Limited research has looked at therapist and client variables that may contribute to therapeutic alliance/engagement, and clinical outcomes. The current study proposes to explore two variables that are hypothesized to contribute to outcomes based on the theoretical framework CBASP is grounded on, namely therapist and client attachment style and reflective functioning. This will be done by providing CBASP to a small number of participants and gathering outcome data from therapists and clients at each therapy appointment. Participants will also complete the Adult Attachment Interview (AAI), a semi structured interview which can also be coded for reflective functioning. This is a proof of concept case series design that aims to provide an analysis of individual psychological change in relation to the above variables of interest.