Example of an investigation of an "emergent" phenomenon in addiction vigilance: the case of methylphenidate.

Abuse of and addiction to medication are a major public health issue which is evolving fast, in particular in countries like France, one of the largest consumers of medication in Europe. As a single source of information is not generally sufficient to measure a phenomenon as difficult to apprehend as medication-related addiction, as can be seen in the case of methylphenidate, it is essential to mobilise all the tools available, here surveillance programmes developed by the French CEIP Addiction vigilance network, such as suspicious prescriptions indicating possible abuse data (OSIAP) or observatory of illegal or misused psychoactive medications (OPPIDUM), as well as the health insurance databases, and health professional sentinel networks. The latest data available on methylphenidate abuse in France suggests a stabilisation of the phenomenon, which emerged in the Provence-Alpes-Côte-d'Azur (PACA) region in southern France. It also evidences its diffusion to other regions, so that the information needs to be widely relayed, and suggests that health professionals should exercise the greatest caution in the use of this substance, and should look for early signs of its misuse.