Individual differences in cognitive behaviour therapy (CBT): measuring pre-treatment CBT-like attitudes

Investigating predictors of outcome provides an avenue for optimising response to empirically supported treatments like cognitive behaviour therapy (CBT). The match between an individual's pre-treatment attitudes and CBT has not been empirically examined as a predictor of CBT outcome. Across a number of empirical studies this thesis reports on development of the Skills Used In Therapy Survey (SUITS), which was designed to measure broad pre-treatment attitudes aligned with CBT via two short scales (Self and General). Exploratory and confirmatory factor analyses within undergraduate and community samples indicated a strong factor structure for both SUITS scales. Adequate to good internal consistency was demonstrated across university, community, and clinical samples, while satisfactory test-retest reliability was demonstrated within a university sample. Evidence for the discriminant construct validity of the SUITS was found across empirical studies in relation to demographic variables, measures of psychopathology, verbal reasoning, and social desirability. Evidence for the convergent construct validity of the SUITS was found in relation to constructs reflecting therapy skills, adaptive functioning, and adaptive cognitive constructs specifically relevant to CBT. SUITS scores were found to predict credibility ratings of CBT treatment scripts, in isolation and independently of psychopathology, but not pharmacological interventions scripts, in a community sample. SUITS scores were also found to predict clinician-rated judgements of CBT-like attitudes in a university sample. Importantly, SUITS scores were found to predict treatment response immediately and three-months following treatment. Additionally, SUITS Self total scores were found to predict post treatment social anxiety over and above existing attitude predictors like motivation for change, expectancy for change, and treatment credibility. Overall, results from this thesis suggest that the SUITS is psychometrically sound. Pre-treatment CBT-like attitudes represent a promising predictor of CBT outcome that has the potential to inform clinical practice and improve treatment outcome for more clients.