Abstract
Psychotherapies for borderline personality disorder (BPD) utilise a variety of theoretical models and practical approaches to effect changes that ultimately lead to a reduction in BPD symptomatology or related improvements (e.g. quality of life). Different psychotherapies vary in the underlying mechanisms that are theoretically proposed to effect this change. Accordingly, they are composed of differing proposed therapeutic components. This thesis aimed to identify effective therapeutic components in psychotherapies for BPD broadly, and Systems Training for Emotional Predictability and Problem Solving (STEPPS) specifically. Part one of this portfolio presents a review of the empirical literature that specifically examines effective therapeutic components in psychotherapies for BPD. Semantic complexities inherent in conducting this type of process research are considered, and the specific scope of this portfolio within the wider ‘mechanisms of change’ literature is defined. Results synthesise identified effective therapeutic components into four themes that illustrate the broader landscape within which the empirical paper is set. Part two of this portfolio presents an empirical paper that investigated effective therapeutic components in STEPPS, a psychoeducational group treatment for BPD. Results support an association between acquisition of behaviour and emotion regulation skills (the primary treatment component proposed in the STEPPS manual) and improvement in BPD symptoms. Results also support an association between group process (a potential effective therapeutic component related to group alliance) and improvement in BPD symptoms, reflecting results from wider literature. Parts three and four of this portfolio summarise the clinical experience gained on placements throughout the PsychD course, and all other written assignments completed.