Impact of Family Violence on Antisocial Behaviors in Two Developmental Periods: the Investigation of the Moderating Role of a Haplotypic Serotonergic Polygenic Score

Children exposed to family violence, such as child-directed and child-witnessed parental violence, tend to manifest higher levels of antisocial behaviors later in life. Genetically informed studies additionally show that antisocial behaviors are partly inherited. While there is a consensus about the polygenic nature of antisocial behavior, it remains unclear as to whether the differences present at the DNA level moderate the impact of parental violence on antisocial behaviors. This study tested whether children who were the victims of, or who witnessed, family violence exhibit more antisocial behaviors once they reach adolescence and early adulthood, and whether this risk varied according to a serotonergic polygenic index. Participants were 410 male members of the Quebec Longitudinal Study of Kindergarten Children. Child-directed and child-witnessed parental violence and participants’ antisocial behaviors were self-reported or assessed through semi-structured interviews. Previously derived haplotype-based polygenic indexes mapping to 11 serotonergic genes were used. Participants who were the victims of, or witnessed parental violence, were generally at higher risk of manifesting antisocial behaviors. Findings also offered a partial support to prior evidence for gene-environment interactions in some, but not all antisocial outcomes. Participants who were victims of child-directed parental violence and carried lower serotonergic risk were at higher risk of manifesting property or violent crimes in adulthood, supporting the Social-push model. Alternatively, participants who witnessed intra-parental violence were at higher risk of exhibiting symptoms of conduct disorder and antisocial personality disorder if they carried a higher number of haplotypic risk alleles, lending support to the Diathesis-stress model. This study extends prior work by emphasizing the need to separately investigate distinct forms of family violence and to use indicators of risk capturing variants present across multiple genes to better understand their independent and joint contributions to antisocial behaviors over the life course.