The Orbitofrontal Cortex Gray Matter Is Associated With the Interaction Between Insomnia and Depression

Abstract

Insomnia and depression are highly comorbid symptoms in both primary insomnia (PI) and major depressive disorder (MDD). In the current study, we aimed at exploring both the homogeneous and heterogeneous brain structure alteration in PI and MDD patients. Sixty-five MDD patients and 67 matched PI patients were recruited and underwent a structural MRI scan. The subjects were sub-divided into four groups, namely MDD patients with higher or lower insomnia, and PI patients with higher or lower severe depression. A general linear model was employed to explore the changes in cortical thickness and volume as a result of depression or insomnia, and their interaction. In addition, partial correlation analysis was conducted to detect the clinical significance of the altered brain structural regions. A main effect of depression on cortical thickness was seen in the superior parietal lobe, middle cingulate cortex, and parahippocampal gyrus, while a main effect of insomnia on cortical thickness was found in the posterior cingulate cortex. Importantly, the interaction between depression and insomnia was associated with decreased gray matter volume in the right orbitofrontal cortex, i.e., patients with co-occurring depression and insomnia showed smaller brain volume in the right orbitofrontal cortex when compared to patients with lower insomnia/depression. These findings highlighted the role of the orbitofrontal cortex in the neuropathology of the comorbidity of insomnia and depression. Our findings provide new insights into the understanding of the brain mechanism underlying comorbidity of insomnia and depression.

Epidemiological differences in levels of depressive signs among nocturnal symptoms of insomnia; results from the HUNT study

“…This combination of symptom may be the result of a peculiar etiopathology or of the presence of different, concomitant factors. Previous studies reported sleep onset insomnia increasing the risk for debilitating mental problems (Canivet et al, 2014) while neuroimaging brings evidence of a connection between early morning awakenings and depression (Stoffers et al, 2012;Yu et al, 2018). Speculatively, it is possible that the two insomnia symptoms and depression are connected in a consecutive and escalating manner.…”

“…Moreover, magnetic resonance imaging (MRI) studies seems to support biological differences for individual insomnia symptoms, as orbitofrontal grey matter appeared reduced only in patients experiencing early morning awakenings (Stoffers et al, 2012). The DSM-5 report specifically this nocturnal symptom of insomnia among the diagnostic criteria for melancholic depression and indeed patients with comorbid depression and insomnia show also reduced grey matter in the OFC (Yu et al, 2018).…”

Diurnal Preference and Grey Matter Volume in a Large Population of Older Adults: Data from the UK Biobank

“…This is in contrast to the findings reported by Takeucki and colleagues [28] who observed an association between eveningness and lower grey matter volume in in orbitofrontal cortex and Rosenberg et al [29], who observed no between-group differences in these regions. Lower lateral orbitofrontal grey matter volume has been observed in substance use disorder [56,57], substance dependence [58], a number of psychiatric disorders including depression [59,60] and internet-gaming disorder [61]. Eveningness has also been associated with substance use [48,49], depression [22,[62][63][64] and with increased mobile-phone gaming [65].…”

The Cerebral Mechanism of Acupuncture for Chronic Insomnia with Gastrointestinal Disorder: Protocol for a Randomized Controlled Trial

“…Our previous study was a preliminary exploration of the pathogenesis of insomnia (rather than CID with GI disorder) in terms of brain function and structure. [20][21]50] Other research teams have con rmed that insomnia patients have abnormal brain metabolism using MRS technology. [24][25][26] At present, there are no brain imaging studies on patients with CID with GI.…”

“…Using fMRI, we previously con rmed that the core pathological features of patients with CID are evident in the structural and functional plasticity of the brain. [20][21] Some DTI research indicates that the white matter tracts in the anterior internal capsule, right arcuate fasciculus, and superior longitudinal fasciculus of patients with insomnia are abnormal. [22][23] MRS is the only noninvasive method that can quantify biochemical substances in the brain, [24] and MRS studies have identi ed abnormal brain metabolic activity in insomnia patients.…”