This study was designed to explore correlations between single-item Visual Analog Scales (VAS) and a multiple-question Likert-type scale along with their relations to drug use in outpatients with bipolar disorder and cocaine dependence. The assessment scales included the 10-item Cocaine Craving Questionnaire (CCQ), a VAS Now and Week version, and a self-reported days of cocaine use in the past week.
Twenty-nine participants diagnosed with bipolar disorder and cocaine dependence were examined from one of two previously reported 12-week studies using lamotrigine or quetiapine. The patients were evaluated at baseline and assessed either weekly or biweekly, depending on the study. To gauge the effectiveness of the drugs, the CCQ and VAS scales were administered at each visit to measure cocaine craving.
Twenty-seven of the patients returned for at least one postbaseline assessment and were included in the data analysis. Significant correlations found were between VAS Now and VAS Week, VAS Now and CCQ Now, and VAS Week and CCQ Now at baseline, exit, and change from baseline to exit (all r > .53, P < .01). None of the scales correlated significantly with drug use.
These results suggest that for craving assessments in research and clinical settings, the faster and more easily administered VAS scales could possibly be substituted for the lengthier and more tedious 10-item CCQ. The shorter VAS scales may be valuable not only to the researcher but also to the clinician who wishes to measure a patient's craving objectively.