the short SERT allele is associated with increased risk of early onset depression in response to maltreatment in childhood (Caspi et al., 2003) thus demonstrating a gene by ELS interaction. In Rhesus monkeys, Bennett et al. (2002) showed that animals carrying one “short” SERT gene were more sensitive to adverse early care. There are numerous interactions between serotonin and GCs during development (Lopez et al., 1998; Mitchell et al., 1992). Furthermore, there is evidence that disturbances to the serotonin system produced by early parental deprivation in the rat may be mediated by activity of the L-HPA system (Vazquez et al., 2002). Studies of the interaction of polymorphisms in genes regulating the serotonin system and stressors affecting the L-HPA system during development are needed in both animal models and studies of human development.
