The publication of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, (DSM-5) extends a profession and practice-defining direction for family therapy. Warranting and expediting this medicalised direction has been a scientific and administrative coupling of diagnosed symptomatic conditions with evidence-based treatments for addressing those conditions. For systemically or poststructurally oriented family therapists tensions can follow from this direction which we elaborate upon in this article. Specifically, we examine the premises behind this medicalised direction for family therapy, juxtaposing these premises with systemic and post-structural premises of practice. We relate these juxtapositions to tensions family therapists may need to reconcile in their work with families. We close with an overview of this special issue's contributions that pertain to the DSM-5 and family therapy.1 The continuing symptomological and individualistic focus of DSM-5 creates tensions for family therapists who practice from systemic and post-structuralist orientations. 2 A discursive approach enables us to understand how DSM-5 discourse both enables and constrains our understanding of human concerns. 3 DSM-5 does not address relational aspects of practice and creates "linguistic poverty" in limiting understandings of family concerns. 4 Evidence-based practice tied to a medicalised diagnostic classification framework is a seductively algorithmic practice, which reproduces normative, standardised conversations in mapping client concerns to DSM-5based diagnoses. 5 DSM-5-based algorithms of evidence-based practice ignore the importance of context and the ever-changing conversations of human concerns and multiple practices are required to reflect, articulate and work with family concerns effectively.So what is it about the biopolitics of life itself…that provides the spaces within which bioethical authority seems to be required and simultaneously circumscribes the issues to which such ethical concerns appear relevant? (Rose, 2007, p. 31) Welcomed or not, the American Psychiatric Association's (2013) Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) will influence the conversations therapists have with families. In writing about diagnostic language as it relates to relationships, Tom Andersen (1996) long ago wrote that "language is not innocent". The diagnoses of DSM-5 cannot be regarded as neutral scientific discoveries, nor can the expected diagnostic practices accompanying the DSM-5's use be