Chapter 7: Differentiated Harms? Comparing the Impact of Parental Alcohol Versus Drug Problems on Offspring in Childhood and Early Adulthood

It is well established that problematic parental substance use (PSU) has an impact on children’s development, yet most research either treats drug and alcohol use as a uniform exposure or considers only one substance. This chapter examines whether the type of PSU – alcohol, drugs, or both – has differentiated effects on youth outcomes. Using national Danish register data for a representative cohort of 9,808 young people, we identified PSU during the child’s upbringing. We investigated differences in school performance (grade point average (GPA) at the final exam) and early adult adverse outcomes (not in education/employment, psychiatric diagnoses, and criminal convictions) between peers without problematic parental substance use (No PSU) and three groups of youth exposed to PSU. Compared to the No PSU group, all PSU groups had more family-related problems. Young people who had experienced PSU had a significantly lower GPA and higher odds of early adult adverse outcomes. The analysis showed no significant differences between the three PSU groups. These findings suggest that differences in early adulthood between individuals with and without exposure to PSU during childhood may be better explained by a shared experience of high levels of family adversity, rather than by the specific type of PSU. Interventions should prioritize the broader social and psychological contexts of PSU-affected families rather than focus narrowly on the substance type.