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.

An inhibition-based stochastic countable-time decision model.

A new stochastic model to account for reaction-time fluctuation in prolonged work tasks is presented. Transition probabilities from work periods to distraction periods and vice versa are dependent on inhibition, which increases during work and decreases during distractions. The model presented here differs from all other inhibition-based models in that transitions can take place only at certain random points in time, and is referred to as a countable-time decision model. It is argued that the proposed model is a more plausible alternative to other existing inhibition-based models, while at the same time being highly flexible in that it is able to approximate other models arbitrarily well. This model is compared to an existing inhibition-based continuous-time decision model and the probability distribution functions for work and distraction periods are derived.

Latent trait standardization of the benzodiazepine dependence self-report questionnaire using the Rasch scaling model.

The aim of the present study was to obtain standardized scores that correspond with the raw scores on the four Rasch scales of the Benzodiazepine Dependence-Self Report Questionnaire (Bendep-SRQ). The eligible normative group for standardization of the Bendep-SRQ scales consisted of 217 general practice (GP) patients, all using benzodiazepines. Two standardization methods were used and compared: "classical standardization," which transforms raw scores into standard scores on the unit normal distribution, and "latent trait standardization," which transforms raw scores into latent trait scores. The latter requires the Rasch model with the additional assumption of a normally distributed latent trait, which held true for the scales "problematic use," "lack of compliance," and "withdrawal," but not for "preoccupation." The observed unequal item spacing on the "preoccupation" scale was hypothesized to induce a response tendency of nondeviation, causing a local violation of the assumption of a normally distributed latent trait. Nevertheless, comparison of the results of the two standardization methods revealed such a high degree of resemblance, that latent trait standardization could be used for "preoccupation" just as well as classical standardization. The presented standard scores and corresponding percentile ranks make raw Bendep-SRQ scores clinically interpretable in relation to the normative GP sample. Incorporation of the Rasch scaling methodology into the development of the Bendep-SRQ marks the adoption of the item response theory in the field of applied test methodology. In this process, it appears that equal item spacing has to be taken into account to prevent local violations of the Rasch model with the additional assumption of a normally distributed latent trait.

Cross-validation of the benzodiazepine dependence self-report questionnaire in outpatient benzodiazepine users.

The aim of this study was to cross-validate the Benzodiazepine Dependence Self-Report Questionnaire (Bendep-SRQ), which reflects the severity of benzodiazepine (BZD) dependence. The Bendep-SRQ, Symptom Checklist-90 (SCL-90) Schedules for Clinical Assessments in Neuropsychiatry (SCAN), and Addiction Severity Index-Revised (ASI-R) were administered to 102 general practice (GP) patients and 126 psychiatric outpatients who were using BZDs. The scalability and reliability of the Bendep-SRQ scales were reassessed in terms of Rasch homogeneity, subject discriminability, item discriminability, and test-retest stability. Present and original Rasch item orders were compared to evaluate construct validity. A matrix of all measures was factor-analyzed to assess concurrent and discriminant validity. The scalability of the Bendep-SRQ scales was confirmed. The reliability results were fairly good. Present and original Rasch item orders corresponded. The Bendep-SRQ scales and concurrent measures had high loadings on one factor, the discriminant measures on two other factors. In spite of some differences with respect to sociodemographic characteristics and pattern of BZD use, the cross-validation results agreed well with the results of the original study on the Bendep-SRQ. The Bendep-SRQ has presently acquired enough support of favorable and consistent results for clinical and scientific use.

Assessment of benzodiazepine dependence in alcohol and drug dependent outpatients: a research report.

In this study on 99 outpatients who were being treated for alcohol and/or drug dependence and also using benzodiazepines (BZDs), prevalence rates of DSM-III-R and ICD-10 substance dependence diagnoses were ascertained and scalability, reliability and validity of the scales of the Benzodiaepine Dependence Self-Report Questionnaire (Bendep-SRQ) were assessed. The latter properties were investigated by Rasch analyses, discriminability coefficients, test-retest coefficients and factor analyses. BZD dependence was found to be a prevalent additional diagnosis. The psychometric findings appear to support the use of the Bendep-SRQ at outpatient addiction centers, which could contribute to a more differentiated treatment for poly-substance dependence.

Scalability, reliability, and validity of the benzodiazepine dependence self-report questionnaire in outpatient benzodiazepine users.

As there is no multidimensional instrument available that reflects the severity of benzodiazepine (BZD) dependence comprehensively, the Benzodiazepine Dependence Self-Report Questionnaire (Bendep-SRQ) was developed and investigated. The Bendep-SRQ, Symptom Checklist-90 (SCL-90), Schedules for Clinical Assessments in Neuropsychiatry (SCAN), and Addiction Severity Index-Revised (ASI-R) were administered to 115 general practice (GP) patients, 124 psychiatric outpatients, and 33 self-help patients who were using BZDs. Factor and Rasch analyses were applied to construct scales. Reliability assessments were made in terms of subject discriminability, item discriminability, and test-retest stability. To support the construct validity of the scales, theoretical rationales were required to explain the specific item order provided by the Rasch scale values. To assess the concurrent and discriminant validity, a matrix consisting of the above-mentioned measures was factor-analyzed. Four Rasch-homogeneous scales were delineated: problematic use, preoccupation, lack of compliance, and withdrawal. Nearly all subject discriminability, item discriminability, and test-retest results indicated good reliability. A BZD dependence factor was extracted with high loadings for the Bendep-SRQ scales and the concurrent measures. The discriminant measures had high loadings on other factors. The scalability, reliability, and validity of the Bendep-SRQ scales appeared to be good. The Bendep-SRQ shows great promise as a useful and easily manageable instrument for assessment of the severity of BZD dependence in clinical practice and scientific research.

An evaluation of DSM-III-R and ICD-10 benzodiazepine dependence criteria using Rasch modelling.

AIMS: To evaluate the homogeneity of the elements of the Substance Dependence Syndrome (SDS) as applied to benzodiazepines (BZDs) by Rasch modelling. MEASUREMENTS: The Rasch scaling model was applied to data obtained by administering the SCAN (Schedules for Clinical Assessments in Neuropsychiatry) substance dependence sections. Subsequently, Rasch-homogeneous sets of DSM-III-R and ICD-10 BZD dependence criteria were assessed for subject and item discriminability. To support their construct validity a theoretical rationale was formulated based on the Rasch scale values. PARTICIPANTS: A heterogeneous sample of 599 outpatient BZD users. FINDINGS: Only particular subsets of the DSM-III-R and ICD-10 BZD dependence criteria met the requirements for Rasch-homogeneity, which appears to be due to medical aspects of BZD use. The subject and item discriminability results were sufficiently good. CONCLUSIONS: The DSM-III-R and ICD-10 BZD dependence constructs may need to be redefined. The use of a BZD dependence severity model based on a Rasch-homogeneous scale appears to have greater clinical value than a dichotomous diagnostic model based on an arbitrary cut-off point. We recommend Rasch modelling to investigate the homogeneity of the elements of the SDS across other psychoactive substances.