Introduction: Depression is one of the most dominant universal mental health
disorders and has a high rate of persistency and recurrence. Interpersonal theories
posit that it is interpersonal, or relational, factors that serve to cause and maintain
depression, which is supported by a growing evidence base. CBASP is an
interpersonally-focused psychotherapy specifically designed for the treatment of
chronic depression and employs a variety of cognitive, behavioural and interpersonal
techniques within the therapeutic relationship to help individuals evaluate their
interpersonal exchanges and consider the implications. Research has highlighted the
effectiveness of CBASP for this client group, however there is limited research
investigating therapist and client factors that contribute to positive outcomes.
Attachment style and mentalization are two such factors that are theoretically and
empirically linked to an individual’s way of relating to others but have not been
investigated in relation to outcomes in CBASP. Aims: A systematic review aimed to
identify and evaluate significant social and interpersonal mediators that account for
the relationship between attachment style and depressive symptoms. An empirical
study then explored the role of therapist and client attachment style, mentalisation,
and therapeutic alliance on clinical outcomes in CBASP. Methods: A systematic
search of the literature exploring social and interpersonal mediators between
attachment style and depressive symptoms was conducted in order to identify and
evaluate mediators. The empirical study used a longitudinal case series design where
both therapist and client attachment style, mentalization and the therapeutic alliance
were assessed, and clinical outcomes were measured at each session to allow
evaluation of change over time. Results: The systematic review provided evidence
that specific social and interpersonal variables mediate the relationship between
attachment and depressive symptoms, specifically social support, social anxiety,
social self-efficacy, relationship satisfaction, interpersonal negative events, and
interpersonal dependency. Two studies failed to find mediating effects of social
support and social self-efficacy. The findings of this review are interpreted with
caution as there contained several methodological limitations that affect the ability to
generalize to other populations and infer causation. Findings from the empirical
study provided evidence for the role of therapist attachment style and mentalization
in relation to the therapeutic alliance and clinical outcomes in chronic depression in
CBASP. Client attachment style and mentalization were not found to have a
significant impact on the process of change but did account for some variance in
symptoms of depression. Findings should be cautioned due to the small sample size
and lack of statistical power to detect smaller effects. Discussion: The findings of
this thesis suggests that there exist social and interpersonal factors that mediate the
relationship between attachment style and depressive symptoms, and this has clear
socio-political and clinical implications. However more research using robust
methods of design and statistical analysis are needed in order to provide clarity in
this field. The empirical study provided rich and novel data that suggests that
therapist attachment style and mentalization, more so than client factors, are
important in developing the therapeutic alliance and promoting symptom reduction
over the course of treatment. Further research utilizing a larger sample size could
provide more robust evidence for this association