CHICAGO - Americans can thank the legacy of Leon Trotsky for some of the most influential research on the addictive qualities of food.
It was Trotsky's great-granddaughter who helped make obesity a top priority of the federal government's National Institute on Drug Abuse. When Nora Volkow became director of the institute in 2003, it was far better known as the home of research on drug addicts, not junk food.
But Volkow's restless interests expanded in recent years from cocaine abuse to include the puzzle of why people overeat.
Intellectual upheaval is the birthright of Volkow, an intense, fast-talking scholar with weaknesses for decaffeinated Frappuccinos and long-distance running.
She was born and grew up in the house in Mexico City where her great-grandfather, the exiled Russian revolutionary, had been assassinated in 1940 with an ice pick. Volkow, 48, said her family's history helped shape her ambitions.
"It's a sense of doing something that can improve the quality of life for people," Volkow said. "Of course I admire (Trotsky), I think he was an incredibly visionary individual."
Volkow built her career using brain-imaging technology to study schizophrenics and later drug addicts at Brookhaven National Laboratory in New York.
She helped cement the idea that drug addiction is a brain disease, and some people become addicts because their brains are vulnerable to the effects of drugs.
Her recent focus on the food reward system was partly pragmatic, she said.
"I could have gone for gambling or sex addiction," said Volkow, who has published nearly 300 scholarly papers. "But I went for obesity because of the tremendous impact it has."
Using scanning technology that shows activity in the living brain, Volkow's team found many parallels between the longings of addicts and the urge for food.
"There's a pattern of brain changes that we have shown is common across various types of addiction that we've also seen in pathologically obese individuals," Volkow said.
"It's a compulsion, it's a need that goes beyond the ability to consciously control it, and in that respect it's very similar to drug addiction."
In the past, Volkow and her Brookhaven colleague Gene-Jack Wang had done brain scans of cocaine addicts while showing them emblems of their addiction - white powder, syringes, cash and crack pipes.
When the researchers turned to food, they summoned cravings in non-addicts using different cues - such as the sight of ice cream and the smell of cheeseburgers.
The drug and food cravings triggered many of the same brain areas, including the orbitofrontal cortex, a region tied to motivation, emotion and how people pick out important information.
Volkow's team also found that drug users and obese people had similar deficiencies in brain cells that process dopamine, a compound central to how people feel pleasure and initiate activity.
Obese people may overeat in part to compensate for that deficit - the extra food brings more dopamine, which brings a feeling of reward.
When the Brookhaven group published a lengthy review of their obesity findings in 2004, the name of the venue where it appeared carried some symbolism: The Journal of Addictive Diseases.
(c) 2005, Chicago Tribune. Distributed by Knight Ridder/Tribune News Service.