MONTREAL - Heroin-related debris, like discarded needles, dropped 46 per cent in a Montreal neighbourhood after an injection clinic opened there in 2005, a newly published study suggests.

The researcher who examined the clinic is urging the Conservative government in Ottawa to pay close attention to the findings -- and perhaps reconsider its opposition to such facilities.

"I think so," said Serge Brochu, a Universite de Montreal criminologist. "Harm reduction principles in different studies have been proved to be successful and to have a lot more impact than repression in some cases.

"Right now we have the tendency to look only at repressive measures and it's not the way to go."

The study published Wednesday in the Canadian Journal of Public Health indicates the establishment of an experimental prescription medical heroin clinic did not have an appreciable negative effect on the neighbourhood.

The analysis is being released as the Supreme Court of Canada is considering the future of a Vancouver safe-injection clinic which has been opposed by the Conservatives.

Prime Minister Stephen Harper has said his government's national drug strategy is based on prevention and treatment. The government doesn't condone the Vancouver safe injection site, saying it fosters addiction.

The analysis carried out by Universite de Montreal researchers looked at trash patterns in a 200-metre area around the clinic and saw a major drop in the amount of debris such as needles.

"Some people were afraid that prescribing heroin to heroin addicts would attract a lot of problems in the neighbourhood where the clinic is established," Brochu said in an interview.

"We certainly show that it is not the case. We shouldn't say no to these types of clinics on the basis of the fact that we will attract people disturbing the neighbourhood.

"It's not true."

The study released Wednesday follows another one by Brochu and other researchers, published in 2009, which looked at crime patterns around the Montreal clinic and one in Vancouver before and after the clinics opened.

Basing their analysis on statistics provided by Montreal and Vancouver police, they found that there was nothing to suggest an increase or decrease in crime because of the presence of the clinics.

The study released Wednesday indicated that fears that more drug addicts would be drawn to an area serviced by the clinic were unfounded, saying that injection debris had almost been cut in half.

"When they were using the clinic, they didn't bring their own stuff because it was stuff prepared by St-Luc Hospital and they had to shoot themselves (up) in the clinic," he said. "So for sure there wasn't any debris from these (injections)."

There was no indication the area had become a "honeypot" attracting new users.

The study did not specify the location of the clinic, which is no longer operating. It closed after the research grant for it and the Vancouver site ran out.

The NAOMI project examined how patients respond to heroin, methadone and other opiate treatment.

Funded by an $8.1-million research grant from the Canadian Institutes of Health Research and approved by Health Canada, the project treated 251 of the most seriously addicted in Montreal and Vancouver over a three-year period.

The study discovered that illicit heroin use among participants dropped by about 70 per cent. It also found that the number of participants who committed crimes fell to 36 per cent, from 70 per cent.

Spending on drugs also plummeted, with participants who laid out an average of $1,500 per month on drugs cutting that amount to $300 and $500 per month by the time they finished the treatment phase.

Several Canadian cities including Victoria, Toronto and Quebec City have shown interest in opening safe-injection clinics modeled after Vancouver's Insite, which is currently the subject of a Supreme Court challenge.

The top court is to decide whether the controversial Insite is a health-care facility under provincial jurisdiction, and whether closing it violates the rights of drug addicts living in one of Canada's poorest neighbourhoods.

The Vancouver clinic opened in 2003 and allows addicts to inject their drugs in a clean environment under a nurse's supervision.

Supporters, including the B.C. government, point to peer-reviewed studies that conclude Insite prevents overdose deaths, reduces the spread of HIV and hepatitis, and curbs crime and open drug use.

Insite was allowed to operate after the Liberal government of the day granted the facility an exemption from federal drug laws.

There is no indication when the Supreme Court will rule on the current challenge.

The Montreal study looked at a clinic which was established in 2005 as part of the North American Opiate Medication Initiative and is authored by criminologists Marc-Andre Ally, Serge Brochu and Etienne Blais.

The researchers noted that decision-makers often opposed safe-injection sites because of potential negative impacts, such as drawing new drug users to the neighbourhood and the accumulation of debris such as used needles.

There was also a belief that area residents felt less secure.

The researchers walked a section of the area and looked at what was left behind.

"Results show that the opening of the clinic was followed by a significant drop in the amount of injection debris," the study states.

"This reduction appears proportional to the number of clinic participants."

The authors recommended further studies to evaluate how the presence of the clinic affected local residents' feelings of security.