Grant: Travel Awards - Institute Community Support

As the infant temperamental trait negative emotionality (NE) has been frequently linked to childhood anxiety and depression, understanding its biological and environmental origins will help to better understand how these disorders develop. Maternal stress is one potential environmental factor that, when experienced by the developing fetus during pregnancy, has been found to increase susceptibility to adversity later in life. In some cases prenatal maternal stress has been found to interact with 5-HTTLPR, a vulnerability gene, such that infants who are carriers of a specific genetic variant of the 5-HTTLPR genotype have experienced an increase in susceptibility to adverse behavioural outcomes only when exposed to stress during the prenatal period. The present investigation examined if this link might predict behaviour patterns of NE in infants between 3 and 36 months of age. In addition, as development is continuous during pregnancy, we also examined whether stress exposure during trimester 2 and/or trimester 3 would differentially affect NE in infancy. Our analysis revealed that both anxiety and depression experienced during the 2nd and 3rd trimester of pregnancy predicted maternal ratings of NE at 3 months of age only in infants who were carriers of the vulnerability genetic variant in 5-HTTLPR. These results suggest the importance of stress prevention during pregnancy and that prenatal stress experienced as early as the second trimester can have behavioural effects. Since the interaction effect was no longer significant at 18 and 36 months, one wonders about other environmental factors, such as postnatal maternal depression, as they may be involved in the development of infant NE after 6 months of age.