This article offers insights into the subjectivities that emerge as patients negotiate treatment modalities in Norwegian opioid substitution treatment (OST). In the accounts, I explore patients’ growing engagements with legal imaginaries, and highlight the transformative powers of the law, to develop a concept of the legal self. The analysis shows the power of the law in an imagination of harm and the ways in which the law impacts social and personal change. In the ethnographic insights into the legal structures as a landscape of possibilities for disadvantaged groups, I illustrate the interstices between legal consciousness and mobilisation. This allows for and adds a new dimension to the concept of patienthood beyond the strictly medical experience in which legal narratives provide frames by which people construct meanings for their lived experiences. I consider an examination of both the effectiveness and the effects of the law as crucial for studies of citizenship.