La prévalence de l’hyperactivité/TDAH fait l’objet d’intenses débats au niveau international. En France, la seule étude disponible pointe un taux de prévalence du TDAH de 3,5 à 5,6 % des enfants âgés de 6 à 12 ans. Les auteurs estiment également que 3,48 % des 6–12 ans sont traités par psychostimulant. Notre article s’appuie sur les données de l’Assurance Maladie pour discuter ces résultats.

Il est possible de procéder à une étude rigoureuse du taux diagnostic et du niveau de prescription du méthylphénidate en France en analysant les données de l’Assurance Maladie. Dans cette perspective, nous avons utilisé les informations extraites de la base du Système National d’Information Inter-Régime de l’Assurance Maladie (SNIIRAM) présentées en 2017 dans un rapport de l’Agence Nationale de Sécurité du Médicament et des produits de santé (ANSM).

Les données de l’Assurance maladie permettent d’établir une estimation de la prévalence du TDAH de 0,3 % en France.

Ce résultat appelle des investigations plus approfondies dans la base du SNIIRAM. Il questionne les raisons du faible taux de médication du TDAH en France en comparaison d’autres pays occidentaux. Il interroge les biais méthodologiques et les conflits d’intérêts susceptibles d’orienter les études de prévalence du TDAH en France et au niveau international.

Prevalence estimates for ADHD have therefore been at the core of an international debate in the last two decades. In France, the only available study carried out telephone inquiries in 2008 from a 7912 randomly selected sample of households. The researchers estimated 3.5% children suffered from ADHD, while 2.2% other children were treated with psychostimulants for attention deficit or hyperactivity symptoms without having formally been diagnosed. The use of a rigorous scientific approach and a strong methodology let the authors conclude the prevalence rate of children suffering from ADHD in France ranged from 3.5 to 5.6%. They also noted that among the 3.5% of children who were diagnosed with ADHD, 36.5% were being treated with methylphenidate. Therefore, they estimated 3.48% of children aged 6–12 were effectively treated with psychostimulants. In 2017, a report was issued by the National Agency for Medicines and Health Products Safety using data from The French National Social Security System (SNIIRAM) concerning methylphenidate consumption among children aged 6–11. This report showed 19,613 children aged 6–11 were effectively treated with methylphenidate in 2014. The study also states the prescription rate for methylphenidate increased by 44% between 2008 and 2012, then again by 13% between 2013 and 2014, though 34.2% of the children being treated with methylphenidate are not diagnosed as suffering from ADHD but from other psychiatric pathologies. Our paper compares these two data sets: one concerning ADHD prevalence and the ratio of ADHD children treated with methylphenidate in France, the other regarding the provision of methylphenidate-based medication among children. We highlight the gap between the two studies’ results and call for supplementary investigations of the French Healthcare Insurance database as a way to obtain better information on ADHD diagnosis and medication in France.

Methylphenidate is the only psychostimulant which prescription is authorized in the case of an ADHD diagnosis in France. To determine the prevalence of methylphenidate-based medication use in children aged 6–11, we first collected data concerning methylphenidate consumption from the SNIIRAM database and analyzed them in regard to the 2008 demographic survey issued by the National Institute for Statistics and Economic Studies (INSEE). Using this information and ADHD prevalence data, we secondly inferred an ADHD diagnosis rate in France. Consequently: Since methylphenidate is the only drug precription in France for ADHD, without any other therapeutic authorization; By taking into account (1) the ratio of children diagnosed ADHD and treated with methylphenidate in France (36.5%) and (2) the data concerning methylphenidate consumption in France (19,613 children aged 6–11 in 2014); It is possible to obtain accurate information on ADHD diagnosis in France from the provision of methylphenidate-based medication. We finally compared the prevalence rate of methylphenidate prescription and the estimation of ADHD diagnosis as reported in the SNIIRAM database, to the psychostimulant consumption level and the ADHD prevalence rate as highlighted in the initial prevalence study.

Figures extracted from the SNIIRAM database show 19,613 children aged 6–11 were effectively treated with methylphenidate in 2014. Knowing the prescription rate for this molecule and this population increased by 44% between 2008 and 2012, then again by 13% between 2013 and 2014, we calculated methyphenidate consumption concerned 9555 of children aged 6–11 in 2008. Comparing this number to the National Institute of Statistics and Economic Studies (INSEE) children census, which reported 4,752,571 French children in 2008^{1Those figures are available at: https://www.insee.fr/fr/statistiques/2016358?geo=FE-1&sommaire=2133806#consulter-sommaire.} , one can estimate about 0,2% of children aged 6–11 were effectively given methylphenidate that year. If 9555 of children aged 6–11 were treated by methylphenidate in 2008 according to the French National healthcare insurance system, and if 36.5% of ADHD children are treated with methylphenidate in France, then a correct estimate of the number of children who had been diagnosed with ADHD in 2008 would be 9555+9.555×0.635=15,622 children. This would mean around 0.3% of this population was diagnosed with ADHD in France in 2008.

The real methylphenidate consumption rate among 6–11 children in France is at best 17 times lower than the estimation initially provided by the Lecendreux et al. prevalence study (0.2% the 6–11 children versus 3.48% of the 6–12 aged children). The discrepancy we highlight in this paper questions conflicts of interest and methodological biases at work in telephone inquiries or in any indirect methodology willing to establish ADHD prevalence rates.

The results we present in this communication support more in-depth investigations of the SNIIRAM database when it comes to determining precise ADHD diagnosis and methylphenidate prescription rates in France. Accessing national, official databases would give researchers relevant information concerning potential variations in diagnosis and prescription rates over time, according to regions and hospitals, the age of the child at the time of diagnosis or treatment initiation, multiple co-morbidities and prescriptions outside of recommendations, associated therapeutic practices (psychotherapy), etc. Such complementary studies could also shed light on the factors contributing to the low rate of prescription drugs in the treatment of ADHD in France.