Neurobiology of Addiction: From Wires to Waves

Why Treatment Doesn’t Rewire Your Brain

Almost everything you’ve been told about the neurobiology of addiction is outdated. You’ve heard the pop psychology theory of addiction: alcohol or drugs “hijack” the brain’s dopamine pathways, damage the wiring, and recovery “rewires” these circuits.

That picture is not completely wrong. It’s just 30 years out of date.

Recently, I remodeled my home’s kitchen. We removed the old TV cable and a phone jack that had not been attached to a landline in decades. When I opened the jack, I found a bundle of yellow, blue, red, and black wires screwed into the small box, installed when the house was built in the early 1990s. It felt quaint. I haven’t used a landline in years, and I suspect many readers have never used one at all. Phones were literally tethered to the wall.

Early neurobiological theories of addiction came from that world. We imagined the brain as a bundle of physical wires and addiction as a strong connection in the dopamine pathways. Drugs strengthened that connection by altering the neurons’ physical properties. Neurons presumably grew more branches, or the branches were pruned. Another theory was that the physical changes were not in the neurons per se, but in the receptors, which could increase or decrease their sensitivity to neurotransmitters. The story was clear; the exact mechanism never was.

Today, my TV streams over a wireless signal. I walk around with my phone in my pocket. Information moves as patterns of interactive waves, not just through fixed wires.

It’s time to update our model of the addicted brain in the same way, from wires to waves. In this lesson, I will describe a new picture of addiction. A model that can better explain why people keep using drugs even when they no longer enjoy them, why relapse often feels sudden and without cause, and how a medication like naltrexone works.

If you are ready to challenge some familiar ideas and trade a simple, flawed story for one more complex but accurate, stay with me. The journey will be well worth it. First, let’s challenge some common myths of the standard neurobiological model of addiction.

Addiction is not a “brain disease.”

Two courses defined the classic medical model of disease: Gross Anatomy and Pathology. While Gross Anatomy is well gross, it gets its name from the macro (gross) aspects of human anatomy. All first-year medical students begin their medical education by dissecting a human cadaver. The idea is to get a sense of what normal organs look like.

Later, students take a course in Pathology to get a sense of what diseased organs look like. This includes both macroscopic physical appearance changes in shape, color, or weight, and microscopic defects. I remember one afternoon we examined the liver of a patient who died of cirrhosis, shrunken and filled with the pale white nodules of fibrosis.

Then we went smaller. Looking at organs under the microscope, we learned to identify malformed cells in cancer, plaques in Alzheimer’s disease, infarcted cells of a heart attack, and various bacteria in infectious diseases.

The point is that, in classical medical models, disease was assumed to be a physical lesion, something that could be observed with the naked eye or through an instrument at a single point in time. Medical diseases represented something physically broken in the body.

That is the model many people take with them when they call addiction a medical disease. But if it’s a “brain disease” in the traditional sense, then there should be a characteristic lesion in the brain that defines it in the same way cirrhosis defines liver disease.

There is not.

What Brain Scans Actually Show

To be clear, people with severe alcohol addiction often have structural brain changes, and the brain changes with recovery. Some individuals experience brain shrinkage (enlarged ventricles), white matter alterations, and changes in parts of the brain involved in memory or decision-making. Chronic drug use can lead to modifications in dopamine receptors and pathways. However, there is no single structural change that is both necessary and sufficient to diagnose addiction. Many heavy drinkers have little or no visible damage, while others show changes without meeting clinical criteria for addiction.

Structural brain changes are generally a result of the toxic effects of drugs and alcohol, and these changes may be reversible with less toxic exposure. The addition of new dendrites and new synapses is a testament to the brain’s ability to repair itself when the toxic agent is removed. But like the structural changes caused by addiction, changes in brain structure in recovery are a consequence of less toxic exposure, not the primary mechanism for addiction treatment.

The mistake is treating addiction as a physical lesion in the brain.

Strictly speaking, improvements in cognitive functioning, such as those in the brain itself, may enhance executive decision-making and impulse control, thereby improving treatment outcomes. But one can have successful treatment without these structural brain changes, and effective treatment may occur regardless of whether they do.

Functional Medical Disorders

Modern medicine already recognizes diseases that have no single lesion. Migraine, irritable bowel, and metabolic syndrome come to mind. Hypertension is a disorder of regulation between systems, and cardiac arrhythmias are problems with the timing and patterns of cardiac activity. Addiction belongs to this family. It is a disorder of function, not a rotting chunk of tissue or a piece of wire attached to the wrong terminal.

Why this matters

Saying addiction is a “chronic brain disease” was meant to help reduce blame and stigma, and it has been useful politically in bringing addiction into the medical fold. But for a person hearing that they have a chronic brain disease, the message can lead to doomed feelings, “I can never be cured,” or defensive reactions, “my MRI is normal, so I must not have an addiction”. Waiting for structural brain changes to call something an addiction is like waiting till a person has a stroke or heart attack before someone is treated for cardiovascular or heart disease.

The biggest advances in the treatment of heart disease are identifying risk factors, such as hypertension, and aggressively treating these symptoms before structural pathology. Seeing addiction as a disorder of dynamic interactions and patterns opens up something more useful: hope that patterns can change, and early intervention can prevent the occurrence of structural brain changes.

Dopamine Is Not the Pleasure Chemical

We have been told a simple story: dopamine is the brain’s “pleasure chemical.” You feel good when dopamine levels are high and bad when dopamine levels are low and below baseline.

That story sounds good in a podcast, but it’s wrong or at least badly incomplete.

At least in the ways we measure it in labs, dopamine acts more like a “want” signal than a “like” signal. Yes, dopamine levels often rise when we enjoy something, but they can also go up when we are anxious, stressed, or bracing for something bad. Dopamine activity tracks importance and novelty more than simple enjoyment. While it often shows up when you are feeling good, it’s not the feeling itself.

Think of dopamine as the signal that screams, “Pay attention, this matters, remember this, do it again.” Like a good teacher, dopamine helps to focus attention on important matters, motivates students to perform, and gives feedback based on that performance.

Liking, the sense of “this feels good,” is mediated by several neurotransmitter systems besides dopamine. Endogenous opioids such as endorphins, endocannabinoids, serotonin, oxytocin, and others all contribute to the pleasurable sense of warmth, satisfaction, and meaning. Wanting, the urge to go after something, is mostly dopamine’s job.

Kent Berridge’s rats illustrated this vividly. Kent was a Penn graduate student at about the same time I was on the floor above him in the research lab building, getting rats to drink alcohol. He gave rats a sweet solution, and imagine this: when the sweet taste hit the rats’ tongues, they showed a “happy” face. I didn’t think much of his research at the time; I should have.

Later, Kent became a professor at the University of Michigan and continued his research on the neurobiology of “liking”. He found that when dopamine was depleted, rats still showed a happy face when they got sugar for free, but they didn’t walk three steps to earn it. The pleasure signal still works. The motivation signal is gone.

On the other hand, when they artificially increased dopamine levels, rats worked harder to obtain the reward, but their facial expressions of liking did not increase. They wanted more without liking more.

In working with patients, I have seen the importance of decoupling liking something from wanting it. I clearly recall one patient with a crack cocaine addiction who told me that he hated using crack, but once he lit the crack pipe, he couldn’t stop using crack until it was gone. He called the pipe the “devil’s dick”. Wanting and liking had split apart.

I see something similar with my patients with alcohol addiction. Initially, the drinking experience is a lot of fun, and after a couple of drinks, the urge to have another drink increases. Well into their addiction, the experience of drinking is not so much fun, but the cues associated with drinking compel the person to want to drink. Alcohol becomes a need, not a pleasure. As one patient told me, when he sits at the bar, “I automatically pick up a beer, it’s as if my arm doesn’t belong to me anymore.”

That decoupling is the heart of addiction. Early on, users like and want the substance. But over time, they keep chasing the high even though they no longer enjoy it. They want it desperately, even though liking it has faded. It’s like a car without brakes. You stopped enjoying the ride miles ago, but the engine won’t quit. Speed without joy.

Why this matters

When someone says, “I don’t even enjoy it anymore, I drink out of habit,” or when they start drinking, “I planned to have one or two drinks, but it keeps turning into 5 or 6,” they are telling the truth. The problem isn’t that they love drinking so much. The problem is that the wanting system is firing independently of pleasure. You can’t logically argue them out of that by pointing out how little fun they are having.

Addiction Treatment Does Not Rewire the Brain

People say recovery “rewires the brain.” The useful part of that claim is the idea of plasticity: experience changes the brain. The misleading part is the image of broken wires permanently repaired.

This is not how addiction or recovery works. Addiction and recovery are better understood as shifting patterns that strengthen, weaken, compete, and reappear depending on the context.

The physical changes that result from learning are constantly changing and reversible. Even so-called “habits” are probabilistic tendencies, not soldered joints. Our brain is in a constant state of dynamic interaction with the environment and within its various neural networks. To better understand addiction, we need to stop thinking like electricians and start thinking more like soundboard engineers, paying attention to patterns, timing, and signal interference.

The wiring metaphor is basically cartoon neuroanatomy that looks and sounds scientific but is, in fact, phrenology with modern graphics.

Why This Matters

If you have an addiction and are told you have a “broken spot” in the brain, you may either feel doomed, “I have a chronic medical disease that can never be cured, only managed with medications,” or defensive, “my MRI is normal, so I don’t have a problem”. Seeing it as a disorder of dynamic patterns opens the possibility of something more useful: patterns can change.

So if addiction isn’t a broken wire and treatment does not rewire the what IS actually happening? The answer sits in your living room.

From Wires to Waves: A Better Picture of Addiction

After I remodeled the kitchen, I replaced the old TV with a new 65″ smart TV that’s mounted on the wall. It is no longer connected to a cable box; it relies on streaming data packets over the air, creating a nearly perfect 4k image. These days, many of us don’t need physical cables for TV at all. As I tried to set up my new TV (with some cussing when my cable company wanted to charge extra for remote access), it occurred to me that a wave model might be a better way to think about the brain and addiction.

If the brain is not simply a bundle of fixed wires that can be cut and reattached, what is it? A better picture is a set of overlapping waves of activity that rise and fall across different areas of the brain and over time. At any given moment, billions of neurons are firing in patterns that rise and fall in overlapping waves. Some patterns dominate and guide behavior, while others are in the background, ready to emerge under the right conditions. It is a dynamic system, and the key question is not “which wire goes where,” but “which patterns are loudest at any given moment.”

Another Look at Extinction

When people asked how naltrexone works, my stock answer in the past was that it blocked the high or reward from drinking. Once someone did not get a pleasurable experience from drinking, the response would no longer be rewarded and would gradually fade or extinguish.

The neurobiological explanation was that for some people, alcohol drinking leads to an increase in endorphin activity. Increased endorphins increase the release of dopamine into the brain’s reward centers. By blocking opioid receptors, alcohol no longer boosts dopamine, so there is no pleasure, and the response weakens.

That weakened response has often been framed as the brain “rewiring itself.” David Sinclair called this extinction by a pharmacological mechanism, or pharmacological extinction.

This explanation may capture part of the story, but there was something I was never comfortable with. As someone who studied learning theory in graduate school, I knew that extinction has certain qualities that do not fit the simple picture of simple rewiring. Learning theory shows that extinguished responses often reappear; they can return with the passage of time (spontaneous recovery), when the context changes (renewal), or when the reward is reintroduced (reinstatement).

If the critical neurons had literally been pruned away, how could this happen?

In my kitchen, the TV cable was removed. There is no way my TV will spontaneously reconnect to the cable box. Yet the rewiring story asks us to imagine that, after the “cable” has been cut, the brain’s neurons somehow reattach themselves without anyone bringing back the electrician.

Clinically, I see reinstatement often in my patients. Someone may have stopped drinking after taking naltrexone for three months. They no longer report a desire to drink, have minimal craving, and declare themselves cured. Then their context changes, or they have a small sip of alcohol, and suddenly all the old behaviors are back as if they never underwent extinction. Filled with guilt and remorse, they wonder how such a slip could lead to such disastrous events.

From a physical wiring perspective, this makes no sense.

But then I thought of my experience last week when I connected my Bluetooth noise-canceling headphones to the new TV. Once again, I was able to make a connection without any physical wires. But the key insight was how the headphones block noise. They do not filter out the sound; they create waves that are opposite to the noise waves, so the person wearing the headphones experiences competing waves that cancel each other out, creating silence.

Extinction is more like that. The old learning is still there, but a new pattern can interfere with or override it most of the time. Under the right conditions, if that canceling pattern weakens or disappears, the original “noise” can return. Relapse is not the brain “rewiring back”; it’s what happens when the canceling pattern drops out, and the old wave is exposed to be heard again.

So how do we understand the neurobiology of addiction: what pleasure is, what addiction is, and how naltrexone works?

The brain as a system of interactive waves is a metaphor, but a useful one. Brain regions constantly synchronize to amplify their signals or cancel each other out. These are dynamic processes, invisible in any snapshot.

You won’t find addiction’s pathology by dissecting a brain or peering through a microscope. Standard CAT scans and structural MRI machines show anatomy, not the real-time interaction of systems. A single dopamine measurement tells you almost nothing. A dopamine level of 50 means something entirely different depending on context: Did it just spike from 20, or crash from 90? The trajectory matters far more than the number.

We need tools that capture change over time. Wave patterns, not static images, reveal what’s actually happening in the brain.

So, how do we replace the myths outlined above with more useful concepts?

What Is Pleasure? The Orchestra Revealed

We talk about pleasure as if it’s a simple thing. We know it when we feel it. But neurobiology reveals that pleasure is far more complex and distributed than our everyday language suggests.

Pleasure isn’t a chemical. It’s not dopamine. Not endorphins. Pleasure is an orchestra with multiple systems in coordinated patterns, creating something greater than any single instrument. Remove the string section, and you lose the magic. It’s the interactive pattern that matters.

The Instruments of Pleasure

The various neurotransmitters activate various parts of the brain, creating a beautiful pattern of various rhythms and crescendos. It’s the pattern that is pleasing, not a particular note in isolation.

Dopamine, as we’ve discussed, has three roles. It flags what matters, pushes you to act, and locks in memories. It doesn’t create pleasure itself, but when an unexpected pleasure occurs, it shines a spotlight on that part of the orchestra, increases its volume, and invites future repetition. Without dopamine, the other instruments play, but get little attention.

It’s Not Just the Notes, It’s the Space Between Them

But here’s what’s crucial: pleasure isn’t just about which chemicals are present. It’s about their timing, their relationships, their dynamics.

A single burst of dopamine without the slow, sustaining warmth of endorphins feels frantic and hollow. Endorphins without dopamine’s motivational signal feel dull and listless. Oxytocin without serotonin's grounding can feel chaotic. The pleasure emerges from how these systems interact—from tension and resolution, from anticipation and satisfaction, from the rhythm of engagement and rest.

Listen to a beautiful piece of music: the power comes not from individual notes, but from how they build, resolve, create tension, and release. It’s the space between the notes, the silence that gives meaning to the sound. Remove the silence, play all the notes at once, and you make noise.

The same is true of pleasure. A meal is pleasurable not because of constant stimulation but because of the interplay between hunger (dopamine, anticipation) and satisfaction (endorphins), between taste (sensory dopamine) and the comfort of nourishment (endorphins, serotonin). The pleasure lives in the rhythm.

Why This Matters for Understanding Addiction

In healthy pleasure, all these systems work together in a coordinated, dynamic way. But addiction disrupts this orchestra.

When a drug floods the system with dopamine, it creates a manic conductor, who amplifies one instrument to the point that it drowns out everything else. The strings are still playing, but you can’t hear them. The woodwinds are there, but they’re inaudible. Even the steady percussion section can’t compete with the loud blaring of the horn section.

This is why someone can say, as one of my patients did, “I hate using, but I can’t stop.” The drug is no longer producing pleasure in the rich orchestral sense. It’s just producing a loud crescendo: a signal of importance and motivation that has become divorced from actual enjoyment. The person is compelled to hear the noise and pursue something that brings them no pleasure at all.

Recovery Means Restoring the Orchestra

Understanding pleasure in this way changes how we think about recovery. It’s not about blocking a single chemical or rewiring a single pathway. It’s about slowly, patiently restoring an entire orchestra that has been ignored and fallen silent.

It means giving naltrexone time to lower the noise. It means therapy that teaches people to notice subtle pleasures again, such as the taste of tea, the feeling of the sun on skin, and the quiet satisfaction of a task completed. It means rebuilding relationships and finding or creating meaning.

It means understanding that pleasure is not a destination you “get back” after treatment. It’s a skill the brain relearns as the noise drops and the full orchestra is heard again. The person in recovery isn’t waiting for their brain to rewire. They’re learning to listen to an orchestra they’d forgotten how to hear.

How Naltrexone Works: The Mechanism Explained

Naltrexone is one of the most effective medications we have for treating alcohol addiction. It often gets described as blocking the “high” or reward from alcohol, which in turn rewires the brain to stop the urge to drink. There is likely an element of truth in this mechanism, but it is definitely incomplete.

Here’s what happens in the brain when someone drinks alcohol: for some people, alcohol releases endogenous opioids, which in turn increases dopamine activity. Dopamine helps to focus attention on what the person did to get the good feeling from alcohol, helps establish a connection between what the person did to get alcohol, and all the cues associated with alcohol. Dopamine floods the reward centers, creating that powerful signal: “This matters, remember this, do it again.”

With repeated use, the brain adapts. It expects this artificially amplified system and causes associated with drinking themselves increase the levels of dopamine, fueling craving. Alcohol drinking itself may become less pleasurable, and the person may try to compensate by increasing the amount of alcohol they drink.

The normal pleasures, such as food, connection, and meaning, can’t compete with this artificially amplified signal. The orchestra has been drowned out.

Naltrexone fits into this story by changing how the conductor responds to alcohol. When you drink without naltrexone, alcohol’s endorphins hit opioid receptors, and dopamine gives the conductor a strong “great job, play that again” signal. That is the special boost the horn section has been enjoying. Naltrexone sits on those opioid receptors and blocks endorphins from binding. The conductor still feels the alcohol, but is no longer compelled to give the horn section all the spotlight.

In practical terms:

· The first drink feels less rewarding

· There is less urge to continue drinking

· Over time, the cues associated with alcohol cause less craving, especially when combined with new habits and support

In plain language, your brain is very much involved in addiction, but not as a broken machine that must be rewired. It is an orchestra that has been overplaying one loud, familiar tune. Treatment is the process of teaching it new music.

In short, naltrexone doesn’t “rewire the brain.” It turns down the renegade horn section so the rest of the orchestra can finally be heard.

In short, addiction is not a broken-wire problem; it’s a pattern problem gone rogue. Which means recovery is not about fixing something that’s permanently damaged. It’s about learning to listen differently. Medications like naltrexone can help turn down the volume. Therapy and psychosocial support teach you new music. And both together? That’s how your brain learns to change.

It changes how we talk to people in treatment. It changes what we ask of treatment. Because suddenly treatment isn’t something that happens to you. It’s a synchronous dance between neurobiology, learning, and connection with others.

What’s your experience? Have you noticed this distinction between wanting and liking in your own life or someone else’s? Share in the comments below.

This is lesson six in an ongoing series on the science of addiction and recovery. If you haven’t read the earlier lessons, you may want to start there. There are only two installments left, so hit subscribe if you’d like a heads-up when the next one comes out.

Joe Volpicelli