Pubdate: Mon, 25 Dec 2000
Source: U.S. News and World Report (US)
Copyright: 2000 U.S. News & World Report
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Author: Susan Brink

OBSESSED WITH OBSESSIONS

Gamblers, new mothers, over-eaters, and substance abusers. One might say 
they're all obsessed, making them a lot like psychiatric researcher Nora 
Volkow. Her particular obsession is figuring out why people become 
obsessed. "It's a pleasure for me to try to understand things that are not 
obvious. It's a drive," says Volkow, now 44, and a year ago, the youngest 
person to be appointed associate laboratory director for life sciences at 
Long Island's Brookhaven National Laboratory. "It makes me high; there's no 
way around it."

Volkow, who was elected to the prestigious Institute of Medicine in 
October, can't stop thinking about what lies behind addictions. She relates 
the lure of drugs and alcohol to her own life experiences: falling in love, 
watching new mothers like her sister think only of the baby, and working 
12-hour days, seven days a week, in pursuit of a thrilling idea. She wants 
to understand what addictions have in common with such appropriate 
obsessions and how the brain chemistry of pleasure can fuel both the good 
of love and the evil of drug addiction. The answers could lead to new 
pharmaceutical treatments for everything from alcoholism to cigarette 
smoking to heroin cravings.

Monkey business. Human and animal behavior has fascinated Volkow since she 
was a little girl, growing up in the Mexico City home of her 
great-grandfather, exiled Russian revolutionary Leon Trotsky (he was no 
longer alive, but she remembers playing with his clothes still in household 
closets). As a child, she took in strays, but as a scientist, her love of 
animals limited her work. She once stopped an experiment in which a monkey 
had to press a lever thousands of times for a minimal amount of drinking 
water. "I came in on the weekend and saw this animal was totally 
withdrawn," she recalls in her Spanish-accented English. "So I gave him water."

Her eureka moment came while reading an article in Scientific American in 
1980. The subject was the new field of neuroimaging-taking pictures of the 
living brain. "It sounded like science fiction," she says. But it presented 
her with a way to satisfy her curiosity about behavior without 
experimenting on animals.

What she found as a researcher at the University of Texas-Houston in 1985 
began to put to rest the myth that cocaine was a harmless drug. A world 
leader in addiction research, she has studied cocaine's path of euphoria 
through the brain by using powerful imaging technology called positron 
emission tomography, or PET. "I had images that showed that the brains of 
cocaine addicts looked like the brains of stroke patients," she says of her 
discovery that the drug interrupts blood flow to the brain. "I showed that 
cocaine was toxic to the brain."

Volkow has spent more than a decade exploring the living landscape of 
addiction. Her work has led the way in debunking sheer willpower as a cure 
by showing that brain chemistry can trigger addictions, which then go on to 
further alter brain chemistry. The findings could lead to new drugs that 
could identify those most vulnerable to addiction and begin to calm the 
cravings of those already caught in its grip.

Right now, Volkow's obsession centers on dopamine, a brain chemical linked 
to pleasure and elation. A bite of cheesecake can trigger its release; so 
can a baby's smile or an A on an exam. What she's found in sorting out the 
red, yellow, and blue blotches on brain images is that addicts have fewer 
available dopamine receptors than do normal people. Long-term alcoholics 
have even fewer receptors. The receptors transmit dopamine signals to the 
reward circuits in the brain; the lower the number of receptors, the weaker 
the signals-and the less joie de vivre. A common thread among drugs of 
abuse, including alcohol, cocaine, heroin, marijuana, and nicotine, is 
their ability to elevate dopamine levels.

Prone to snort. One brain chemical alone cannot create an addict. But when 
a brain that is unable to produce adequate dopamine collides with a 
stressful environment, and then is presented with opportunities to drink, 
snort, smoke, or shoot up, the result can be addiction. "There is an 
addictive personality," insists Volkow.

The addict's brain may be doubly jinxed. Fewer receptors not only make 
people more vulnerable to addiction but also may prevent them from feeling 
normal pleasures-like love or a sunset.

Volkow knows the lure of such joys and can empathize with those who need 
chemicals to make it happen. "I get excited by ideas. I am addicted to 
Bach. I get addicted to writers. Now I'm reading [Japanese novelist] Haruki 
Murakami. I know I will read everything by him," she says. She speaks 
quickly, as though her mind is crackling with the next idea before the 
words describing the last idea are fully out.

Volkow is now looking at an area of the brain, the frontal cortex, 
associated with higher thinking. Few had deemed it a culprit in addiction. 
PET images of that area showed similar activity in both addicts and people 
with obsessive/compulsive disorder.

"It hit me completely," she says. "These two diseases both have 
obsessive/compulsive behavior in common. One is an uncontrollable urge to 
take drugs, the other a compulsion about rituals." And that would take the 
brainscape of addiction one step further. Addiction may not simply be a 
search for pleasure. Drugs could change brain chemistry in ways that 
trigger a compulsion to take more drugs, long after the early stage of 
quick pleasure wears off. "Drugs feel good, but that's the trivial 
explanation. What is the role of brain dopamine in the loss of control?" 
she asks. One can only imagine the pleasure-releasing surge of dopamine 
through the synapses of her brain as she sparkles with another idea.

Innovators 2001: The best minds at work
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