Research linking basal cortisol levels with internalizing and
externalizing behavior problems in youths has yielded inconsistent
results. We hypothesize that the high moment to moment variation in
adrenocortical activity requires an analytical strategy that separates
variance in cortisol levels attributable to “stable traitlike”
versus “state or situationally specific” sources. Early
morning saliva samples were obtained from 724 youths (M age =
13.5 years; range = 6–16 years in Year 1) on 2 successive days 1
year apart. Latent state–trait modeling revealed that 70% of the
variance in cortisol levels could be attributed to statelike sources, and
28% to traitlike sources. For boys only, higher levels of externalizing
problem behaviors were consistently associated with lower cortisol
attributable to traitlike sources across 3 years of behavioral assessment.
The inverse association between individual differences in cortisol and
externalizing problem behavior has previously only been reported in
studies of at-risk or clinical groups. The present findings suggest the
relationship is a stable phenomenon that spans both normative and atypical
child development. Studies are needed to reveal the biosocial mechanisms
involved in the establishment and maintenance of this phenomenon, and to
decipher whether individual differences in this hormone–behavior
link confers risk or resilience.This
research was supported in part by the Behavioral Endocrinology Laboratory,
and the Population Research Institute (PRI) at Pennsylvania State
University, as well as the W. T. Grant Foundation (Grant 9617796). PRI has
core support from the National Institute of Child Health and Development
(Grant 1-HD28263). Collection of data on family process and child
psychosocial functioning was supported by two grants from the National
Institute of Child Health and Human Development (HD 32336 and HD 29409) to
Ann Crouter and Susan McHale.