Negative life stress, sleep disturbance, and depressive symptoms: The moderating role of anterior insula activity in response to sleep-related stimuli

Disrupted brain functional asymmetry at rest in patients with major depressive disorder associated with sleep disturbances

Sleep disturbances (SD) are common in major depressive disorder (MDD) patients. Brain functional asymmetry is crucial for understanding MDD pathophysiology. Previous studies using the parameter of asymmetry (PAS) approach have found brain functional asymmetry disruption in MDD. However, this has not been explored in MDD patients with SD. This study examined 26 MDD patients with SD, 34 MDD patients without SD, and 34 healthy controls using resting-state functional magnetic resonance imaging scans. SD symptoms were quantified using the 17-item Hamilton Rating Scale for Depression. PAS approach was used to evaluate functional asymmetry. MDD patients with SD displayed increased PAS in the left middle frontal gyrus (MFG)/inferior frontal gyrus (IFG) and decreased PAS in the left parahippocampal gyrus (PHG) compared to MDD patients without SD. Increased PAS in the left MFG/IFG was positively correlated with SD severity, and a negative correlation was found between decreased PAS in the left PHG and SD scores in all MDD patients. Receiver operating characteristic analysis indicated that increased PAS in the left MFG/IFG and decreased PAS in the left PHG may serve as potential neuroimaging markers to differentiate MDD patients with SD from those without SD with Area Under Curve values of 0.8157 and 0.8068, respectively. These results highlighted that increased PAS in the left MFG/IFG and decreased PAS in the left PHG may be considered a prominent feature associated with SD symptoms of MDD patients, potentially serving as imaging markers to discriminate between MDD patients with and without SD.

The brain in chronic insomnia and anxiety disorder: a combined structural and functional fMRI study

Background

Chronic insomnia disorder (CID) is usually associated with Generalized Anxiety Disorder (GAD), which may change brain structure and function. However, the possible brain markers, imaging characteristics, and pathophysiology are unknown.

Objective

To look at the probable brain markers, imaging characteristics, and pathogenesis of CID in combination with GAD.

Methods

A total of 57 patients with CID concomitant GAD and 57 healthy controls (HC) were enrolled. Voxel-based morphometry (VBM) and functional connectivity (FC) were utilized to measure gray matter volume (GMV) and functional changes. Correlation analysis was utilized to identify relationships between brain changes and clinical characteristics.

Results

Patients had decreased GMV in the left cerebellum, right cerebellar peduncle, and left insula; increased FC between the left cerebellum and right angular gyrus, as well as between the left insula and anterior left cingulate gyrus; and decreased FC in several areas, including the left cerebellum with the middle left cingulate gyrus and the left insula with the left superior postcentral gyrus. These brain changes related to CID and GAD. These data could be used to identify relevant brain markers, imaging features, and to better understand the etiology.

Conclusion

The intensity of insomnia in patients was strongly related to the severity of anxiety. The lower GMV in the cerebellum could be interpreted as an imaging characteristic of CID. Reduced GMV in the insula, as well as aberrant function in the cingulate gyrus and prefrontal lobe, may contribute to the pathophysiology of CID and GAD. Abnormal function in the postcentral gyrus and angular gyrus may be associated with patients' clinical complaints.

The sleep response to stress: how sleep reactivity can help us prevent insomnia and promote resilience to trauma

Sleep reactivity is a predisposition to sleep disturbance during environmental perturbations, pharmacological challenges, or stressful life events. Consequently, individuals with highly reactive sleep systems are prone to insomnia disorder after a stressor, engendering risk of psychopathology and potentially impeding recovery from traumatic stress. Thus, there is tremendous value in ameliorating sleep reactivity to foster a sleep system that is robust to stress exposure, ultimately preventing insomnia and its downstream consequences. We reviewed prospective evidence for sleep reactivity as a predisposition to insomnia since our last review on the topic in 2017. We also reviewed studies investigating pre-trauma sleep reactivity as a predictor of adverse post-traumatic sequelae, and clinical trials that reported the effect of behavioural treatments for insomnia on mitigating sleep reactivity. Most studies measured sleep reactivity via self-report using the Ford Insomnia Response to Stress Test (FIRST), demonstrating high scores on this scale reliably indicate a sleep system with a lower capacity to tolerate stress. Nascent evidence suggests elevated sleep reactivity prior to trauma increases the risk of negative posttraumatic outcomes, namely acute stress disorder, depression, and post-traumatic stress disorder. Lastly, sleep reactivity appears most responsive to behavioural insomnia interventions when delivered early during the acute phase of insomnia. Overall, the literature strongly supports sleep reactivity as a premorbid vulnerability to incident acute insomnia disorder when faced with an array of biopsychosocial stressors. The FIRST identifies individuals at risk of insomnia a priori, thereby guiding early interventions toward this vulnerable population to prevent insomnia and promote resilience to adversity.

The Influence of Life Stress and Sleep Disturbance on White Matter Integrity

OBJECTIVE

This study investigated whether sleep and stress mutually interact to induce changes in white matter integrity.

METHODS

Diffusion tensor imaging (DTI) was conducted on 36 participants (male=22, female=14; mean age=38.33±12.78 years). Participants were divided into three groups depending on their sleep quality and stress levels: poor sleepers with stress, poor sleepers without stress, and good sleepers. Sleep quality and stress level were evaluated using the Pittsburgh Sleep Quality Index and the Life Experiences Survey, respectively. Fractional anisotropy (FA) values were calculated employing DTI tractography.

RESULTS

After controlling for age and sex, poor sleepers with stress exhibited a lower FA of the left inferior cerebellar peduncle (ICP) than did poor sleepers without stress (t=2.81, p=0.02). Poor sleepers without stress showed a higher FA of the right middle longitudinal fasciculus (MdLF) than did good sleepers (t=3.35, p=0.006).

CONCLUSION

The current study reports the effects of sleep, stress, and their interaction on the white matter integrities of the ICP and MdLF. ICP change seems to be associated with sleep disturbances related to stress, while MdLF change would be associated with sleep disturbances unrelated to stress.

The association of amygdala-insula functional connectivity and adolescent e-cigarette use via sleep problems and depressive symptoms

BACKGROUND

Adolescent electronic cigarette (e-cigarette) use remains high. Elucidating contributing factors may enhance prevention strategies. Neurobiologically, amygdala-insula resting-state functional connectivity (rsFC) has been linked with aspects of sleep, affect, and substance use (SU). As such, we hypothesized that amygdala's rsFC with the insula would be associated with e-cigarette use via sleep problems and/or depression levels.

METHODS

An adolescent sample (N = 146) completed a rs-fMRI scan at time 1 and self-reports at time 2 (∼15 months later). Given consistent associations between mental health outcomes and the rsFC of the laterobasal amygdala (lbAMY) with the anterior insula, we utilized a seed region (lbAMY) to region of interest (ROI) analysis approach to characterize brain-behavior relationships. Two serial mediation models tested the interrelations between amygdala's rsFC with distinct anterior insula subregions (i.e., ventral insula [vI], dorsal insula [dI]), sleep problems, depression levels, and days of e-cigarette use.

RESULTS

An indirect effect was observed when considering the lbAMY's rsFC with the vI. Greater rsFC predicted more sleep problems, more sleep problems were linked with greater depressive symptoms, and greater depressive symptoms were associated with more e-cigarette use (indirect effect = 0.08, CI [0.01,0.21]). Indicative of a neurobiological dissociation, a similar indirect effect linking these variables was not observed when considering the lbAMY's rsFC with the dI (indirect effect = 0.03, CI [-0.001,0.10]).

CONCLUSIONS

These outcomes highlight functional interactions between the amygdala and insula as a neurobiological contributor to sleep problems, depressive symptoms, and ultimately SU thereby suggesting potential intervention points to reduce teen e-cigarette use.

Neural activation underlying emotional interference of cognitive control in rotating shift workers: moderating effects of the prefrontal cortex response on the association between sleep disturbance and depressive symptoms

Study Objectives

This study investigated the altered neural function involved in emotional interference and its role in linking sleep disturbance and depressive/anxiety symptoms in rotating shift workers.

Methods

Sixty rotating shift workers and 61 controls performed the emotional Stroop task in three blocks (emotional-related, sleep-related, and neutral words) during functional magnetic resonance imaging (fMRI) assessments. Sleep disturbance and depressive/anxiety symptoms were assessed using self-report measures and sleep diaries. Actigraphy was used to assess the sleep and circadian variables. fMRI scans were performed to compare brain activation during the emotional Stroop task. The proposed moderating models were tested using the PROCESS macro in SPSS software.

Results

A significant condition effect on reaction time was detected. Regardless of the group, reaction times were longer in the negative emotional word and sleep-related conditions than in the neutral word condition. Whole-brain analysis revealed that rotating shift workers show greater neural activation in the left dorsolateral prefrontal cortex (DLPFC) compared with controls while performing the emotional Stroop task with negative emotional words. Sleep disturbance was more strongly associated with depressive symptoms when activation of the left DLPFC was higher during the emotional Stroop task with negative words.

Conclusions

The left DLPFC may play important roles in increased sensitivity to emotional information, possibly due to circadian misalignment, and has moderating effects on the association between sleep disturbance and depressive symptoms in rotating shift workers. These findings will help to identify possible brain regions where interventions can be performed to correct sleep and mood problems in rotating shift workers.

Exposure to domestic violence and depressive symptoms in Chinese adolescents: Sleep problems as a mediator

INTRODUCTION

Exposure to domestic violence has been shown to be an important risk factor of depression in western studies, but has received less attention in Chinese context. Additionally, the underlying mechanism of its link with depression has not been fully studied. With a longitudinal design, we examined the mediating role of sleep problems between exposure to domestic violence and depressive symptoms in Chinese adolescents, and further considered potential age and gender differences in the direct and indirect pathways.

METHODS

Participants were recruited from primary and junior high schools in China and were surveyed across two waves with a 6-month interval. There were 1949 participants at Wave 1 and 1283 at Wave 2. Structural equation model was conducted to examine the mediating role of sleep problems in the association between exposure to domestic violence and depressive symptoms. Multigroup analyses were applied to test potential age and gender differences in the process.

RESULTS

Participants' exposure to domestic violence predicted increasing sleep problems, which further predicted more depressive symptoms. Age and gender moderated the indirect pathway from exposure to domestic violence to depressive symptoms through sleep problems, such that the mediating effects of sleep problems were significantly stronger in early-age adolescents and girls than middle-age ones and boys.

IMPLICATION

Parents should avoid the use of corporal punishment and protect their children from domestic violence. For adolescents who have underwent domestic violence, parents and clinicians might consider to decrease their depressive symptoms by ameliorating sleep problems, especially for the early-age adolescents and girls.