In other words, the planning of primary care team roles needs to be driven by the diversity of clinical subpopulations in terms of the full spectrum of mental health or substance use severity. [...] The purpose of this discussion paper is to provide an overview of research evidence and organizational models relating to the improvement of health outcomes through enhanced primary care team responses to mental health and substance use issues. [...] According to the Institute of Medicine (1994): “Primary care is the provision of integrated, accessible health care services by clinicians who are accountable for addressing a large majority of personal health care needs, developing a sustained partnership with patients, and practicing in the context of family and community.” The Saskatchewan Ministry of Health (2011) observes that primary health [...] At its best, primary health care provides a medical home for patients, is the link to other parts of the health system, and serves the patient by helping them to navigate the complexities and services of the health system.” Building on the above understanding, primary care teams can be defined as groups of health and allied professionals who have a formal arrangement to collaborate in the provisio [...] Page | 16 To underscore, all levels of severity and corresponding primary team roles require effective use of mental health and substance use practitioners who are members of the primary care team as well as requiring effective use of external mental health and substance use specialists.