The Severity of Dependence Scale (SDS) in an adolescent population of cannabis users: reliability, validity and diagnostic cut-off.

The Severity of Dependence Scale (SDS) is a five-item scale that has been reported to be a reliable and valid screening instrument for dependence and a measure of dependence severity in adults across several substance classes. To date no data have been reported on its performance in a population of adolescent cannabis users. The current study assessed the psychometric properties of the SDS in a community sample of 14-18-year-old adolescent cannabis users (n=100). Internal consistency (alpha=0.83) and test-retest coefficients (ICC=0.88) were high and a principal components analysis of the scale found all items to load on a single factor. Total SDS score correlated significantly with frequency of cannabis use and number of DSM-IV dependence criteria met, indicating good concurrent validity. Receiver Operating Characteristic curve analysis was used to determine the most appropriate SDS cut-off score for use as an indicator of cannabis dependence, with optimal discrimination at an SDS score of 4. These findings indicate that the SDS is a reliable and valid measure of severity of cannabis dependence among adolescents, has high diagnostic utility, and that an SDS score of 4 may be indicative of cannabis dependence.