The French addictovigilance network clinical assessment: Z-drugs, true false twins

In France, an addictovigilance network is responsible for evaluating drug dependence, by drawing on pharmacoepidemiological studies, clinical studies and by assessing healthcare professionals' reports on problematic consumption.

The aim of this study was to determine whether zolpidem and zopiclone have different dependence profiles, based on healthcare professionals' reports, and to identify various consumer dependence profiles among zolpidem users and among zopiclone users. Dependence in reports was assessed using the EGAP scale; a scale developed using the DSM diagnostic dependence criteria.

The comparison of dependence profiles for zolpidem and zopiclone showed differences both in total EGAP score and EGAP item positivity. The descriptive analysis showed that EGAP scores were higher for zolpidem than for zopiclone, suggesting more severe problematic consumption with zolpidem. For zolpidem 2 subpopulations of consumers were identified, with one subpopulation's consumption being more severe than the other, with a significantly higher total EGAP score and more harmful consequences. No subpopulation was highlighted for zopiclone.

These results were in favour of a higher prevalence of physical and compulsive signs of dependence and of harmful consequences of dependence, with zolpidem than with zopiclone.