This paper describes how two complementary theories from complexity science can guide the successful design and implementation of integrated systems of health and social care for older adults who need multiple forms of care. Specifically, it describes two related theories: "complex adaptive systems" (CAS) theory and "relational network theory" (RNT), which provide overlapping frameworks for understanding the structure and dynamic function of care systems and their components. The paper begins by showing how these theories can guide the integration of the structures, people, and processes that provide care to older adults with multiple care needs. Then, to illustrate their application, it describes the early years of the All-Inclusive Care for Older Adults ("ALICE") program, which has co-created and co-managed an evolving health and social care system for an aging population in New South Wales, Australia. As other populations of older adults around the world expand, such effective integration of multi-faceted care will be necessary to optimize their well-being and quality of life. Future applications of CAS and RNT to the design and implementation of integrated health and social care promises to improve the quality and the effectiveness of the care of other older populations that need multiple forms of care.
Reiss-Brennan et al. (2026) studied this question.