Ambiguous indifference -fatal overdoses among marginalized drug users after discharge from inpatient treatment BACKGROUND -In the European context, Norway is one of the countries with the highest overdose-related mortality rate. Research proves that the risk of overdose mortality among marginalized drug users is particularly high during the first weeks after discharge from inpatient treatment. AIM -It is therefore interesting to investigate whether there might be a connection between marginalization and treatment culture to understand fatale overdoses after discharge from inpatient treatment. DESIGN & METHODS -The case study is based on a previous field study connected to the death register. The study focuses on a single individual, Sam, and his treatment process. Data is analyzed in the light of a cultural analytical perspective. RESULTS -The results shows how the treatment system can be a social arena for institutional exclusion and marginalization that aggravate the person's self-esteem and life situation. One central aspect of the process of treatment was that it generated indifference. Sam's treatment motivation developed into treatment indifference. In the last part of the article, the author discusses indifference as a risk aspect of overdose mortality after discharged from treatment. It is not possible to conclude if Sam's overdose death was an accident or suicide. However, in the light of action theory the case shows that indifference can be a central aspect of both an unintentional and intentional overdose. Sam's death can be understood in the light of the concept ambiguous indifference. CONCLUSION -The case shows that there may be a relationship between marginality, treatment culture and overdose mortality. Cultural and structural aspects of the treatment system put Sam in an empty and risky situation that probably contributed to his death. In a comparison of risk situations in this case-history with recent research on treatment system, we can see several worrisome resemblances considering overdose mortality after discharge from inpatient treatment.