Adolescent Major Depressive Disorder: Neuroimaging Evidence of Sex Difference during an Affective Go/No-Go Task

Sex differences in aberrant functional connectivity of three core networks and subcortical networks in medication-free adolescent-onset major depressive disorder

Major depressive disorder demonstrated sex differences in prevalence and symptoms, which were more pronounced during adolescence. Yet, research on sex-specific brain network characteristics in adolescent-onset major depressive disorder remains limited. This study investigated sex-specific and nonspecific alterations in resting-state functional connectivity of three core networks (frontoparietal network, salience network, and default mode network) and subcortical networks in adolescent-onset major depressive disorder, using seed-based resting-state functional connectivity in 50 medication-free patients with adolescent-onset major depressive disorder and 56 healthy controls. Irrespective of sex, compared with healthy controls, adolescent-onset major depressive disorder patients showed hypoconnectivity between bilateral hippocampus and right superior temporal gyrus (default mode network). More importantly, we further found that females with adolescent-onset major depressive disorder exhibited hypoconnectivity within the default mode network (medial prefrontal cortex), and between the subcortical regions (i.e. amygdala, striatum, and thalamus) with the default mode network (angular gyrus and posterior cingulate cortex) and the frontoparietal network (dorsal prefrontal cortex), while the opposite patterns of resting-state functional connectivity alterations were observed in males with adolescent-onset major depressive disorder, relative to their sex-matched healthy controls. Moreover, several sex-specific resting-state functional connectivity changes were correlated with age of onset, sleep disturbance, and anxiety in adolescent-onset major depressive disorder with different sex. These findings suggested that these sex-specific resting-state functional connectivity alterations may reflect the differences in brain development or processes related to early illness onset, underscoring the necessity for sex-tailored diagnostic and therapeutic approaches in adolescent-onset major depressive disorder.

Correlation research on physical activity and executive function in female college students with subclinical depression

Researchers have found that there may be a correlation between physical activity, executive function, and depression for college students with depression. However, there is limited information available regarding the relationship and interaction between subclinical depression, physical activity, and executive function among college students with subclinical depression. The purpose of this study is to assess the correlation and interaction between subclinical depression, physical activity, and executive function in female college students with subclinical depression. The ActiGraph GT3X was utilized to measure physical activity time, and the colour-word Stroop task was employed to evaluate the executive function of the participants. The findings revealed that female college students with subclinical depression had a significantly lower time for moderate-intensity physical activity compared to healthy female college students. Additionally, the subclinical depression group took significantly longer to complete the colour-word Stroop task compared to the healthy group of female college students. The results of correlation and mediation analyses suggest a negative correlation between BDI-II scores and physical activity time and executive function in female college students with subclinical depression. Moreover, executive function appears to play a partial mediating role in the relationship between physical activity and subclinical depression.

In Context: Lessons About Adolescent Unipolar Depression From the Improving Mood With Psychoanalytic and Cognitive Therapies Trial

This paper summarizes the results of the Improving Mood with Psychoanalytic and Cognitive Therapies (IMPACT) study and its implications for psychological treatment of adolescents with moderate to severe unipolar major depression. IMPACT was a pragmatic, superiority, randomized controlled trial conducted in the United Kingdom, which compared the clinical and cost-effectiveness of short-term psychoanalytic therapy (STPP), cognitive-behavioral therapy (CBT), and a brief psychosocial intervention (BPI) in reducing depression symptoms in 465 adolescents with unipolar major depression, aged 11 to 17 years. Although this was a clinically heterogeneous group of adolescents, some symptoms (eg, sleep and concentration difficulties, irritability/anger) were common and disabling. The trial reported no significant difference among the 3 treatments in reducing depression symptoms. One year after treatment, 84% of participants showed improvement in depressive symptoms (<50% of baseline symptoms) and improved psychosocial functioning, achieving this through different symptom reduction trajectories. Although participants attended fewer treatment sessions than planned, the 3 treatments were delivered with fidelity to their respective models. Ending treatment without therapist agreement occurred in 37% of cases. This was not associated with outcomes by treatment group. Adolescents emphasized the importance of the therapeutic relationship in all 3 treatments. Results suggest that although most adolescents respond to time-limited, structured psychological therapy, subgroups of depressed adolescents are likely to need additional treatment or support. These include adolescents who live in complex circumstances and/or who believe that their needs are not met in therapy, some who stop treatment early, and the 16% to 18% of adolescents who do not respond to treatment. CLINICAL TRIAL REGISTRATION INFORMATION: Improving Mood and Preventing Relapse With Psychoanalytic Psychotherapy and Cognitive Behaviour Therapy; https://www.isrctn.com; ISRCTN83033550.

Cross-Domain Identification of Multisite Major Depressive Disorder Using End-to-End Brain Dynamic Attention Network

Establishing objective and quantitative imaging markers at individual level can assist in accurate diagnosis of Major Depressive Disorder (MDD). However, the clinical heterogeneity of MDD and the shift to multisite data decreased identification accuracy. To address these issues, the Brain Dynamic Attention Network (BDANet) is innovatively proposed, and analyzed bimodal scans from 2055 participants of the Rest-meta-MDD consortium. The end-to-end BDANet contains two crucial components. The Dynamic BrainGraph Generator dynamically focuses and represents topological relationships between Regions of Interest, overcoming limitations of static methods. The Ensemble Classifier is constructed to obfuscate domain sources to achieve inter-domain alignment. Finally, BDANet dynamically generates sample-specific brain graphs by downstream recognition tasks. The proposed BDANet achieved an accuracy of 81.6%. The regions with high attribution for classification were mainly located in the insula, cingulate cortex and auditory cortex. The level of brain connectivity in p24 region was negatively correlated ( [Formula: see text]) with the severity of MDD. Additionally, sex differences in connectivity strength were observed in specific brain regions and functional subnetworks ( [Formula: see text] or [Formula: see text]). These findings based on a large multisite dataset support the conclusion that BDANet can better solve the problem of the clinical heterogeneity of MDD and the shift of multisite data. It also illustrates the potential utility of BDANet for personalized accurate identification, treatment and intervention of MDD.

Brain-based Sex Differences in Depression: A Systematic Review of Neuroimaging Studies

Major depressive disorder (MDD) is a common psychiatric illness with a wide range of symptoms such as mood decline, loss of interest, and feelings of guilt and worthlessness. Women develop depression more often than men, and the diagnostic criteria for depression mainly rely on female patients' symptoms. By contrast, male depression usually manifests as anger attacks, aggression, substance use, and risk-taking behaviors. Various studies have focused on the neuroimaging findings in psychiatric disorders for a better understanding of their underlying mechanisms. With this review, we aimed to summarize the existing literature on the neuroimaging findings in depression, separated by male and female subjects. A search was conducted on PubMed and Scopus for magnetic resonance imaging (MRI), functional MRI (fMRI), and diffusion tensor imaging (DTI) studies of depression. After screening the search results, 15 MRI, 12 fMRI, and 4 DTI studies were included. Sex differences were mainly reflected in the following regions: 1) total brain, hippocampus, amygdala, habenula, anterior cingulate cortex, and corpus callosum volumes, 2) frontal and temporal gyri functions, along with functions of the caudate nucleus and prefrontal cortex, and 3) frontal fasciculi and frontal projections of corpus callosum microstructural alterations. Our review faces limitations such as small sample sizes and heterogeneity in populations and modalities. But in conclusion, it reflects the possible roles of sex-based hormonal and social factors in the depression pathophysiology.

Observed Parenting and Adolescent Brain Structure

Parent-youth relationships and parenting are critically important to adolescents' development. The present study examined associations between parenting behaviors (which included observed parent emotion expression and negative and positive parenting behaviors during a parent-adolescent interaction) and adolescent brain structure, and sex differences in associations, in 66 12-14 year-olds. The study found that 1) among all adolescents in the sample, greater parent negative emotion expression in parent-youth interactions was associated with greater adolescent gray matter volume (GMV) in the left hippocampus, 2) parent positive emotion expression was not associated with adolescent GMV, 3) several associations differed by sex. These findings suggest that parenting is important for adolescent brain structure and future work should consider this by sex.

Aberrant frontolimbic circuit in female depressed adolescents with and without suicidal attempts: A resting-state functional magnetic resonance imaging study

Background

The neurobiological basis of suicidal behaviors among female adolescents with major depressive disorder (MDD) remains largely unclear.

Materials and methods

Fifty-eight drug-naïve, first-episode female adolescent MDD [including 31 patients with suicidal attempt (SA group) and 27 patients without SA (non-SA group)], and 36 matched healthy controls (HCs) participated in the present study. Resting-state functional magnetic resonance imaging (MRI) was performed on each subject. The metrics of the amplitude of low-frequency fluctuation (ALFF), fractional ALFF (fALFF), and regional homogeneity (ReHo) were compared among the three groups. Then seed-based functional connectivity (FC) was conducted based on the ALFF/fALFF and ReHo results, which were then correlated to clinical variables.

Results

Compared with the non-SA group, the SA group exhibited increased fALFF in the bilateral insula and right precentral gyrus, and enhanced ReHo in the left superior temporal gyrus, left middle cingulate cortex, right insula, and right precentral gyrus. Relative to the HCs, the SA group demonstrated additionally reduced fALFF and ReHo in the left middle frontal gyrus. Moreover, the SA group showed increased FC between the right precentral gyrus and the left middle frontal gyrus and left insula, and between the right insula and anterior/middle cingulate cortex compared to the non-SA and HC groups. In addition, the fALFF in the left middle frontal gyrus was positively correlated with the 17-item Hamilton Depression Rating Scale scores, and the values in the fALFF/ReHo in the right insula were positively correlated with the duration of MDD within the patient group.

Conclusion

These findings highlight the multiple abnormalities of the frontolimbic circuit, which may enhance our understanding of the neurobiological basis underlying female MDD with SA during adolescence.

Identifying Specific Emotion Regulation Deficits that Associate with Nonsuicidal Self-injury and Suicide Ideation in Adolescents

It is not known how emotion regulation deficits and strategies may differentially relate to nonsuicidal self-injury (NSSI) and suicide ideation in samples of community-based adolescents. The current study examined emotion regulation using comprehensive multi-method assessment to identify which specific deficits are uniquely related to NSSI and suicide ideation in a sample of high school students. Regarding specific deficits, it was expected that lack of emotional awareness, lack of access to emotion regulation strategies, poor cognitive reappraisal, and poorer automatic emotion processing would uniquely associate with past-year NSSI engagement. It was also predicted that lack of access to strategies, lack of impulse control, lack of awareness, and nonacceptance of emotion would uniquely associate with past-year presence of suicide ideation and suicide ideation severity. The sample included 696 adolescents (54.8% female; ages 14-17; mean age = 15.5) recruited from public high schools. Self-report measures were administered assessing suicide ideation, NSSI engagement, dimensions of emotion regulation, and automatic emotion processing (Emotion Stroop). Emotion suppression was the only unique and significant predictor of past-year NSSI engagement, and lack of access to emotion regulation strategies was the strongest predictor of both past-year presence of suicide ideation and recent suicide ideation severity when accounting for all deficits in the same model. Acquiring emotion regulation skills during the period of adolescence has great potential to buffer from occurrence of NSSI and severity of suicide ideation.

Sexual Dimorphism in the Brain Correlates of Adult-Onset Depression: A Pilot Structural and Functional 3T MRI Study

Major Depressive Disorder (MDD) is a disabling illness affecting more than 5% of the elderly population. Higher female prevalence and sex-specific symptomatology have been observed, suggesting that biologically-determined dimensions might affect the disease onset and outcome. Rumination and executive dysfunction characterize adult-onset MDD, but sex differences in these domains and in the related brain mechanisms are still largely unexplored. The present pilot study aimed to explore any interactions between adult-onset MDD and sex on brain morphology and brain function during a Go/No-Go paradigm. We hypothesized to detect diagnosis by sex effects on brain regions involved in self-referential processes and cognitive control. Twenty-four subjects, 12 healthy (HC) (mean age 68.7 y, 7 females and 5 males) and 12 affected by adult-onset MDD (mean age 66.5 y, 5 females and 7 males), underwent clinical evaluations and a 3T magnetic resonance imaging (MRI) session. Diagnosis and diagnosis by sex effects were assessed on regional gray matter (GM) volumes and task-related functional MRI (fMRI) activations. The GM volume analyses showed diagnosis effects in left mid frontal cortex (p < 0.01), and diagnosis by sex effects in orbitofrontal, olfactory, and calcarine regions (p < 0.05). The Go/No-Go fMRI analyses showed MDD effects on fMRI activations in left precuneus and right lingual gyrus, and diagnosis by sex effects on fMRI activations in right parahippocampal gyrus and right calcarine cortex (p < 0.001, ≥ 40 voxels). Our exploratory results suggest the presence of sex-specific brain correlates of adult-onset MDD-especially in regions involved in attention processing and in the brain default mode-potentially supporting cognitive and symptom differences between sexes.

In search of sex-related mediators of affective illness

Sex differences in the rates of affective disorders have been recognized for decades. Studies of physiologic sex-related differences in animals and humans, however, have generally yielded little in terms of explaining these differences. Furthermore, the significance of these findings is difficult to interpret given the dynamic, integrative, and highly context-dependent nature of human physiology. In this article, we provide an overview of the current literature on sex differences as they relate to mood disorders, organizing existing findings into five levels at which sex differences conceivably influence physiology relevant to affective states. These levels include the following: brain structure, network connectivity, signal transduction, transcription/translation, and epigenesis. We then evaluate the importance and limitations of this body of work, as well as offer perspectives on the future of research into sex differences. In creating this overview, we attempt to bring perspective to a body of research that is complex, poorly synthesized, and far from complete, as well as provide a theoretical framework for thinking about the role that sex differences ultimately play in affective regulation. Despite the overall gaps regarding both the underlying pathogenesis of affective illness and the role of sex-related factors in the development of affective disorders, it is evident that sex should be considered as an important contributor to alterations in neural function giving rise to susceptibility to and expression of depression.

Romantic Relationship Dissolution, Microbiota, and Fibers

Microbiota inhabit nearly every part of our body with the gut microbiota representing the greatest density and absolute abundance. The gut-microbiota-brain axis facilitates bidirectional communication between gut microbiota and the brain. For instance, romantic relationship not only brings joy, it is also associated with increased gut microbiota diversity and health benefits whereas reduced microbiota diversity is related to obesity, cardiac disease, type 2 diabetes, and inflammatory disorders. Research has shown that dietary fibers may increase microbiota diversity and exert antidepressant effect. Among a plethora of life stressors, romantic relationship dissolution is a relatively common and painful experience that people encounter from time to time. Depressed mood, social isolation and poor intake are all associated with romantic relationship dissolution. In this article, it is hypothesized that romantic relationship dissolution is accompanied by decreased gut microbiota diversity which could be corrected with the ingestion of dietary fibers with an additional antidepressant benefit.

Intrinsic connectivity of the prefrontal cortex and striato-limbic system respectively differentiate major depressive from generalized anxiety disorder

Major depressive disorder (MDD) and generalized anxiety disorder (GAD) are highly prevalent and debilitating disorders. The high overlap on the symptomatic and neurobiological level led to ongoing debates about their diagnostic and neurobiological uniqueness. The present study aims to identify common and disorder-specific neuropathological mechanisms and treatment targets in MDD and GAD. To this end we combined categorical and dimensional disorder models with a fully data-driven intrinsic network-level analysis (intrinsic connectivity contrast, ICC) to resting-state fMRI data acquired in 108 individuals (n = 35 and n = 38 unmedicated patients with first-episode GAD, MDD, respectively, and n = 35 healthy controls). Convergent evidence from categorical and dimensional analyses revealed MDD-specific decreased whole-brain connectivity profiles of the medial prefrontal and dorsolateral prefrontal cortex while GAD was specifically characterized by decreased whole-brain connectivity profiles of the putamen and decreased communication of this region with the amygdala. Together, findings from the present data-driven analysis suggest that intrinsic communication of frontal regions engaged in executive functions and emotion regulation represent depression-specific neurofunctional markers and treatment targets whereas dysregulated intrinsic communication of the striato-amygdala system engaged in reinforcement-based and emotional learning processes represent GAD-specific markers.

MRI Insights Into Adolescent Neurocircuitry-A Vision for the Future

Adolescence is the time of onset of many psychiatric disorders. Half of pediatric patients present with comorbid psychiatric disorders that complicate both their medical and psychiatric care. Currently, diagnosis and treatment decisions are based on symptoms. The field urgently needs brain-based diagnosis and personalized care. Neuroimaging can shed light on how aberrations in brain circuits might underlie psychiatric disorders and their development in adolescents. In this perspective article, we summarize recent MRI literature that provides insights into development of psychiatric disorders in adolescents. We specifically focus on studies of brain structural and functional connectivity. Ninety-six included studies demonstrate the potential of MRI to assess psychiatrically relevant constructs, diagnose psychiatric disorders, predict their development or predict response to treatment. Limitations of the included studies are discussed, and recommendations for future research are offered. We also present a vision for the role that neuroimaging may play in pediatrics and primary care in the future: a routine neuropsychological and neuropsychiatric imaging (NPPI) protocol for adolescent patients, which would include a 30-min brain scan, a quality control and safety read of the scan, followed by computer-based calculation of the structural and functional brain network metrics that can be compared to the normative data by the pediatrician. We also perform a cost-benefit analysis to support this vision and provide a roadmap of the steps required for this vision to be implemented.

Cognitive behavioral therapy may have a rehabilitative, not normalizing, effect on functional connectivity in adolescent depression

BACKGROUND

Whether the differences in brain structure and function, characteristic of adult major depressive disorder (MDD¹), are present in adolescent MDD is still unclear, but it has been shown that cognitive behavioral therapy (CBT²) affects resting-state functional connectivity in both adult and adolescent MDD patients, with the claim that CBT has a normalizing effect on MDD-related functional disruption, but this has not been directly tested.

METHODS

128 adolescent MDD patients and 40 adolescent controls were enrolled in the study. We investigated pre-treatment differences in cortical thickness, white matter volume, and resting-state functional connectivity. We also investigated the longitudinal effects of CBT on resting-state functional connectivity, and the relationship between pre-treatment functional disruption and CBT-related changes to resting-state functional connectivity was assessed by the correlation of pre-treatment cross-sectional effects and longitudinal CBT-related effects across multiple brain regions.

RESULTS

Patients had greater cortical thickness and white matter volume within fronto-limbic regions of the brain. Patients had greater pre-treatment resting-state functional connectivity within the default-mode, fronto-limbic, central-executive, and salience networks. CBT increased resting-state functional connectivity of the subgenual anterior cingulate and amygdala seeds with predominantly frontal regions. Regions showing the greatest pre-treatment functional disruption showed the weakest CBT-related changes.

LIMITATIONS

For ethical reasons, there was no placebo group.

CONCLUSIONS

Adolescent MDD is associated with structural and functional differences also seen in adult patients. CBT-related changes in resting-state functional connectivity do not appear to show a normalizing effect, but instead indicate rehabilitative effects on resting-state functional connectivity.

The Cognitive Neuropsychology of Depression in Adolescents

Purpose of Review

Adolescent depression is a major public health concern associated with severe outcomes. A lack of efficacious interventions has triggered an increase in cognitive neuropsychology research to identify relevant treatment targets for new interventions. This review summarises key neurocognitive findings in adolescent depression and explores the potential of neurocognitive markers as treatment targets in new interventions.

Recent Findings

Studies support difficulties in the voluntary deployment of attention towards and away from emotional stimuli, negative interpretation biases and overgeneralised autobiographical memories in adolescent depression; however, little evidence is given to a general decline in executive function. There is consistent evidence for abnormalities in several distributed neural networks in adolescent depression, including dysfunction in and between the amygdala, medial prefrontal cortex and ventral striatum.

Summary

The relationships between different cognitive biases and abnormalities in specific neural networks remain unclear. Several new experimental interventions targeting these neurocognitive markers await evaluation.

Altered Connectivity in Depression: GABA and Glutamate Neurotransmitter Deficits and Reversal by Novel Treatments

The mechanisms underlying the pathophysiology and treatment of depression and stress-related disorders remain unclear, but studies in depressed patients and rodent models are beginning to yield promising insights. These studies demonstrate that depression and chronic stress exposure cause atrophy of neurons in cortical and limbic brain regions implicated in depression, and brain imaging studies demonstrate altered connectivity and network function in the brains of depressed patients. Studies of the neurobiological basis of the these alterations have focused on both the principle, excitatory glutamate neurons, as well as inhibitory GABA interneurons. They demonstrate structural, functional, and neurochemical deficits in both major neuronal types that could lead to degradation of signal integrity in cortical and hippocampal regions. The molecular mechanisms underlying these changes have not been identified but are thought to be related to stress induced excitotoxic effects in combination with elevated adrenal glucocorticoids and inflammatory cytokines as well as other environmental factors. Transcriptomic studies are beginning to demonstrate important sex differences and, together with genomic studies, are starting to reveal mechanistic domains of overlap and uniqueness with regards to risk and pathophysiological mechanisms with schizophrenia and bipolar disorder. These studies also implicate GABA and glutamate dysfunction as well as immunologic mechanisms. While current antidepressants have significant time lag and efficacy limitations, new rapid-acting agents that target the glutamate and GABA systems address these issues and offer superior therapeutic interventions for this widespread and debilitating disorder.