All subjects were interviewed using the Semi-Structured Assessment for Drug Dependence and Alcoholism (SSADDA)5,9 to derive diagnoses for lifetime CD and other major psychiatric traits according to DSM-IV10 criteria. CIP was assessed with a specific item on the SSADDA, which we have previously shown to be valid.11 The inter-rater reliability of the SSADDA for the diagnosis of CD was excellent (κ=0.83),9 as was the reliability for the CIP trait assessment (κ =0.86).
