Previous research suggests that common relationship factors are composed of two overarching factors, "Confidence in the therapist" and "Confidence in the treatment." The aim of this naturalistic process-outcome study was to investigate the reciprocal relationships between these two constructs and patients' symptom level across treatment. The sample consisted of 587 patients who were admitted to an inpatient program and treated with psychotherapy for a range of mental health disorders, such as chronic depression, anxiety disorders, and eating disorders. Our data consisted of weekly measures of symptomatic distress (Patient Health Questionnaire) and the common relationship factors were measured weekly using a newly developed scale. Latent curve modeling with structured residuals was used to investigate the between- and within effects of week-to-week changes in the two components as predictors of subsequent symptom level. An increase in both relationship factors predicted a decrease in subsequent levels of symptoms at the within-patient level, and the other way around, but the two relationship factors did not systematically relate to one another at the within-patient level over the course of treatment. Our findings indicate that patients' perceptions of the therapist as a person and their appraisal of the treatment, are important, different predictors of therapeutic change. Furthermore, they support prior research demonstrating a reciprocal relationship between common relationship factors and symptomatic distress and add to existing common factor theory by exploring the role of two central relationship dimensions and using a method which examines reciprocal relationships and within-patient effects simultaneously. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
Trial registration: ClinicalTrials.gov NCT03503981.