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Scientist probes teen brains for addiction clues

/ Source: The Associated Press

Call it the science of peer pressure. When teenagers fail to just say no to drugs, Dr. Nora Volkow blames their brains, not their willpower — they lack links between some crucial brain regions that won't fully form until they're adults.

Age matters a lot when it comes to drug abuse. It's an evolving view of addiction that Volkow brings as head of the government's National Institute on Drug Abuse. And it's a career born of a tragic family history — she's the great-granddaughter of assassinated Russian revolutionary Leon Trotsky — that sparked an urge to help others.

"I do believe we all have a responsibility with our lives," Volkow says with passion. "It's just an extraordinary miracle that we exist, as a person with our unique characteristics."

Unique is a word many use to describe Volkow, who grew up in the Mexico City house where her famous ancestor was killed, and moved to the United States in her 20s to pioneer research peering inside living people's brains to trace the effects of drugs.

She first achieved acclaim by discovering that cocaine was neurotoxic, a radical notion in the early 1980s. Since then, Volkow, 49, has systematically probed alcohol, nicotine, heroin, methamphetamine, even overeating — obesity, she recently reported, shares many compulsive traits with drug abuse — to uncover the brain circuitry that underpins addiction.

Individual vulnerability

Now, three years into a stint directing the government's $1 billion anti-drug research program, Volkow is channeling new energy into determining exactly how the brains of addicts and those who never get hooked differ — so scientists can develop better ways to prevent and treat drug abuse.

"What is it that makes a person more vulnerable to take drugs or not?" she asks.

It's a far more complex view of addiction than urging people to just say no, says Joanna Fowler, a chemist at the Brookhaven National Laboratory who has collaborated with Volkow for more than two decades.

"Now we have Nora's picture rather than a picture of fried eggs," Fowler says, referring to an old government anti-drug campaign that compared a brain on drugs to a sizzling egg. "We can go beyond that knee-jerk picture of a brain to a real brain."

Volkow is showing that addiction "has to be seen as a health issue as well as a criminal or social justice issue," says Alan Leshner, chief of the American Association for the Advancement of Science and her predecessor at NIDA. "She has definitely moved neuroscience forward."

Adds Fowler: "If you can conceptualize it (addiction) as a brain disease rather than a moral weakness or lack of willpower, you can more easily bring resources to bear."

A fascination with free will, and how it can be thwarted, took root in Volkow's childhood.

A brief history: Trotsky, her great-grandfather, had been a leader of the Russian revolution and one of Vladimir Lenin's right-hand men until the Bolshevik ruler's death in 1924. Trotsky then was expelled as Soviet dictator Josef Stalin consolidated power, and most of the family died during Stalin's purges. Trotsky, with his second wife and orphaned 13-year-old grandson, wound up in Mexico City, where in 1940, a Stalin agent killed Trotsky in his study.

Volkow was born in the same house 16 years later, and learned her family history largely from visitors touring her home; her traumatized father didn't discuss it with his own daughters until they were almost grown.

"When you start to live in a situation like that ... it creates a sense of responsibility to your own life to do something that can help others," Volkow says.

A fascination with the human brain, and recalling the struggles of a "very charming" but alcoholic uncle, helped lead to addiction research. "To me, there was an extraordinary opportunity to try to understand what happens in the brain when you've lost that ability for free will."

Addiction starts at young age

It starts young. Consider: People who don't use drugs before age 21 hardly ever get hooked later in life.

Teens are particularly vulnerable because their brains don't finish forming until the early 20s. The frontal cortex, among the last regions to mature, is where the brain's cognitive or reasoning side creates connections with emotion-related regions.

So, put teens in an emotionally charged situation — say, surrounded by friends egging them on — and their ability "to stand up and say 'I'm not going to do it' is much harder than (for) an adult," Volkow explains.

Also, teens are more willing to take risks, also because of weak links between the "why-not" side of the brain and the "remember the consequences" side.

In fact, Volkow fears anti-drug programs that attempt to scare teens may inadvertently spur drug experimentation.

"It is that notion of 'I dare you,'" she says. "It may be appealing to an adolescent because they are seeking for danger in many instances."

Volkow's own research shows a promising avenue: Drugs essentially hijack a brain chemical called dopamine that's involved with sensing pleasure, until eventually abusers can no longer sense pleasure from anything but a high. Social acceptance boosts dopamine, so something as simple as group therapy may help fight drug relapses.

"One of the most powerful things that makes us feel good is when someone we admire, appreciate, for example, values us," Volkow explains.