Professional Education


  • Bachelor of Arts, University of California Berkeley (2006)
  • Doctor of Philosophy, University of California San Diego (2012)

Stanford Advisors


All Publications


  • Feasibility and Preliminary Efficacy of a Novel RDoC-Based Treatment Program for Adolescent Depression: "Training for Awareness Resilience and Action" (TARA)-A Pilot Study FRONTIERS IN PSYCHIATRY Blom, E. H., Tymofiyeva, O., Chesney, M. A., Ho, T. C., Moran, P., Connolly, C. G., Duncan, L. G., Baldini, L., Weng, H. Y., Acree, M., Goldman, V., Hecht, F. M., Yang, T. T. 2017; 7
  • Resting-state functional connectivity of the amygdala and longitudinal changes in depression severity in adolescent depression JOURNAL OF AFFECTIVE DISORDERS Connolly, C. G., Ho, T. C., Blom, E. H., LeWinn, K. Z., Sacchet, M. D., Tymofiyeva, O., Simmons, A. N., Yang, T. T. 2017; 207: 86-94

    Abstract

    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.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).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.Only a subset of depressed participants was assessed at follow-up and treatment type and delivery were not standardized.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.

    View details for DOI 10.1016/j.jad.2016.09.026

    View details for Web of Science ID 000389088600013

    View details for PubMedCentralID PMC5149416

  • DTI-based connectome analysis of adolescents with major depressive disorder reveals hypoconnectivity of the right caudate JOURNAL OF AFFECTIVE DISORDERS Tymofiyeva, O., Connolly, C. G., Ho, T. C., Sacchet, M. D., Blom, E. H., LeWinn, K. Z., Xu, D., Yang, T. T. 2017; 207: 18-25

    Abstract

    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.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.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.Use of DTI-based tractography, one atlas-based parcellation, and FA values to characterize brain networks represent this study's limitations.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.

    View details for DOI 10.1016/j.jad.2016.09.013

    View details for Web of Science ID 000389088600003

    View details for PubMedCentralID PMC5107159

  • Large-Scale Hypoconnectivity Between Resting-State Functional Networks in Unmedicated Adolescent Major Depressive Disorder NEUROPSYCHOPHARMACOLOGY Sacchet, M. D., Ho, T. C., Connolly, C. G., Tymofiyeva, O., LeWinn, K. Z., Han, L. K., Blom, E. H., Tapert, S. F., Max, J. E., Frank, G. K., Paulus, M. P., Simmons, A. N., Gotlib, I. H., Yang, T. T. 2016; 41 (12): 2951-2960

    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.

    View details for DOI 10.1038/npp.2016.76

    View details for Web of Science ID 000385212700017

    View details for PubMedID 27238621

  • The neuroscience and context of adolescent depression. Acta paediatrica Henje Blom, E., Ho, T. C., Connolly, C. G., LeWinn, K. Z., Sacchet, M. D., Tymofiyeva, O., Weng, H. Y., Yang, T. T. 2016; 105 (4): 358-365

    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.Attention to the relevant neurocircuitry and contextual factors implicated in adolescent depression is necessary to advance prevention and treatment development.

    View details for DOI 10.1111/apa.13299

    View details for PubMedID 26663379

  • Fusiform Gyrus Dysfunction is Associated with Perceptual Processing Efficiency to Emotional Faces in Adolescent Depression: A Model-Based Approach FRONTIERS IN PSYCHOLOGY Ho, T. C., Zhang, S., Sacchet, M. D., Weng, H., Connolly, C. G., Blom, E. H., Han, L. K., Mobayed, N. O., Yang, T. T. 2016; 7