Abstract
Research demonstrates that patients' expectations about treatment outcome are an important predictor of actual psychotherapeutic treatment outcome. So far, only few psychometrically sound expectancy questionnaires are available to assess treatment expectancy. The Anxiety Change Expectancy Scale (ACES) is a promising 20-item questionnaire which measures patients' expectations about being able to change anxiety regarding and regardless from treatment. Psychometric properties of the Dutch language version of the ACES (ACES-NL) are investigated in 212 patients referred to a mental health institute because of suspected anxiety disorders. Reliability (i.e., internal consistency, inter-item, test-retest reliability) is investigated. Validity is examined in terms of internal structure and relations with the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF), Beck Hopelessness Scale (BHS) and Self-Efficacy Scale (SES). Reliability statistics are good to excellent. Factor analysis reveals a one factor solution. Meaningful relations with relevant MMPI-2-RF scales are established. BHS and SES scores demonstrate satisfactory concurrent and discriminant validity. Treatment outcome expectancy is discussed against the background of relevant models. Further research on predictive validity of the ACES-NL is warranted.
