Individual differences in early adolescents' latent trait cortisol: Interaction of early adversity and 5-HTTLPR

•Greater early adversity was linked to lower latent trait cortisol (LTC).•5-HTTLPR moderated the association between early adversity and LTC.•The inverse link of early adversity and LTC was larger among L-carriers of 5-HTTLPR.•5-HTTLPR may contribute to the variability in cortisol responses to adversity.

The present study aimed to examine the interaction of 5-HTTLPR and early adversity on trait-like levels of cortisol. A community sample of 117 early adolescent girls (M age = 12.39 years) provided DNA samples for 5-HTTLPR genotyping, and saliva samples for assessing cortisol 3 times a day (waking, 30 min post-waking, and bedtime) over a three-day period. Latent trait cortisol (LTC) was modeled using the first 2 samples of each day. Early adversity was assessed with objective contextual stress interviews with adolescents and their mothers. A significant 5-HTTLPR × early adversity interaction indicated that greater early adversity was associated with lower LTC levels, but only among individuals with either L/L or S/L genotype. Findings suggest that serotonergic genetic variation may influence the impact of early adversity on individual differences in HPA-axis regulation. Future research should explore whether this interaction contributes to the development of psychopathology through HPA axis functioning.