Low salivary cortisol levels are associated with externalizing but not internalizing behavior problems

by Shirtcliff, Elizabeth A.

Research relating salivary cortisol levels with internalizing and externalizing behavior problems in youth has yielded inconsistent results. The high day-to-day variation in adrenocortical activity may require an analytical strategy that separates variance in cortisol levels attributable to “stable trait-like” versus “state- or situationallyspecific” sources. Early morning saliva samples were obtained from 654 low risk youth (M age = 13.5 yrs; range 6-16 yrs in year 1) on two successive days one year apart. Latent state trait modeling revealed that 70% of the variance in cortisol levels could be attributed to state-like sources, and 28% to trait-like sources. For boys only, higher levels of externalizing problem behaviors were consistently associated with lower cortisol attributable to trait-like sources across all three years of behavioral assessment. The inverse association between individual differences in children’s cortisol and externalizing problem behavior is reported in studies of at-risk and clinical groups. The present findings confirm the relationship spans both normative and atypical child development, and supports speculations that boys with low cortisol may be at risk for externalizing behavior problems. iv