Temporary parental separation at birth and substance use disorder in adulthood. A long-term follow-up of the Finnish Christmas Seal Home Children.

BACKGROUND: Adversities in the early mother-infant relation pose a hypothetical risk for addiction. We studied the association between very early separation and later development of substance use disorder.
METHOD: A follow-up study was performed of subjects temporarily isolated from their family immediately after birth to adequate nursing homes in order to protect them against morbidity and mortality for tuberculosis. The average separation time was 7 months. The index cohort consisted of 3,020 subjects born in 1945-1965. For every index subject, two reference subjects were matched for sex, year of birth and place of birth. We were able to obtain the SES of the family of origin as recorded in 1971 from Statistics Finland. Finnish Hospital Discharge Register was used to identify subjects with substance use disorder arising from childhood to middle age, between January 1,1971 and December 31, 1998.
RESULTS: The 28-year cumulative incidence of alcohol use disorders was 4.2% in the index cohort and 3.1% in the reference cohort (rate ratio, RR 1.4, 95% CI 1.1-1.8). The incidences of hospital-treated drug abuse or dependence were 0.6% and 0.2% (RR 2.5, 95% CI 1.2-5.1), respectively. The differences in socioeconomic status of the family of origin did not explain the differences found.
CONCLUSIONS: Substance use disorders were more prevalent among subjects temporarily separated at birth from their mothers because of tuberculosis in the family than in the reference cohort. While risks experienced during pregnancy, delivery and childhood are alternative explanations, this result suggests that very early temporal separation from the mother at birth may have had unfavourable but modest effects on later psychological development, including vulnerability to addiction.