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March 19, 2004|Volume 32, Number 22



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Dr. Nora Volkow



NIDA director discusses complicated causes and devastating effects of drug addiction

Dr. Nora Volkow, director of the National Institute on Drug Addiction (NIDA) got a first-hand reminder of the devastating consequences of addiction while visiting a women's prison in the Chicago area, she told a Yale audience during a March 5 talk on campus.

The women there had lost everything to drugs, she said. "They had no jobs, they had no family. They talked about how, when they were doing drugs, nothing else mattered. The ability to do what they wanted to do was gone. The drugs had taken over." This was true even for some women who had children, she noted.

The visit, she said, gave her additional insight into the difficult road back from addiction. "They see a very different world than we do, when they are looking out from where they are," she told the standing-room-only crowd in the Connecticut Mental Health Center auditorium. "We are looking at a lot of different possibilities. They are not."

Volkow was chosen as this year's Jellinek Lecturer at Yale because of her commitment to a scientific understanding of addiction, said Dr. Stephanie O'Malley, who introduced her. O'Malley is director of the Division of Substance Abuse Research in the Department of Psychiatry and the principal investigator of the Center for Nicotine and Tobacco Use Research at Yale (CENTURY), which is funded in part by NIDA.

Research has reinforced the experience of the women she met in prison, Volkow said, adding that trying to understand addiction is an obsession of hers.

The loss of control experienced by some addicts may be related to the dopamine D2 receptor, she explained. Those receptors play a role in the brain's ability to determine what is important and what is not, allowing people to make correct choices that ensure their survival. In a study of cocaine addicts, for example, the addicts had lower levels of the receptor than normal controls, and those levels stayed low for at least four months after they quit the drug, she noted.

"That's significant, but that's not the end of the story," Volkow said, pointing out that the study raised the question of why the lower levels made people susceptible to addiction. That could be because lower levels of receptors made some people less sensitive to what might otherwise motivate them, she explained, and drugs that increase the release of dopamine, such as cocaine, would then send a larger signal to the brain, indicating it was more important than other reinforcers.

"That means that they would be responsive to drugs of abuse, but they will be less responsive to other things," Volkow said. "The normal things in everyday life are no longer reinforcing."

The research also raised the question of why the receptor levels were lower in addicts, she said: "Were they born with decreased levels, or was it caused by drug abuse?"

Volkow pointed out that some people have relatively low levels of receptors, but they are not addicted to drugs, noting that one study took people who were not addicts and gave them a non-addictive stimulant drug that provokes a response similar to cocaine. Some reported that the effects were unpleasant; others said the effects were pleasant, she said. After further evaluation, researchers found that those with lower levels of the dopamine D2 receptors reported the drugs as pleasant and those with higher levels reported it as unpleasant.

"How do the lower levels of the receptor make you more susceptible to drug abuse? If your first experiences are pleasant, you will be more inclined to take it again," Volkow said. "The view I favor is that higher levels of the receptor could be a protective factor; it could make someone perceive the effects of the drug as aversive."

While some people are predisposed to drug abuse, Volkow said, research has shown that environment and stress play an important role as well. She was reminded of this recently, she told the audience, when she drove by a large parking lot and saw a bunch of teenagers standing around, presumably with nothing better to do that night. Clearly, if drugs provide someone with their only source of significant pleasure in life, they will be more apt to continue taking them, she said.

Volkow pointed out that some studies have shown that if children perceive drug use as risky, that can reduce the chances that they will try drugs. Also, she said, some studies have shown that if people don't try drugs before they are 21 years old, that can reduce their chances of being addicted. She noted that she is particularly interested in seeing more research into the effects of drugs on developing adolescents.

Another research interest, Volkow said, is treatment intervention, "including those that interfere with the acute effects of the drug, and those that compensate for the chronic effects of long-term use linked to dopamanergic effects." She gave as an example research being done by Dr. Tom Kosten, the principal investigator of the NIDA Yale Medications Development Center for Cocaine and Opiate Dependence. Kosten's research has shown that tiagabine, a drug sometimes prescribed to control certain kind of epileptic seizures, can be more effective than some other drugs at reducing cocaine use in cocaine abusers who are stabilized on methadone.

Volkow also cited research done by Dr. Tony George, an investigator with CENTURY, on selegiline. His preliminary research has shown that the drug, normally used to treat people with Parkinson's disease, may help smokers quit because it can increase the levels of dopamine in the brain.

Research like this, Volkow said, may ultimately increase the ability of people to deal with their addictions.

-- By Pem McNerney,

Center for Nicotine and Tobacco Use Research at Yale


T H I SW E E K ' SS T O R I E S

Yale scientist on team that discovered new planetoid

Robert Blocker has been reappointed to third term . . .

Center to foster research on cerebral cortex

Bulldogs' Nate Lawrie busy preparing himself for NFL Draft

Political scientist Ian Shapiro named YCIAS director

Zbigniew Brzezinski . . . to present talk on campus

Magic, comic mayhem prevail in re-telling of old tale

'Digital Cops in a Virtual Environment' will explore . . .

Conference to consider 'The Future of Secularism'

Exhibit features works by artist who combined fact and fantasy . . .

NIDA director discusses complicated causes . . . of drug addiction

Castle Lectures to explore materialism in today's culture

English faculty to present staged reading of 'Pentecost'

'Enclave' to explore architectural aspects of ports of commerce

In Focus: Office of Cooperative Research

Geologist John Rodgers, specialist on mountain ranges, dies

Memorial Services

They came . . . they saw . . . they learned

Meritorious service

Six undergraduates earn prizes for their private collections of books

Black cancels Yale show

Campus Notes

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