In many cities, a bride brings the equipment for smoking opium as part of her dowry. Before the 1979 revolution, the government gave opium to addicts to enable them to avoid drug dealers.

“Opium in our culture is like Champagne in France,” said Dr. Ali Alavi, with the United Nations Office on Drugs and Crime. “Many use it for entertainment.”

Drug abuse is even more common outside Tehran and other large cities, particularly in the provinces along the drug-trafficking routes that run from Iran’s long eastern border with Afghanistan, where opium poppies are grown, to the northwest, where it is transported to Turkey and Europe.

More than 93 percent of the opium produced for the world’s illicit narcotics markets comes from Afghanistan, according to the United Nations Office on Drugs and Crime, and Iran is the main trafficking route for nearly 60 percent of the opium grown in Afghanistan.

With opium production skyrocketing in Afghanistan, some Iranian officials accuse the American military of ignoring poppy cultivation in Afghanistan, even though it is a major source of revenue for the Taliban and Al Qaeda.

“We think the Americans want to keep this source of infection near us,” said Mr. Jahani, the Iranian antidrug official. “Because of the animosity between Iran and the U.S., this is the best way to keep our resources and forces occupied.”

Image A ceremony in Tehran in May celebrated a recovering addicts first anniversary free of drugs. Credit... Aslon Arfa for The New York Times

The government grew so concerned about drug trafficking that it spent $6 billion in 2006 to build a wall 13 feet high, with barbed wire, and a trench 13 feet deep and 16 feet wide along a third of Iran’s border with Afghanistan. Iran seizes more illicit opiates than any other country, the United Nations Office on Drugs and Crime said, and it burns tons of confiscated drugs in a ceremony every year.