This study analyzes how staff in Swedish alcohol and other drug (AoD) treatment interpellate service users as people who can benefit from relapse prevention. Relapse prevention is a widely used intervention. Research is scarce, however, on how relapse prevention is practiced locally and how treatment staff perceive the relationship between AoD use as a problem and relapse prevention as a solution. Drawing on Actor-Network Theory and critical studies of AoD issues within this tradition, we elucidate how staff through specific interpellative logics enact service users, their individual characteristics, and living conditions. The data derive from interviews with 18 professionals working with assessment, counseling, case-management, therapy, and healthcare at AoD treatment agencies in the Stockholm region. The results show that the participants drew on four interpellative logics, and thereby enacted service users as four different object types. Region and network logics pinpointed that individuals have stable observable characteristics that determine their problems and eligibility for treatment (e.g., living conditions, diagnoses). Fluid and fire logics emphasized that their characteristics also vary depending on context and can be present and absent at the same time (e.g., harms, agency). This flexible interpellation of service users echoes the tendency among treatment staff to embrace sometimes irreconcilable understandings of AoD problems and to enact multiple realities of addiction. This suits a professional field where many factors are thought to cause and help resolve problems, but where the treatment supply is often limited to specific interventions. We conclude that it is easier to create a reasonable match between the service delivered and the potential service user if the characteristics of the latter are considered diverse and flickering. This exemplifies Carol Bacchi’s tenet that problem representations are adjusted to fit the solution at hand.