Principal components of electrocortical activity during self-evaluation indicate depressive symptom severity

Catch the drift: Depressive symptoms track neural response during more efficient decision-making for negative self-referents

Background

Adolescence is a time of heightened risk for developing depression and also a critical period for the development and integration of self-identity. Despite this, the relation between the neurophysiological correlates of self-referential processing and major depressive symptoms in youth is not well understood. Here, we leverage computational modeling of the self-referential encoding task (SRET) to identify behavioral moderators of the association between the posterior late positive potential (LPP), an event-related potential associated with emotion regulation, and youth self-reported symptoms of depression. Specifically, within a drift-diffusion framework, we evaluated whether the association between the posterior LPP and youth symptoms of major depression was moderated by drift rate, a parameter reflecting processing efficiency during self-evaluative decisions.

Methods

A sample of 106 adolescents, aged 12 to 17 (53% male; Mage = 14.49, SD = 1.70), completed the SRET with concurrent high-density electroencephalography and self-report measures of depression and anxiety.

Results

Findings indicated a significant moderation: for youth showing greater processing efficiency (drift rate) when responding to negative compared to positive words, larger posterior LPPs predicted greater depressive symptom severity.

Limitations

We relied on a community sample and our study was cross-sectional in nature. Future longitudinal work with clinically depressed youth would be beneficial.

Conclusions

Our results suggest a neurobehavioral model of adolescent depression wherein efficient processing of negative information co-occurs with increased demands on affective self-regulation. Our findings also have clinical relevance; youth's neurophysiological response (posterior LPP) and performance during the SRET may serve as a novel target for tracking treatment-related changes in one's self-identity.

Self-referential Processing in Remitted Depression: An Event-Related Potential Study

Background

Identifying mechanisms of major depressive disorder that continue into remission is critical, as these mechanisms may contribute to subsequent depressive episodes. Biobehavioral markers related to depressogenic self-referential processing biases have been identified in adults with depression. Thus, we investigated whether these risk factors persisted during remission as well as contributed to the occurrence of stress and depressive symptoms over time.

Methods

At baseline, adults with remitted depression (n = 33) and healthy control subjects (n = 33) were administered diagnostic and stress interviews as well as self-report symptom measures. In addition, participants completed a self-referential encoding task while electroencephalography data were acquired. Stress interviews and self-report symptom measures were readministered at the 6-month follow-up assessment.

Results

Drift diffusion modeling showed that compared with healthy individuals, adults with remitted depression exhibited a slower drift rate to negative stimuli, indicating a slower tendency to reject negative stimuli as self-relevant. At the 6-month follow-up assessment, a slower drift rate to negative stimuli predicted greater interpersonal stress severity among individuals with remitted depression but not healthy individuals while controlling for both baseline depression symptoms and interpersonal stress severity. Highlighting the specificity of this effect, results were nonsignificant when predicting noninterpersonal stress. For self-relevant positive words endorsed, adults with remitted depression exhibited smaller left- than right-hemisphere late positive potential amplitudes; healthy control subjects did not show hemispheric differences.

Conclusions

Self-referential processing deficits persist into remission. In line with the stress generation framework, these biases predicted the occurrence of interpersonal stress, which may provide insight about a potential pathway for the re-emergence of depressive symptoms.

Neurophysiological Markers Related to Negative Self-referential Processing Differentiate Adolescent Suicide Ideators and Attempters

Background

Adolescent suicide is a major public health concern, and presently, there is a limited understanding of the neurophysiological correlates of suicidal behaviors. Cognitive models of suicide indicate that negative views of the self are related to suicidal thoughts and behaviors, and this study investigated whether behavioral and neural correlates of self-referential processing differentiate suicide ideators from recent attempters.

Methods

Adolescents with depression reporting current suicidal ideation and no lifetime suicide attempts (suicide ideators, n = 30) and past-year suicide attempts (recent attempters, n = 26) completed a self-referential encoding task while high-density electroencephalogram data were recorded. Behavioral analyses focused on negative processing bias (i.e., tendency to attribute negative information as being self-relevant) and drift rate (i.e., slope of reaction time and response type that corresponds to how quickly information is accumulated to make a decision about whether words are self-referent). Neurophysiological markers probing components reflecting early semantic monitoring (P2), engagement (early late positive potential), and effortful encoding (late late positive potential) also were tested.

Results

Adolescent suicide ideators and recent suicide attempters reported comparable symptom severity, suicide ideation, and mental disorders. Although there were no behavioral differences, compared with suicide ideators, suicide attempters exhibited greater P2 amplitudes for negative versus positive words, which may reflect enhanced attention and arousal in response to negative self-referential stimuli. There were no group differences for the early or late late positive potential.

Conclusions

Enhanced sensory arousal in response to negative stimuli-that is, attentional orienting to semantic, emotional, and self-relevant features-differentiates adolescent suicide attempters from ideators and thus may signal risk for suicidal behavior.

The glass is half empty: Negative self-appraisal bias and attenuated neural response to positive self-judgment in adolescence

Substantial changes in cognitive-affective self-referential processing occur during adolescence. We studied the behavioral and ERP correlates of self-evaluation in healthy male and female adolescents aged 12-17 (N = 109). Participants completed assessments of depression symptoms and puberty as well as a self-referential encoding task while 128-channel high-density EEG data were collected. Depression symptom severity was associated with increased endorsement of negative words and longer reaction times. In an extreme group analysis, a negative appraisal-bias subsample (n = 28) displayed decreased frontal P2 amplitudes to both positive and negative word stimuli, reflecting reduced early attentional processing and emotional salience. Compared to the positive appraisal-bias subsample (n = 27), the negative appraisal-bias subsample showed reduced LPP to positive words but not negative words, suggesting attenuated sustained processing of positive self-relevant stimuli. Findings are discussed in terms of neural processes associated with ERPs during negative versus positive self-appraisal bias, and developmental implications.

Review of Abnormal Self-Knowledge in Major Depressive Disorder

Background: Major depressive disorder (MDD) is an affective disorder that is harmful to both physical and mental health. Abnormal self-knowledge, which refers to abnormal judgments about oneself, is a core symptom of depression. However, little research has summarized how and why patients with MDD differ from healthy individuals in terms of self-knowledge. Objective: To gain a better understanding of MDD, we reviewed previous studies that focused on the behavioral and neurological changes of self-knowledge in this illness. Main Findings: On the behavioral level, depressed individuals exhibited negative self-knowledge in an explicit way, while more heterogeneous patterns were reported in implicit results. On the neurological level, depressed individuals, as compared with non-depressed controls, showed abnormal self-referential processing in both early perception and higher cognitive processing phases during the Self-Referential Encoding Task. Furthermore, fMRI studies have reported aberrant activity in the medial prefrontal cortex area for negative self-related items in depression. These results revealed several behavioral features and brain mechanisms underlying abnormal self-knowledge in depression. Future Studies: The neural mechanism of implicit self-knowledge in MDD remains unclear. Future research should examine the importance of others' attitudes on the self-concept of individuals with MDD, and whether abnormal self-views may be modified through cognitive or pharmacological approaches. In addition, differences in abnormal self-knowledge due to genetic variation between depressed and non-depressed populations remain unconfirmed. Importantly, it remains unknown whether abnormal self-knowledge could be used as a specific marker to distinguish healthy individuals from those with MDD. Conclusion: This review extends our understanding of the relationship between self-knowledge and depression by indicating several abnormalities among individuals with MDD and those who are at risk for this illness.

Sustained engagement of attention is associated with increased negative self-referent processing in major depressive disorder

This study investigated the link between self-reference and attentional engagement in adults with (n=22) and without (HC; n=24) Major Depressive Disorder (MDD). Event-related potentials (ERPs) were recorded while participants completed the Self-Referent Encoding Task (SRET). MDD participants endorsed significantly fewer positive words and more negative words as self-descriptive than HC participants. A whole-scalp data analysis technique revealed that the MDD participants had larger difference wave (negative words minus positive words) ERP amplitudes from 380 to 1000ms across posterior sites, which positively correlated with number of negative words endorsed. No group differences were observed for earlier attentional components (P1, P2). The results suggest that among adults with MDD, negative stimuli capture attention during later information processing; this engagement is associated with greater self-referent endorsement of negative adjectives. Sustained cognitive engagement for self-referent negative stimuli may be an important target for neurocognitive depression interventions.

Brain-Based Biomarkers for the Treatment of Depression: Evolution of an Idea

An ambition of depression biomarker research is to augment psychometric and cognitive assessment of clinically relevant phenomena with neural measures. Although such applications have been slow to arrive, we observe a steady evolution of the idea and anticipate emerging technologies with some optimism. To highlight critical themes and innovations in depression biomarker research, we take as our point of reference a specific research narrative. We begin with an early model of frontal-limbic dysfunction, which represents a conceptual shift from localized pathology to understanding symptoms as an emergent property of distributed networks. Over the decades, this model accommodates perspectives from neurology, psychiatry, clinical, and cognitive neuroscience, and preserves past insight as more complex methods become available. We also track the expanding mission of brain biomarker research: from the development of diagnostic tools to treatment selection algorithms, measures of neurocognitive functioning and novel targets for neuromodulation. To conclude, we draw from this particular research narrative future directions for biomarker research. We emphasize integration of measurement modalities to describe dynamic change in domain-general networks, and we speculate that a brain-based framework for psychiatric problems may dissolve classical diagnostic and disciplinary boundaries. (JINS, 2017, 23, 870-880).