Association between adolescent alcohol use and cognitive function in young adulthood: A co-twin comparison study

Area of Science:

• Neuroscience
• Psychology
• Genetics

Background:

• Adolescent alcohol use research often struggles to isolate causal effects from shared genetic or environmental factors.
• Nicotine use and other substance comorbidities also impact cognition, complicating direct alcohol-cognition links.

Purpose of the Study:

• To clarify the relationship between adolescent alcohol consumption and young adult cognitive function.
• To differentiate alcohol's effects from shared etiological influences, including genetics and co-occurring substance use.

Main Methods:

• Utilized a random effects model to control for measured confounders within a family structure.
• Employed co-twin comparisons, including monozygotic (MZ) twin pairs, to account for unmeasured genetic and environmental factors.
• Analyzed data from the longitudinal FinnTwin12 study in Finland, including 812 individuals.

Main Results:

• Higher frequency of adolescent alcohol use and intoxication was associated with lower young adult vocabulary scores.
• These associations remained significant even after controlling for shared genetic and environmental factors in co-twin analyses.
• No significant effects were found for other cognitive measures.

Conclusions:

• Little evidence suggests adolescent alcohol use causes widespread cognitive deficits in young adulthood in this Finnish cohort.
• A modest association exists between higher adolescent alcohol use and reduced vocabulary in young adulthood.
• The findings highlight the importance of controlling for genetic and familial factors in substance use and cognition research.