Emotional and behavioural problems are common in young people and mental health problems are frequently intertwined with social problems. Both involuntary psychiatric treatment and taking into care may be used in order to manage youth behavioural problems. Compulsory interventions always endanger violating basic civil rights and therefore careful monitoring of them is warranted. The aim of this study was to evaluate trends in Finland in involuntary psychiatric inpatient treatment and taking into care 12- to 17-year-old adolescents from the mid-1990s to the early 2000s. A nationally representative retrospective register study of the period 1996–2003 using the hospital discharge register and child welfare register in Finland. Both types of compulsory interventions increased vastly during the study period. The numbers of involuntary psychiatric treatment periods and child welfare placements of adolescents varied considerably in relation to each other, and across different regions of the country. As there is no evidence of a vast increase in mental disorders or serious behavioural problems in young people, there is an obvious need for further research on reasons of the significant increase in the use of coercion and for the wide regional variation. Possible explanations discussed are different service structures and treatment cultures.