Pediatric obsessive-compulsive disorder (OCD) is a heterogeneous disorder associated with functional impairment and deleterious effects at the family level. Caregivers are often enmeshed in the disorder, coping with the child’s OCD-related distress and engaging in accommodating behaviors. Given the developmental level of these youth and the impactful nature of OCD, caregivers may experience considerable burden and decreased quality of life (QoL). However, extant literature on these constructs is largely limited to caregivers of patients with chronic illnesses, and the few existing studies examining OCD samples are limited to adult patients. As such, this study sought to examine burden and QoL in caregivers of youth enrolled in an intensive outpatient or partial hospitalization program for their severe OCD. Specifically, the relationships between caregiver QoL and burden and the following variables were investigated: OCD symptom severity, functioning (youth functional impairment, general family functioning), family (family accommodation, parental relationship satisfaction, positive aspects of caregiving), and comorbid psychopathology (caregiver anxiety and depressive symptoms, youth internalizing and externalizing behaviors). Seventy-two child and caregiver dyads participated in the study and completed a battery of clinician- and self-rated questionnaires. Different components of caregiver QoL correlated with caregiver-rated functional impairment, family accommodation, youth externalizing behaviors, and caregiver psychopathology. Various aspects of caregiver burden correlated with OCD symptom severity, functional impairment related to OCD, as well as caregiver and child comorbid psychopathology. Caregiver depressive symptoms predicted caregiver QoL, and caregiver depressive symptoms and child externalizing symptoms both predicted caregiver burden. Caregiver burden did not mediate the relationship between obsessive-compulsive symptom severity and caregiver QoL. Ultimately, elucidating factors associated with increased caregiver burden and poorer QoL are pertinent for the identification of at-risk families and development of targeted interventions.

Although researchers have often focused on the victims of aggression, the detrimental effects of engaging in aggression and/or displaying symptoms of externalizing disorders have been clearly identified in children and adolescents. Longstanding consequences of externalizing problems include internalizing difficulties such as depression. There is an increasing interest in identifying the direction of effect and understand whether externalizing problems precede internalizing problems, vice-versa, or whether they share a bi-directional relation. However, the study of the temporal sequence between aggression, externalizing disorders, and internalizing disorders in children and adolescents has yielded inconsistent findings. The sequential relation between externalizing and internalizing difficulties in children and adolescents was examined in this dissertation consisting of three studies. In Study 1, the moderating role of worry in the relation between aggression and depression was examined. The sample consisted of girls nominated as either relationally or physically aggressive by their peers. Results indicated that worry exacerbated the risk of reporting elevated depressive symptoms concurrently and one year later for physically aggressive girls. In Study 2, three competing hypotheses on the longitudinal relation between aggression and depression were compared. Findings from this study supported the hypothesis that symptoms of depression are preceded by aggressive behaviour. Additionally, it was found that engaging in physical aggression predicted depressive symptoms for girls but not for boys. The results of the first two studies suggest that for girls, engaging in non-normative forms of aggression is associated with greater mental health problems. In Study 3, the temporal relation between symptoms of externalizing disorders, namely oppositional defiant disorder and conduct disorder, and symptoms of depression was examined. Results provided support that the progressive relation between symptoms of externalizing and internalizing disorders was bi-directional. In summary, although it seems that engaging in externalizing behaviour, such as aggression, predicts symptoms of depression, findings from the third study suggest that the sequential relation between symptoms of externalizing problems, which may or may not include aggressive behaviour, and symptoms of depression seem to share a reciprocal relation.

The current study aimed to evaluate multiple longitudinal determinants of externalizing behavior problems in twins/triplets aged 7 to 12 years. Specifically, a prospective longitudinal design was utilized to assess relationships between age 5 sleep problems, age 5 temperament traits, and later externalizing problems. Additionally, heritability of sleep problems was assessed by utilizing the twin method, and genetic contributions of two specific genes – DRD4 and 5-HTTLPR – were evaluated. A total of 93 twins/triplets (40 boys and 53 girls) and their parents participated in the current study, and data were collected through self-report, parent-report, and molecular and behavioral genetic methods. Results suggest that sleep disturbances are significantly heritable, and that neither early sleep problems, temperament traits, nor specific genes significantly predicted follow-up externalizing problems. Post-hoc analyses assessing gene X environment interactions showed that externalizing problems were significantly predicted by the interaction between stressful life events and DRD4 risk, which is consistent with differential susceptibility models. This study has implications for future research as well as clinical practice, including for early screening, prevention, and intervention efforts aimed at decreasing childhood externalizing and sleep problems.

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The current study utilized laboratory tasks (Conners' Continuous Performance Test, CPT; Behavioral Inhibition Task, BIT) to examine the relationships among motivation, executive functioning, and parent and teacher-reported attention, internalizing, and externalizing problems in a clinical sample of 132 children with or without Attention-Deficit/Hyperactivity Disorder, Combined Type (ADHD-C; 69% male, mean age = 9.88). Specificity was examined through total, unique, and interactive effects via hierarchical regression. Higher CPT scores (i.e., executive disinhibition) were related to greater externalizing problems in total and unique effect analyses, while a relationship between lower CPT scores (i.e., executive inhibition) and greater internalizing problems was found only in unique effect analyses. No significant effects were found for motivational inhibition (i.e., low BIT) or disinhibition (i.e., high BIT). ADHD-C was associated with greater attention and externalizing problems in total effect analyses, but only externalizing problems showed a significant relationship in unique effect analyses. Interactive effects were found for ADHD-C and executive functioning, as lower levels of CPT (i.e., executive inhibition) coupled with ADHD-C resulted in greater parent-reported attention problems. In addition, higher CPT scores (i.e., executive disinhibition) were associated with greater parent-reported externalizing problems in Non-ADHD-C children. Although some main effects were predicted, the interactive effects were somewhat surprising, particularly in relation to ADHD-C, executive inhibition, and parent-reported attention problems. Exploratory analyses revealed that this effect may have been due to greater internalizing problems in ADHD-C children at lower levels of CPT (i.e., executive inhibition). Results are discussed in relation to past studies and laboratory task validity. / Master of Science

My thesis project aimed to assess potential meaningful differences in the behavioral subtypes of externalizing behaviors in children. Externalizing behaviors are a style of behavioral adjustment that are characteristic of early childhood behavior problems. They are commonly measured in developmental and clinical research using the Externalizing Scale of the Child Behavior Checklist (CBCL). The scale is comprised of Aggressive and Rule-Breaking Behaviors, which are divergent in their developmental trajectory and personological distinctions: aggressive behaviors have emotional underpinnings like frustration, whereas rule-breaking is linked to behavioral impulsivity. In situations of low regulation, negative affectivity may differentially predispose children to these behaviors due to a reactive propensity for anger and frustration. Attentional control can act to regulate these behaviors through shifting and focusing of attention, but may execute this regulation differently based on the situational context. The role of contextual attentional control in predicting two distinct externalizing behaviors has not been sufficiently evaluated in children. AC was behaviorally coded for during a frustrating context. Child behavior problems and temperament were assessed via parent report. Two mediation models were assessed with NA, AC, and aggressive and rule-breaking behaviors, but no indirect effects were found. When individual components of AC were assessed separately as moderations as opposed to mediations, attention shifting played a prominent role and moderated both the aggressive and rule-breaking models. Findings further clarify the role of attention in the relation between temperament and childhood behavior problems. / M.S. / Behavior problems in early childhood consist of aggressive and rule-breaking behaviors, which are distinct behaviors with meaningful differences in how they develop. Aggressive behaviors are marked by physical tendencies such as hitting and fighting, whereas rule-breaking behaviors tend to be non-aggressive, consisting of more impulsive behaviors like stealing, cheating, and lying. Negative affectivity in toddlerhood is a predictor of both behaviors, reflecting a heightened predisposition towards negative emotions like anger and frustration. Attentional control is a form of self-regulation, consisting of shifting and focusing attention, that may be responsible for regulating the impact of negative affectivity on each externalizing behavior. Additionally, attentional control in childhood may regulate each behavior differently based on context. The goal of the current study was to understand how negative affectivity predicts each behavior differently through attentional control, specifically based on the context it is measured in. Aggressive behaviors, rule-breaking behaviors, and negative affectivity were measured using parent-report questionnaire, and attentional control was behaviorally coded for during a frustrating puzzle task. Two mediation models were assessed with negative affectivity, attentional control, and aggressive and rule-breaking behaviors, but there were no significant findings. When individual components of attentional control (shifting and focusing) were assessed separately as moderators, attention shifting moderated the relation between negative affectivity and both aggressive and rule-breaking behaviors. Findings further clarify the role of attention in the relation between temperament and childhood behavior problems.

Aggression is a heterogeneous behavior that has been conceptualized by two distinct but inter-related functions: proactive and reactive aggression (Dodge, 1991). Proactive aggression has been linked to externalizing behaviors and reactive aggression to internalizing behaviors (Vitaro, Gendreau, Tremblay, & Oligny, 1998). There has been some evidence to suggest that family environment may influence the relationship between the aggressive functions and the related forms of psychopathology (Dodge, 1991). However, given the limited research pertaining to the relationships among aggression, family environment, and subsequent psychopathology, the current study explored the nature of the relationships among these variables in more detail. The present study hypothesized that proactive aggression would be related to externalizing symptoms (delinquency, hyperactivity), and these relationships would be moderated by family conflict. In addition, it was predicted that reactive aggression would be related to internalizing symptoms and inattention, and these relationships would be moderated by family conflict, cohesion, and control. The study included a sample of 135 children and their parents who completed several self-report measures. Overall, the findings did not support the hypotheses, though there was mixed support for the relationship between the aggressive functions and internalizing and externalizing symptoms. / Master of Science