Development and psychometric evaluation of the Benzodiazepine Craving Questionnaire.

AIM To assess the scalability, reliability and validity of a newly constructed self-report questionnaire on craving for benzodiazepines (BZs), the Benzodiazepine Craving Questionnaire (BCQ). SETTING AND PARTICIPANTS The BCQ was administered once to a sample of 113 long-term and 80 former long-term general practice BZ users participating in a large BZ reduction trial in general practice. MEASUREMENTS (1) Unidimensionality of the BCQ was tested by means of the Rasch model. (2) The Rasch-homogeneous BCQ items were assessed for subject and item discriminability. (3) Discriminative and construct validity were assessed. FINDINGS The BCQ met the requirements for Rasch homogeneity, i.e. BZ craving as assessed by the scale can be regarded as a unidimensional construct. Subject and item discriminability were good. Construct validity was modest. Highest significant associations were found with POMS depression (Kendall's tau-c = 0.15) and Dutch Shortened MMPI negativism (Kendall's tau-c = 0.14). Discriminative validity was satisfactory. Highest discriminative power was found for a subset of eight items (Mann-Whitney U Z = - 3.6, P = 0.000). The first signs of craving are represented by the acknowledgement of expectations of positive outcome, whereas high craving is characterized by direct intention to use. CONCLUSIONS The BCQ proved to be a reliable and psychometrically sound self-report instrument to assess BZ craving in a general practice sample of long-term BZ users.