The Home Office has published a Psychoactive Substances Act 2016 Review Framework [link]. There is no doubt that the PSA has had the effect of closing down most, if not all, of the high street retail outlets selling ‘new psychoactive substances’ (i.e. those substances not controlled under the MDA 1971). Less clear, I suggest, is the extent to which (i) prevalence has changed since the PSA came into force, (ii) the quantities of NPS being sourced (e.g. online or from street dealers), and (iii) the substances most frequently consumed: see recent BBC news items [link], including news that the prison service found 1/4 metric tonne of drugs in one year [link].