title: Stability and change in cortisol and behavioral response to stress during the first 18 months of life.
abstract: Observation of cortisol and behavioral responses to routine inoculation was conducted at 18 months for infants in a longitudinal sample whose stress responses had been observed at 2, 4, and 6 months of age. At 18 months, infants showed an increase in cortisol level over base to the perturbation. The magnitude of this response did not differ from the 6-month response. Moreover, level of cortisol response at 18 months was related to level of cortisol response at 6 months, but not at 2 or 4 months of age. In light of previous findings for a decline in cortisol response between 2 and 6 months had for the emergence of consistent individual differences in cortisol response by 4 to 6 months, the present findings indicate that a developmental shift in adrenocortical functioning has occurred by 6 months of age.
authors.affiliation: Institute for the Study of Child Development, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, New Brunswick 08903-0019, USA.
authors.forename: M
authors.initials: M
authors.lastname: Lewis
authors.forename: D
authors.initials: D
authors.lastname: Ramsay
mesh_terms: D000223:Adaptation, Psychological / Q000502:physiology; D000302:Adrenal Cortex / Q000503:physiopathology; D000367:Age Factors; D001143:Arousal / Q000502:physiology*; D002657:Child Development / Q000502:physiology*; D005260:Female; D006185:Habituation, Psychophysiologic / Q000502:physiology; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007223:Infant; D008297:Male; D013315:Stress, Psychological / Q000150:complications* / Q000503:physiopathology
chemical_list: D006854:Hydrocortisone