Variants and determinants of Novel Psychoactive Substance (NPS) use Potential implications for Policy and Practice

Abstract
Background - The public health impact of substance misuse is a global challenge (UNDOC 2017, ECMDDA 2017). Contemporary data reflects an increasingly graduated and fractured drug scene. “New psychoactive substances” (NPS), are contributing to this fragmentation. We aimed to provide public health-related research evidence on (NPS) addressing eleven research questions ranging from those looking at types and patterns of NPS use; including the quantity and frequency of consumption, the setting of use as well as sources of obtaining the drug, through to questions on how our research findings can be integrated into a framework to inform existing service provision/policy formation, and educational initiatives relevant across the UK and further afield.
Methods - the study used a three-phase mixed methods design with a shared conceptual framework:
Phase 1: a quantitative phase, involving secondary data analysis of the Longitudinal Belfast Youth Development Study (BYDS). A latent class analysis using the 2,039 BYDS participants. Phase 2: extensive qualitative analysis via narrative interviews of participants, sampled from BYDS, drug and alcohol service settings and the prison estate, to explore trajectories of NPS use.
Phase 3: the final quantitative phase. Generalisability of the shared risk factor part of the model was tested using the three-Step Approach manual method to examine risk factors associated with latent class membership. Several integration analyses were built into the design to maximise the utility of the sequential mixed-methods design. Specifically by integrating quantitative material with qualitative information, this allowed emerging findings to be further explored and cross validated and later phase methodologies to be refined.
Findings – Our data supports that NPS are best conceptualised as having a place within a poly drug use trajectory. Models indicated that there was no distinctive NPS class and at a population level there was little to distinguish risks surrounding NPS from other drug use. However, in presenting our findings we differentiate within that overall premise. The detail provided by the narrative accounts helped understand the subjective interplay of the range of risks and protective factors as recounted in the lived experience of respondents. From our narrative data we developed a four group taxonomy of user. Through the lens of our taxonomy groups - 1. ‘The Limited Experimentals’, 2 ‘The Past Recreationals’ 3. The Contemporary Regulars 4. ‘The Dependent’s - we presented empirical data and critical commentary of how various types of NPS appeared to be located within and across a range of poly drug use trajectories. Building on the detail provided on groups, we added further evidence by anchoring the trajectories within a risk and protective framework as well as articulating drivers for their use. Knowledge, perceptions and experience of harm were also embedded. All of this built to discussion on how best to respond to the various patterns of use, we provide a map of interventions ranging from education through to drug treatment options as they relate to our findings. We highlighted the special consideration of SC’s within our data and the potential for NPS as a ‘snare’ for more problem use.