📙 The Biology of Desire
Author: Marc Lewis
Full Title: The Biology of Desire
Addiction results, rather, from the motivated repetition of the same thoughts and behaviours until they become habitual. Thus, Addiction develops—it’s learned—but it’s learned more deeply and often more quickly than most other habits, due to a narrowing tunnel of attention and attraction.
As with other developing habits, this process is grounded in a neurochemical feedback loop that’s present in all normal brains. But it cycles more persistently because of the frequent recurrence of desire and the shrinking range of what is desired.
Addiction arises from the same feelings that bind lovers to each other and children to their parents. And it builds on the same cognitive mechanisms that get us to value short-term gains over long-term benefits.
Medical researchers are correct that the brain changes with Addiction. But the way it changes has to do with learning and development—not disease.
Addiction can therefore be seen as a developmental cascade, often foreshadowed by difficulties in childhood, always boosted by the narrowing of perspective with recurrent cycles of acquisition and loss.
Addiction is a habit, which, like many other habits, gets entrenched through a decrease in self-control.
Each rewarding experience builds its own network of synapses in and around the striatum (and OFC), and those networks continue to draw dopamine from its reservoir in the midbrain. That’s true of Paris, romance, football, and heroin. As we anticipate and live through these experiences, each network of synapses is strengthened and refined, so the uptake of dopamine gets more selective as rewards are identified and habits established.
Thus, love and Addiction are characterized by many of the same psychological and neural features. In fact, these authors use the phrase “partner Addiction,” and that certainly seems accurate for many couples. Conversely, people who have struggled with substance Addiction often describe their attraction to a particular substance as feeling like being in love.
When our experience of the world is fraught with strong feelings—whether of attraction, threat, pleasure, or relief—brain change takes on extra momentum. What drives this momentum? Emotions focus our attention and our thinking, and particular emotions (in response to something) call up particular thoughts and behaviours, thereby fuelling the same feedback cycle every time that something is encountered. When those emotions recur over and over, with each repetition of the feedback cycle, our overly focused brains inevitably change in a particular direction, entrenching a certain emotional experience a little more each time. Most relevant to addiction, the feeling of desire for something specific shapes the brain more acutely than other feelings. As you will see, desire-laced experiences mould the brain into a vehicle for creating similar experiences, also rooted in desire, for a long time to come.
People have referred to Addiction as a habit throughout recent history. That’s just what it is. It’s a nasty, often relentless habit. A serious habit. An expensive habit. But what makes it so enduring, so relentless, so difficult to change? What makes it different from what we might call more benign habits? Three things. First, it’s a habit of thinking and feeling—a mental habit—not just a behavioural habit. It’s easier to stop singing in the shower than it is to stop seeing the world as violent or unfair. Second, the feeling part of Addiction always includes the feeling of Desire, which is of course the theme of this book. And third, it’s a habit that becomes compulsive—a topic that will be explored in detail later. Perhaps all habits, once formed, are compulsive to some degree. The brain is certainly built to make any action, repeated enough times, into a compulsion. But the emotional heart of Addiction—in a word, Desire—makes compulsion inevitable, because unslaked Desire is the springboard to repetition, and repetition is the key to compulsion.
Like all habits, addiction quite simply grows and stabilizes, in brain tissue that is designed (by evolution) to change and stabilize. Yet addiction belongs to a subset of habits: those that are most difficult to extinguish. To understand addiction, we need to see it as the outcome of a normally functioning brain, not a diseased brain.
Plants grow, and so do brains, ecosystems, corporations, and climate patterns. But plants grow along the lines their genes have dictated. Cells divide and follow instructions, so oak trees and tulips look very much like their parents. In contrast, human brains, ecosystems, corporations, and climate patterns grow unpredictably, filling the world with enormous diversity.
If you bite into a piece of chocolate cheesecake and feel a gush of pleasure, and if you’re left with a lingering desire (which surfaces the next time you eat out), you have begun a trajectory of “loving chocolate cheesecake.” At first, maybe just a few synapses have been altered by such an experience. But those changes increase the chance that you will encounter chocolate cheesecake on a future occasion. You will notice it more, acquire it more, and eat it more. And before long a string of subjective experiences will give rise to a string of neural changes that continue to feed back to the ever more predictable consumption of chocolate cheesecake. Congratulations: you have now developed a habit.
I could summarize who you are, in the simplest terms, by listing your most distinct habits, especially those evoked by negative emotions. Isn’t that what we do when someone asks us, “What’s he or she like?”
Neural patterns forged by desire can certainly complement and merge with those born of depression or anxiety. In fact, that’s an important bridge to the self-medication model of addiction. In his 2010 book, In the Realm of Hungry Ghosts, Gabor Maté persuasively shows how early emotional disturbances steer us toward the relief that becomes addiction.
Different experiential feedback loops create different parts of us, based on different brain patterns, like the work of a painter who does one section of a painting, then another, then another, then goes back and works some more on the first. Of course it wouldn’t be a very good painting if those parts didn’t hold together with some degree of coherence, and the painter knows this very well. When it comes to human development, we don’t necessarily believe that there’s a painter in charge. But there is still a lot of coherence in the end result, and that coherence is often what we call personality.
If everything I just described is more or less correct, if this is how humans develop, how they form, then you don’t need an external cause like “disease” to explain the growth of bad habits, or even a set of interlocking bad habits (like being a drug addict and a criminal and a liar).
Bad habits self-organize like any other habits. Bad habits like addiction grow more deeply and often more quickly than other bad habits, because they result from feedback fuelled by intense Desire, and because they crowd out the availability or appeal of alternative pursuits. But they are still, fundamentally, habits—habits of thinking, feeling, and acting.
Learning usually requires at least moderately strong emotions, and it is greatly facilitated by repeated experiences (or else one or two extremely powerful experiences). These create the first layer of a new synaptic pattern, a new lattice of synaptic connections. Novel patterns show up as networks—villages or towns connected by dozens of little roads. But the networks become more robust and more efficient with repetition, and the learning gets deeper. Think of the dozens of little roads being replaced by several main roads and maybe eventually a freeway.
Your first snort of cocaine probably produced a novel firing pattern. (If not, you’d have tried a second snort or found another dealer.) Then, each time you (not you personally, of course) snorted coke, more synapses were changed, reinforcing this firing pattern, this “cocaine” configuration. That configuration would soon connect regions all over your brain. These include parts of the cortex—the perceptual cortex, in charge of seeing and hearing; the prefrontal cortex, in charge of thinking and planning; and the motor regions, in charge of putting those plans into action. But they also include the limbic regions involved in feelings and motives—the amygdala and hippocampus, as well as the striatum (which is not usually defined as “limbic” per se but . . . close enough). So it’s more or less the whole brain—the parts involved in thought and perception and the parts dedicated to feelings and instincts—that gets included in the “cocaine” network. Which is why thoughts, feelings, and action patterns change and crystallize together. To repeat: it’s the whole brain that programs itself, self-organizes, develops a habit—a habit that eventually becomes integrated with all your other habits.
Orbitofrontal cortex (OFC): bottom surface of the prefrontal cortex; closely connected to the amygdala and accumbens; uses signals from these regions to create context-specific interpretations of highly motivating situations; generates expectancies and helps initiate an appropriate response.
Meth was like a sun that was always at the centre of his trajectory. It was never further away than the next thought. And living life in orbit changes the way you get from hour to hour and day to day. Wanting it was one thing. Even needing it—yes, he needed it; he’d admit that. But this constant tugging at his thoughts, at the atoms of his attention . . . this went beyond wanting and needing. This was a cognitive mutation.
The amygdala is a small structure embedded beneath the cortical layers on each side of the head. The amygdala is subcortical: in other words, it’s a more primitive system (around the same vintage as the striatum, hundreds of millions of years old), and it’s responsible for the emotional spray paint that stains every important experience, almost instantly, with emotional tone and colour: the fear you suddenly feel when you hear footsteps behind you on a dark street, or the jolt of shame you experience when you spill coffee all over your pants, or the sudden excitement and pleasure that Brian felt as soon as “crystal” came to mind.
Whether it came from his visual system, because he’d suddenly discerned the pipe on the bedside table, or from his memory system, where thousands of meth associations swam about like fish in an aquarium, the image of “crystal” was immediately imbued with emotional meaning by his amygdala, whose synapses had been sculpted over two years of continuous use.
But the OFC is far more sophisticated when it comes to directing the play—organizing diverse cognitive agents into a mental phalanx, a mind with a mission. The OFC joins the amygdala within fractions of a second, picking up and amplifying its emotional beam. The OFC is a patch of tissue on the bottom surface of the prefrontal cortex; its job is to connect emotion to expectancies and fashion a rough action plan—both (relatively primitive) functions of the prefrontal cortex.
Because the next hit of meth seemed so valuable. It’s not that his brain was working improperly; it’s just that he’d arranged his life around a single goal, an inanimate lover, and his brain did what brains do—it revised itself accordingly. It composed a hierarchy of goals in which Vera, even Megan, were no longer on top.
Perhaps Brian could now imagine a future self valuable enough to pursue—a future self that was a continuation of the thoughtful, insightful self he was now becoming. A self that formed an unbroken path from his childhood to the rest of his life. And because he’d stopped using regularly, the disconnect between the dorsal regions of his prefrontal cortex and his striatum could reverse, reknit, regrow. Perspective could regain its foothold and get stronger with time.
Meth lost its relevance for Brian. And because his own habits no longer fertilized the synaptic pathways he’d laid down all these years, those pathways gradually faded away. The seductive value of meth was expunged. The growth of new foliage began to obscure the trail he’d been following for so long, until that trail was hardly noticeable. Now the forest spread in every direction, revealing pathways he’d never seen before.
The brain evolved to pursue goals by focusing attention and motivation on likely sources of pleasure or relief, especially those right in front of our noses. Delay discounting—now appeal—is simply a label for the shortsighted nature of this highly focused state. Yet its outcome, the shrinking of perspective and funnelling of desire, is an evolutionary adaptation that has allowed us to survive and thrive, maximizing opportunities for enhancing our lives and those of our offspring.
By pursuing the same goal repeatedly, as we often do when we find something or someone we constantly desire, we strengthen synaptic networks in the parts of the brain that underpin motivation and focus, parts that fashion long-standing representations of what is valuable and important.
The medial PFC is the core of the social brain, where interpersonal reality is sorted into two fundamental entities: self and other. The medial PFC is where we make sense of others’ actions, translate them and interpret them as to intentions and goals, and evaluate our own actions and goals in response. Here we formulate our perspectives, our prejudices, attempting to connect with those we admire or love and distance ourselves from those we distrust.
In fact, the medial PFC is part of a much larger web that comes alive when we imagine, daydream, and rehearse possible interactions with others. But the medial PFC is particularly important for connecting our self-image with our emotional goals.
The medial PFC is activated when we judge ourselves, adjust ourselves, become ourselves. So it’s not surprising that it gets reconfigured by the repetition of an experience with immense social and emotional meaning. That experience might be falling in love, either with a lover or a child, or breaking the law, or joining a religious sect. Or it might be drug use, since drugs directly stimulate core bodily sensations and usually perturb interpersonal relationships. Experiences of this sort are the agents of developmental change in identity, morality, even personality.
“Recovery” implies going backward, becoming normal again. And it’s a reasonable term if you consider addiction a disease. But many of the addicts I’ve spoken with—including Donna—see themselves as having moved forward, not backward, once they quit, or even while they were quitting. They often find they’ve become far more aware and self-directed than the person they were before their addiction. There’s no easy way to explain this direction of change with the medical terminology of disease and recovery. Instead of recovering, it seems that addicts keep growing, as does anyone who overcomes their difficulties through deliberation and insight.
Here was the feedback loop that would bring him to his knees years later: anxiety, relief, then loss and longing, round and round, digging ruts in the fertile soil of his striatum, laying down pathways to his midbrain and back. Along those pathways, springs of dopamine pooled—released in a flash flood when it was time to drink again.
It took Johnny about four years to shift from normal drinking to serious drinking, as he calls it. During this period, the cues that pointed to the pub, after work or after a game, activated fields of synapses—grown heartier with each repetition—that stood for something different. Alcohol became a Symbol, the core of a network that included a promise of Peace, cessation of stress, relaxation. Neurally and psychologically, it invaded and overtook the companionship network, like crabgrass colonizing a lawn.
Of course, the pub was most attractive, not because of the company or the food alone, but because of the particular way these human needs interlaced with his need for alcohol. The sense of a home away from home and the liquid that muted his restlessness converged at the pub.
The accumbens is the front-runner of Addiction because it is highly attuned to the perceived value of the goal. It is oriented to rewards; and drugs, sex, booze, and gambling are all about rewards.
Obsessive-compulsive disorder (OCD) is the hallmark of unbridled compulsion, and a lot of the brain changes in addiction parallel the neural signature of OCD: both include activation of the dorsal striatum when learned cues are perceived. What’s important to realize is that many goal-directed actions start off impulsive, but when they’re repeated for weeks, months, or years, they end up as compulsions.
In general, synaptic changes in the striatum—propelled by repeated experiences—go north over time, from ventral to dorsal territory, and that’s pretty much where they end up.
What a strange collusion between hot desire and the cold, almost calculating mechanics of stimulus-response! But that is how addiction develops—from pure desire to a chronic automaticity, accompanied by hope for what is to come. That’s why impulsive individuals are more likely to develop into compulsive drug users. Whether their impulsivity was granted by genetics or by a sudden romance with feel-good chemicals, it is destined to extend to compulsivity over time. When that stage comes, the blending of ventral and dorsal activation is what allows addicts who pursue their fix robotically to remain hopeful that this time will be special—maybe as special as it felt in the early days.
In OCD, often considered the first cousin of addiction, Rituals are performed to avoid or to ease anxiety. There is no reward in washing your hands for the fiftieth time, or checking the light switch yet again. Compulsive behaviour is a highly automatic response to a stimulus, but it can combine with the motivational flare of the accumbens and the fear networks of the amygdala, laid down over years of personality development. The dorsal striatum does not act in isolation, and the accumbens and amygdala are its most vociferous neighbours. According to Robbins, this combination of neural forces may best explain full-blown addiction.
According to Barry Everitt and Trevor Robbins, “There is nothing aberrant or unusual about devolving behavioural control to a dorsal striatal S-R habit mechanism.”
How do we reconcile a natural process of neural change and stabilization with the grotesque pattern of consumption that so often rules in addiction?
Jealousy, even in relatively healthy relationships, often has compulsive qualities and remains difficult to control—sometimes impossible to control. And so, of course, does blame, the background music of so many normal marriages.
What alcoholics need, he believes, is to become aware of their personal baggage. “They need to know why they drink, and what triggers them to drink. Otherwise,” he declared in our last interview, “treatment is useless.” Yet just being with other people in the treatment centre did something important for Johnny. Habits thrive on consistency—consistency in one’s environment, one’s daily routines, and one’s social world or lack thereof. His time in treatment interrupted that regularity and offered the promise of new and different habits.
A study published in PLOS ONE, the journal of the Public Library of Science, in 2013 showed that the reduction of grey matter volume in specific regions of the prefrontal cortex, thought to progress with the length of addiction, reversed over several months of abstinence. Grey matter volume returned to a normal baseline level within six months to a year of abstinence (from heroin, cocaine, and alcohol), and similar results have been found by other studies as well. But then—and here comes the first surprise—grey matter volume (synaptic density) in these regions continued to increase, beyond the normal baseline level, the level recorded for people who’ve never been addicted. Which probably means that top-down cognitive control regions—what I call the bridge of the ship—became more elaborate, or sophisticated, or flexible, or resilient, than those of people who had never taken drugs.
Addiction, like everything else we think and do, has a biological basis. And the final stages of Addiction, when impulsivity gives way to compulsivity, result from synaptic patterns that reinforce themselves over countless repeated occasions—a creeping vine that eventually strangles the other flowers in the garden. Motivated repetition results in compulsion through biological changes in a brain that digs its own ruts. But that’s not a disease, and it’s not permanent.
In fact, real choice is not a one-shot deal. It is not a moment in time or a fork in the road. Rather, self-control thrives, as does addiction, when new mental habits are fashioned, and rehearsed, and strengthened by ongoing self-reinforcement. Choice may indeed be an antidote to compulsion, but it is also an evolving skill, fuelled by desire—in Johnny’s case, desire for the strength and freedom he had always coveted.
I believe that getting past one’s addiction is a developmental process—in fact, a continuation of the developmental process that brought about the addiction in the first place.
Neuroplasticity is strongly amplified when people are highly motivated. Which is why all learning requires some emotional charge, and why entrenched habits like addiction grow from intense Desire. Clearly, the Desire to recapture a potent experience of pleasure or relief is the motivational on-ramp to addiction. But does motivation also foster recovery? Is the high beam of Desire necessary to find the road out?
People learn addiction through neuroplasticity, which is how they learn everything. They maintain their addiction because they lose some of that plasticity. As if their fingers had become attached together, they can no longer separate their desire for well-being from their desire for drugs, booze, or whatever they rely on. Then, when they recover, whether in AA, NA, SMART Recovery, or standing naked on a thirty-third-floor balcony of the Chicago Sheraton in February, their neuroplasticity returns. Their brains start changing again—perhaps radically. As we can see in each of the five biographies, they start to separate one set of desires from another and to act on them independently.
When addictive rewards colonize dopamine circuitry, and long-term rewards become increasingly hard to recall, addictive rewards become the only game in town.
Ego fatigue is like a microcosm of addiction: a loss of top-down cognitive control, augmented rather than diminished by attempts to suppress impulses. Ego fatigue reflects a disconnect between the bridge of the ship—the dorsolateral PFC—and its motivational engines in and around the striatum. Most important, the same disconnect, the loss of communication between these brain systems, becomes entrenched through synaptic pruning when addiction crystallizes over months and years.
So Addiction is an aspect of personality development, often an extension of patterns formed by failed attempts to deal with negative emotions in childhood. In fact, addictive patterns aren’t just an outcome of personality development; they’re a continuation of that development. Addicts continue to grow and modify their self-image, generally for the worse, and so Addiction becomes a part of the self, characterized by the imprint of earlier failures.
It appears that Natalie and Brian began to outgrow their addictions when they were able to reflect on their lives, connect their past to their present conundrum, and imagine a future very different from the present. I believe that this process of reflection and perspective taking was precisely what helped them overcome the now appeal of drugs.
Now appeal is not just a devaluation of future goodies; in the case of Addiction, it’s a gorge carved across the continuum of a person’s life, dividing personality development into an unexamined past and an unimagined future.
They asked teens to talk about their lives, about their goals, and about their futures. What they found was that young people from the high-suicide communities didn’t have stories to tell. They were incapable of talking about their lives in any coherent, organized way. They had no clear sense of their past, their childhood, and the generations preceding them. And their attempts to outline possible futures were empty of form and meaning. Unlike the other children, they could not see their lives as Narratives, as stories. Their attempts to answer questions about their life stories were punctuated by long pauses and unfinished sentences. They had nothing but the present, nothing to look forward to, so many of them took their own lives.
Where the youths had stories to tell, continuity was already built into their sense of self by the structure of their society. Tribal councils remained active and effective organs of government. Elders were respected, and they took on the responsibility of teaching children who they were and where they had come from. The language and customs of the tribe had been preserved conscientiously over the decades. And so the youths saw themselves as part of a larger Narrative, in which the stories of their lives fit and made sense.
In contrast, the high-suicide communities had lost their traditions and Rituals. The kids ate at McDonald’s and watched a lot of TV. Their lives were islands clustered in the middle of nowhere. Their lives just didn’t make sense. There was only the present, only the featureless terrain of today.
To me the message is clear: humans need to be able to see their own lives progressing, moving, from a meaningful past to a viable future. They need to see themselves as going somewhere, as characters in a Narrative, as making sense.
In Addiction, the relentless preoccupation with immediate rewards carves a small burrow out of the potential richness of time.
The addict’s life is lived in the tomb of the present, dead because it has lost its connection with the story from which it came.
In neural terms, as we have seen, this state corresponds to the breakdown of communication between the motivational core of the brain (the striatum, OFC, and amygdala) and the bridge of the ship (the dorsolateral PFC). By virtue of this disconnection, desire drives behaviour in small redundant circles, independent of insight, perspective, and higher-order goals.
Bruce Alexander, who conducted the Rat Park studies (reviewed in Chapter One), has outlined a broad social theory of addiction in his 2008 book, The Globalization of Addiction, where he investigates societal dislocation and its negative impacts. Carl Hart (also introduced in Chapter One) showed how members of minority groups living in the inner city chose to take drugs because other choices seemed unavailable or meaningless. Clearly these populations have something in common with Chandler’s high-suicide communities—the loss of a viable cultural Narrative in which their individual Narratives made sense.
It seems that the creation of this larger Narrative is intended to build a sense of continuity that works as scaffolding for individual Narratives, and that’s what made the difference in suicide rates among Native youth.
The facility for viewing one’s life as a Narrative may be what’s missing in Addiction.
Addicts experience something breathtaking when they can stretch their vision of themselves from the immediate present back to the past that shaped them and forward to a future that’s attainable and satisfying. It feels like shifting from momentary blobs of experience to the coherence of being a whole person. It feels like being the author and advocate of one’s own life. It feels like being real.
From making choices that are obviously self-destructive, there is a shift to making choices that are self-enhancing and self-sustaining. The value of this transformation cannot be overstated. Addicts can live for years without experiencing a kernel of self-trust.
To experience a sense of continuity between me now, me then, and me in the future is precious. But when it’s been missing for a while, perhaps for one’s whole life, it’s not easy to find. It requires a perspective that can only be obtained by addressing the future in the context of the past. And it requires one other thing, one fundamental resource: Desire itself.
In my view, the nature of perspective taking can’t be fully appreciated or understood without considering the mechanics of now appeal, whereby addictive goals pump dopamine directly into the motivational core of the brain and time contracts to the immediate present.
Stories don’t work without emotional themes. They would be impossible to follow. There would be no impetus to get to the next paragraph or the next chapter, either for the main character or for the reader. In the same way, real-life Narratives can’t be held in mind without the feelings that give them shape. Desire is the most potent of those feelings. Desire has the power to propel us through life, to get us from now to later. The trick to overcoming addiction is thus the realignment of Desire, so that it switches from the goal of immediate relief to the goal of long-term fulfillment.
If addicts can access self-narrative in the heat of the moment, even briefly, then Desire has the potential to jump like static electricity to new possibilities and burnish them with drive.
Treatment just requires the attention of one other human being who can hold, possibly distil, and hopefully extend the Narrative energized by the cresting wave of an individual’s Desire to change.
If the brain region that allows us to imagine the future is synched up with the brain regions that propel us toward our goals, and if that linkage is practiced and reinforced, so that synaptic highways become smooth and efficient, then Addiction need be no more than a stage in the development of the self.
Opiates relaxed you by abolishing the sensation of threat and letting your mind wander freely in the fanciful landscape left in its place.
So when Steve got a new batch of Oxys, which seemed to happen more and more often, Natalie felt a glow of anticipation, as if she were going home for the weekend—not her real home, but a dream home of soft edges and benevolent beings. That’s when the synapses in her brain began a new wave of growth, forging a new set of connections. And when those synapses were activated, it felt to her like an approaching brightness, an arrow of hope.
Then there was nothing more to worry about, from the moment the needle pierced the vein, even before the drug transformed the chemistry of her nervous system. That wash of Peace started with the knowledge that this was a sure thing, no longer a maybe. This was what she’d been looking for, perhaps for a very long time.
It seems Natalie was immersing herself in a dark liturgy. The skin and the steel, the bluish tint of the vein. The spoon and the flame, that moment of bubbling alchemy that marked the entrance into another dimension. And when the needle penetrated her own body, the feeling of the drug itself. The taste of it from inside. The click of shackles released all over her nervous system, reaching back to smooth every jagged memory, and forward, a guarantee of the hours to come, a guardian against harsh thoughts and images, the settling in of a consciousness infused with Peace.
This harmony of sensations took up residence in Natalie’s mind as networks of synapses converged in her brain. And from that headquarters a heightened urgency began to rule. It took less than a month from the time she started injecting heroin until her days became sloped in a singular direction, each afternoon a curled surface that would wrap into the shape of a funnel, a downward slanting tube that must empty into the reservoir of the moment. That moment—the moment of shooting up. Inevitable, from the first lurching rotation of her mind’s eye to a point in time still hours away.
In her fantasies, she composed a peculiar drama: I’m a drug addict, that’s who I am. My life is a movie, and I’m the raunched-out chick playing the blues in the bus station, hunched over, tragic. Not the quiet little Natalie who reads a lot of books and doesn’t get out much. She was living on the edge, no question, and that gave her life contour, thrust, colour, meaning—and this precipitous anxiety, this unquenchable craving, this quiet desperation that got louder by the hour as she waited for Steve to get back to her.
There are parts of the brain wrapped deeply within the cortical layers that we share with animals going all the way back to fish. These structures include a large and highly complicated crescent of tissue that sort of curls around the very centre of the brain. It’s called the striatum (shown in Figure 1) and it’s the main character—the villain—when it comes to Addiction.
The striatum evolved to select actions that lead to the achievement of goals. In fact, there’s not much point to actions that don’t lead to goals, so the striatum evolved for the express purpose of connecting actions with goals. The striatum gets a goal on its radar and then sends an action “script” to other parts of the brain (like the motor cortex) to execute, to move the muscles in such a way as to get whatever it is you’re after: tapping the keys on your phone, reaching for your wallet, mouthing the words that will get the right response.
If mammals were going to learn from their experiences—unlike their cold-blooded forebears—they would need a more flexible operating system than the fixed action patterns responsible for the flinching of the worm and the darting of the frog’s tongue. So the part of the brain preserved deep within the cortex—the action brain, the striatum—also became the brain’s motivational centre. And it took charge of the one emotion that gets us to pursue our goals, often relentlessly: the emotion of Desire.
The striatum learns from experience. It adjusts its wiring according to what felt good in the past and how hard it was to achieve that feeling. Thus it translates past pleasures into present desires.
When Natalie felt that wash of craving for a shot of heroin, imagining how good it was going to feel, working out what she had to do to get it, her striatum was buzzing. The synaptic networks in her striatum included in the “heroin” pattern (flashing all over her brain) were alive with neuronal transmissions—firing rates well into the red zone, marked “urgent.” At the same time, her other goals, like pleasing her boss at the restaurant, getting on better with Grace, and calling her mom, all faded, became insubstantial. The networks that supported those goals dimmed and then turned dark.
The accumbens is a dugout of ancient tissue, and it hums like an engine buried under the moving parts it controls—the other brain regions. The accumbens is the brain part you hear about most when it comes to Addiction. It embodies the “hot” end of the striatum, the end with the most connections to other regions that give rise to emotions, expectancies, and actions.
The power of the accumbens to control attention, perception, feeling, and action is immense, and it uses that power to override the ragtag crowd of alternative goals, so that just one goal is left, now glowing with immediacy, pounding with importance.
Craving intensifies when the midbrain sends dopamine up to the accumbens. The more dopamine, the more the accumbens is activated, and the more we experience craving. I just really want it, and I want it right now! I know it’s going to feel good, or at least a whole lot better than how I feel without it. And nothing else matters.
Wanting something is not the same as liking something, and most of the accumbens is devoted to wanting. Pleasure is a pastry puff, a dessert, a flash in the pan. Desire is what gets us moving, whether that means calling your dealer, driving to the liquor store, or stealing twenty bucks from your aunt’s purse. Dopamine—at least where it’s absorbed in the striatum—is the fuel of Desire, not fun.
Natalie had not been happy. In fact, looking back, she realized she’d spent most of her adolescence in a swamp of depression. Her interactions with other kids were always tentative: How did they feel about her? Did they really like her? Yet being at home was another kind of purgatory. So she stayed in her room. It was a habit she’d acquired as an even younger kid, reading books from beginning to end while lying on her bed, not wanting to witness the deterioration of her parents’ marriage.
Natalie had to find a self before she could find self-control. She needed the time to reflect, to meditate, to remember and mourn her wounded childhood. All that time in the worst possible environment became the silver lining to a very dark cloud. But the wide avenue of synapses between Natalie’s striatum and her prefrontal cortex was a two-way street. And now a lot of the traffic was coming from the other direction. Now her prefrontal cortex (PFC)—the part of the brain that plans, regulates, and controls impulses—began to form new patterns, new habits, based on a more coherent, more conscious sense of who she was. Those patterns became strong enough to survive, to resist disintegration, so they could help stave off the cresting of desire from her striatum. Finally, abstinence itself became a pattern, a habit of its own.
Natalie has not used heroin since her release from prison. In fact, she’s abstained from all opiates, except for one grey afternoon when she downed a few Percocets. The result was not pleasant. “Once the familiar feeling crept over me, I was filled with dread and disgust,” she told me, “because it is permanently linked to all the shitty things that happened as a result of my addiction. I cried and cried; it couldn’t wear off fast enough.” That was it. That was the only reminder she needed.
Attraction and repulsion now came in one package. Yet the striatal engines of desire were not extinguished. That would have left a zombie in place of a striving, growing human being. Instead, desire was rerouted. It was now in league with other goals: self-preservation, self-control, a respite from her weariness.
Addicts are notorious for shucking off self-control, for abandoning it like a worn-out car. Anorexics seem to have the opposite problem: they can’t take their hands off the steering wheel. Yet anorexia and addiction are as similar as twin sisters. Both get their enormous power from compulsivity, and that compulsivity remains hidden from oneself long after it becomes obvious to others.
In each Addiction narrative, we can see an underlying current of anxiety, anger, or fear of rejection, and an unconscious collusion between the child and his or her caregivers to accept the burden of inadequacy. That collusion is exhausting. It creates a kind of emotional starvation.
In another sense, anorexics are classic addicts because they relentlessly pursue a Symbol. Symbols gather our cognition, our thoughts and associations, into coherent emblems, full of meaning yet consisting of very little in themselves. Symbols always represent something else. Symbols include beautiful women, flashy cars, fatherly love, financial security, even the idea of youth. Each of these is an arrow on a map, or an array of arrows aligned with each other, a direction to pursue. Each shrinks a cluster of related goals into a single goal we can chase after unambiguously. For Alice, that goal may have been attractiveness, leading to positive regard, at least in childhood and adolescence. By now it was simply self-mastery, that crystalline sense of control—a symbol far more refined, more idealized, than anything she had previously sought. Drugs are also symbolic, in a way that is rarely if ever discussed by the experts. But what they symbolize is likely to evolve and mutate. Symbols develop, and development takes time.
As we saw with Brian, the careening arousal of a meth high took many months to mean what it eventually came to mean: clarity, power, and self-confidence.
There is no single brain region or system where symbols are created and activated. But the prefrontal cortex (PFC) is a critical player, connecting present experience to the cluster of elements the Symbol stands for.
That’s how symbols govern our actions, from humanity’s greatest accomplishments—scientific discoveries, symphonies, works of art—to its greatest tragedies—crime, persecution, and, yes, addiction. But the Symbol and the passion don’t always converge instantaneously. They can arise in parallel, then connect, then develop some more, as did Alice’s anorexia, from a child’s pride at self-control to the austere habits that defined her body and mind twenty years later. Both anorexia and addiction rely on neural networks that grow.
The striatum is ignited by cues: stimuli (words and images) or events that foretell the addictive act. And symbols grow like glistening spiderwebs, each with a central hub connected to multiple anchor points. Rituals combine actions and goals into strings of events that are themselves symbols. And they are powerful.
OCD is often considered a pure form of the compulsive drive that marks the final stage of Addiction. And we know that people with OCD arrange their lives into repetitive Rituals. So it shouldn’t be surprising that most addicts find comfort, but also excitement, in the Rituals that lead up to the act itself. The fastidious preparation of the heroin injection; the arrangement of a glass surface and a blade to pulverize crystals of cocaine; the dressing up that precedes a night of gambling or sexual excess. The Rituals become gratifying in themselves, part of the webbing of symbolic significance.
The dorsolateral PFC does indeed perform some high-wire acts of cognitive organization, integration, and selection. But rather than view it as the rider of a rebellious animal, we should see it as the bridge of a ship—where broad perspective allows for long-range planning as well as short-term steering.
Ego fatigue shows the same disconnect, between the bridge of the ship and its motivational engines, and the same loss of control in volitional behaviour. The momentary state of ego fatigue now looks like a microcosm of the enduring state we know as addiction.
What Alice had to do, and what all addicts have to do to move beyond their addiction, is reconnect Desire with the higher levels of cognition.
I've been reading 📙 The Biology of Desire, a fascinating book about Addiction by Marc Lewis, who became a professor of neuroscience as he himself was recovering from a decade of compulsive drug use. He, like many others, challenges the "brain disease model" of addiction, describing addiction instead as an especially potent and harmful instance of the same processes of desire-driven learning that is normally adaptive and integral to finding safety, happiness, and well-being.
📙 The Biology of Desire is a perfect source for this line of thinking.
There's one key word of this web site that hasn't showed up here so far, and which I also wasn't expecting to see in 📙 The Biology of Desire, but which turns out to play a crucial part towards the end. The word is Narrative. Lewis describes a study of Inuit tribes that tried to find out why some of these tribes have tragically high suicide rates while in some tribes, the rate is zero.