The primary phenotypic instrument, the Semi-Structured Assessment for Drug Dependence and Alcoholism (Thai SSADDA), was derived from the English version of the instrument, which has been shown to yield reliable diagnostic criteria and diagnoses (Pierucci-Lagha et al., 2007; Pierucci-Lagha et al., 2005). Translation of the parent instrument into Thai was conducted by two Thai psychiatrists (RK and AS) who are fluent in English and Thai, in collaboration with two addiction genetics psychiatrists with substantial experience with the SSADDA (RM and JG; fluent in English only), incorporating culturally relevant forms (e.g., opium, in addition to heroin), names, and units for all drug categories (relying on the expertise of Thai study physicians and the input of local villagers). A dually literate, non-physician, lay translator independently back translated the initial draft. Thai and U.S. study physicians (RK, AS, RM and JG) reviewed inconsistencies in the back translated and original English versions and amended the original version through consensus to create the final instrument. The current study employed three sections of the Thai SSADDA: Demographic Information (Section A), Medical History (Section B), and Opioid Dependence (Section G).
