On 19th November, the Home Office published this review of the operation of the Act which targeted the so-called former “legal highs” and their abuse. It notes that there have been 3 types of legal challenges to the PSA, concerning the medicinal products exemption for nitrous oxide, the psychoactivity of nitrous oxide and the psychoactivity of synthetic cannabinoids (all of which have been held to be caught by the Act). Data from police forces suggests that the PSA has led to head shops either closing down or no longer selling new psychoactive substances (NPS), with 332 retailers identified as having ceased the sale of NPS. The Act has not completely eliminated the supply of NPS, given the large numbers of offences and seizures of suspected NPS recorded. The emergence of new NPS in the UK has not ceased following the introduction of the Act, based on forensic analysis of drug samples, albeit this is based on a small number of observations. Evidence indicates that there has been a considerable reduction in NPS use among the general adult population since the PSA, mainly driven by a reduction in use among those aged 16 to 24. However, the report concludes that while most of the main aims of the Act appear to have been achieved (with the open sale of NPS largely eliminated, a significant fall in NPS use in the general population, and a reduction in health-related harms which is likely to have been achieved through reduced usage), some areas of concern have remained or emerged since the Act, such as the supply of NPS by street dealers, the continued development of new substances, the potential displacement from NPS to other harmful substances, and continued high levels of synthetic cannabinoid use among the homeless and prison populations.