Measurement invariance of DSM-IV alcohol, marijuana and cocaine dependence between community-sampled and clinically overselected studies

Aims To examine whether DSM‐IV symptoms of substance dependence are psychometrically equivalent between existing community‐sampled and clinically overselected studies. Participants A total of 2476 adult twins born in Minnesota and 4121 unrelated adult participants from a case–control study of alcohol dependence. Measurements Life‐time DSM‐IV alcohol, marijuana and cocaine dependence symptoms and ever use of each substance. Design We fitted a hierarchical model to the data, in which ever use and dependence symptoms for each substance were indicators of alcohol, marijuana or cocaine dependence which were, in turn, indicators of a multi‐substance dependence factor. We then tested the model for measurement invariance across participant groups, defined by study source and participant sex. Findings The hierarchical model fitted well among males and females within each sample [comparative fit index (CFI) > 0.96, Tucker–Lewis index (TLI) > 0.95 and root mean square error of approximation (RMSEA)