[Increasing methylphenidate abuse: Tracking and profiles during 13-years]

Methylphenidate is indicated for attention deficit hyperactivity disorder (ADHD). Several studies have evaluated its abuse in specific populations (students, drug users) and few in the general population. This work describes the extent of its abuse in a region of more than 5 million inhabitants.

Based on regional health insurance data from 2005 to 2017, the clustering method identifies different methylphenidate use profiles according to several characteristics (number of different prescribers and pharmacies, number of dispensations, number of defined daily dose dispensed). The groups characterised by high values of these variables will be qualified as "deviant".

In 13 years, the number of patients with at least one dispensation in the first quarter has been multiplied by 5.8 times. The proportion of adults has increased (20% in 2017) and their number has been multiplied by 10. Five groups are identified, three of them are characterised by "deviant" behaviour. Group 5 (n=11, 0.04%) has higher values than 4 (n=112, 0.4%) and 3 (n=407, 1.6%). These patients are older and more frequently use benzodiazepines and opiate substitution drugs. Groups 1 (n=13,132, 51%) and 2 (n=11,941, 46.7%) are more likely to be taken up by young subjects. The number of subjects with "deviant" behaviour increased until 2011 and after a decrease, the highest number of subjects concerned has been observed since 2015.

In view of the increase of subjects with "deviant" behaviour, it is necessary to make the medical community and patients aware on the risk of abuse of methylphenidate. The recent extension of the indication for ADHD in adults and the broadening of the conditions of prescription require increased vigilance.