Reviews summarizing hundreds of studies cite Parent Management Training (PMT) and Cognitive-Behaviour Therapy (CBT) as some of the most effective interventions for aggressive youth (e.g., Brestan and Eyberg, 1998). However, variability in outcomes persists, and we have yet to understand why certain interventions only produce behaviour change in some children. Using a clinical sample of 57 children (53 boys, 4 girls) and their mothers enrolled in a combined PMT/CBT program, the current study examined the relation between changes in real-time parent-child interactions, and children’s externalizing outcomes from pre- to post-treatment. Results showed that dyads who were regulated in their interactions over time reported greater reductions in externalizing symptoms from pre- to post-treatment compared to dysregulated dyads. Changes in mean levels of affective content (e.g., negativity) were not associated with aggressive outcomes. Findings suggest that dyadic regulation may be an important process associated with treatment success for aggressive youth.

Research has shown that social pressure is related to treatment motivation and plays an important role in treatment engagement in adults with problematic substance use. Despite the shifts in autonomy and decision-making in emerging adulthood, the factors affecting treatment motivation (e.g., readiness to comply with treatment) and motivation to change (e.g., problem recognition and taking steps towards change) during this period have been largely ignored. In this study, 134 youth presenting to an outpatient substance abuse program completed questionnaires investigating substance use history, mental health, social pressure to reduce use and enter treatment, and motivation. Results indicated that peer pressure accounted for significant variance in internal positive and internal negative treatment motivation. Family pressure was related only to external treatment motivation. Neither social network source had a significant impact on motivation to change. Limitations, directions for future research and treatment implications are discussed.

Paediatric posterior fossa tumors are often effectively controlled with a combination of radiation, chemotherapy and surgery. However, therapeutic craniospinal radiation has been associated with widespread cognitive late effects. Working memory is one such cognitive ability that has yet to be fully examined in this clinical population. Bilateral tracts connecting the cerebellum with the DLPFC were delineated using DTI tractography in all participants, replicating the cerebrocerebellar pathway outlined in an animal model. There were observable differences in white matter integrity (quantified by DTI measures of anisotropy, and mean, axial, and radial diffusivity) of the cerebellum-DLPFC pathway in patients versus controls. Additionally, working memory deficits that were found in patients were correlated with DTI indices pertaining to the cerebellum-DLPFC pathway. Therefore, this thesis is the first to explore the possible relations between white matter integrity of this pathway following treatment for paediatric posterior fossa tumors and working memory function.

Trauma research has been predominantly focused on the study of the negative psychological sequelae of traumatic experience. Recently, however, increased empirical attention has been paid to the potential for positive changes, or posttraumatic growth, derived from survivors’ struggle with trauma. There is evidence accumulating in support of this phenomenon following various types of traumatic events. Using an online, cross-sectional design, the present study examined posttraumatic growth among 143 survivors of interpersonal violence. Furthermore, the relationship between posttraumatic growth and the severity of psychological distress symptoms, as well as between growth and hope was explored. Results indicated that the severity of depressive symptoms was negatively related to growth, while the severity of posttraumatic stress disorder symptoms and hope were found to positively predict growth. Associations between posttraumatic growth and demographic and interpersonal violence characteristics did not emerge. The potential implications of these findings and directions for future research are discussed.

Knowledge of the literature pertaining to patterns of performance in normal individuals is essential if we are to understand intraindividual variability in neurocognitive test performance in neuropsychiatric disorders. Twenty-five healthy individuals with a high-level of education were evaluated on a short neuropsychological battery which spanned several cognitive domains. ---Results indicated that cognitive abilities are not equally distributed within a sample of healthy, high-level functioning individuals. This may be of interest to neuropsychologists who might base clinical inference about the presence of cerebral dysfunction, at least in part, on marked variation in a patient’s level of cognitive test performance. The practice of deductive reasoning in clinical neuropsychology may be prone to false-positive conclusions about cognitive functioning in neuropsychiatric disorders where base-rates of cognitive impairments are low and pre-existing educational achievements are high.

This study examined the self-efficacy for learning beliefs of male and female youth with ADHD, and explored whether symptoms of inattention predict self-efficacy beliefs beyond internalizing symptoms and academic achievement. Thirty-one youth with ADHD (18 males, 13 females) and 31 youth without ADHD (17 males, 14 females) between the ages of 13 and 18 completed self-report questionnaires examining self-efficacy for learning, ADHD symptomatology, academic achievement, and internalizing problems. Results indicated that female youth with ADHD felt less confident in their ability to regulate their learning effectively. In addition, regression analyses with the full sample revealed that inattention predicted self-efficacy for learning beliefs beyond internalizing difficulties and academic achievement. These results suggest that youth reporting high levels of inattention may also have lower perceptions of their ability to accomplish many academic tasks that require self-regulation.

While neuropsychological deficits have been reported in healthy individuals who use cannabis, data in patients with multiple sclerosis (MS) are lacking. Given that MS is associated with cognitive deterioration, the aim of this study was to determine the cognitive effects of inhaled or ingested cannabis in this population. Fifty MS patients (25 cannabis users and 25 non-users) completed the Minimal Assessment of Cognitive Function in MS battery of neuropsychological tests. Cannabis users had significantly poorer performance on measures of information processing speed, executive functions, and visuospatial perception, and were twice as likely to be classified as globally cognitively impaired. Similar results were found after controlling for potential confounding variables. This study provides evidence that prolonged cannabis use in MS patients is associated with poorer performance on cognitive domains commonly affected in this population. The therapeutic benefits patients may derive from using cannabis should be weighed against the associated cognitive side-effects.

Working memory (WM), which is essential for many academic skills, has been found to predict inattentive behaviours and is a common deficit in ADHD and LD. Recent studies have suggested that WM can be improved by intensive and adaptive computerized training. The purpose of this study is to investigate the effects of a WM training program on WM, attention, behaviour and academics in adolescents with severe LD/ADHD. A total of 60 12 to 17 year olds with ADHD/LD were randomised to one of two computerized intervention programs: working memory training or math training and evaluated before and at three weeks after completion. Adolescents in the WM training group showed greater improvements in some measures of WM than those in the Math training group, but no training effects were observed on any other measures. Findings are discussed in the context of theoretical and practical implications of WM training.

A growing body of literature is focusing on the influence of personality and emotion regulation on psychological health. Using archival data from an expressive writing project, the current study investigated the relationship between perfectionistic self-presentation and emotion regulation, and the influence of the interaction of these variables on psychological health among trauma survivors. The results indicate that both perfectionistic self-presentation and more difficulties in emotion regulation contribute to symptoms of distress. As well, higher levels of perfectionistic self-presentation were associated with more difficulties in emotion regulation. Further, emotion regulation mediated the relationship between perfectionistic self-presentation and psychological distress but not common physical complaints. More specifically, the non-acceptance subscale of emotion regulation was found to be significant in a test of multiple mediator model.

Trauma research has been predominantly focused on the study of the negative psychological sequelae of traumatic experience. Recently, however, increased empirical attention has been paid to the potential for positive changes, or posttraumatic growth, derived from survivors’ struggle with trauma. There is evidence accumulating in support of this phenomenon following various types of traumatic events. Using an online, cross-sectional design, the present study examined posttraumatic growth among 143 survivors of interpersonal violence. Furthermore, the relationship between posttraumatic growth and the severity of psychological distress symptoms, as well as between growth and hope was explored. Results indicated that the severity of depressive symptoms was negatively related to growth, while the severity of posttraumatic stress disorder symptoms and hope were found to positively predict growth. Associations between posttraumatic growth and demographic and interpersonal violence characteristics did not emerge. The potential implications of these findings and directions for future research are discussed.