Prevalence and patterns of methylphenidate use in French children and adolescents.

Objective: The aim of the study was to describe the prevalence and utilization patterns of methylphenidate (MPH) in children and adolescents in France.
Methods: This was a population-based retrospective study in which the cohort consisted of patients for whom data were extracted from the dispensation drug claims database of the national health insurance (NHI) fund for self-employed workers. Annual prevalence of MPH use was evaluated on patients aged 6-18 years who were reimbursed for at least one MPH prescription a year. Between January 2004 and June 2005, features of MPH medication and user profile were described for the "new starters" having a screening period of 1 year without receiving a MPH prescription and a follow-up >or=12 months. Time to interruption of MPH regular use was analysed by Kaplan-Meier survival analysis. Mean duration of exposure to MPH treatment was computed with the 95% confidence interval (CI).
Results: Annual prevalence of MPH per 1000 persons was 1.1 in 2003, 1.5 in 2004 and 1.8 in 2005 (relative increase of 63.5%). New starters (n = 447) received their first MPH prescription through the hospital (65.1%) or through private practitioners (34.9%). The user profiles were: short (16.6%), occasional (33.8%) and regular (49.6%). Among the new starters, the median time to interruption of MPH regular use was 10.2 months (95% CI: 7.9-12.4). The mean duration of exposure to MPH treatment was: occasional (4.9 months, 95% CI: 4.3-5.5) and regular (25.7 months, 95% CI: 24.6-26.8).
Conclusion: Although there is a low prevalence of MPH use in France, this survey revealed a wide profile of users and heterogeneous use patterns.