Alcohol and drug abuse among young adults who grew up in substitute care — Findings from a Swedish national cohort study

Abstract

To what extent substitute long term care modifies intergenerational transmission of substance abuse has rarely been investigated. Using register data, we followed a national cohort born 1973-1985 consisting of 1012 national adoptees, 2408 former children from long term foster care, 348/846 environmental siblings of adoptees/foster children, and 952,935 majority population peers, from their 15th birthday to age 27-35. Using Cox regression, we calculated hazard ratios (HR) for hospital care and criminality associated with illicit drug/alcohol abuse, with adjustments for socio-demographic indicators of caring families, and substance abuse in caring and birth parents. Among 37% of foster children, 9% of adoptees, and 1% of majority population peers, both birth parents had indications of substance abuse. In age/sex adjusted models foster children had four to sevenfold elevated HR for substance abuse outcomes, and adoptees two to threefold HR, in comparison with majority population peers. Estimates were only marginally attenuated after adjustments for socio-demographic indicators and morbidity of caring parents. After adjustments for birth parental substance abuse, HR decreased to around 1.5 for adoptees and foster children equally. Biological children of substitute parents did not differ substantially from majority population peers.