[Increasing trend in prescription of methylphenidate in general practices in the north-east of The Netherlands, 1998-2003].

OBJECTIVE

To obtain information on the frequency of and the indications for prescription of methylphenidate in general practices in the north-east of The Netherlands.

DESIGN

Descriptive.

METHOD

Data were collected from 1998 to 2003 from 6 general practices in the north-east of The Netherlands (17 general practitioners, approximately 30,000 patients) that were affiliated to the Registration Network in Groningen. The number of new and existing patients who were prescribed methylphenidate was calculated by age group per 1000 person-years per calendar year. The indication on which the drug was prescribed was looked at, as was the number of patients who were referred to a specialist on that indication.

RESULTS

The number of new users per 1000 person-years more than doubled from 17 in 1999 to 42 in 2003. In all years studied the highest number of new users fell into the age group 5-9 years. The total number of users per 1000 person-years tripled (boys: 1.8 in 1998 and 6.2 in 2003; girls: 0.5 in 1998 and 0.8 in 2003). The prevalence of use in boys was 3 to 8 times as high as that of girls and increasing more quickly. In people under 59 years of age attention deficit hyperactivity disorder (ADHD) was the most frequent indication (55%). In the group aged > or = 60 years methylphenidate was mainly prescribed in the palliative phase of somatic morbidity. Over half of the 140 new patients (57%) were referred nor to a specialist in the year before neither in the year after the first prescription of methylphenidate.