structures that facilitate the communication of neurons. High and frequent doses of opioids cause the disappearance of dendritic spines, which then leads to difficulties with thinking through problems. That’s what keeps the opioid addicts firmly in the clutch of their addiction.

Finally, locus coeruleus is the stress-associated part of the brain which gets shut down by opioids to eliminate the negative body response. That’s the part that causes withdrawal symptoms — after a while the neurons in the locus coeruleus become supercharged, and once the effect of opioids starts leaving the body, this part of the brain goes into overdrive.

Why Are Opioids So Potent?

Part of the reason why opioids have such a substantial effect on us is that they can cross the blood-brain barrier. Additionally, all the changes in our brains caused by the prolonged use of opioids contribute to the addiction. It creates a vicious circle that is difficult to escape. Addiction affects different opioid receptors and alters the physiological properties of the brain so that it’s harder to quit and certainly easier to have a fatal relapse.

What Are the Current Treatments for Opioid Addiction?

Usually, opioid addiction is fought with more opioids. As hard as scientists are working on treatments that wouldn’t involve them, there’s only been a few non-opioid medications that can help treat opioid addiction. Lofexidine is a high blood pressure medicine that can treat opioid withdrawal symptoms. Similarly, non-opioid treatment naltrexone can bind to opioid receptors and block the effects of opioids. The only problem is that an opioid user can’t start naltrexone treatment until their physical withdrawal symptoms stop.

Therefore, the most frequently used opioid addiction treatments remain opioid in nature — methadone, and buprenorphine. Both bind to the same brain receptors that the opioids do, and their job is to prevent the negative symptoms of withdrawal as well as the high caused by opioid drugs. Buprenorphine is especially efficient, as it is only a partial agonist that makes it possible for the brain to be slowly reconditioned to normal processes given time.

Can the Brain Be Rewired to Counter Addiction?

Rewiring the neurobiological changes caused by opioid abuse eventually is possible. Some of the changes can revert quickly to the pre-opioid state, while some may linger.

However, there have been specific scientific findings that link addiction to genetics. More research is needed, but the scientists did discover specific DNA markers that were high-risk for developing a severe addiction.

It only raises more concerns about our current care for opioid addicts. What we should aim at is making it more varied and based on the patients’ genetic characteristics. Without that kind of awareness, treatments will fail despite the best interests and effort by both the opioid addict and the people who are helping them.

Ultimately, opioids induce addiction by changing and wiring our brain to provide instant pleasure and ask for more. Until scientists have complete information about the brain processes in people with opioid dependence, they will find it hard to come up with a non-opioid effective cure.

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