The number of heroin and crack cocaine users needing treatment in England has fallen by 10,000 in two years.
The National Treatment Agency for Substance Abuse said the number of adults that began treatment for the class A drugs fell from 62,963 in 2008/09 to 52,933 in 2010/11.
The steepest decline was in the under-30 age group.
The number of people accessing treatment for all drugs also fell for the second year running.
The latest figures also show an increase in the number of drug users "recovering" from addiction - people who no longer need treatment.
Some 27,969 users were classed as recovering in 2010/11, a rise of 18% on the previous year and 150% higher than 11,208 in 2005/06.
The figures showed that, of the 255,556 people who entered a drugs treatment programme since April 2005 for the first time, 28% (71,887) had successfully completed the course and did not need further treatment.
Paul Hayes, the NTA's chief executive, said the figures showed that "recovery is now becoming a reality for more individuals each year".
"More drug users are recovering from addiction, fewer need treatment, and more are getting over their addiction quickly," he said.
Mr Hayes went on to say he thought the figures showed England had "probably passed the high watermark of the impact of epidemic of the late '80s and early '90s and that younger groups of people were reluctant to begin patterns of behaviour... that they've seen cause damage to their older siblings, people in their community, sometimes, sadly their mums and dads."
"They realise the consequences of heroin and crack use and they're turning their backs on that," he said.
He said officials were also seeing "significant declines in purity" which "suggests that attempts to restrict supply are having an impact".
"It's extremely likely, from where we sit, that the different aspects of the government's drugs strategy are coming together to have a positive effect," he added.
But he warned that addiction remained a "serious problem" for many communities, particularly the poorest ones.
"We need to remain vigilant, particularly in a tough economic climate.
"There's absolutely no inevitability that rising unemployment among young people will see a rise to '80s levels of heroin use, but we need to watch that situation very carefully," he said.
Simon Antrobus, chief executive of Addaction, said it was "hugely encouraging" that young people were shunning heroin and crack cocaine.
He said underlying drug use still needed tackling, and it was important "not to let our guard down".
"While these figures suggest that fewer young people were turning to crack and heroin, Addaction is concerned that an older generation of long-term problem users remains; causing huge problems not only for themselves, but for their children.
"And we know that the children of this group are more likely to develop their own problems.
"So, while we hope today's figures prove to be a milestone in the tackling of the UK's drug problems, we certainly cannot be complacent."
Turning Point's director of substance misuse, John Mallalieu, said the figures were "promising" and the drug support charity had witnessed greater numbers of people recovering from drug addiction.
"This is made easier for them because as a nation, we are becoming more ambitious for drug users and giving them more opportunities to become part of society again.
"It is important that we ensure the right methodologies are kept in place to tackle the wide range of problems that contribute to a person's substance misuse such as mental health, unemployment, housing and physical health.
"The current momentum must be continued so that those 27,969 who are still in treatment have a better chance of turning their lives around too," he said.