Common Factors i psykoterapi: Psykometrisk analys av ny mätskala

Sammanfattning: Understanding what constitutes a positive outcome in psychotherapeutic treatment remains a challenge, whether attributed to Common Factors (CF) shared across therapies or specific therapeutic methods. The definition of CF varies and can be traced to all aspects of therapy, including patient and therapist factors and the process of change. This study, as part of the POSE-project, examined the psychometric properties of a newly developed rating scale, aimed to measure CF linked to therapist behavior, and consisted of 10 items including empathy, encouragement, and promotion of agency. Data was collected by assessing 40 therapy sessions, 20 PFPP (PDT) and 20 PCT (CBT), individually by two evaluators, from the project's database. The specific factors were assessed using CPPS subscales for both groups. To investigate the scale's predictive validity, the study examined whether scores on the scale could predict outcomes measured in symptom severity (PDSS) at the end of treatment and at a 12-month follow-up. The scale achieved excellent inter-rater reliability ICC(2,1) .90. The scale was found to be related to the therapeutic alliance (measured with WAI) through a moderate correlation, r(38)=.58. Pearson’s correlation indicated a weak correlation between the CF-scale and method-specific elements. Multiple regression analyses showed that scores on the CF scale, along with symptom severity at the start of treatment, explained 28% of the variance in outcomes at the end of treatment. The scale was deemed to have good reliability and predictive validity, with some caution regarding the generalizability of results to other evaluators, therapists, and patient groups.