Combining monitoring data to evaluate responses to NPS: the case of 4-FA in the Netherlands
In the past decade, a growing number of new psychoactive substances (NPS) have been reported to the European early warning system, part of which has been subjected to (inter)national controls. While a variety of monitoring sources are used for assessing the health risks of NPS, the data are not systematically used to follow-up (un)intended consequences once measures have been implemented. In the Netherlands, a unique system of monitoring sources allowed to trace developments in use, and associated consequences, of 4-fluoramphetamine (4-FA) before and after (policy) responses.
Trend data from different monitoring sources were integrated to depict the development of 4-FA use, risks and indicators of its availability, covering different periods before and after a warning campaign in September 2016, and the prohibition of 4-FA on May 25, 2017. Data were collated from population surveys, repeated surveys among club and partygoers, drug-related emergencies, composition of 4-FA samples delivered to drug test services and Google trend and drug forum analyses.
Repeated surveys in the nightlife population showed that the combination of the warning followed by the prohibition seemed to be effective in the sense that a large part of 4-FA users adjusted their use (e.g. diminished or stopped use of the substance). Moreover, the number of samples delivered to drug test services went down; yet, the purity of the remaining samples decreased, as evidenced by an increase in the proportion of adulterants. There was also a drop in the proportion of 4-FA related health emergencies, however their severity increased. Moreover, forum data showed a clear reduction in newly started 4-FA discussions.
The various monitoring sources combined allowed to trace developments in use, availability and (unintended) consequences of policy measures relating to 4-FA. The use of additional sources and methodologies could be useful to fully appreciate the consequences of policy responses in future cases.