Excessive drinking in adolescence is a public health issue with major consequences on both an individual and societal level. Elucidating genetic and environmental influences could be particularly informative for prevention efforts. One potential source of genetic influence is sensitivity to environmental influences. It was hypothesized that parent knowledge would interact with genetic sensitivity to the environment to indirectly reduce risk for alcohol problems through less adolescent rule breaking behavior. Participants (N=316) provided genetic data and reported their rule breaking behavior and past year frequency of heavy drinking, and participants’ custodial parents reported their perceived knowledge of their child’s activities. A novel index of genetic sensitivity to environmental influence was created using published methylation quantitative trait locus data from the frontal lobe. Study hypotheses were mostly not supported. The study results likely reflect the poor distribution of study variables and the limitations of the current study’s sensitivity gene score. The current study underscored the importance of adhering to methodological rigor and explored alternate conceptualizations and methods that future research could use to elucidate the role of inherited to sensitivity to environmental influences in adolescent drinking.

The transition from adolescence to young adulthood is an important developmental period, as youth experience rapid changes in many domains of their lives (Settersten & Ray, 2010). These transitions have been linked to both positive and negative turning points in youths’ behavior and psychosocial wellbeing (Elder & Shanahan, 2007). Being disengaged from work and school, two important social institutions involved in the transition to adulthood (Havighurst, 1972), has been associated with poorer mental health and increases substance use; in this literature, there is still a dearth of research among youth in the United States of America and on the developmental implications of disengagement (Hilley et al., 2019). Therefore, this dissertation includes two studies to address these gaps with respect to mental health and substance use. Study 1 explores the heterogeneity in youths’ engagement and disengagement from work and school at two developmentally relevant time points across the transition to adulthood rather than impose a priori definitions of disengagement. Next, this study explores whether risk and protective factors predict membership in these subgroups. Finally, this study examines subgroup differences in problematic substance use concurrently and longitudinally. Study 2 investigates the cross-lagged associations between opportunity youth (or youth who are neither in school nor working) status and mental health over the transition to adulthood and explores whether familial social support and socioeconomic status mitigate or exacerbate the influence of opportunity youth status on mental health. Findings from these studies support the developmental nature of disengagement (despite its heterogeneity) and its connection with mental health and substance use, as well as suggest the need for additional research into risk and protective factors.

Studies have demonstrated that telomere length is influenced by a person’s perception of stressors and other studies suggest that interparental conflict is a stressor for children. The current study sought to determine if child perception of interparental conflict is a better predictor of telomere length than parent perception of interparental conflict. This study also sought to determine whether behavior problems are the medium for how child perception of conflict influences telomere length. Using multiple regression analyses between reports of interparental conflict, reports of child behavior problems, and child telomere length ratios, it was determined that child report of conflict was a better predictor of behavior problems and telomere length. Child report of behavior problems was the medium whereby child report of conflict predicted telomere length. While these results were not significant, it does provide the first evidence that child perception of interparental conflict influences telomere length more than parental report of interparental conflict. This suggests that intervention programs designed to reduce conflict between parents should include a method for helping children process their feelings about of interparental conflict to preserve telomere length.

Rapidly growing research on mothers’ perinatal depression, has demonstrated significant links among mothers’ depressive symptoms during pregnancy and the first year postpartum, their parenting, and multiple aspects of children’s development. This prospective longitudinal study contributes to research on mothers’ perinatal depression by examining the mechanisms by which maternal perinatal depression is associated with children’s adjustment early in development in a sample of 204 Mexican-origin adolescent mothers (Mage at Wave 1 = 16.80, SD = 1.0) and their children (58% boys). I expected that adolescent mothers’ negative parenting behaviors would mediate the associations between mothers’ perinatal depressive symptoms and three child outcomes: internalizing symptoms, externalizing behaviors, and cognitive ability. I further hypothesized that mothers’ perceived social support from their family would modify the extent to which mothers’ perinatal depressive symptoms negatively impact their parenting behaviors and their children’s developmental outcomes. Mothers reported on their own depressive symptoms, their perceived social support from their family and their children’s internalizing and externalizing problems; negative parenting was assessed using observational methods; and children’s cognitive ability was assessed using standardized developmental assessments. In this sample, adolescent mothers’ negative parenting behaviors did not significantly mediate the relations between mothers’ perinatal depression and children’s developmental outcomes. Further, perceived social support did not significantly buffer the effects of mothers’ perinatal depression on mothers’ negative parenting or children’s developmental outcomes. However, in line with hypotheses, results indicated that mothers’ prenatal depression had a wider impact on children’s adjustment outcomes than mothers’ postpartum depression, which appeared more specific to children’s internalizing problems. Discussion focuses on implications for intervention addressing adolescent mothers’ perinatal depression, as well as the need to continue to explore protective factors that have the potential to disrupt the negative intergenerational transmission of risks.

This study examined whether early adversity at 30-months moderated the heritability of common and individual components of EF at 8 years. It was hypothesized that early adversity would not moderate the common EF factor, but instead moderate individual EF components. The sample included 208 twin pairs from the Arizona Twin Project. Early Adversity, assessed at 30 months of age, included Parenting Daily Hassles, low perceived MOS social support, punitive punishment (Parental Responses to Child Misbehavior), home chaos (Confusion, Hubbub, and Order Scale), CES-D maternal depression, and low maternal emotional availability. EF at 8 years included the Eriksen Flanker Task, Continuous Performance Task, Digit Span Forward and Backward, and parent-reported Attentional Focusing and Inhibitory Control (Temperament in Middle Childhood Questionnaire). For both early adversity and EF, the first principal components were extracted as composites. A confirmatory factor analysis was also conducted to index common EF. Genetic analyses were tested on the common EF composites as well as each individual task using umx. Univariate models revealed genetic influences on all individual measures and common EF, with broad sense heritability from .22 (Digit Span Backwards) to .61 (parent-reported inhibitory control). Shared environmental influences were found for the Flanker Task (.13) and parent-reported inhibitory control (.24), and E was moderate to high (.40-.73) for all measures except parent-report inhibitory control (.15) and attentional focusing (.31). Moderation of heritability was not observed in for Digit Span Forward, Digit Span Backward, and Attentional Focusing. However, the nonshared environment was moderated for Common EF, and the Flanker Task, and additive genes and the nonshared environment were moderated for the Continuous Performance Task and Inhibitory Control. Generally, total variance decreased as early adversity increased, suggesting that homes with low levels of adversity may allow children to interact with more proximal processes that can promote EF development.

Adolescent mental health problems are predicative of future problems such as depression, anxiety, ADHD, compulsive disorder, and substance use. Previous studies show that in emerging adulthood, the high prevalence and associated burdens of psychopathology increase vulnerability to disorders. These diagnoses are less common but are more severe and chronic (Tanner et al., 2009). The causes of these disorders are still being explored with recent studies showing that these mental health problems are genetically influenced. This makes understanding which gene that corresponds to what biological system is important in determining mental health. From recent studies, genes that code for calcium channels are good candidates for mental health problems. These voltage-gated channels are important mediators for physiological functions in the central nervous system and their activation provides unique responses within the brain. In a previous study, it supports the association of polymorphisms in calcium and potassium channels with the genetic risk for bipolar disorders and other mental illness (Imbrici et al., 2013). The purpose of the study was to examine if calcium channel genes influence childhood psychiatric symptoms. The first goal of this study was to form a polygenic risk score representing genetic influence on calcium channels. The second goal was to use this risk score in genetic association analyses to understand genetic risk for childhood psychopathology. Overall, the study did accomplish the goal as a polygenic risk score was created and was used to examine genetic association with child psychopathology. Based on the results, the polygenic risk score was not correlated with either parent or child- reported symptoms; however, results did show that disorders were related to each other and differed by race.

Effortful Control (EC) is a person's ability to self-regulate when presented with an environmental stimulus (Rothbart, et al., 2003). It has been well-established that high levels of EC are associated with multiple positive social and academic outcomes in adolescence (Spinrad et al., 2009). Research suggests that parents have a strong impact on numerous child outcomes, such as EC, through both genetic and environmental pathways. Past research has also examined how parents diagnosed with psychopathology contribute to maladaptive outcomes in their children, including poor regulation, through both genetic and environmental processes (Ellis, et al., 1997). However, less is known about the longitudinal effects of parent dysfunction on the child's environment and regulatory abilities and potential mediators of those effects. The current study tested the hypotheses that parent Alcohol Use Disorder (AUD) would specifically predict early adversity, biological mother conscientiousness, and child EC longitudinally and that early adversity and biological mother conscientiousness would predict child EC. Participants were from a longitudinal study of familial alcoholism (N = 195). Regression analyses indicated that parent AUD was not specifically associated with child EC or with biological mother conscientiousness. However, parent AUD was related to higher levels of early adversity. Additionally, biological mother conscientiousness was associated with higher levels of child EC and early adversity was associated with lower levels of child EC when controlling for earlier EC. Given these findings, future research should test mediation models in which parent AUD predicts child EC indirectly through early adversity.