Psychometric study of Therapeutic Alliance Scale for Children (TASC) and investigation of Therapeutic Alliance Relationship in Mentalization-based Therapy for Children

Therapeutic alliance is consistently found to be one of the main predictors of outcome however the literature on how alliance works in child psychotherapy is scarce. In order to contribute to this area, this study aims to adapt the Therapeutic Alliance Scale for Children (TASC), explore the psychometric properties of both the child and therapist versions and use these adapted versions in investigating the therapeutic alliance rela-tionship in a mentalization-based intervention for children. For the psychometric study, 218 children and 78 therapists participated and were asked to fill out TASC forms as well as scales measuring empathic skills. The factor analysis revealed a two-factor structure ('Positive Therapeutic Alliance' and 'Negative Therapeutic Alliance') for both therapist and child forms. The internal consistency scores were acceptable for both forms. Convergent validity analyses showed that therapeutic alliance factors were significantly correlated with empathy scores for both sample groups. Divergent validi-ty showed that TASC factors significantly differentiated therapy phases (beginning, middle, termination). Findings indicate that TASC child and therapist forms are ac-ceptably valid and reliable tools in order to measure therapeutic alliance in child psy-chotherapy settings. However, the psychometric properties of the scale need to be re-peated with different samples. For the second part of the study, the adapted TASC forms were used with children and therapist who were part of a randomized controlled study to investigate the effectiveness of Mentalization-based Therapy for Children (MBT-C). Hypotheses included (1) attachment security and reflective functioning to predict the strength of early alliance ratings, (2) the trajectory of alliance ratings to show a quadratic (high-low-high) shape, (3) and the strength and change in alliance will predict children's therapy outcome. 58 children who received the MBT-C inter-vention participated in the second part of the study: alliance ratings were gathered three times during MBT-C process. Results showed that hypotheses were only partially given evidence for. Reflective functioning acted as a mediator between attachment se-curity and early alliance strength (alliance rating at the end of 3rd session). The trajec-tory of alliance within this intervention showed a linear increase rather than a quadratic change. And lastly the change in emotional regulation (as the outcome variable) was significantly predicted by the therapist and children's ratings of alliance (both with the strength and the change in alliance were predictors). The change in internalizing symp-toms was only significantly predicted by therapist ratings of alliance (with both the strength and the change). Externalizing problems and total problems were not predicted by alliance. Results are in line with the literature as to attachment and reflective func-tioning being positively related to therapeutic alliance. This phenomenon was not stud-ied frequently in child psychotherapies therefore this study will contribute to the cur-rent literature. Moreover, different therapy techniques may show different alliance pat-terns: especially short-term and task-focused therapies tend to show a linear increase. Informant discrepancies are also discussed. Limitations include small subject size; par-ent alliance ratings and observation-based alliance ratings not being included in the study. Keywords: Therapeutic Alliance, Mentalization Based Therapy, Alliance Trajectory, Child Psychotherapy, Alliance-Outcome Relationship, Alliance Measurement Scale