Plasticity, defined as the capacity to modify brain functioning and mental states, is increasingly recognized as a fundamental construct in psychology and psychiatry because it enables the reorganization of neural and mental processes underlying transitions from psychopathology to wellbeing. Despite its central role, a standardized approach to quantify plasticity has been lacking. Recently, the network theory of plasticity has been introduced, proposing connectivity strength among system elements as an operational measure of plasticity and thus of the system capacity for change. Within this framework, the weaker the connectivity, the higher the plasticity of the system. When conceptualizing an individual as a network of interconnected symptoms, the individual’s plasticity -- and thus their ability to transition from psychopathology to wellbeing -- is predicted to be inversely related to the connectivity strength among symptoms. Empirical evidence supports the reliability of this approach, revealing a strong and inverse correlation between baseline connectivity strength among symptoms and subsequent improvement over four weeks. Furthermore, the operationalization of plasticity significantly differentiated individuals based on their recovery timelines according to the principle that higher plasticity (i.e., weaker connectivity) predicts faster transitions to wellbeing and vice versa. Overall, this framework provides a novel quantitative and generalizable approach to measuring plasticity, which holds the potential to capture a system capacity to change across levels of analysis and research domains.