Psychological flexibility is a key aspect of psychological health, encompassing the ability to adapt to situational demands, shift mindset or behavior, maintain balance in life domains, and act in alignment with personal values. Traditional views of psychological health focus on positive emotions, strengths, and basic psychological needs, but these fail to capture the dynamic, fluctuating nature of human behavior. Psychological flexibility, however, is a broader concept that involves dynamic processes such as adapting to changing situations, reconfiguring mental resources, shifting perspectives, and balancing competing desires. It is essential for psychological health and is often absent in psychopathology, where rigidities like rumination, worry, and poor coping strategies are common. Research across various fields, including emotion regulation, mindfulness, social psychology, and neuropsychology, supports the importance of psychological flexibility. Evidence shows that flexibility is linked to better adjustment, resilience, and well-being, while inflexibility is associated with psychopathology. For example, in depression, inflexibility manifests as rumination, unresponsive behavior, and physiological dysregulation. In anxiety disorders, inflexibility is seen in avoidance behaviors and reduced autonomic flexibility. Studies on cardiac vagal control (CVC) suggest that flexibility is tied to physiological and cognitive processes that support self-regulation and adaptive responses. CVC, a measure of parasympathetic nervous system function, is associated with better executive functioning, emotional regulation, and resilience. Research indicates that higher CVC is linked to better performance on cognitive tasks and improved coping in social situations. The causal relationship between inflexibility and psychopathology remains unclear, but studies suggest that inflexibility may be both a cause and a consequence of mental illness. Future research should explore the role of inflexibility in health and psychopathology, using longitudinal and experimental designs to clarify its status as a risk factor. Key factors influencing psychological flexibility include executive functioning, default mental states, and personality configurations. Executive functioning, particularly attentional control and working memory, is crucial for adapting to changing situations. Default mental states, such as openness and acceptance of emotions, also play a role in flexibility. Personality configurations that promote flexibility, such as openness and curiosity, are associated with better psychological health. In summary, psychological flexibility is a dynamic, multifaceted construct that contributes to psychological health and well-being. It involves the ability to adapt, regulate emotions, and act in alignment with personal values. Research highlights the importance of flexibility in preventing and treating psychopathology, and future studies should focus on clarifying its role in health and illness.Psychological flexibility is a key aspect of psychological health, encompassing the ability to adapt to situational demands, shift mindset or behavior, maintain balance in life domains, and act in alignment with personal values. Traditional views of psychological health focus on positive emotions, strengths, and basic psychological needs, but these fail to capture the dynamic, fluctuating nature of human behavior. Psychological flexibility, however, is a broader concept that involves dynamic processes such as adapting to changing situations, reconfiguring mental resources, shifting perspectives, and balancing competing desires. It is essential for psychological health and is often absent in psychopathology, where rigidities like rumination, worry, and poor coping strategies are common. Research across various fields, including emotion regulation, mindfulness, social psychology, and neuropsychology, supports the importance of psychological flexibility. Evidence shows that flexibility is linked to better adjustment, resilience, and well-being, while inflexibility is associated with psychopathology. For example, in depression, inflexibility manifests as rumination, unresponsive behavior, and physiological dysregulation. In anxiety disorders, inflexibility is seen in avoidance behaviors and reduced autonomic flexibility. Studies on cardiac vagal control (CVC) suggest that flexibility is tied to physiological and cognitive processes that support self-regulation and adaptive responses. CVC, a measure of parasympathetic nervous system function, is associated with better executive functioning, emotional regulation, and resilience. Research indicates that higher CVC is linked to better performance on cognitive tasks and improved coping in social situations. The causal relationship between inflexibility and psychopathology remains unclear, but studies suggest that inflexibility may be both a cause and a consequence of mental illness. Future research should explore the role of inflexibility in health and psychopathology, using longitudinal and experimental designs to clarify its status as a risk factor. Key factors influencing psychological flexibility include executive functioning, default mental states, and personality configurations. Executive functioning, particularly attentional control and working memory, is crucial for adapting to changing situations. Default mental states, such as openness and acceptance of emotions, also play a role in flexibility. Personality configurations that promote flexibility, such as openness and curiosity, are associated with better psychological health. In summary, psychological flexibility is a dynamic, multifaceted construct that contributes to psychological health and well-being. It involves the ability to adapt, regulate emotions, and act in alignment with personal values. Research highlights the importance of flexibility in preventing and treating psychopathology, and future studies should focus on clarifying its role in health and illness.