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Acceptance and commitment therapy: efficacy and mechanisms of therapeutic action

Waters, Cerith ORCID: 2012. Acceptance and commitment therapy: efficacy and mechanisms of therapeutic action. ClinPsy Thesis, Cardiff University.
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The individual, organisational and societal impact of psychological distress among working populations is well established. Recently, Acceptance and Commitment Therapy (ACT) has been identified as a promising approach for improving the psychological wellbeing of distressed employees. Nonetheless, few studies have examined the efficacy of ACT in the occupational context and even fewer studies have conducted comprehensive tests of the mechanisms of therapeutic action in ACT. The current research examined the efficacy of a one day ACT intervention that was delivered to NHS employees experiencing psychological distress. A key focus of this research was an examination of the mechanisms of therapeutic action in ACT. In study one, a non-randomised controlled design was used with 17 participants assigned to the ACT intervention and 18 participants assigned to a waiting list. A two-week and three-month follow-up period was used in this study. Participants originally assigned to the waiting list went on to receive the intervention after the three month follow-up and were again assessed at two-weeks and three-months post-treatment. In study two, six of the participants were interviewed about their views on the aspects of the ACT intervention that promoted psychological changes and their responses were analysed thematically. Compared to the control group, participants who received the intervention displayed statistically significant reductions in the severity of psychological distress at two-weeks and three-months post-treatment. Importantly, the majority of participants displayed clinically significant change at both assessments. In line with ACT’s theoretical underpinnings, the intervention significantly increased participants’ psychological flexibility and mindfulness skills and decreased cognitive fusion. However, in a multiple-mediator statistical analysis, improvements in psychological distress were only mediated by improvements in psychological flexibility. The themes generated from the thematic analysis converge with the quantitative data—resembling closely the construct of psychological flexibility. Limitations of the study and implications for future research are discussed.

Item Type: Thesis (DClinPsy)
Status: Unpublished
Schools: Psychology
Subjects: B Philosophy. Psychology. Religion > BF Psychology
Uncontrolled Keywords: Acceptance and commitment therapy; ACT; Mechanisms; Efficacy; Occupational stress; Psychological distress; Mediators of change
Funders: Cardiff and Vale University Health Board
Date of First Compliant Deposit: 30 March 2016
Last Modified: 16 Oct 2023 13:31

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