Social genetic effects for drug use disorder among spouses.

Aims: Preclinical and human studies suggest that a social partner's genotype may be associated with addiction‐related outcomes. This study measured whether spousal genetic makeup is associated with risk of developing drug use disorder (DUD) during marriage and whether the risk associated with a spouse's genotype could be disentangled from potentially confounding rearing environmental effects. Design: Univariable and multivariable logistic regression analyses. Setting: Sweden. Participants: Men and women born between 1960 and 1990 and in opposite‐sex first marriages before age 35 (n = 294 748 couples). Measurements Outcome was DUD diagnosis (inclusive of opioids, sedatives/hypnotics/anxiolytics, cocaine, cannabis, amphetamine and other psychostimulants, hallucinogens, other drugs of abuse and combinations thereof) obtained from legal, medical and pharmacy registries. The focal predictor was family genetic risk scores for DUD (FGRS‐DUD), which were inferred from diagnoses in first‐ through fifth‐degree relatives and weighted by degree of genetic sharing. FGRS‐DUD were calculated separately for each partner in a couple. Findings Marriage to a spouse with a high FGRS‐DUD was associated with increased risk of developing DUD during marriage, ORmales = 1.68 (95% CI = 1.50, 1.88) and ORfemales = 1.35 (1.16, 1.56), above and beyond the risk associated with one's own FGRS‐DUD. The risk associated with a spouse's FGRS‐DUD remained statistically significant after covarying for parental education. As indicated by a series of null interaction effects, there was no evidence that the risk associated with a spouse's FGRS‐DUD differed depending on whether the spouse was DUD‐affected, probands' probable contact with in‐laws and whether the spouse was raised by his/her biological parents or in another home. Conclusions: There is relatively robust evidence that a person's risk for developing drug use disorder is associated with the genetic makeup of the person's spouse. [ABSTRACT FROM AUTHOR]