Assessing the validity and responsiveness of a generic preference quality of life measure in the context of posttraumatic stress disorder.

PURPOSE: There is limited research exploring the usefulness of generic preference-based quality of life (GPQoL) measures used to facilitate economic evaluation in the context of posttraumatic stress disorder (PTSD). The aim of the current study was to explore the validity and responsiveness of a common GPQoL measure (Assessment of Quality of Life 8 Dimension [AQoL-8D]) in relation to a PTSD condition-specific outcome measure (Posttraumatic Stress Disorder Checklist for the DSM-5 [PCL-5]). METHOD: This aim was investigated in a sample of individuals (N = 147) who received trauma-focused cognitive-behavioural therapies for posttraumatic stress disorder. Convergent validity was investigated using spearman's correlations, and the level of agreement was investigated using Bland-Altman plots. Responsiveness was investigated by exploring the standardised response means (SRM) from pre-post-treatment across the two measures, which allow the comparison of the magnitude of change between the measures over time. RESULTS: Correlations between the AQoL-8D (dimensions, utility and summary total scores) and the PCL-5 total score ranged from small to large and agreement between the measures was considered moderate to good. While SRMs were large for the AQoL-8D and PCL-5 total scores, the SRM for the PCL-5 was nearly double that of the AQoL-8D. CONCLUSION: Our findings demonstrate that the AQoL-8D has good construct validity but present preliminary evidence that economic evaluations using only GPQoL measures may not fully capture the effectiveness of PTSD treatments.

Client Versus Clinicians' Standards of Clinically Meaningful Change and the Effects of Treatment Expectations on Therapeutic Outcomes in Individuals With Posttraumatic Stress Disorder.

There is limited research on the concordance between client perceptions and clinician standards of the degree of symptom change required to achieve meaningful therapeutic improvement. This was investigated in an adult sample (N = 147) who received trauma-focused cognitive-behavioral therapies for posttraumatic stress disorder (PTSD). We examined whether clients' benchmarks of change were related to actual outcomes and the relationship between client expectations and their treatment outcomes. Clients completed measures indexing the level of symptom reduction required (in their view) to reflect a benefit or recovery from treatment and treatment expectations. Actual PTSD severity was indexed pre- and posttreatment via self-report and clinician-administered interview. Results demonstrated that the amount of change clients said they required to experience a benefit or recovery was significantly larger than typical clinical research standards. Nonetheless, the majority of client benchmarks of change (79.7-81.8%) were consistent with clinical research standards of what constitutes benefit or recovery. Client benchmarks were generally positively correlated with their actual outcomes. Clients' belief that treatment would be successful was associated with greater reductions in PTSD symptoms. These findings provide preliminary evidence that the standards used to determine clinically significant change are somewhat consistent with clients' own perceptions of required symptom change.