A patient watched pictures appear one by one: First, a bicycle. Next, a treat: a cupcake. Then a picture of the drug heroin.

Researchers followed her brain's reactions to the sight of the drug that she has tried to stop taking.

U.S. government scientists are starting to study the brains of people caught in the opioid epidemic in the United States. They want to see if medicines proven to treat substance abuse, like methadone, do more than ease the person's desire for the drug.

Do these medicines also heal a brain damaged by drug dependency? Which medicine works best for which patient?

Studies have found that three medicines can effectively treat what specialists are calling opioid use disorder. They are methadone, buprenorphine and extended-release naltrexone

Patients who use methadone or buprenorphine cut their chances of death in half. That is a finding from a report by the National Academies of Sciences, Engineering and Medicine.

Nora Volkow is the director of the U.S. National Institute on Drug Abuse, or NIDA. She is leading the new study.

"The brain responds differently to these medications [methadone, buprenorphine and extended-release naltrexone] than to heroin. It's not the same," she says.

Opioid addiction changes the brain in ways that can make people likely to relapse. They start using the drug again after a period of improvement. Researchers believe these changes lessen with long-term abstinence.

Volkow thinks medication-based treatment will help those damaged neural networks start getting back to normal faster.

To study that idea, she needs to compare brain images from people like the woman who stopped using heroin with active users and people who are in the early days of treatment.

"Can we completely recover? I do not know that," Volkow said. But with the medications, "you're creating stability" in the brain, she said. That helps train the brain to react to everyday pleasures again.

The problem now is finding enough people willing, and healthy enough, to have their brains scanned for science.

When you find something pleasurable, such as a song or the touch of a loved one, the brain releases a natural chemical called dopamine. It trains the body to remember that it liked something.

That is the brain's reward system. Opioids can damage it by causing production of more dopamine than nature ever could. Repeated opioid use overloads nerves in different areas of the brain, including those involved with learning and memory, emotion, judgment and self-control.

At the same time, the brain slowly releases less dopamine when reacting to other things the person once found pleasurable.

Eventually people seek more of the drug not to get high, but to avoid feeling low.

Drug addiction is a brain disease, "not a choice, not a personality flaw, not a moral failing," says Jody Glance. She is an addiction specialist at the University of Pittsburgh Medical Center.

Glance hopes NIDA's brain scans will help improve the reaction of public health officials to the opioid crisis. Not offering the medicines to people who need them "is like not offering insulin to someone with diabetes," she said.

Volkow plans to test a mix of untreated heroin users and patients using different medication-based treatments. The patients go inside brain scanning equipment at the National Institutes of Health's research hospital.

Her team has screened more than 400 people who showed interest in the study. They have found only about 40 people who met the requirements. Of those, seven are taking part in the program.

The main problem: Those being tested must have no other health problem that might affect the brain's chemistry or operation.

Volkow said it is worth the struggle to find such rare volunteers if before-and-after scans end up showing truly different looking brains as people get treated.

"You should be able to see it with your eyes, without having to be an expert," she said.

I'm John Russell.

Lauran Neergaard reported on this story for the Associated Press. John Russell adapted the report for VOA Learning English. George Grow was the editor.

Words in This Story

epidemic – n. when a disease spreads quickly and affects many people at the same time

relapse – v. a return to bad behavior that you had stopped doing

network – n. a system of interconnected things

stability – n. firmness or strength

scan – v. to examine systematically

reward – n. something that is given in return for some service

flaw – n. a small fault or weakness

insulin – n. a substance that your body makes and uses to turn sugar into energy

diabetes – n. a serious disease in which the body cannot properly control the amount of sugar in your blood because it does not have enough insulin

screen – v. to examine methodically in an effort to separate into different groups

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