Experts warned, however, that the danger of relapse means permanently kicking the habit probably requires ongoing care. A senior U.S. White House official said the results validated England's approach to treating drug addicts and called for similar efforts to evaluate American drug addiction programs.
British researchers monitored more than 14,600 patients across England addicted to either heroin, crack cocaine, or both. Heroin addicts were treated with oral methadone for at least six months between January and November 2008. Some patients also received counseling.
Since there is no recommended substitute drug treatment for crack, cocaine addicts only received the psychological therapy. The researchers did not compare the treated addicts to addicts who tried to quit on their own.
After six months, 42 percent of heroin users reported they had stopped injecting the drug. Among crack users, 57 percent said they had stopped. About half of the people addicted to both drugs said they had either quit or cut down.
The study was paid for by Britain's National Treatment Agency for Substance Misuse. On average, it costs the government up to >5,000 ($7,991) per person per year to provide addiction treatment.
Experts said the results were encouraging, but drug addicts would likely need more than six months of care. "It is quite possible that many of those with a positive outcome experienced relapse," said Jeffrey Parsons, an addiction specialist at Hunter College in New York who was not linked to the research.
Dr. Thomas McLellan, deputy director of the White House's Office of National Drug Control Policy, said treating heroin and crack cocaine addicts was similar to managing patients with diabetes or high blood pressure. Just as diabetes patients wouldn't only be treated for six months before being released without medication, McLellan said drug addicts needed continuing care.
"Addiction is best thought of as a chronic condition," McLellan said. "There is no cure, but we can manage it."
McLellan said Britain's approach was an advance over similar programs in the U.S., where substance abuse treatments mostly focus on an acute period.
He said ongoing treatment would ultimately lower the medical and social costs of drug addiction, including crime and lost productivity. "The cost savings will be astronomical," he said.