Cross-national differences in methylphenidate utilization in primarily adult psychiatric inpatients

Methylphenidate (MPH) is a stimulant primarily used to treat attention-deficit/hyperactivity disorder (ADHD). This study examined cross-national differences in MPH utilisation among primarily adult psychiatric inpatients in Germany, Austria, and Switzerland. Data were collected between 2007 and 2017 from psychiatric hospitals in Germany, Austria, and Switzerland participating in the AMSP pharmacovigilance program. Among 102,740 inpatients, 560 (0.55%) received MPH. The sample was young with a mean age of 33.9 years. The proportion of inpatients treated with MPH was highest in Switzerland (2%) and markedly lower in Germany and Austria (both 0.3%). Among MPH-treated patients, depressive disorders, neurotic and personality disorders and substance-related disorders were most prevalent. Overall, only 287 patients (51.3%) had an ADHD diagnosis. Men represented 58.6% of the MPH group and received higher daily doses than women. 87.1% of MPH-treated patients received at least one additional psychotropic drug. Adult MPH use in adult psychiatric inpatient care was rare, showed marked cross-national variation and was typically embedded in complex psychopharmacological regimens. The finding that only about half of MPH-treated inpatients had a documented ADHD diagnosis underscores the need for more detailed studies on indications, clinical decision-making and outcomes of MPH treatment in routine psychiatric practice.