| 1. |
- Belov, Vladimir, et al.
(författare)
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Multi-site benchmark classification of major depressive disorder using machine learning on cortical and subcortical measures
- 2024
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Ingår i: Scientific Reports. - : NATURE PORTFOLIO. - 2045-2322. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Machine learning (ML) techniques have gained popularity in the neuroimaging field due to their potential for classifying neuropsychiatric disorders. However, the diagnostic predictive power of the existing algorithms has been limited by small sample sizes, lack of representativeness, data leakage, and/or overfitting. Here, we overcome these limitations with the largest multi-site sample size to date (N = 5365) to provide a generalizable ML classification benchmark of major depressive disorder (MDD) using shallow linear and non-linear models. Leveraging brain measures from standardized ENIGMA analysis pipelines in FreeSurfer, we were able to classify MDD versus healthy controls (HC) with a balanced accuracy of around 62%. But after harmonizing the data, e.g., using ComBat, the balanced accuracy dropped to approximately 52%. Accuracy results close to random chance levels were also observed in stratified groups according to age of onset, antidepressant use, number of episodes and sex. Future studies incorporating higher dimensional brain imaging/phenotype features, and/or using more advanced machine and deep learning methods may yield more encouraging prospects.
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| 2. |
- Blom, Eva Henje, et al.
(författare)
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Feasibility and Preliminary Efficacy of a Novel RDoC-Based Treatment Program for Adolescent Depression : "Training for Awareness Resilience and Action" (TARA)-A Pilot Study
- 2017
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Ingår i: Frontiers in Psychiatry. - : Frontiers Media SA. - 1664-0640. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Background: The novel group treatment program Training for Awareness, Resilience, and Action (TARA) was developed to target specific mechanisms based on neuroscience findings in adolescent depression and framed within the National Institute of Mental Health Research Domain Criteria. TARA contains training of autonomic and emotional self-regulation, interoceptive awareness, relational skills, and value-based committed action.Methods: We performed a single-arm trial to test the feasibility and preliminary efficacy of TARA in reducing depression and anxiety levels and assessed whether the specific targeted domains of function reflected the hypothesized symptom change. Twenty-six adolescents (14–18 years old, 7 males and 19 females) participated in the 12-week group program. Assessment was performed before (T0), immediately after (T1), and 3 months after the end of TARA (T2).Results: Significant improvement was seen in depression symptoms (Reynolds Adolescent Depression Scale Second Edition) between T0–T1 (t-value = −3.56, p = 0.002, CI = −6.64, −1.77) and T0–T2 (t-value = −4.17, p < 0.001, CI = −11.20, −3.75) and anxiety symptoms (Multidimensional Anxiety Scale for Children) between T0–T1 (t-value = −2.26, p = 0.033, CI = −4.61, −0.21) and T0–T2 (t-value = −3.06, p = 0.006, 95% confidence interval = −9.02, −1.73). Significant improvements in psychological flexibility, sleep, and mindfulness skills were also found between T0 and T2.Limitations: The sample size was small without a control condition. The pilot design did not allow for testing the hypothesized brain changes and effect of TARA on relevant systemic biomarkers.Conclusion: TARA is feasible in a sample of clinically depressed and/or anxious adolescents and preliminary efficacy was demonstrated by reduced depression and anxiety symptoms. The specific symptom and behavioral outcomes corresponded well with the hypothesized mechanisms of change.
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| 3. |
- Henje Blom, Eva, 1962-, et al.
(författare)
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The development of an RDoC-based treatment program for adolescent depression : "Training for Awareness, Resilience, and Action" (TARA).
- 2014
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Ingår i: Frontiers in human neuroscience. - : Frontiers Media SA. - 1662-5161. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Major depressive disorder (MDD) is one of the current leading causes of disability worldwide. Adolescence is a vulnerable period for the onset of depression, with MDD affecting 8-20% of all youth. Traditional treatment methods have not been sufficiently effective to slow the increasing prevalence of adolescent depression. We therefore propose a new model for the treatment of adolescent depression - Training for Awareness, Resilience, and Action (TARA) - that is based on current understanding of developmental and depression neurobiology. The TARA model is aligned with the Research Domain Criteria (RDoC) of the National Institute of Mental Health. In this article, we first address the relevance of RDoC to adolescent depression. Second, we identify the major RDoC domains of function involved in adolescent depression and organize them in a way that gives priority to domains thought to be driving the psychopathology. Third, we select therapeutic training strategies for TARA based on current scientific evidence of efficacy for the prioritized domains of function in a manner that maximizes time, resources, and feasibility. The TARA model takes into consideration the developmental limitation in top-down cognitive control in adolescence and promotes bottom-up strategies such as vagal afference to decrease limbic hyperactivation and its secondary effects. The program has been informed by mindfulness-based therapy and yoga, as well as modern psychotherapeutic techniques. The treatment program is semi-manualized, progressive, and applied in a module-based approach designed for a group setting that is to be conducted one session per week for 12 weeks. We hope that this work may form the basis for a novel and more effective treatment strategy for adolescent depression, as well as broaden the discussion on how to address this challenge.
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| 4. |
- Ho, Tiffany C, et al.
(författare)
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Functional connectivity of negative emotional processing in adolescent depression.
- 2014
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Ingår i: Journal of Affective Disorders. - : Elsevier BV. - 0165-0327 .- 1573-2517. ; 155, s. 65-74
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The subgenual anterior cingulate cortex (sgACC) and its connected circuitry have been heavily implicated in emotional functioning in adolescent-onset major depressive disorder (MDD). While several recent studies have examined sgACC functional connectivity (FC) in depressed youth at rest, no studies to date have investigated sgACC FC in adolescent depression during negative emotional processing.METHODS: Nineteen medication-naïve adolescents with MDD and 19 matched healthy controls (HCL) performed an implicit fear facial affect recognition task during functional magnetic resonance imaging (fMRI). We defined seeds in bilateral sgACC and assessed FC using the psychophysiological interaction method. We also applied cognitive behavioral modeling to estimate group differences in perceptual sensitivity in this task. Finally, we correlated connectivity strength with clinical data and perceptual sensitivity.RESULTS: Depressed adolescents showed increased sgACC-amygdala FC and decreased sgACC-fusiform gyrus, sgACC-precuneus, sgACC-insula, and sgACC-middle frontal gyrus FC compared to HCL (p<0.05, corrected). Among the MDD, sgACC-precuneus FC negatively correlated with depression severity (p<0.05, corrected). Lastly, MDD adolescents exhibited poorer perceptual sensitivity in the task than HCL, and individual differences in perceptual sensitivity significantly correlated with sgACC FC and depression scores (p<0.05, corrected).LIMITATIONS: Subjects were clinically homogenous, possibly limiting generalizability of the findings.CONCLUSIONS: Adolescent depression is associated with biased processing of negative stimuli that may be driven by sgACC dysregulation and may possibly lead to an imbalance among intrinsic functional brain networks. This work also establishes the use of combining neuroimaging and cognitive behavioral modeling methods to investigate cognitive and neural differences between psychiatric and healthy populations.
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| 5. |
- Connolly, Colm G., et al.
(författare)
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Resting-state functional connectivity of the amygdala and longitudinal changes in depression severity in adolescent depression
- 2017
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Ingår i: Journal of Affective Disorders. - : Elsevier. - 0165-0327 .- 1573-2517. ; 207, s. 86-94
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Tidskriftsartikel (refereegranskat)abstract
- Background: The incidence of major depressive disorder (MDD) rises during adolescence, yet the neural mechanisms of MDD during this key developmental period are unclear. Altered amygdala resting-state functional connectivity (RSFC) has been associated with both adolescent and adult MDD, as well as symptom improvement in response to treatment in adults. However, no study to date has examined whether amygdala RSFC is associated with changes in depressive symptom severity in adolescents.Method: We examined group differences in amygdala RSFC between medication-naïve depressed adolescents (N=48) and well-matched healthy controls (N=53) cross-sectionally. We then longitudinally examined whether baseline amygdala RSFC was associated with change in depression symptoms three months later in a subset of the MDD group (N=24).Results: Compared to healthy controls, depressed adolescents showed reduced amygdala-based RSFC with the dorsolateral prefrontal cortex (DLPFC)and the ventromedial prefrontal cortex (VMPFC). Within the depressed group, more positive baseline RSFC between the amygdala and insulae was associated with greater reduction in depression symptoms three months later.Limitations: Only a subset of depressed participants was assessed at follow-up and treatment type and delivery were not standardized.Conclusions: Adolescent depression may be characterized by dysfunction of frontolimbic circuits (amygdala-DLPFC, amygdala-VMPFC) underpinning emotional regulation, whereas those circuits (amygdala-insula) subserving affective integration may index changes in depression symptom severity and may therefore potentially serve as a candidate biomarker for treatment response. Furthermore, these results suggest that the biomarkers of MDD presence are distinct from those associated with change in depression symptoms over time.
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| 6. |
- Henje Blom, Eva, 1962-, et al.
(författare)
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Altered insular activation and increased insular functional connectivity during sad and happy face processing in adolescent major depressive disorder.
- 2015
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Ingår i: Journal of Affective Disorders. - : Elsevier BV. - 0165-0327 .- 1573-2517. ; 178, s. 215-23
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Major depressive disorder (MDD) is a leading cause of disability worldwide and occurs commonly first during adolescence. The insular cortex (IC) plays an important role in integrating emotion processing with interoception and has been implicated recently in the pathophysiology of adult and adolescent MDD. However, no studies have yet specifically examined the IC in adolescent MDD during processing of faces in the sad-happy continuum. Thus, the aim of the present study is to investigate the IC during sad and happy face processing in adolescents with MDD compared to healthy controls (HCL).METHODS: Thirty-one adolescents (22 female) with MDD and 36 (23 female) HCL underwent a well-validated emotional processing fMRI paradigm that included sad and happy face stimuli.RESULTS: The MDD group showed significantly less differential activation of the anterior/middle insular cortex (AMIC) in response to sad versus happy faces compared to the HCL group. AMIC also showed greater functional connectivity with right fusiform gyrus, left middle frontal gyrus, and right amygdala/parahippocampal gyrus in the MDD compared to HCL group. Moreover, differential activation to sad and happy faces in AMIC correlated negatively with depression severity within the MDD group.LIMITATIONS: Small age-range and cross-sectional nature precluded assessment of development of the AMIC in adolescent depression.CONCLUSIONS: Given the role of the IC in integrating bodily stimuli with conscious cognitive and emotional processes, our findings of aberrant AMIC function in adolescent MDD provide a neuroscientific rationale for targeting the AMIC in the development of new treatment modalities.
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| 7. |
- Henje Blom, Eva, 1962-, et al.
(författare)
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The neuroscience and context of adolescent depression
- 2016
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Ingår i: Acta Paediatrica. - : Wiley. - 0803-5253 .- 1651-2227. ; 105:4, s. 358-365
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Forskningsöversikt (refereegranskat)abstract
- Adolescent depression is a growing public health concern with an increased risk of negative health outcomes, including suicide. The use of antidepressants and psychotherapy has not halted its increasing prevalence, and there is a critical need for effective prevention and treatment. We reviewed the neuroscience of adolescent depression, with a focus on the neurocircuitry of sustained threat and summarised contextual factors that have an impact on brain development and the pathophysiology of depression. We also reviewed novel treatment models.Conclusion: Attention to the relevant neurocircuitry and contextual factors implicated in adolescent depression is necessary to advance prevention and treatment development.
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| 8. |
- Ho, Tiffany C, et al.
(författare)
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Emotion-Dependent Functional Connectivity of the Default Mode Network in Adolescent Depression.
- 2015
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Ingår i: Biological Psychiatry. - : Elsevier BV. - 0006-3223 .- 1873-2402. ; 78:9, s. 635-46
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Functional magnetic resonance imaging research suggests that major depressive disorder (MDD) in both adults and adolescents is marked by aberrant connectivity of the default mode network (DMN) during resting state. However, emotional dysregulation is also a key feature of MDD. No studies to date have examined emotion-related DMN pathology in adolescent depression. Comprehensively understanding the dynamics of DMN connectivity across brain states in individuals with depression with short disease histories could provide insight into the etiology of MDD.METHODS: We collected functional magnetic resonance imaging data during an emotion identification task and during resting state from 26 medication-free adolescents (13-17 years old) with MDD and 37 well-matched healthy control subjects. We examined between-group differences in blood oxygenation level-dependent task responses and emotion-dependent and resting-state functional connectivity of the two primary nodes of the DMN: medial prefrontal cortex and posterior cingulate cortex (PCC). Additionally, we examined between-group differences in DMN functional connectivity and its relationship to depression severity and onset.RESULTS: Relative to healthy control subjects, unmedicated adolescents with MDD demonstrated reduced medial prefrontal cortex and PCC emotion-related deactivation and greater medial prefrontal cortex and PCC emotion-dependent functional connectivity with precuneus, cingulate gyrus, and striatum/subcallosal cingulate gyrus. The PCC-subcallosal cingulate connectivity remained inflexibly elevated in the subjects with MDD versus healthy control subjects during resting state. Stronger PCC emotion-dependent functional connectivity was associated with greater depression severity and an earlier age of depression onset.CONCLUSIONS: Adolescent depression is associated with inflexibly elevated DMN connections. Given more recent evidence of DMN maturation throughout adolescence, our findings suggest that early-onset depression adversely affects normal development of functional brain networks.
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| 9. |
- Ho, Tiffany C., et al.
(författare)
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Fusiform gyrus dysfunction is associated with perceptual processing efficiency to emotional faces in adolescent depression : a model-based approach
- 2016
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Ingår i: Frontiers in Psychology. - Lausanne : Frontiers Media S.A.. - 1664-1078. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- While the extant literature has focused on major depressive disorder (MDD) as being characterized by abnormalities in processing affective stimuli (e.g., facial expressions), little is known regarding which specific aspects of cognition influence the evaluation of affective stimuli, and what are the underlying neural correlates. To investigate these issues, we assessed 26 adolescents diagnosed with MDD and 37 well-matched healthy controls (HCL) who completed an emotion identification task of dynamically morphing faces during functional magnetic resonance imaging (fMRI). We analyzed the behavioral data using a sequential sampling model of response time (RT) commonly used to elucidate aspects of cognition in binary perceptual decision making tasks: the Linear Ballistic Accumulator (LBA) model. Using a hierarchical Bayesian estimation method, we obtained group-level and individual-level estimates of LBA parameters on the facial emotion identification task. While the MDD and HCL groups did not differ in mean RT, accuracy, or group-level estimates of perceptual processing efficiency (i.e., drift rate parameter of the LBA), the MDD group showed significantly reduced responses in left fusiform gyrus compared to the HCL group during the facial emotion identification task. Furthermore, within the MDD group, fMRI signal in the left fusiform gyrus during affective face processing was significantly associated with greater individual-level estimates of perceptual processing efficiency. Our results therefore suggest that affective processing biases in adolescents with MDD are characterized by greater perceptual processing efficiency of affective visual information in sensory brain regions responsible for the early processing of visual information. The theoretical, methodological, and clinical implications of our results are discussed.
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| 10. |
- LeWinn, Kaja Z., et al.
(författare)
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An exploratory examination of reappraisal success in depressed adolescents : Preliminary evidence of functional differences in cognitive control brain regions
- 2018
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Ingår i: Journal of Affective Disorders. - : Elsevier. - 0165-0327 .- 1573-2517. ; 240, s. 155-164
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Tidskriftsartikel (refereegranskat)abstract
- Background: Most neuroimaging studies of adolescent depression employ tasks not designed to engage brain regions necessary for the cognitive control of emotion, which is central to many behavioral therapies for depression. Depressed adults demonstrate less effective activation of these regions and greater amygdala activation during cognitive reappraisal; we examined whether depressed adolescents show similar patterns of brain activation.Methods: We collected functional magnetic resonance imaging (fMRI) data during cognitive reappraisal in 41 adolescents with major depressive disorder (MDD) and 34 matched controls (ages 13-17). We examined group differences in (1) activations associated with reappraisal and reappraisal success (i.e., negative affect reduction during reappraisal) using whole brain and amygdala region-of-interest analyses, and (2) functional connectivity of regions from the group-by-reappraisal success interaction.Results: We found no significant group differences in whole brain or amygdala analyses during reappraisal. In the group-by-reappraisal success interaction, activations in the left dorsomedial prefrontal cortex (dmPFC) and left dorsolateral PFC (dlPFC) were associated with reappraisal success in healthy controls but not depressed adolescents. Depressed adolescents demonstrated reduced connectivity between the left dmPFC and the anterior insula/inferior frontal gyri bilaterally (AI/IFG) and between left dlPFC and left AI/IFG.Limitations: Our results should be considered exploratory given our less conservative statistical threshold in the group-by-reappraisal interaction.Conclusions: We find preliminary evidence that depressed adolescents engage cognitive control regions less efficiently than healthy controls, suggesting delayed maturation of regulatory prefrontal cortex regions; more research is needed to determine whether cognitive therapies improve functioning of these regions in depressed youth.
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| 11. |
- Sacchet, Matthew D., et al.
(författare)
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Large-scale hypoconnectivity between resting-state functional networks in unmedicated adolescent major depressive disorder
- 2016
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Ingår i: Neuropsychopharmacology. - London : Nature Publishing Group. - 0893-133X .- 1740-634X. ; 41:12, s. 2951-2960
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Tidskriftsartikel (refereegranskat)abstract
- Major depressive disorder (MDD) often emerges during adolescence, a critical period of brain development. Recent resting-state fMRI studies of adults suggest that MDD is associated with abnormalities within and between resting-state networks (RSNs). Here we tested whether adolescent MDD is characterized by abnormalities in interactions among RSNs. Participants were 55 unmedicated adolescents diagnosed with MDD and 56 matched healthy controls. Functional connectivity was mapped using resting-state fMRI. We used the network-based statistic (NBS) to compare large-scale connectivity between groups and also compared the groups on graph metrics. We further assessed whether group differences identified using nodes defined from functionally defined RSNs were also evident when using anatomically defined nodes. In addition, we examined relations between network abnormalities and depression severity and duration. Finally, we compared intranetwork connectivity between groups and assessed the replication of previously reported MDD-related abnormalities in connectivity. The NBS indicated that, compared with controls, depressed adolescents exhibited reduced connectivity (p<0.024, corrected) between a specific set of RSNs, including components of the attention, central executive, salience, and default mode networks. The NBS did not identify group differences in network connectivity when using anatomically defined nodes. Longer duration of depression was significantly correlated with reduced connectivity in this set of network interactions (p=0.020, corrected), specifically with reduced connectivity between components of the dorsal attention network. The dorsal attention network was also characterized by reduced intranetwork connectivity in the MDD group. Finally, we replicated previously reported abnormal connectivity in individuals with MDD. In summary, adolescents with MDD show hypoconnectivity between large-scale brain networks compared with healthy controls. Given that connectivity among these networks typically increases during adolescent neurodevelopment, these results suggest that adolescent depression is associated with abnormalities in neural systems that are still developing during this critical period.
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| 12. |
- Tymofiyeva, Olga, et al.
(författare)
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Application of machine learning to structural connectome to predict symptom reduction in depressed adolescents with cognitive behavioral therapy (CBT)
- 2019
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Ingår i: NeuroImage. - : Elsevier. - 2213-1582. ; 23
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Adolescent major depressive disorder (MDD) is a highly prevalent, incapacitating and costly illness. Many depressed teens do not improve with cognitive behavioral therapy (CBT), a first-line treatment for adolescent MDD, and face devastating consequences of increased risk of suicide and many negative health outcomes. "Who will improve with CBT?" is a crucial question that remains unanswered, and treatment planning for adolescent depression remains biologically unguided. The purpose of this study was to utilize machine learning applied to patients' brain imaging data in order to help predict depressive symptom reduction with CBT.Methods: We applied supervised machine learning to diffusion MRI-based structural connectome data in order to predict symptom reduction in 30 depressed adolescents after three months of CBT. A set of 21 attributes was chosen, including the baseline depression score, age, gender, two global network properties, and node strengths of brain regions previously implicated in depression. The practical and robust J48 pruned tree classifier was utilized with a 10-fold cross-validation.Results: The classification resulted in an 83% accuracy of predicting depressive symptom reduction. The resulting tree of size seven with only three attributes highlights the role of the right thalamus in predicting depressive symptom reduction with CBT. Additional analysis showed a significant negative correlation between the change in the depressive symptoms and the node strength of the right thalamus.Conclusions: Our results demonstrate that a machine learning algorithm that exclusively uses structural connectome data and the baseline depression score can predict with a high accuracy depressive symptom reduction in adolescent MDD with CBT. This knowledge can help improve treatment planning for adolescent depression.
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| 13. |
- Tymofiyeva, Olga, et al.
(författare)
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DTI-based connectome analysis of adolescents with major depressive disorder reveals hypoconnectivity of the right caudate
- 2017
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Ingår i: Journal of Affective Disorders. - : Elsevier. - 0165-0327 .- 1573-2517. ; 207, s. 18-25
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Adolescence is a vulnerable period for the onset of major depressive disorder (MDD). While some studies have shown white matter alterations in adolescent MDD, there is still a gap in understanding how the brain is affected at a network level.METHODS: We compared diffusion tensor imaging (DTI)-based brain networks in a cohort of 57 adolescents with MDD and 41 well-matched healthy controls who completed self-reports of depression symptoms and stressful life events. Using atlas-based brain regions as network nodes and tractography streamline count or mean fractional anisotropy (FA) as edge weights, we examined weighted local and global network properties and performed Network-Based Statistic (NBS) analysis.RESULTS: While there were no significant group differences in the global network properties, the FA-weighted node strength of the right caudate was significantly lower in depressed adolescents and correlated positively with age across both groups. The NBS analysis revealed a cluster of lower FA-based connectivity in depressed subjects centered on the right caudate, including connections to frontal gyri, insula, and anterior cingulate. Within this cluster, the most robust difference between groups was the connection between the right caudate and middle frontal gyrus. This connection showed a significant diagnosis by stress interaction and a negative correlation with total stress in depressed adolescents.LIMITATIONS: Use of DTI-based tractography, one atlas-based parcellation, and FA values to characterize brain networks represent this study's limitations.CONCLUSIONS: Our results allowed us to suggest caudate-centric models of dysfunctional processes underlying adolescent depression, which might guide future studies and help better understand and treat this disorder.
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| 14. |
- Tymofiyeva, Olga, et al.
(författare)
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High levels of mitochondrial DNA are associated with adolescent brain structural hypoconnectivity and increased anxiety but not depression
- 2018
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Ingår i: Journal of Affective Disorders. - Amsterdam : Elsevier. - 0165-0327 .- 1573-2517. ; 232, s. 283-290
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Adolescent anxiety and depression are highly prevalent psychiatric disorders that are associated with altered molecular and neurocircuit profiles. Recently, increased mitochondrial DNA copy number (mtDNA-cn) has been found to be associated with several psychopathologies in adults, especially anxiety and depression. The associations between mtDNA-cn and anxiety and depression have not, however, been investigated in adolescents. Moreover, to date there have been no studies examining associations between mtDNA-cn and brain network alterations in mood disorders in any age group.METHODS: The first aim of this study was to compare salivary mtDNA-cn between 49 depressed and/or anxious adolescents and 35 well-matched healthy controls. The second aim of this study was to identify neural correlates of mtDNA-cn derived from diffusion tensor imaging (DTI) and tractography, in the full sample of adolescents.RESULTS: There were no diagnosis-specific alterations in mtDNA-cn. However, there was a positive correlation between mtDNA-cn and levels of anxiety, but not depression, in the full sample of adolescents. A subnetwork of connections largely corresponding to the left fronto-occipital fasciculus had significantly lower fractional anisotropy (FA) values in adolescents with higher than median mtDNA-cn.LIMITATIONS: Undifferentiated analysis of free and intracellular mtDNA and use of DTI-based tractography represent this study's limitations.CONCLUSIONS: The results of this study help elucidate the relationships between clinical symptoms, molecular changes, and neurocircuitry alterations in adolescents with and without anxiety and depression, and they suggest that increased mtDNA-cn is associated both with increased anxiety symptoms and with decreased fronto-occipital structural connectivity in this population.
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| 15. |
- Tymofiyeva, Olga, et al.
(författare)
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Reduced anxiety and changes in amygdala network properties in adolescents with training for awareness, resilience, and action (TARA)
- 2021
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Ingår i: NeuroImage. - : Elsevier. - 2213-1582. ; 29
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Tidskriftsartikel (refereegranskat)abstract
- Mindfulness-based approaches show promise to improve emotional health in youth and may help treat and prevent adolescent depression and anxiety. However, there is a fundamental gap in understanding the neural reorganization that takes place as a result of such interventions. The Training for Awareness, Resilience, and Action (TARA) program, initially developed for depressed adolescents, uses a framework drawn from neuroscience, mindfulness, yoga, and modern psychotherapeutic techniques to promote emotional health. The goal of this study was to assess the effects of the TARA training on emotional health and structural white matter brain networks in healthy youth. We analyzed data from 23 adolescents who underwent the 12-week TARA training in a controlled within-subject study design and whose brain networks were assessed using diffusion MRI connectomics. Compared to the control time period, adolescents showed a significant decrease in anxiety symptoms with TARA (Cohen's d = -0.961, p = 0.006); moreover, the node strength of the Right Amygdala decreased significantly after TARA (Cohen's d = -1.026, p = 0.004). Post-hoc analyses indicated that anxiety at baseline before TARA was positively correlated with Right Amygdala node strength (r = 0.672, p = 0.001). While change in Right Amygdala node strength with TARA was not correlated with change in anxiety (r = 0.146, p = 0.51), it was associated with change in depression subscale of Anhedonia / Negative Affect (r = 0.575, p = 0.004, exploratory analysis), possibly due to overlapping constructs captured in our anxiety and depression scales. Our results suggest that increased structural connectivity of Right Amygdala may underlie increased anxiety in adolescents and be lowered through anxiety-reducing training such as TARA. The results of this study contribute to our understanding of the neural mechanisms of TARA and may facilitate neuroscience-based prevention and treatment of adolescent anxiety and depression.
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| 16. |
- Yuan, Justin P., et al.
(författare)
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Gray Matter Changes in Adolescents Participating in a Meditation Training
- 2020
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Ingår i: Frontiers in Human Neuroscience. - : Frontiers Media S.A.. - 1662-5161. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Meditation has shown to benefit a wide range of conditions and symptoms, but the neural mechanisms underlying the practice remain unclear. Magnetic resonance imaging (MRI) studies have investigated the structural brain changes due to the practice by examining volume, density, or cortical thickness changes. However, these studies have focused on adults; meditation's structural effects on the adolescent brain remain understudied. In this study, we investigated how meditation training affects the structure of the adolescent brain by scanning a group of 38 adolescents (16.48 +/- 1.29 years) before and after participating in a 12-week meditation training. Subjects underwent Training for Awareness, Resilience, and Action (TARA), a program that mainly incorporates elements from mindfulness meditation and yoga-based practices. A subset of the adolescents also received an additional control scan 12 weeks before TARA. We conducted voxel-based morphometry (VBM) to assess gray matter volume changes pre- to post-training and during the control period. Subjects showed significant gray matter (GM) volume decreases in the left posterior insula and to a lesser extent in the left thalamus and left putamen after meditation training. There were no significant changes during the control period. Our results support previous findings that meditation affects regions associated with physical and emotional awareness. However, our results are different from previous morphometric studies in which meditation was associated with structural increases. We posit that this discrepancy may be due to the differences between the adolescent brain and the adult brain.
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| 17. |
- Yuan, Justin P., et al.
(författare)
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Test-retest reliability of graph theoretic metrics in adolescent brains
- 2019
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Ingår i: Brain Connectivity. - : Mary Ann Liebert. - 2158-0014 .- 2158-0022. ; 9:2, s. 144-154
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Tidskriftsartikel (refereegranskat)abstract
- Graph theory analysis of structural brain networks derived from diffusion tensor imaging (DTI) has become a popular analytical method in neuroscience, enabling advanced investigations of neurological and psychiatric disorders. The purpose of this study was to investigate: 1) the effects of edge weighting schemes, and 2) the effects of varying interscan periods on graph metrics' test-retest reliability within the adolescent brain. We compared a binary (B) network definition with three weighting schemes: fractional anisotropy (FA), streamline count (SC), and streamline count with density and length correction (SDL). Two commonly used global and two local graph metrics were examined. The analysis was conducted with two groups of adolescent volunteers who received DTI scans either 12 weeks apart (16.62±1.10yrs) or within the same scanning session (30 minutes apart) (16.65±1.14yrs). The intraclass correlation coefficient (ICC) was used to assess test-retest reliability and the coefficient of variation (CV) was used to assess precision. On average, each edge scheme produced reliable results at both time intervals. Weighted measures outperformed binary measures, with SDL-weights producing the most reliable metrics. All edge schemes except FA displayed high CV values, leaving FA as the only edge scheme that consistently showed high precision while also producing reliable results. Overall findings suggest that FA-weights are more suited for DTI connectome studies in adolescents.
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