The study, So Prohibition Can Work?, looked specifically at the use of “new psychoactive substances” (NPS)/headshop drugs by adolescents attending the Youth Drug and Alcohol outpatient service in Dublin, comparing the six months immediately prior to the ban in May 2010 to the same six-month period the following year.
The average age of the groups studied was 17 and predominantly male.
Researchers found that the percentage of problematic NPS users dropped from 34% in the first group to 0% in the second group. The percentage who had occasionally used any headshop drug in the previous three months also dropped dramatically from 82% in the pre-ban group to 28% in the post-ban group.
The study’s authors concluded that criminalising the sale of once-legal highs, and the closure of 93% of headshops, had “substantially reduced” the use of NPS’s among these people in the year after the legislative changes were introduced.
The study, published in the International Journal of Drug Policy, also showed that those who continued to use headshop drugs in the post-ban era did so in a lower-risk manner and that the legislative ban did not result in increased use of other substances such as cocaine and amphetamines by those attending treatment.
Lead researcher Dr Bobby Smyth, clinical senior lecturer in public health and primary care at Trinity, said the findings had confounded concerns raised by some academics prior to the legislative changes that banning headshop drugs and closing headshops would drive users into other criminal supply networks, and that use would continue unabated.
Their study instead found that the ban “did indeed coincide with a fall in NPS use among this high-risk group of teenagers”.
Other factors which may have contributed to the fall in use of headshop drugs, according to Dr Smyth, included substantial negative publicity regarding adverse effects of NPS’s.
At the time of the introduction of the ban in Ireland in May 2010, there were 102 headshops, equating to one shop per 45,000 people. By September 2010, there were only 10-12 headshops.
NPS’s include powdered stimulant drugs which typically are snorted, smoked synthetic canabinoids, and pills with amphetamine-type effect.