Effects of Candidate Genes and Polygenic Risk on the Development of Depression in Youth Experiencing Peer Victimization

Kim, Min Jae

Effects of Candidate Genes and Polygenic Risk on the Development of Depression in Youth Experiencing Peer Victimization

dc.contributor.advisor	Arnold, Paul D.
dc.contributor.author	Kim, Min Jae
dc.contributor.committeemember	Bousman, Chad A.
dc.contributor.committeemember	Long, Quan
dc.date	2024-11
dc.date.accessioned	2024-10-16T19:06:20Z
dc.date.available	2024-10-16T19:06:20Z
dc.date.issued	2024-10-16
dc.description.abstract	Background: Peer victimization is a common form of childhood adversity, where children who have experienced victimization have an increased susceptibility to various psychiatric disorders including depression. However, environmental influences have varying degrees of effect between individuals, and therefore our study focused on how genetic predisposition in conjunction with environmental factors interacts to confer risk for depression. Gene by environment (G x E) interaction studies with a focus on candidate genes and polygenic risk scores (PRS-depression) have been conducted in the past for depression, but with inconsistent findings. Testing both candidate genes and PRS, and their interaction with environmental factors, may be a promising approach for understanding the complex aetiology of depression. Methods: Longitudinal data from the McMaster Teen Study have been obtained, where students initially assessed from age 10 (Grade 5) were followed to age 26 (n=875). A computer-based self-reported questionnaire was used to obtain participants’ peer victimization experience and depressive symptoms from age 10 to 26, along with their genotype data. Dopamine transporter gene (DAT1/SLC6A3), monoamine oxidase A gene (MAOA), and the serotonin transporter gene (SLC6A4) were selected for candidate gene analysis. Depression-PRS was calculated using the genome-wide metaanalysis of depression by Howard et al. (2019). Results: Peer victimization was significantly associated with depressive symptoms in adolescence (p < 0.05). Candidate gene polymorphisms and depression-PRS were not significantly associated with depressive symptoms (p > 0.05). Furthermore, there were no significant candidate gene by peer victimization and PRS-depression by peer victimization interactions associated with depressive symptoms. Conclusion: Through our study, findings suggest that exposure to peer victimization experience was independently associated with an increased risk of depressive symptoms in adolescence. Both candidate genetic variants and polygenic risk scores did not have a significant main effect on depression risk. Lastly, neither candidate gene risk nor polygenic risk of study participants were significantly associated with depression following peer victimization experiences. Future studies will greatly enhance our knowledge on how genetic risk plays a potential role in explaining individual differences in the development of depression following adverse environmental exposures, including peer victimization. Keywords: Peer victimization, depression, candidate gene, polygenic risk score, gene by environment interaction, adolescence
dc.identifier.citation	Kim, M. J. (2024). Effects of candidate genes and polygenic risk on the development of depression in youth experiencing peer victimization (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.
dc.identifier.uri	https://hdl.handle.net/1880/119980
dc.language.iso	en
dc.publisher.faculty	Graduate Studies
dc.publisher.institution	University of Calgary
dc.rights	University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subject	Depression
dc.subject	Peer Victimization
dc.subject	Candidate Gene
dc.subject	Genome Wide Association Study
dc.subject	Polygenic Risk Score
dc.subject	Gene by Environment Interaction
dc.subject	Adolescence
dc.subject.classification	Genetics
dc.subject.classification	Mental Health
dc.title	Effects of Candidate Genes and Polygenic Risk on the Development of Depression in Youth Experiencing Peer Victimization
dc.type	master thesis
thesis.degree.discipline	Medicine – Medical Sciences
thesis.degree.grantor	University of Calgary
thesis.degree.name	Master of Science (MSc)
ucalgary.thesis.accesssetbystudent	I do not require a thesis withhold – my thesis will have open access and can be viewed and downloaded publicly as soon as possible.