The study, in Science's April 13 issue, tested an experimental treatment for addiction on 66 former heroin users confined at two facilities in Beijing.

Joseph Amon, director of the health and human rights division at Human Rights Watch, charged in the letter that in both places addicts are "detained without due process" and, he told Reuters, "held in a closed institution where monitoring of human rights abuses is not allowed." It is not clear from the study whether the addicts "were voluntary patients" at the facilities or forcibly held, Amon said in his letter.

Human Rights Watch has interviewed detainees recently released from the centers as well as a former guard and Chinese government officials who have been inside others.

Under American law, federally funded research on inmates must be approved by a panel that includes at least one prisoner who volunteers to serve, said bioethicist Karen Maschke of The Hastings Center, a think tank in Garrison, New York, who is not involved in the controversy.

The authors of the study include 11 scientists at Peking University, led by Yan-Xue Xue, and two at the National Institute on Drug Abuse (part of the U.S. National Institutes of Health). NIDA provided financial support for the paper in the form of salaries to co-authors David Epstein and Yavin Shaham, who advised on the experiment's design, among other contributions. NIDA declined to make them available to speak about the study.

In a reply to Amon, also published in Science on Thursday, eight of the Peking scientists said they "saw no indication of the abuses" he described, which would violate Chinese law.

Beijing's drug treatment centers "provide comprehensive care," they wrote, including methadone for heroin addicts, "psychological counseling" and "regular medical treatment."

The two NIDA researchers did not sign the response, nor did three of the Peking University scientists. Lead authors Ping Wu and Lin Lu told Reuters by email, "All authors are fine with the letter but only authors on human experiments were on the letter; the other authors only did rats experiments."

"The NIDA investigators did not sign the letter because they were not engaged in the human studies," NIDA said in a statement to Reuters.

The institute did not respond to a question about the discrepancy between that assertion and a written statement in April, obtained by Reuters, saying its scientists were "involved in the data analyses and the preparation of the manuscript."

INVOLUNTARY CONFINEMENT

Drug detention centers in Beijing have been the subject of reports by Chinese and Western news organizations, human rights groups, scientists, and the United Nations. A 2010 article in China Daily said drug users at Ankang Hospital, one of the facilities where addicts were studied by Xue and colleagues, are typically confined involuntarily for two years. Therapies include boxing, playing in sand, and crossing rope bridges, none of which have been shown to be effective against addiction. Ankang is staffed by 20 psychologists and 30 policemen, China Daily reported, and houses hundreds of detainees, according to Human Rights Watch.

A 2010 investigation by the New York Times found that drug users are confined to the facilities by police without trials or the possibility of appeal and endure "an unremitting gantlet of physical abuse and forced labor without any drug treatment."

In what it called a "landmark" statement, the UN in March called on member countries to close compulsory drug detention centers.

Amon brought Human Rights Watch's concerns to NIDA in April, asking it to "conduct an independent investigation of the research and denounce the arbitrary detention of the roughly 200,000 people currently in compulsory drug detention centers in China." The figure is based on HRW's research.

NIDA has not responded to that request, though it told Reuters it is not currently funding research in drug detention centers in Asia.

The institute and its scientists "seem to have dismissed their own ethical obligation as both funders and authors," said Amon, who is also an associate in the department of epidemiology at the Bloomberg School of Public Health at Johns Hopkins University and a lecturer in public and international affairs at Princeton University.

In the study, the Beijing scientists tested a technique called "memory retrieval-extinction" to prevent drug cravings in heroin users. Other research had shown that presenting addicts with a reminder of their addiction, such as the sight of a crack pipe, without letting them experience the drug's effects can make the cue less likely to trigger craving. But that effect fades within weeks or even days.

The study concluded that the technique works longer, up to six months, if the addict's memories of the drug are first triggered ("retrieved," via a five-minute video about the drug) before the link between the reminder and the drug is "extinguished."

The scientists concluded that memory retrieval-extinction offers "a promising nonpharmacological method" for fighting addiction.

As concerns about research ethics have grown in recent years, top journals have retracted studies that did not adhere to standards protective of human subjects.

Studies published by Science must have approval from an ethics board; the Chinese scientists say their study had such approval from Peking University.

"The journal is not an investigative body," a spokeswoman for Science told Reuters. "On the basis of the authors' response as well as (the editors') own internal review, which included a science ethicist, the concerns about human rights seem to have been addressed, and the paper remains in good standing at this time."

(Edited by Michele Gershberg and Prudence Crowther)

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