Browsing by Author "MacQueen, Glenda M."

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    Adolescent Mental Health: Canadian Psychiatric Risk and Outcome Study (PROCAN)- Exercise Intervention Pilot Study
    (2019-01-16) Corbett, Syl; Addington, Jean; MacQueen, Glenda M.; Bray, Signe L.; Swain, Mark Gordon
    BACKGROUND: The Canadian Psychiatric Risk and Outcome Study (PROCAN), a longitudinal study of youth at risk of serious mental illness (SMI), aims to better understand the trajectory of SMI. This study was conducted as a pilot exercise intervention on a subsample of the PROCAN cohort. OBJECTIVES: The primary objective was to examine the feasibility of an exercise intervention in youth at risk of SMI. The secondary objectives were to determine whether symptoms of mental illness and memory would improve, and hippocampal volume would increase, following participation in a moderate to high intensity aerobic exercise program. METHODS: Forty-four male and female youth at risk of SMI were recruited through the PROCAN project. Participants completed clinical, cognitive, neuroimaging and fitness assessments prior to and following a sixteen-week moderate to high intensity aerobic exercise intervention. Sixty-minute exercise sessions were held three times per week. Forty-one participants completed the entire intervention and assessments, including twenty-six that completed the neuroimaging portion. Twenty-eight age and gender matched healthy controls were recruited as a baseline comparison for neuroimaging. RESULTS: Exclusion, consented, and retention rates were; 22.7, 57.6 and 93.2% respectively. Significant (p < .05) improvements in aerobic fitness (p < .0001) were achieved over the course of the intervention. Likewise, reductions in anxiety (p = .024), depression (p = .012), and general prodromal symptoms (p < .0001) occurred, however distress did not diminish (p= .131). Right whole (p < .001) and right anterior (p = .001) hippocampal volumes significantly increased. Forward Span (p = .552), Backward Span (p = 1.000) and Letter Number Span (p = .606) did not significantly change. CONCLUSION: Aerobic exercise is a feasible and sound intervention strategy for reducing symptoms and improving overall physical health, including brain health, in youth at risk for SMI. Further research is required to replicate these findings and to expand knowledge of the mechanisms, optimum dose and factors that influence the efficacy of exercise.
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    Neuroimaging Biomarkers for Youth At-Risk for Serious Mental Illness
    (2020-08) Nogovitsyn, Nikita; MacQueen, Glenda M.; Addington, Jean M.; Ismail, Zahinoor; Protzner, Andrea; Taylor, Valerie H.
    Background: Serious mental illness (SMI) is a constellation of psychiatric illnesses, commonly referring to major depressive disorder (MDD), bipolar disorder(s) (BD), and schizophrenia (SCZ). The diagnosis of SMI relies on a descriptive collection of behaviors with no objective measurements. Young individuals with early signs of developing mental illness are often misdiagnosed or diagnosed at later stages of illness when the opportunity for effective early intervention has passed. Therefore, there is a need for biomarkers that can identify youth at risk for SMI and stratify individuals into clinical stages so that appropriate interventions can be offered. Objective: The overreaching goal of my research is to enhance our understanding of the neurobiological changes underlying the early brain pathophysiology of (SMI). The ultimate aim of this dissertation is to identify neurobiological biomarkers for SMI that will have diagnostic or informative value in the classification of risk stages. Methods: By making use of data generated from two large Canadian studies, the Canadian Psychiatric Risk and Outcome Study (PROCAN), and the Canadian Biomarker Integration Network in Depression (CAN-BIND), I investigate specific structural and functional brain changes accompanying various stages risk and evolution of SMI. Results: This manuscript-based thesis presents structural and functional neuroimaging findings that parallel clinical presentation in youth-at-risk and adults with an existing mood disorder. Subtle structural changes within the hippocampus, amygdala, and thalamus were found in symptomatic at-risk youth with either attenuated or distress syndromes. Volume deficits within the body of the hippocampus were detected even in asymptomatic youth at risk due to the family history of an SMI. Moreover, in at-risk youth with a history of childhood abuse, structural deficits within the basal nuclei of the amygdala mediated the severity of depressive and anxiety symptoms at present. In adult patients diagnosed with MDD, specific patterns of hippocampal disproportions were not only indicative of depression status but also informed about the rate and the likelihood of successful antidepressant treatment. While deviations in subcortical limbic structures supported the transdiagnostic clinical staging model, functional connectivity changes within cerebello-limbic pathways were nearly exclusively indicative of high clinical risk for psychosis. Conclusions: Distributed limbic brain changes can precede the clinical onset of the mental illness, possibly, reflecting the cumulative impact of pernicious effects of stress. Together, these results can be offered in support of a transdiagnostic clinical staging for youth at risk of SMI.
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    The Role of Adipokines in Understanding the Associations between Obesity and Depression
    (2010-07-28) Taylor, Valerie H.; MacQueen, Glenda M.
    Objective. Two major causes of disability, major depression and obesity, share overlapping psychosocial and pathophysiological etiologies. Studies are now focused on biological mechanisms linking the two illnesses, and there is interest in the role that adipokines may have in mediating the association between obesity and depression. We reviewed the literature to look at what is currently known about this association, focusing on the adipokines leptin, adiponectin, and resistin. Methods. A MEDLINE search, citing articles from 1966 onward, supplemented by a review of bibliographies, was conducted to identify relevant studies. Results. This paper identified plausible pathways underlying a link between adipokines and depression. Only a few studies have yet been conducted specifically examining these biomarkers in patients with depression, but the results are intriguing. Conclusion. This paper is one of the first to examine the association between adipokines and depression. It provides an overview of the physiological role of adipokines and summarizes the data suggesting that they may be dysregulated in major depression. This area of research may become increasingly important as new treatment strategies are developed.