Collaborative and Shared Leadership Dynamics in Healthcare Action Teams: A Systematic Literature Review.

Background: Healthcare Action Teams (HATs) operate under high-pressure, time-sensitive conditions where effective collaboration is critical for patient outcomes. While collaborative leadership is increasingly recognized as beneficial in such contexts, the literature remains fragmented, with inconsistent terminology and limited integration of findings. Aim: This study systematically reviews how collaborative leadership is conceptualized, operationalized, and evaluated in HATs. It identifies different forms of collaborative leadership, the mechanisms that support or constrain its effectiveness, the organizational factors that influence its implementation, and the outcomes for team performance and patient care. Methods: A systematic literature review is conducted based on PRISMA guidelines and using a comprehensive and expanded search query in Web of Science and EBSCOhost. More than 250 studies were identified in the initial screening, and 56 peer-reviewed articles, published through September 2025, that addressed collaborative leadership in HATs were ultimately selected and included in further analyses. Analysis was guided by four research questions and integrated based on functional leadership theory and models of social differentiation in teams. Results: Two main forms of leadership were identified: vertical differentiation (authority shifts across hierarchical roles) and horizontal differentiation (distributed leadership among peers). Collaborative leadership enhances team adaptability, shared mental models, psychological safety, and communication. However, its effectiveness depends on factors such as organizational hierarchy, professional identity salience, task complexity, and team member interpersonal familiarity. A functional definition of collaborative leadership was proposed, emphasizing four leadership functions: activating resources, framing the task environment, mobilizing support, and synthesizing collaboration. Conclusion: Collaborative leadership in HATs is a dynamic, context-sensitive process that enables adaptive coordination in complex clinical settings. When supported by appropriate organizational structures and team-level conditions, it enhances communication, trust, and patient safety. However, under rigid hierarchies or unclear role structures, its effectiveness may be reduced. This study offers a functional lens for understanding collaborative leadership in HATs and provides future research directions.