The causes of parent-offspring transmission of drug abuse: a Swedish population-based study.

ABSTRACT: While drug abuse (DA) is strongly familial, we still have limited knowledge about the causes of its cross-generational transmission.We examined DA ascertained from national registers in offspring of three family types from the Swedish population [intact (n = 2,111,074), 'not-lived-with' (n = 165,315, where biological parents never lived with their offspring) and 'step' (n = 124,800 offspring)], which reflected, respectively, the effects of genes + rearing, genes only and rearing only. We replicated these results in three high-risk co-relative designs.Combined across mothers and fathers, the hazard ratio (HR) for DA in offspring given DA in parents was 3.52 in intact, 2.73 in 'not-lived-with' and 1.79 in stepfamilies. In 968 biological full or half-sibling pairs one of whom was reared by and the other never lived with their parent with DA, the HR for DA was greater in the reared than 'not-lived-with' child (HR 1.57). In 64 offspring pairs of a parent with DA, the HR for DA was greater in a reared biological v. step-parented non-biological child (HR 3.33). In 321 pairs of offspring of a parent with DA one of whom was a not-lived-with biological child and the second a step-parented non-biological child, the HR for DA was greater in the biological v. stepchild (HR 1.80).Both genetic and environmental factors contribute substantially to parent-offspring resemblance for DA. The general population contains informative family constellations that can complement more traditional adoption designs in clarifying the sources of parent-offspring resemblance.

SUBMITTER: Kendler KS 

PROVIDER: S-EPMC4232482 | biostudies-literature | 2015 Jan

REPOSITORIES: biostudies-literature