Amphetamine withdrawal: I. Reliability, validity and factor structure of a measure.

OBJECTIVE

The aim of this study was to create a short, reliable and valid questionnaire for the evaluation of amphetamine withdrawal, which we shall call the Amphetamine Withdrawal Questionnaire (AWQ).

METHOD

Items of the AWQ included in this study were based on the fourth edition of the Diagnostic and Statistical Manual for Mental Disorders (DSM-IV) and a comprehensive review. A field trial for assessing the reliability, validity and factor structure was conducted in outpatients and inpatients with amphetamine withdrawal.

RESULTS

Thirty and 102 patients' data were included in the reliability-validity tests and the factor study, respectively. Due to the very low mean score of insomnia item, this item was excluded from subsequent analyses. The AWQ internal consistency was satisfactory with a Cronbach's alpha of 0.77. For test-retest reliability, a Spearman rank order correlation coefficient of the AWQ total score was 0.79. The AWQ total score for criterion validity was moderately correlated with the other two accepted measures. Principal component analysis, eigenvalue-one test and a varimax rotation performed to elicit the factors of AWQ yielded a three-factor model of AWQ: namely hyperarousal, reversed vegetative and anxiety factors.

CONCLUSIONS

The AWQ is a short, reliable and valid measure for assessing amphetamine withdrawal symptoms. Further studies with a larger number of patients should be conducted to confirm the results of this factor analysis.