IntroductionNeuroticism has societal, mental and physical health relevance, with an etiology involving genetic predisposition, psychological influence, and their interaction.ObjectivesTo understand whether the association between polygenic risk score for neuroticism (PRS-N) and neuroticism is moderated by affective well-being.MethodsData were derived from TwinssCan, a general population twin cohort (age range=15-35 years, 478 monozygotic twins). Self-report questionnaires were used to measure well-being and neuroticism. PRS-N was trained from the Genetics of Personality Consortium (GPC) and United Kingdom Biobank (UKB). Multilevel mixed-effects models were used to test baseline and changes in well-being and neuroticism.ResultsBaseline wellbeing and neuroticism were associated (β=-1.35, p<0.001). PRSs-N were associated with baseline neuroticism (lowest p-value: 0.008 in GPC, 0.01 in UKB). In interaction models (PRS x wellbeing), GPC PRS-N (β=0.38, p=0.04) and UKB PRS-N (β=0.81, p<0.001) had significant interactions.PRSs-N were associated with changes in neuroticism (lowest p-value: 0.03 in GPC, 0.3 in UKB). Furthermore, changes in wellbeing and neuroticism were associated (β =-0.66, p<0.001). In interaction models (PRS x change in wellbeing), only UKB PRS-N had a significant interaction (β=0.80, p<0.001).ConclusionsInteraction between polygenic risk, wellbeing and neuroticism, were observed regarding baselines measures and change over time. Depending on the analysis step, the direction of the effect changed.Disclosure of InterestNone Declared