FILE - In this Sept. 6, 2016, file photo, Hamilton County Ohio coroner Dr. Lakshmi Sammarco announces toxicology reports on people who died of drug overdoses in July and August had the drug Carfentinal in their system in Cincinnatti. Behind her is Hamiliton County Sheriff Jim Neil. Reeling from a surge in heroin overdoses, authorities in the Cincinnati area made an offer: Hand in potentially deadly drugs and you won't be charged. But the blanket immunity granted by a judge Sept. 7, 2016, hasn't brought in any heroin as of Tuesday, Oct. 11. "Turn it in, get it off the streets; get it out of your homes, out of your families," Sammarco, pleaded. (Patrick Reddy/The Cincinnati Enquirer via AP, File)
FILE - In this Sept. 6, 2016, file photo, Hamilton County Ohio coroner Dr. Lakshmi Sammarco announces toxicology reports on people who died of drug overdoses in July and August had the drug Carfentinal in their system in Cincinnatti. Behind her is Hamiliton County Sheriff Jim Neil. Reeling from a surge in heroin overdoses, authorities in the Cincinnati area made an offer: Hand in potentially deadly drugs and you won't be charged. But the blanket immunity granted by a judge Sept. 7, 2016, hasn't brought in any heroin as of Tuesday, Oct. 11. "Turn it in, get it off the streets; get it out of your homes, out of your families," Sammarco, pleaded. (Patrick Reddy/The Cincinnati Enquirer via AP, File) Credit: Patrick Reddy

Authorities in the Cincinnati area made an offer last month: Hand in potentially deadly drugs and you won’t be charged.

But the blanket immunity there hasn’t brought in any heroin so far.

An Associated Press review has found that results from similar efforts elsewhere have been mixed. But that hasn’t dissuaded supporters who feel like their backs are against the wall as they try to combat the opiate epidemic.

National addiction experts stress simply offering immunity for turning in drugs isn’t enough. They need to be combined with efforts to end the cycle of drug abuse, arrest and incarceration.

In Gloucester, Mass., addicts can turn in their drugs to police without fear of arrest. But officials say less than 20 percent of the over 500 addicts placed into treatment since June 2015 has actually done so.