A systematic review and integrative framework of psychotherapy microprocess: Linking the science of psychological interventions with the art of moment-to-moment practice

Despite advancements in psychotherapy research on effectiveness and critical therapy processes, there remains a significant gap between the science and the art of psychotherapy, specifically on how to understand what to do moment-to-moment with each patient. A burgeoning research literature addresses this question by examining psychotherapy microprocesses, which typically referred to within-session changes of therapy processes, aiming to bridge psychotherapy research with clinical practice. In this pre-registered systematic review, we reviewed 86 empirical quantitative studies examining observational psychotherapy microprocesses over 35 years. We extracted 28 microprocess constructs across six categories (affective/emotional, behavioral, cognitive, relational/interpersonal, linguistic, and movement), four key methodological features of operationalizing microprocesses, and three types of research questions that focused on within-session change patterns, dyadic and intra-personal momentary associations, and associations with outcomes/macroprocesses/predictors. The literature demonstrated unique advantages in embracing theoretical plurality, real-world settings, and dyadic influences, while being limited by theoretical and methodological challenges such as the scatteredness in construct operationalizations, limited inclusion of diverse samples/therapy modalities and culture-related constructs, disconnections from theoretically driven hypotheses, and a lack of standard in reporting methodological features. To address these challenges, we propose the Multilevel Integrative Microprocess Model (MIMM), an integrative framework that situates microprocesses within the broader context of psychotherapy research traditionally centered on macro-level processes and outcomes. We conclude by suggesting a future research agenda that provides a checklist for future microprocess studies to enhance theoretical coherence and methodological rigor.