Drug utilisation studies, essentially based on Northern American data, have consistently demon-strated that the prevalence and duration of use of anti-psychotics (APs) are increasing over time in the paediatric population. The aim of this study was to describe prev-alence and incidence of AP use in children and adoles-cents from five European countries.Methods
This was a dynamic retrospective cohort study. Data were extracted from five population-based elec-tronic healthcare databases in Europe: the THIN database in the UK; the PHARMO in the NL; the Aarhus University Hospital Database in Denmark; the GePaRD database in Germany and the Emilia Romagna Regional database in Northern Italy. Study population comprised all children and adolescents registered with the databases during the study period. All drugs under the ‘N05A’ pharmacologi-cal subgroup of the ATC classification system (except for lithium) were included. Prevalence and incidence of AP expressed per 1000 PYs. A Poisson regression model was applied to determine the influence of increasing calendar year on annual AP use.Results
During study period, in Denmark (2001–2008), prevalence increased from 1.44 to 3.41/1000 PYs and in the NL (2000–2009) from 2.69 to 6.22/1000 PYs. Incidence rates also increased from 0.69 to 1.52/1000 PYs in Den-mark and from 1.12 to 2.13/1000 PYs in the NL. In the UK (2000–2009), prevalence slightly increased from 2.8 to 3.24/1000 PYs and in Germany (2005–2008) from 1.53 to 1.74/1000 PYs. Similarly, incidence rates varied from 1.53 to 1.74/1000 PYs in the UK and from 0.79 to 0.8/1000 PYs in Germany. In Italy (2006–2010) both prevalence and in-cidence respectively decreased from 0.61 to 0.34/1000 PYs and from 0.32 to 0.2/1000 PYs. Overall, use of APs increased parallel to age, with a maximal use observed between 15 and 18 years, and a more prevalent and lon-ger use in boys than girls at all ages. However, maximal prevalence and incidence of use was observed in boys between 10 and 14 years of age in NL and in girls be-tween 15 and 18 years in the UK, while mean duration of prescription was longer in girls than boys at all ages in IT. Also, although use was altogether more frequent among adolescents, the use observed in younger age groups (5–9 years) was found to be comparatively high in some countries such as the NL. Risperidone was the most fre-quently prescribed antipsychotic in all countries with the exception of IT where chlorpromazine is generally pre-scribed at all ages. Prescriptions of second generation APs were privileged however, in some countries clinicians still favoured first generation APs especially in the youngest.Conclusion
A steady increase in AP use in children and adolescents was observed in some European countries over the calendar years although use remained un-changed in others. The high use of AP in children of less than 9 years of age clearly underlines their off-label use and should be carefully monitored as the risk/benefit ra-tio of these medications remains unclear in the youngest. Altogether, AP use was found to be lower in Europe than in North America.