Impact of Circadian Rhythm Disturbances in Bipolar Disorder

Abstract

<p>This thesis presents research examining the impact circadian rhythm disturbances experienced in bipolar disorder (BD) have at two levels of investigation. First, circadian rhythm disturbance is studied with regard to quality of life in individuals with BD. The results of an analysis investigating the impact of self-reported circadian rhythm disturbance on quality of life (QOL) show circadian rhythm is strongly associated with poor QOL in patients with BD, independent of severity of depressive symptoms, sleep disturbance and use of sleep medications. Next, the impact of circadian rhythm disturbance on oxidative stress was studied. Oxidative stress has previously been implicated in BD, yet no studies have investigated the relationship between these systems in the context of the disorder. We demonstrate that circadian rhythm disturbance is related to increased lipid peroxidation in BD patients, which is not seen in controls. This study provides a basis for further investigation of the links between oxidative stress and circadian rhythms in the pathophysiology of BD. Taken together, these results provide evidence that circadian rhythms have a widespread impact on two separate aspects of BD: personal sense of well being and a biological marker of oxidative stress. These novel findings contribute to the mounting evidence indicating circadian rhythm disturbance as one of the core features of BD, and an important target for treatment.</p>