Patient Number One is a thin man with all the hair removed from his head.

　　Years of drug use cost him his wife, his money and his self-respect.

　　Now, he meets with a surgeon who will operate on him in 72 hours. The doctor plans to cut two small holes in the man's head and connect electrodes to his brain.

　　Doctors have long used the treatment, known as deep brain stimulation, or DBS, for movement disorders like Parkinson's disease. Now, they are performing the first clinical trial of DBS for methamphetamine addiction at the Ruijin Hospital in Shanghai, China.

　　Patient Number One was the first patient in the study.

　　The surgeon plans to implant a device that acts like a pacemaker for the brain. It electrically stimulates targeted areas.

　　Researchers in Europe have struggled to get patients for their DBS addiction studies. In the United States, complex social and scientific questions have made it hard to move forward with studies of the treatment.

　　Eight registered DBS clinical trials for drug addiction are taking place around the world. Six of those are in China. That information comes from the U.S. National Institutes of Health.

　　Patient Number One, whose last name is Yan, said doctors told him the surgery was not dangerous. "But I still get nervous," he said. "It's my first time to go on the operating table."

　　Treating Addiction in China

　　Before brain implants, there was brain lesioning. In China, families of heroin users paid doctors thousands of dollars to destroy small masses of brain tissue. Many patients had side effects, including emotional disorders and lost memories.

　　In 2004, China's Ministry of Health ordered a stop to the use of brain lesioning.

　　DBS builds on that history. But unlike lesioning, which kills brain cells, DBS devices offer a treatment that is, at least in theory, reversible.

　　In China, DBS devices can cost less than $25,000. Many patients pay with money they have saved up.

　　Li Dianyou is Yan's surgeon. "You can rest assured for the safety of this operation," he told Yan. "It is no problem. When it comes to effectiveness, you are not the first one, nor the last one. You can take it easy because we have done this a lot."

　　In fact, there are risks.

　　Yan could suffer brain damage. He could have had changes to his personality; he could have developed seizures. He may have even gone right back to drugs.

　　DBS in the US

　　Critics believe the surgery should not be permitted. They argue that these experiments fail to deal directly with the issues that drive addiction.

　　Scientists do not fully understand how DBS works. They still debate where they should place electrodes to treat addiction.

　　Two U.S. clinical trials on DBS for depression failed around five years ago. At least two U.S. laboratories dropped clinical trials of DBS for treating alcoholism over concerns about study design. The partial results did not seem to justify the risks, researchers told the Associated Press.

　　The U.S. Centers for Disease Control and Prevention reports that over 500,000 Americans died of drug overdoses between 2008 and 2017. That is more than the total number of U.S. soldiers who died in World War II and Vietnam combined.

　　In February, the Food and Drug Administration approved a small trial of DBS for opioid use disorder.

　　The FDA did not comment on the action.

　　"People are dying," said Ali Rezai, the leader of the study at West Virginia University's Rockefeller Neuroscience Institute on Drug Abuse. "Their lives are devastated. It's a brain issue. We need to explore all options."

　　Nader Pouratian is a neurosurgeon at the University of California, Los Angeles. He is investigating the use of DBS for chronic pain. Pouratian said it is an "appropriate time" to research DBS for drug addiction, but only "if we can move forward in ethical, well-informed, well-designed studies."

　　What is this machine doing inside my head?

　　Yan, Patient Number One, had his surgery about six months ago. He was awake when the doctor used a drill to cut through his skull. The noise made him shake.

　　Later the same day, he was given drugs so he could sleep through a second operation. Doctors implanted a battery pack in his chest to power the electrodes in his skull.

　　Hours after, Yan still had not woken up from the anesthesia. His father began crying. Doctors wondered if his drug use had changed how his body reacted to anesthesia.

　　Finally, 10 hours later, Yan opened his eyes.

　　Two days after the surgery, doctors turned on his DBS device.

　　When the device turned on, he felt energized. He stayed awake that night; he said he spent the whole night thinking about drugs.

　　The next day, Doctor Li used a tablet computer to adjust the machine connected to Yan's head.

　　The doctor asked how Yan felt. "Agitated," Yan said.

　　Li made a few changes. "Any feelings now?" he asked.

　　"Pretty happy now," Yan said.

　　Yan notes that he felt the changes the machine made. "It controls your happiness, anger, grief and joy," he said.

　　Six months later, Yan said he is still off drugs. His skin has improved and he has gained some weight.

　　Sometimes, in his new life, Yan touches the hard cable wiring in his neck. It leads from the battery pack to the electrodes in his brain. And he wonders: What is the machine doing inside my head?

　　I'm John Russell.

　　And I'm Alice Bryant

　　Erika Kinetz reported on this story for the Associated Press; Associated Press researcher Chen Si contributed to the report. John Russell adapted it for Learning English. George Grow was the editor.