The three-year, $US1.6m study is being conducted at Adelaide University, Australia, in collaboration with the University of California, Los Angeles (UCLA).
Adelaide's Department of Clinical & Experimental Pharmacology is heading the study, which highlights a little-known and mysterious, often permanent side effect of heroin and other opiate drug use.
The side effect is extreme sensitivity to pain. Former users of heroin, methadone, even long-term morphine users can develop a "hypersensitivity" to pain, causing enormous problems for their quality of life. Those who suffer from this condition are often not helped by any available treatment for acute and chronic pain. And in another mystery, not all kinds of pain have the same response in sufferers.
"The problem is, there are no real guidelines on how to assess and manage pain for these people," says Adelaide's Professor of Addiction Studies, Jason White.
"The aim of the study is to gather the best possible information about people's responses to pain, and to various current treatments of pain. Hopefully the results of our study will go some way towards solving a few of the main mysteries which continue to puzzle clinicians and scientists alike."
The Department of Clinical & Experimental Pharmacology has built up a national and international reputation in the field of drug abuse and treatment. While its target so far has been improvements in treatment for heroin and other illicit drug users, "the spin off for other people in the community who also suffer from these symptoms, such as chronic back pain sufferers, could be significant", Professor White says.
"This study will focus on small numbers of people, but studying them intensively to gain a much better understanding of each individuals' response to pain and treatment," he says. "We will be looking at former heroin users who are now on methadone treatment, and comparing them with people on a new drug, buprenorphine."
The study is funded by the National Institute on Drug Abuse in the United States.