Kerstin Stenius´ research has focused on substance use treatment systems as cure, care and control, with comparative (especially Nordic) and historical social policy perspectives. Her research has included a big follow-up study of clients and patients in Stockholm County, followed by a comparative study of this Swedish treatment system and the system in Costa County, US and the co-edition of a book on the history of Nordic substance abuse treatment. One line of Stenius’ research has been new divisions of labour (privatization, medicalization, and de-politization) and steering mechanisms (i.a. NPM) within the treatment systems. Her dissertation (1999) analyzed the relations between private, public and third sectors during the 20th century, with a specific focus on the impact of market models in the 1990s.

In the international collaborative study on AA as a social movement, Stenius studied the relation between AA and the professional treatment systems. Stenius´ later projects have dealt with the meanings and implications of choice for citizens with substance use related problems, the impact of integration between mental health care and substance abuse treatment on the definitions of problems and on treatment supply, and presently public procurement and competitive tendering as steering instruments for treatment systems, again with Nordic comparisons.  

A second special focus in Stenius´ research has been on the role of Nordic local governments in substance abuse treatment. In an historical comparison between local control and care of persons with heavy use of alcohol or drugs in Finland and Sweden, the development of citizenship rights from the 1930s until 2000 was analyzed. The role of compulsory treatment was a central question in this project. The importance of local level innovations was the starting point for a recent Nordic development project. A third research interest has been conceptual history analyses within the alcohol and drug field.

Stenius has edited the journal Nordic Studies on Alcohol and Drugs since the early 1980s. She has been president of the International Society for Addiction Journal Editors (ISAJE) in two periods and is co-editor of the ISAJE book ”Publishing Addiction Science. A guide for the perplexed” (third edition to be out in early 2017). She has been the president of the Kettil Bruun Society for Social and Epidemiological Research on Alcohol, and is a board member of the International Confederation of ATOD Research Associations (ICARA).