COGNITIVE REMEDIATION IN PATIENTS WITH MOOD DISORDERS: BEHAVIOURAL AND NEURAL CORRELATES

Abstract

<p>This thesis presents research documenting the effectiveness of computer-assisted cognitive remediation for patients with mood disorders. The first chapter provides an overview of cognitive impairment in patients with bipolar disorder (BD) and major depressive disorder (MDD), and a concise review of cognitive remediation in patients with schizophrenia, where the efficacy of these interventions has been reasonably well studied. The results of an analysis comparing neuropsychological test performance in patients with BD, MDD, and healthy controls is presented in Chapter 2, where we show a similar degree of deficit in both patient groups on processing speed, working memory, and mental flexibility tasks, and a greater degree of deficit in patients with BD on delayed recall and verbal fluency tasks. In Chapter 3 we present the results of our primary analysis examining the effectiveness of CACR for patients with BD and MDD; we show significant improvement on neuropsychological tests of working memory and delayed memory following remediation, and positive associations between improvement in neuropsychological test performance, and improvement in subjectively-rated cognitive and psychosocial functioning. Finally, in Chapter 4 we present functional neuroimaging evidence that shows increased activation following cognitive remediation in frontal control regions supporting working memory and in the right hippocampus supporting recollection memory. Although behavioural performance on the corresponding tasks was stable, the observation of increased activation in frontal and medial temporal brain regions following remediation is in line with our finding of improvement on neuropsychological tests of working memory and delayed recall post-training. Taken together, the results presented in this thesis provide convergent behavioural and neural evidence to demonstrate the efficacy of computer-assisted cognitive remediation for patients with mood disorders. These novel findings contribute to a growing body of literature that shows cognitive remediation to be an effective cognitive management strategy across a range of psychiatric and neurological disorders.</p>