Inter-rater reliability and concurrent validity of DSM-IV opioid dependence in a Hmong isolate using the Thai version of the Semi-Structured Assessment for Drug Dependence and Alcoholism (SSADDA)

Because isolated populations offer relative genetic and environmental homogeneity, they are important resources for mapping genes for complex traits. Reliable and valid phenotypic characterization of the disease in the population studied is essential. We examined diagnostic reliability and concurrent validity of DSM-IV opioid dependence (OD) in a Hmong population in Thailand with historically high rates of opium (and heroin) use. 578 Thai-speaking Hmong individuals were assessed for lifetime OD, using Thai versions of both the Semi-Structured Assessment for Drug Dependence and Alcoholism (Thai SSADDA) and the Mini-Neuropsychiatric Interview (Thai MINI; adapted for lifetime diagnoses). In a subsample of 123 individuals, two raters interviewed each subject independently within a 2-week period. Chance-corrected agreement on the OD diagnosis was assessed between raters and instruments. Results showed excellent agreement for the DSM-IV diagnosis of OD both for the SSADDA (κ=0.97) and MINI (κ=1.00) and between the SSADDA and MINI (κ=0.97). Consistent with reliability assessments of English versions, our data demonstrate high reliability for Thai versions of the SSADDA and MINI in the diagnosis of OD. The high concordance between instruments supports the concurrent validity of the diagnosis. Either interview provides reliable, valid OD diagnoses in Thai-speaking Hmong individuals.