The Molecule of More

his drinking. That can be an eye-opening experience that may persuade a 
drinker to get alcohol out of his life.
Andrew tried it, and had no difficulty abstaining—except when he was 
in a bar looking for someone to sleep with. There was something about the 
place, something about the familiar experience of the chase, that triggered 
powerful cravings. His therapist became more concerned and felt Andrew 
met the criteria for an alcohol use disorder. He asked Andrew to try going to 
a few Alcoholics Anonymous meetings.
Andrew disagreed with the diagnosis. He was focused on overcoming 
his compulsion for anonymous sex. He was confident that if he could get 
that under control, he wouldn’t have to go to bars anymore, and the alcohol 
problem would take care of itself. The therapy took a long time, and despite 
repeated discussions with his therapist, his drinking increased. Eventually, 
though, he attained his goal. He met someone who captured his interest, and 
to his delight the interest didn’t fade. After a few fits and starts he completely 
gave up one-night stands. He no longer went out to bars much, but he was 
surprised to find that the drinking continued. The drinking had wormed its 
way into his brain, rewired his circuits, and now he couldn’t stop.
Like a guided missile, addictive drugs hit the desire circuit with an 
intense chemical blast. No natural behavior can match that. Not food, 
not sex, not anything.

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DRUGS
Alan Leshner, the former director of the National Institute on Drug 
Abuse, said that drugs “hijack” the desire circuit. They stimulate it far 
more intensely than natural rewards like food or sex, which affect the 
same brain-motivation system. That’s why food and sex addictions have 
so much in common with addiction to drugs. Brain circuits that evolved 
for the crucial purpose of keeping us alive are taken over by an addic-
tive chemical, and repurposed to enslave the addict that gets caught in 
its net.
Drug abuse is like cancer: it starts small but can quickly take over 
every aspect of a user’s life. An alcoholic may start out as a moderate 
drinker. As he moves step by step from, say, a few beers on the weekend 
to a liter of vodka every day, other aspects of his life get swallowed up. 
At first he stops going to his son’s baseball games so he can stay home 
and drink. After a while the parent–teacher conferences go, then all 
family activities, and last of all work, since that supplies money to buy 
the alcohol. But in the end even work goes. Like a tumor, the addic-
tion has spread, and the alcoholic’s entire life becomes focused exclu-
sively on drinking. Was he making rational choices? From the outside it 
doesn’t look like it. 
But from the inside, where we see dopamine in action, it makes 
perfect sense. 
The dopamine system evolved to motivate us to survive and repro-
duce. For most people there is nothing more important than staying 
alive and keeping their children safe. These are the activities that pro-
duce the largest dopamine surges. In a very literal way, large dopamine 
surges signal the need to react to life-and-death situations. Take shelter. 
Find food. Protect your children. These are tasks that hit the dopamine sys-
tem hard. What could be more important?
To an addict, drugs are more important. At least that’s the way it 
feels. That guided-missile dopamine blast overwhelms everything else. 
If making decisions is like weighing options on a balance, an addictive 
drug is an elephant sitting down on one side of the scale. Nothing else 
can compete.
An addict chooses drugs over work, family, everything. You think 
he’s making irrational choices but his brain is telling him that his choices 

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THE MOLECULE OF MORE
are perfectly logical. If someone offered you a choice between a meal 
at a nice restaurant, even the nicest restaurant in town, and a check 
for million dollars, it’s ridiculous to think you’d choose dinner. That’s 
exactly how an addict feels when choosing between, say, paying the 
rent and buying crack. He chooses the one that will lead to the bigger 
dopamine hit. The euphoria of crack cocaine is bigger than just about 
any experience you can name. That’s rational from the point of view of
desire dopamine, which is what drives the behavior of addicts.
Drugs are fundamentally different from natural dopamine triggers. 
When we’re starving, there’s nothing more motivating than getting 
food. But after we eat, the motivation for getting food declines because 
satiety circuits become active and shut down the desire circuit. There 
are checks and balances in place to keep everything stable. But there’s 
no satiety circuit for crack. Addicts take drugs until they pass out, get 
sick, or run out of money. If you ask an addict how much crack he 
wants, there is only one answer: more.
Let’s look at it from another angle. The goal of the dopamine sys-
tem is to predict the future and, when an unexpected reward occurs, to 
send a signal that says, “Pay attention. It’s time to learn something new 
about the world.” In this way, circuits bathed in dopamine become mal-
leable. They morph into new patterns. New memories are laid down, 
new connections are established. “Remember what happened,” says 
the dopamine circuit. “This may be useful in the future.”
What’s the end result? You don’t get surprised the next time the 
reward occurs. When you discovered the website that streamed your 
favorite music, it was exciting. But the next time you visited the site it 
wasn’t. There’s no longer any reward prediction error. Dopamine is not 
meant to be an enduring reservoir of joy. By shaping the brain to make 
surprising events predictable, dopamine maximizes resources, as it is 
supposed to do, but in the process, by eliminating surprise and extin-
guishing reward-prediction error, it suppresses its own activity.
But addictive drugs are so powerful that they bypass the compli-
cated circuitry of surprise and prediction and artificially ignite the 
dopamine system. In this way, they scramble everything up. All that’s 
left is a gnawing craving for more.

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DRUGS
Drugs destroy the delicate balance that the brain needs to func-
tion normally. Drugs stimulate dopamine release no matter what 
kind of situation the user is in. That confuses the brain, and it begins 
to connect drug use to everything. After a while, the brain becomes 
convinced that drugs are the answer to all aspects of life. Feel like 
celebrating? Use drugs. Feeling sad? Use drugs. Hanging out with a 
friend? Use drugs. Feeling stressed, bored, relaxed, tense, angry, pow-
erful, resentful, tired, energetic? Use drugs. People in twelve-step pro-
grams such as Alcoholics Anonymous say that addicts need to watch 
out for three things that might trigger craving and topple them into 
relapse: people, places, and things.
THE ADDICT WHO COULD NO LONGER 
MAKE HIS CLOTHES WHITE AND BRIGHT
Cues among addicts can be strange things. One former 
drug user had to avoid watching cartoons because his 
dealer printed cartoon characters on the drug packages he 
sold. Sometimes addicts don’t even know what’s triggering 
their craving. A struggling heroin addict found that he was 
overcome with craving every time he went to the grocery 
store. He had no idea why. It was causing havoc with his 
treatment. One day he and his counselor went on a field 
trip to the grocery store to try to figure out what was going 
on. The counselor told her patient to let her know as soon 
as the craving hit. They walked up and down each aisle, one 
by one, until suddenly the patient stopped and said, “Now.” 
They were in the laundry detergent aisle, standing in front 
of a shelf full of bleach. Before he entered treatment, the 
addict had reused hypodermic needles by soaking them in 
bleach to avoid HIV infection.

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THE MOLECULE OF MORE
THE REASON ADDICTS THINK SMOKING CRACK 
IS BETTER THAN SNORTING COCAINE
The ability to trigger dopamine in the desire circuit is what makes a 
drug addictive. Alcohol does it, heroin does it, cocaine does it, even 
marijuana does it. Not all drugs trigger dopamine to the same degree, 
though. The ones that hit dopamine the hardest are more addictive 
than ones that are more restrained. By triggering the release of more 
dopamine, the “hard hitters” also make the user feel more euphoric, 
and stimulate the most intense craving when the drug is gone. Intensity 
varies by drug. Pot smokers are generally less desperate to get more of
the drug than cocaine addicts. But beneath all the differences is the 
commonality of the dopaminergic rush and subsequent craving.
Many factors account for the differences. The chemical structure of
the molecules that make up each drug plays a large role; some chem-
icals are better than others at pushing dopamine along its path. But 
there are other considerations as well. For example, the crack cocaine 
that users smoke is essentially the same molecule as powder cocaine 
that users snort, but crack is far more addictive—so much so that when 
crack became widely available in the 1980s, it took the world of recre-
ational drug use by storm.
What’s so “great” about crack that allowed it to take over the 
cocaine market, and chemically enslave thousands of people? From a 
scientific perspective, the answer is simple: the rate of onset of action.
Consider a drug such as alcohol that triggers the release of dopa-
mine. The faster it gets into the brain, the higher it will make its user. 
In Figure 2 the horizontal axis shows how much time has gone by and 
the vertical axis shows how much drug has gotten into a user’s brain. If
someone is sipping a glass of Chardonnay, the graph will gently rise to 
the right. On the other hand, if that same person were to start taking 
shots of vodka, the graph would show a steep slope that quickly shoots 
upward. 

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DRUGS