Cortisol Awakening Response in Preschoolers and Depression Risk: Relations with Maternal History of Depression and Child Temperament

Increasing research suggests that elevations in the cortisol awakening response (CAR), the natural increase of cortisol 30 to 40 minutes after waking, may serve as a vulnerability marker for depression. However, existing studies have focused on adolescence and adulthood; very little is known about the CAR in early childhood and the factors that are associated with it. The current study aimed to examine the validity of the CAR as a potential early-emerging vulnerability marker for depression in a sample of preschool-age children. We examined associations between the CAR and two well-established risk factors for depression: maternal psychopathology and early child temperament (high negative emotionality (NE) and/or low positive emotionality (PE)). The sample consisted of 146 preschool-age children, of whom 71 (49.3%) had a biological mother with a history of depression and 65 (45.5%) had a biological mother with a history of anxiety. To assess the CAR, salivary cortisol samples were collected from the child upon waking, 30 and 45 minutes post-waking on two weekdays. Children’s CAR was examined as the total volume of cortisol secreted (AUCg) and the total increase in cortisol (AUCi) across waking. Evening cortisol was collected 30 minutes before bedtime. Child temperament was assessed using observational laboratory measures. Maternal depression and anxiety were assessed with clinical interviews. Associations with children’s CAR, as indicated by AUCg or AUCi, appeared to be specific to maternal current psychopathology and symptoms of anhedonia. Additionally, we observed significant interactions for both maternal lifetime and current depression and anxiety, in combination with child NE and PE, on elevated evening cortisol levels and flattened diurnal cortisol rhythms, indicating altered patterns of basal cortisol activity in offspring. Our study contributes to the limited but growing knowledge on the development of the CAR in preschool age children and as a marker of early risk. Findings suggest that there is a complex interplay between familial risk, affective vulnerability, and their joint effects on neuroendocrine dysfunction in young children, and highlight the need for future research to examine which aspects of the early diurnal rhythm predict the emergence of later depressive illness.

CIVIL WAR SETTLEMENTS AND COMBATANTS’ BEHAVIORS: STRATEGY, PERCEPTION, AND REPUTATION

Three projects in my dissertation focus on the termination of internal conflicts based on three critical factors: a combatant’s bargaining strategy, perceptions of relative capabilities, and reputation for toughness. My dissertation aims to provide the relevant theoretical framework to understand war termination beyond the simple two-party bargaining context. The first project focuses on the government’s strategic use of peace agreements. The first project suggests that peace can also be designed strategically to create a better bargain in the near future by changing the current power balance, and thus the timing and nature of peace is not solely a function of overcoming current barriers to successful bargaining. As long as the government has no overwhelming capability to defeat all rebel groups simultaneously, it needs to keep multiple rebel groups as divided as possible. This strategic partial peace helps to deter multiple rebel groups from collaborating in the battlefield and increases the chances of victory against non-signatories. The second project deals with combatants’ perceptions of relative capabilities. While bargaining theories of war suggest that war ends when combatants share a similar perception about their relative capabilities, combatants’ perceptions about relative capabilities are not often homogeneous. While focusing on information problems, this paper examines when a rebel group underestimates the government’s supremacy in relative capabilities and how this heterogeneous perception about the power gap influences negotiated settlements. The third project deals with the tension between different types of reputations in the context of civil wars: 1) a reputation for resolve and 2) a reputation for keeping human rights standards. In the context of civil wars, the use of indiscriminate violence by the government is costly, and as such, it signals the government’s toughness (or resolve) to rebel groups. I argue that the rebels are more likely to accept the government’s offer when the government recently engaged in indiscriminate violence against civilians during the conflict. This effect, however, is conditional on the government’s international human rights reputation; suggesting that rebel groups interpret this violence as a signal particularly when the government does not have a penchant for attacking civilians in general.