Influence of law changes affecting synthetic cannabinoid availability and frequency of hospital presentations: 4-year national survey.

AIMS: We previously reported that passage of the 2013 Psychoactive Substances Act (PSA), which limited retail availability of synthetic cannabinoids (SCs), was followed by reduced numbers of presentations to one psychiatric emergency service. This analysis examined national trends in hospital presentations associated with use of SCs, and how these changed after passage of laws in 2011, 2013 and 2014, that altered SC availability.

METHODS: Analysis of 2011-2015 Ministry of Health dataset of patients presenting to hospital associated with use of SCs. The relationship between changes in hospital presentations and the 3 legislative changes was evaluated using time series models.

RESULTS: Monthly hospital presentations peaked in mid-2011, 2013 and 2014. Steep declines in numbers of presentations occurred after law changes between August and September 2011 (current SCs removed from sale), July and August 2013 (reduced number of SC retail outlets), and May and June 2014 (all SCs banned). The 2013 reduction in supply was associated with mean monthly presentations decreasing by 10.6 (95% CI 1.5, 19.7; p=0.023). Patients were predominantly young males, and presented with a range of emotional, psychotic and behavioural symptoms.

CONCLUSIONS: Law changes that reduced SC availability were associated with reduced harms (hospitalisation) associated with use of SCs.