Factors related to change in acceptance and commitment therapy and befriending therapy for medication-resistant psychosis

Submission note: A thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Clinical Psychology (Research) to the School of Psychological Science, Faculty of Science, Technology and Engineering, La Trobe University, Bundoora.

The current research program was designed to investigate factors related to change within therapy for psychosis. This process research formed part of a larger investigation, an outcome study of Acceptance and Commitment Therapy (ACT) versus Befriending Therapy for the treatment of medication-resistant positive symptoms of psychosis. This research aimed to investigate the role of: (1) specific therapy factors, (2) the therapeutic relationship, and (3) client factors in explaining therapy outcome in both therapy types. Outcome variables were assessed pre- and post-treatment that included eight sessions of allocated therapy usually within an 8- to 12-week period. Results showed little support for the hypothesised specific factors in either ACT or Befriending. In relation to ACT, there was no change in experiential avoidance across the trial. Although participants became more defused with thoughts and showed more acceptance related to voices over the duration of therapy, these changes were not specific to ACT and were unrelated to improvement in positive symptoms. The results did not demonstrate support for social connectedness, selfesteem or depression as specific factors of change unique to Befriending. In contrast to predictions, the therapeutic relationship was unrelated to symptom improvement. In relation to client factors, the results failed to support auditory hallucinations as predictive of better treatment response to ACT and poorer response to Befriending. Those who were curious about their illness, as indicated by an integrative recovery style, endorsed ACT more than Befriending and reported feeling more satisfied with the ACT approach. Those avoidant of their illness, as indicated by a sealing-over recovery style, did not differ in their ratings of endorsement or satisfaction with treatment approach. There was no difference in distress or outcome expectancy between the treatment approaches according to recovery style. Recommendations for future research include replication using larger sample sizes and further development and validation of process measures, specific to the ACT and Befriending models.