Polygenic risk score and peer victimisation independently predict depressive symptoms in adolescence: results from the Quebec Longitudinal Study of Children Development

Background Peer victimisation has been associated with depressive symptoms during adolescence, however not all peer victimised adolescents will exhibit such symptoms. This study tested whether having a genetic predisposition to developing depression increased the risk of experiencing depressive symptoms in peer victimised youth. To date, no study has explored such gene–environment interaction using a polygenic risk score for depression (PRS‐depression) in the context of peer victimisation and depressive symptoms in adolescence. Methods The sample included 748 participants born in 1997/98 from the Quebec Longitudinal Study of Child Development with genotype data and prospectively collected information on peer victimisation (12–13 years) obtained from both self‐ and teacher‐reports, as well as self‐reported depressive symptoms (15–17 years). The PRS‐depression was based on the genome‐wide association meta‐analysis of broad depression by Howard et al. (2019). Results Self‐ and teacher‐reported peer victimisation in early adolescence were both associated with depressive symptoms in adolescence (β = 0.34, p