The number of people seeking treatment for so-called "club drugs" has risen in the past six years, according to the National Treatment Agency.
Last year, 6,486 people were treated for substances such as ecstasy and ketamine - up from 4,656 in 2005-06.
But, despite the rise in that period, the last 12 months has seen a fall in those treated for many such drugs.
The report refers to those who sought help in a variety of ways, such as counselling and detoxification.
The NTA estimates that around one million people used club drugs last year, although overall drug use has declined in England over the past six years.
It said club drug users make up just 2% of adults in treatment and 10% of young people in specialist services.
Its research suggests that ecstasy remains the most common club drug people receive treatment for.
However, the number of new adults entering treatment halved, from around 2,000 in 2005-06 to just over 1,000 last year.
Mephedrone and ketamine are thought to be increasingly popular drugs.
Treatment related to use of the latter rose year on year between 2005-06 and 2010-11, from 114 adults to 845. However, it fell back to 751 this year.
Some 900 adults started treatment for mephedrone this year, compared to 839 in the previous year.
Experts warn that so-called club drugs can cause serious physical and mental health problems, such as bladder damage and psychosis.
In its report, entitled Drugs: Emerging Trends and Risks, the NTA said 61% of people aged over-18s and 74% of under-18s who had used the substances left treatment successfully last year.
"It is clear that some club drug users are developing serious health problems and even dependency," said NTA chief executive Paul Hayes.
Mr Hayes added: "While drug use overall is falling, there is an increase in the number of people turning to treatment for club drugs. The numbers remain small compared to heroin and crack addiction, but services need to be geared up to meet these emerging needs."
He said those who do seek treatment "stand a very good chance of overcoming their problems".
"Many have personal support and resources that put them in a good position to recover," he said.