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Group schema therapy for borderline personality disorder: The effects of therapy specific factors versus non-specific factors on outcome

Bastick, Emily (2017) Group schema therapy for borderline personality disorder: The effects of therapy specific factors versus non-specific factors on outcome. Professional Doctorate thesis, Murdoch University.

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The conclusions from initial research on group schema therapy (GST) are that it is a promising treatment for borderline personality disorder (BPD). The overarching aim of this research was to identify whether the unique aspects (or specific factors) of GST effect positive change for patients with BPD. It was hypothesised that both treatment fidelity and group cohesion are important factors in influencing and predicting outcomes in GST for BPD.

With the aim in mind, Study One sought refine and evaluate a fidelity measure for GST, the Group Schema Therapy Rating Scale - Revised (GSTRS-R). Following a pilot study on an initial version of the scale, items were revised and guidelines were modified in order to improve the reliability of the scale. Participants included four therapists and 16 patients across two Australian GST groups. Students highly experienced with the scale rated 10 video recorded GST therapy sessions using the GSTRS-R in addition to a group cohesion measure, the Harvard Community Health Plan Group Cohesiveness Scale – II (GCS-II). The resulting GSTRS-R was found to have excellent internal consistency, substantial inter-rater reliability, and adequate discriminate validity, evidenced by a weak positive correlation with the GCS-II.

Study Two utilised the GSTRS-R to examine the relative contributions of specific treatment factors related to schema therapy and non-specific factors (group cohesion) on the treatment outcome of GST for BPD. Participants included 30 therapists and 122 patients across 15 GST groups within three countries. Specific treatment factors were assessed using GSTRS-R and group cohesion via the GCSII. There was a significant, moderate positive correlation between treatment fidelity (therapist competence) and group cohesion within the GST groups. Better therapist competence was associated with higher participant retention, with one therapy delivery format having significantly better treatment retention than the other. Neither therapist competence nor group cohesion were found to account for a significant amount of variance in change scores (reduction in BPD symptoms). Thus there appears to be unique aspects of schema therapy that improves retention above common therapy factors such as group cohesion. The limitations and clinical implications of both studies are discussed.

Item Type: Thesis (Professional Doctorate)
Murdoch Affiliation(s): School of Psychology and Exercise Science
United Nations SDGs: Goal 3: Good Health and Well-Being
Supervisor(s): Lee, Chris and Arntz, Arnoud
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