Clonazepam is a benzodiazepine (BZD) authorized for treatment of epilepsy in France. Several evidences for clonazepam abuse liability and offlabel use were observed. Authorities changed the legislation to make clonazepam diversion more difficult. We asked if the three successive law changes between 2008 and 2011 have influenced clonazepam use and abuse.

To assess the impact of recent legislation changes on clonazepam abuse in the Paris Metropolitan Region.

A quantitative analysis of all clonazepam data from 2003 to 2012 of three epidemiological tools has been performed: NOT'S is a CEIP database of spontaneous NOTifications of drug abuse and dependence.

Observation of Illegal Drugs and Misuse of Psychotropic Medications (OPPIDUM), data from French health reimbursement system (FHRS) for all the country.

We aimed to compare clonazepam misuse and abuse evolution with diazepam and flunitrazepam to assess the legislation impact on clonazepam.

In NOT'S, between 2003 and 2007 the proportion of clonazepam misuse ans abuse seems to be stable (15% ±2 of all notifications). Clonazepam abuse increases between 2007 and 2010 (up to 30%) then starts to decrease after 2010 until now (23% of all notifications). These results are consistents with data from the FHRS, whereas in the OPPIDUM survey clonazepam use seems to be stable in addiction centres. Diazepam use is constantly increasing in the 3 epidemiologic tools whereas flunitrazepam use is stable or slowly decreasing.

Our results show an influence of the legislation on the misuse of clonazepam particularly in the untreated addicted population.