HLM Analysis of The Cortisol Awakening Response in Abused Adolescents
The cortisol awakening response (CAR) is an increase in the release of cortisol primarily during the first hour after waking up from sleep. Multiple avenues of research have shown that a history of abuse can affect the CAR. This study uses hierarchical linear modeling (HLM) informed by a variety of measured parameters to predict the cortisol awakening response within two populations: depressed adolescents with a history of abuse, and depressed adolescents with no history of abuse. The goal of this study is to help profile some of the neurobiological changes in adolescents who have sustained abuse. Three brain clusters were identified to be particularly important through HLM analysis: a cluster containing the Insula, Superior Temporal Gyrus, Putamen, Lentiform Nucleus, and Brodmann’s Areas (BA) 13, 21, and 22, a cluster containing the Lingual Gyrus, Cerebellum, Fusiform, Parahippocampus, Brainstem, Inferior Temporal Gyrus, Thalamus and BA 13, 21, and 22, and a cluster containing the Cerebellum, Occipital Lobe, Lingual Gyrus, Parahippocampus, Fusiform, Thalamus, Precuneus, BA 19, 20, 27, and 30. The HLM also showed a more general association between salivary cortisol levels from wake-up to 30 minutes after wake-up and the duration of time that an adolescent sustained abuse.