Associations between peer victimization, depressive symptoms, and suicidal ideation: investigating biological underpinnings
Notice bibliographique
Résumé
Peer victimization has consistently been linked to depression and suicidal ideation in adolescence with persisting associations in adulthood. Peer victimization has been defined as harm caused by peers outside the norms of appropriate conduct (e.g., being insulted, harassed, robbed, or hit). This thesis is based on three manuscripts (henceforth referred to as Chapters 1, 2, & 3), and aimed to fill specific gaps in the literature regarding the associations between peer victimization with depressive symptoms and suicidal ideation by using two population-based cohorts; Quebec Longitudinal Study of Child Development (QLSCD) and the 1958 British Birth Cohort (1958BBC). Firstly, it is unclear whether a newer form of peer victimization expressed through electronic devices; cybervictimization, is similarly associated to suicidal ideation, compared to face-to-face peer victimization. Using the QLSCD, Chapter 1 showed that both face-to-face and cybervictimization were cross-sectionally associated to suicidal ideation throughout adolescence, but the magnitude of association was stronger for cybervictimization. Being cybervictimized only or in combination with face-to-face victimization was linked to a higher risk of reporting suicidal ideation, compared to being face-to-face victimized only. However, while face-to-face victimization predicted suicidal ideation 2 years later, cybervictimization was not a predictor after adjusting for baseline suicidal ideation. Secondly, little is known about the biological mechanisms behind the associations between peer victimization with depressive symptoms and suicidal ideation. Several biomarkers, including genetic variants and DNA methylation sites, have been studied in association with peer victimization, depressive symptoms, and suicidal ideation, independently. However, the literature is largely inconsistent, and lacking in the context of peer victimization. Building on Chapter 1 as well as prior findings with QLSCD showing that peer victimization was also associated to depressive symptoms, we sought to further understand who is more at-risk. In Chapter 2, we used a novel marker of genetic vulnerability for depression, the polygenic risk score for depression (PRS-depression), and test whether it influenced the associations between peer victimization, depressive symptoms, and suicidal ideation in adolescence. Chapter 2 results showed that PRS-depression was associated with depressive symptoms in adolescence but did not interact with peer victimization in predicting depressive symptoms or suicidal ideation. Another potential mechanism at the interface between the environment and genetics; epigenetics, was explored using epigenetic indices of biological aging (Horvath, Skin & Blood, and PedBE clocks), epigenetic pace of aging (DunedinPACE), and stress response reactivity (Epistress score). Thirdly, some studies have investigated Horvath epigenetic age in association with early life adversity, depressive symptoms, and suicidal ideation, with inconsistent findings. In addition, few have explored whether epigenetic age partly explained the associations of peer victimization with depressive symptoms and suicidal ideation. Chapter 3 used a two-cohort design using the QLSCD and the 1958BBC with information on depressive symptoms and suicidal ideation in adolescence and adulthood. Our findings unraveled some associations between epigenetic aging, as well as the DunedinPACE score, and depressive symptoms. However, no association was found between epigenetic indices and peer victimization, or suicidal ideation, hence there was no evidence of epigenetic mediation. Overall, this thesis has expanded on studies investigating peer victimization in association with depressive symptoms and suicidal ideation, specifically on potential underlying biological mechanisms, and clarifying the associations with cybervictimization
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,005 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,001 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,001 | 0,001 |
| Science ouverte | 0,001 | 0,001 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».