Furthermore, among studies that examined the GxE interaction, the pattern of that interaction varied. Some studies using measures of major life events replicated the additive effect of the S allele [11–13], but others reported a recessive model (S/S vs. S/L or L/L) [14–18] and many found no GxE interaction [19–24]. Among studies investigating the GxE interaction with trauma, one study replicated the additive effect of the S allele among girls (but not boys) exposed to traumatic family conflicts [12], whereas another reported the reverse relationship (number of L alleles associated with higher risk) among those who experienced traumatic events [25]. Studies focusing on child abuse have reported a recessive effect [26–28], a dominant model [29], or no GxE interaction [28, 29].
