Natalia Sotelo, “Alcohol and Cannabis Use Predicting Hippocampal Volume in Adolescents and Young Adults”
Mentors: Krista Lisdahl and Alex Wallace, Psychology

The hippocampus is responsible for long-term memory formation and previous literature indicates a relationship between decreased hippocampal volume in cannabis (MJ) and alcohol (ALC) users. Fewer studies have examined hippocampal volume in MJ and ALC co-using adolescents and young adults but have shown similar results to independent drug users. 76 adolescents and young adults with MJ and ALC users were recruited from the community and completed a Timeline Follow-Back semi-structured interview to assess lifetime substance use. After 3 weeks of monitored abstinence, participants underwent structural neuroimaging. Scans were processed to obtain anatomical volume. Linear regression analyses were run after controlling for age to assess how controls, ALC users, and co-users predict left and right hippocampal volume. There was no significant relationship between hippocampal volume and MJ and ALC use and co-use. Although not significant, co-users had higher left hippocampal volume compared to ALC users and controls. Post-hoc analyses examining hippocampal asymmetry revealed that co-users had lower hippocampal asymmetry compared to ALC users and controls. The comorbidity of ALC and MJ limited analysis of independent drug use. A trend among ALC and MJ co-users showed increased hippocampal volume which conflicts with previous research. It’s possible that co-use does not have any significant effects on hippocampal volume in adolescents and young adults. However, due to the cross-sectional nature of the study there may be premorbid differences in brain volume that are not being captured. Longitudinal data (such as the Adolescent Brain Cognitive Development (ABCD) Study) could help to parse out these changes in brain volume in developing adolescents