Background There have been no comprehensive studies on trends in psychotropic medication use in child and adolescent inpatient settings. The aim of this nationwide study was to report changes in the psychotropic medication given to child and adolescent psychiatric inpatients across Finland and the factors associated with those changes. Methods We asked the psychiatrist responsible for each inpatient to complete a questionnaire that included questions about the pharmacological treatment and background information. The data were collected on all inpatients on one selected study day in 2000 and 2011. Changes in the use of regular psychotropic medication were studied by comparing the data on 504 patients in 2000 and 412 patients in 2011. Results The study showed that there had been a significant increase in the use of psychotropic medication from 2000 to 2011. According to the multivariate analysis, the increase in psychotropic medication was associated with the study year (in 2000 39%, in 2011 58%), but could not be explained by changes in diagnostic profiles, age distribution, suicidality, violence or the Children′s Global Assessment Scale scores. The use of combined psychotropic medication increased from 9% in 2000 to 25% in 2011. The increase in the use of antipsychotics among child inpatients was particularly noteworthy, with an increase from 10% to 32%. Conclusions There is a need for evidence‐based studies to clarify recommendations for indications and treatment practices when using psychotropic medication in children and adolescents. Cross‐cultural studies of the use of psychotropic medication are warranted.