Following these analyses, the associations between DISC1 RVs and whether subjects had ever used opioids and whether users had experienced OD were investigated in AAs. In the SSADDA interview, all subjects were asked “have you ever used any of the following opiate/drugs? Heroin, codeine, Demerol, morphine, Percodan, Percocet, methadone, Darvon, opium, fentanyl or P-dope, Dilaudid or other opiate.” Subjects who answered yes were considered to have been exposed to opioids. SKAT was used to test the association between DISC1 RVs and opioid exposure. To explore the role of DISC1 RVs in the development of OD after exposure, we restricted the SKAT analysis to subjects who had used opioids before. All tests adjusted for sex, age, AD and CD.
