The reliability and validity of the Severity of Dependence Scale for detecting cannabis dependence in psychosis

Objective: To determine the reliability and validity of the Severityof Dependence Scale (SDS) for detecting cannabis dependencerelative to other predictor variables in a large sample of inpatientswith a psychotic disorder.Methodology: Participants were 153 inpatients with a currentpsychotic disorder in Brisbane, Australia. They were administeredthe SDS for a cannabis use in the past 12 months. Presence ofcurrent cannabis dependence in the past 12 months was assessedusing the Comprehensive International Diagnostic Interview(CIDI).Results: Approximately 54.2% of inpatients met criteria for DSMIVcannabis dependence in the past 12 months. The SDS had highlevels of internal consistency, construct validity and concurrentvalidity with a current DSM-IV cannabis dependence. Individualswith a positive screen on the SDS were nearly 30 times more likelyto have current cannabis dependence, and remained the strongestpredictor of cannabis dependence after controlling for otherpredictor variables.Conclusions: The SDS is a valid and reliable screen for cannabisdependence amongst inpatients with a psychotic disorder and isrecommended as a brief, easy to administer screening tool in thispopulation.