Abstract
BackgroundSubclinical depression (ScD) is a prevalent condition associated with relatively mild depressive states, and it poses a high risk of developing into major depressive disorder (MDD). However, the neural pathology of ScD is still largely unknown. Identifying the spontaneous neural activity involved in ScD may help clarify risk factors for MDD and explore treatment strategies for mild stages of depression.MethodsA total of 34 ScD subjects and 40 age-, sex-, and education-matched healthy controls were screened from 1105 college students. The amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) of resting-state fMRI were calculated to reveal neural activity. Strict statistical strategies, including Gaussian random field (GRF), false discovery rate (FDR), and permutation test (PT) with threshold-free cluster enhancement (TFCE), were conducted. Based on the altered ALFF and ReHo, resting-state functional connectivity (RSFC) was further analyzed using a seed-based approach.ResultsThe right precuneus and left middle frontal gyrus (MFG) both showed significantly increased ALFF and ReHo in ScD subjects. Moreover, the left hippocampus and superior frontal gyrus (SFG) showed decreased ALFF and increased ReHo, respectively. In addition, ScD subjects showed increased RSFC between MFG and hippocampus compared to healthy controls, and significant positive correlation was found between the Beck Depression Inventory-II (BDI-II) score and RSFC from MFG to hippocampus in ScD group.ConclusionSpontaneous neural activities in the right precuneus, left MFG, SFG, and hippocampus were altered in ScD subjects. Functional alterations in these dorsolateral prefrontal cortex and default mode network regions are largely related to abnormal emotional processing in ScD, and indicate strong associations with brain impairments in MDD, which provide insight into potential pathophysiology mechanisms of subclinical depression.
Highlights
Subclinical depression (ScD) is regarded as an early stage or precursor of major depressive disorder (MDD), because people with ScD experience depressive symptoms that are not severe or persistent enough to merit a diagnosis of MDD [1, 2]
A longitudinal study demonstrated that individuals with ScD showed a five-fold increase in their risk of experiencing a first lifetime MDD episode compared to healthy controls [7]
Demographic data comparisons A total of 34 ScD subjects and 40 Healthy control (HC) subjects were subjected to fMRI scans
Summary
Subclinical depression (ScD) is regarded as an early stage or precursor of major depressive disorder (MDD), because people with ScD experience depressive symptoms that are not severe or persistent enough to merit a diagnosis of MDD (i.e., persistent depressed mood and a series of cognition and physical problems) [1, 2]. ScD is an important factor in suicide [6]. A longitudinal study demonstrated that individuals with ScD showed a five-fold increase in their risk of experiencing a first lifetime MDD episode compared to healthy controls [7]. It is of great importance to clarify the impairments in neural activity in ScD individuals, as this will provide insight into understanding its biological pathogenesis and prevent the development to MDD. Subclinical depression (ScD) is a prevalent condition associated with relatively mild depressive states, and it poses a high risk of developing into major depressive disorder (MDD). The neural pathology of ScD is still largely unknown. Identifying the spontaneous neural activity involved in ScD may help clarify risk factors for MDD and explore treatment strategies for mild stages of depression
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call