Despite several decades of research suggesting that psychological interventions are effective in reducing psychological distress, how these interventions lead to change remains unclear. Some factors that are considered important when investigating how interventions lead to change are the levels of adherence, competence and integrity displayed by the therapist when delivering interventions. This thesis aimed to investigate the relationship between therapist competence and patient outcome and involved: 1) an updated and extended meta-analytic review investigating the association between adherence/competence/integrity and outcome, and 2) an empirical study investigating whether practitioner competence is associated with clinical outcomes in guided self-help (GSH) for adults with anxiety disorders.
Section one of this thesis reports a systematic review of 62 studies that investigated the association between therapist adherence/competence/integrity and patient outcome. Meta-analyses were conducted to estimate the overall association between adherence, competence and integrity and outcome across both non-hierarchical (e.g., correlation) and hierarchical (e.g., multilevel modelling) statistical methods. The findings suggest that there is a significant association between therapist integrity and outcome, some association between competence and outcome but no association between adherence and outcome. The findings offered mixed support for the findings of the previous meta-analytic review conducted over a decade ago. This may be the first meta-analysis investigating the integrity-outcome association and thus this needs further investigation. The level of heterogeneity across included studies was high and thus findings should be interpreted with caution.
Section two of this thesis reports an empirical study which was a secondary analysis of outcome data collected during a randomised controlled patient preference trial. This study set out to investigate the association between practitioner competence and patient and service outcomes in the delivery of GSH across and between a new intervention protocol (informed by cognitive analytic principles, n=60) and the standard protocol (informed by cognitive behavioural principles, n=20). A fully crossed design was used to confirm very high inter-rater reliability of competence ratings across competence-levels and treatment conditions. No significant associations were found between practitioner competence, patient outcome, treatment engagement nor need for further intervention. Competence did not predict rate of change in patient self-reported anxiety symptoms. The findings of the study suggest that practitioners of low intensity psychological interventions can competently deliver two distinct versions of GSH with brief training and under regular supervision. Analyses were under powered and thus the association between competence and outcome in GSH needs further exploration.
Taken as a whole, the two studies provide evidence that a practitioner’s adherence to an intervention’s techniques and the skill with which these techniques are applied (in combination) may be associated with the outcome of patients though this association may vary depending on the particular intervention used and the symptoms/diagnoses being treated. Measurement of treatment integrity needs to be integrated into ongoing clinical supervision of therapists/practitioners.
