Investigating the Mutual Changing of Patient’s and Therapist’s Self-States: An Integrative Clinical Research Study of a Single Case

The current study presents an integrative mixed-method examination of a single case using the TPA, or the Two-Person Assimilation of Problematic Experiences Scale (APES). Stemming from the Assimilation Model (Stiles, 2011; Stiles et al., 1991), the TPA integrates relational-psychodynamic thought with an empirical analysis to create a clinical tool that simultaneously tracks and codes change-processes in psychotherapy. The TPA expands the APES by following changes in the quality of movement between self-states, in a continuum ranging from dissociation to dialectic, within both the patient and the therapist. Thus, it allows for an observation of complex intrapsychic and intersubjective processes occurring in therapy, and a simultaneous relating of these processes to symptomatic outcome variables and process variables. The current theory-building case study investigated 26 therapy sessions of a 30-year-old woman who received an evidence-informed psychodynamic-oriented treatment for depression. Sessions were coded quantitatively and then qualitatively analyzed by clinical judges, using the TPA tracking and rating procedure. An improvement in the quality of movement between self-states, as the therapeutic process progressed, was found. In addition, mutual changing (i.e., temporal congruence) between patient’s and therapist’s quality of movement between self-states increased during the last third of the treatment.