In this chapter, we describe a program of research to develop and test criteria that could be used reliably and validly in the field-including by those practitioners without a mental health backgroundfor diagnosing relational problems. We also describe the inclusion of these criteria, in modified form, in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5; American Psychiatric Association, 2013) and in proposals for the 11th edition of the International Classification of Diseases (ICD-11; World Health Organization, 2016).
MENTAL DISORDERS, RELATIONAL PROBLEMS, AND THE DSMFor decades, the DSM's editors have displayed ambivalence about relational problems. Consider how DSM-5 (American Psychiatric Association, 2013) defines what constitutes a mental disorder:A mental disorder is a syndrome characterized by clinically significant disturbance in an individual' s cognition, emotion regulation, or behavior that reflects a dysfunction in the psychological, biological, or developmental processes underlying mental functioning. Mental disorders are usually associated with significant distress in social, occupational, or other important activities. (p. xiv) Now consider how the DSM-5 introduces relational problems: Key relationships, especially intimate adult partner relationships and parent/ caregiver child relationships, have a significant impact on the health of the individuals in these relationships. These relationships can be health promoting and protective; neutral; or detrimental to health outcomes. In the extreme, these close relationships can be associated with maltreatment or neglect, which has significant medical and psychological consequences for the affected individual. (p. 715) On the one hand, relational problems appear to fit the definition of a mental disorder. On the other hand, the DSM-5 implicitly adopts an ecological perspective on functioning (e.g., Bronfenbrenner, 1979). Mental disorders, according to DSM-5 delineation, can exist only within an individual; disorders in the microsystem (i.e., relational problems) may cause or exacerbate individuals' mental disorders and individuals' mental disorders may cause or exacerbate relational problems, but mental disorders and relational problems operate at different ecological levels-they are separable but intertwined. Some (e.g., Kinghorn, 2013) have argued that this is less a philosophical stance than a