A blanket ban on legal highs came into force across the UK, including Northern Ireland, on Thursday.
The drugs had previously existed in a legal format, but had caused controversy due to fears over the impacts they could have on health.
A Bangor teenager, Adam Owens, died on 13 April last year after taking synthetic cannabis, which at the time was a legal high.
The 17-year-old took the substance at a house party in Newtownards and died shortly after, before an ambulance could reach him.
His mother, Adele Wallace, welcomed news in March that the law would change to impose a blanket ban on the psycho-active substances.
Speaking to UTV at the time, she also warned that it would not stop deaths instantly and that some people would still find ways to get access to the drugs.