Testing social status and family socialization hypotheses of alcohol use in young people: a causal mediation analysis

Introduction: Social status may be mediated by family socialization practices in relation to adolescent substance use. However, traditional mediation analysis using a product or difference method is susceptible to bias when assumptions of the method are not addressed. We used a potential outcomes framework to assess assumptions of (1) no exposure-mediator (social status – socialization practices) interaction and (2) no unmeasured confounding of the mediator-outcome path (socialization practices – substance use). Method: Multiple mediator causal mediation analyses were conducted on data reported in Pape, Norström, and Rossow (2017). Participants were 17,761 Norwegian young people (13 to 18 years), 51% female and 49% male. Data were collected through a questionnaire completed by the young people. Social status was operationalised as parental education and employment status (employed or receiving welfare). Drinking behaviour was operationalised as frequency of alcohol consumption and frequency of intoxication in the past year. Socialization practices were operationalised as general parenting measures, alcohol-related parental permissiveness, and parent drinking behaviour. Results: There was no consistent evidence of exposure-mediator interaction. Formal sensitivity analysis of mediator-outcome confounding was not possible in the multiple mediator scenario, but we judged the risk of the mediated effect being negated as being relatively low. In the multiple mediator analysis, we found strong support for the family socialization deficit hypothesis, especially in younger age groups. Conclusion: Assuming no further unmeasured confounders of the socialization-drinking behaviour relation, this analysis supports a family socialization deficit hypothesis to explain young persons’ drinking. One potential implication of this finding is that effective family socialization interventions could help address the social patterning of alcohol misuse in young people.