<p>Symptom reduction remains a central endpoint in psychotherapy, yet it provides an incomplete account of therapeutic benefit, particularly with respect to durability, generalization, and relapse vulnerability. This paper advances a process-based theoretical framework specifying how therapeutic change becomes retained and functionally expressed beyond symptom relief through the development of psychological capacities. Psychological capacities are defined as relatively enduring and context-sensitive patterns of adaptive responding that emerge through repeated cycles of therapeutic learning and remain accessible across changing contexts (e.g., attentional regulation, psychological flexibility, values-based action). The framework distinguishes proximal mechanisms of change from longer-term capacity development, proposing that therapeutic processes contribute to durable recovery insofar as they strengthen capacities that support adaptive functioning under real-world conditions. By positioning psychological capacities as the retained level linking mechanisms of change to long-term adaptation, the model reframes outcome evaluation toward the stability and contextual expression of adaptive functioning rather than symptom change alone. The framework further generates testable predictions regarding long-term outcomes, assessment, intervention design, and relapse prevention.</p>