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.
- Questionnaire development