Legal highs are so popular the only option is to "educate people who are using them" about how they can make safer choices about the drugs they take, an addiction specialist told Good Morning Britain.
Associate medical director of the CRI, David Bremner, said: "In a matter of days a new drug will be released that will have one molecule changed that then beats the law so that it is no longer illegal...all we can do is educate people who are using them on how to make safer choices."
More top news
A man has been killed by thieves who ran him over in his own car after he confronted them outside his home, police said.
One London Marathon runner who helped an exhausted competitor said it was "worth it" to help his rival.
The Irish Coast Guard helicopter went down into the Atlantic last month.