Comparative study of sleep and circadian rhythms in patients presenting unipolar or bipolar major depressive episodes.

Currently, there is a major challenge in distinguishing between unipolar and bipolar major depressive episode. A significant body of research has been dedicated to identifying biomarkers that can aid in this differentiation due to its crucial implications, particularly for therapeutic and prognostic purposes. Among the biomarkers of interest, markers related to sleep and circadian rhythms show promise and could potentially aid in making this distinction. Nevertheless, no study has simultaneously examined sleep-wake disorders, circadian rhythms, and seasonal patterns using both subjective and objective measures. This study aims to characterize and compare the sleep-wake and rhythm disorders including patients with unipolar major depressive episode (n = 72) and with bipolar major depressive episode (n = 43) using both subjective markers (using self-report questionnaires and sleep complaints) and objective markers (using actigraphy). Patients with unipolar major depressive episode seem to experience significantly poorer quality of sleep, more symptoms of insomnia and lower sleep efficiency compared to patients with bipolar major depressive episode. On the other hand, patients with bipolar major depressive episode exhibit significantly more symptoms of motor retardation and hypersomnia compared to patients with unipolar disorder. These results hold significant implications for identifying individuals with unipolar major depressive episode or bipolar major depressive episode using sleep and circadian markers, and for developing recommended and personalized therapeutic strategies.

Major depressive episode with insomnia and excessive daytime sleepiness: A more homogeneous and severe subtype of depression.

Previous studies have noted the crucial role of excessive daytime sleepiness (EDS) in the course of depressive illness, and more recently, a few studies documented its strong associations with an increased risk of suicide. While insomnia is associated with heightened emotional reactivity, suicidal behaviors, and increased relapses and recurrence. Our main hypothesis is that major depressive episodes (MDE) with insomnia and EDS are associated with more severe manifestations of depression. However, to date, no study has directly compared MDE with insomnia without EDS (Ins), and MDE with insomnia with EDS (InsEDS) using both subjective biomarkers (administration of self-assessment questionnaires for psychiatric evaluation and sleep complaints) and objective biomarkers (of sleep and circadian rhythms (using actigraphy). The InsEDS group, compared to the Ins group, exhibited significantly increased suicidal ideation, larger seasonal impacts on mood, alterations in sleep duration, weight, appetite, energy levels, and social activities throughout the year. Furthermore, they had significant delayed onset of daily activity measured with actigraphy. These findings provided new insights into the link between suicide, sleep, alertness, and biological clock. They also hold significant implications for identifying individuals with more severe depressive manifestations and for developing tailored and personalized therapeutic strategies.

Predictors of cognitive behavioral therapy for insomnia (CBT-I) effects in insomnia with major depressive episode.

Insomnia plays a critical role in the onset and maintenance of Major Depressive Episode (MDE). Cognitive behavioral therapy for insomnia (CBT-I) can successfully improve the sleep of patients with insomnia and MDE. Nonetheless, the factors influencing CBT-I's effects in MDE remain uncertain. This study aimed to identify predictors of insomnia improvement following CBT-I, as well as predictors of insomnia response, remission in patients with MDE and specific insomnia subtypes. Initially, we compared a 4-session weekly CBT-I treatment to baseline sleep education (SE) in a control group. This confirmed CBT-I's positive effects and the need to explore predictive factors. Notably, treatment-resistant depression (TRD) predicted reduced insomnia severity with CBT-I. Patients exhibiting seasonal fluctuations in depressive symptoms and sleep patterns throughout the year, or having daytime dysfunction, experienced enhanced CBT-I efficacy, especially for early awakenings insomnia. Conversely, shorter sleep duration predicted a less favorable response to CBT-I, less improvement in daytime dysfunction and sleep disturbance worries. Additionally, MDE with suicide attempts predicted a poorer improvement of daytime dysfunction. Further research is essential to comprehensively grasp the mechanisms behind CBT-I's heightened effectiveness in MDE patients with TRD and seasonal fluctuations.