Neural Indicators of Anhedonia: Predictors and Mechanisms of Treatment Change in a Randomized Clinical Trial in Early Childhood Depression

Infant hedonic/anhedonic processing index (HAPI-Infant): Assessing infant anhedonia and its prospective association with adolescent depressive symptoms

BACKGROUND

Anhedonia, an impairment in the motivation for or experience of pleasure, is a well-established transdiagnostic harbinger and core symptom of mental illness. Given increasing recognition of early life origins of mental illness, we posit that anhedonia should, and could, be recognized earlier if appropriate tools were available. However, reliable diagnostic instruments prior to childhood do not currently exist.

METHODS

We developed an assessment instrument for anhedonia/reward processing in infancy, the Infant Hedonic/Anhedonic Processing Index (HAPI-Infant). Exploratory factor and psychometric analyses were conducted using data from 6- and 12-month-old infants from two cohorts (N = 188, N = 212). Then, associations were assessed between infant anhedonia and adolescent self-report of depressive symptoms.

RESULTS

The HAPI-Infant (47-items), exhibited excellent psychometric properties. Higher anhedonia scores at 6 (r = 0.23, p < .01) and 12 months (r = 0.19, p < .05) predicted elevated adolescent depressive symptoms, and these associations were stronger than for established infant risk indicators such as negative affectivity. Subsequent analyses supported the validity of short (27-item) and very short (12-item) versions of this measure.

LIMITATIONS

The primary limitations of this study are that the HAPI-Infant awaits additional tests of generalizability and of its ability to predict clinical diagnosis of depression.

CONCLUSIONS

The HAPI-Infant is a novel, psychometrically strong diagnostic tool suitable for recognizing anhedonia during the first year of life with strong predictive value for later depressive symptoms. In view of the emerging recognition of increasing prevalence of affective disorders in children and adolescents, the importance of the HAPI-Infant in diagnosing anhedonia is encouraging. Early recognition of anhedonia could target high-risk individuals for intervention and perhaps prevention of mental health disorders.

Novel mechanism-based treatments for pediatric anxiety and depressive disorders

Pediatric anxiety and depressive disorders are common, can be highly impairing, and can persist despite the best available treatments. Here, we review research into novel treatments for childhood anxiety and depressive disorders designed to target underlying cognitive, emotional, and neural circuit mechanisms. We highlight three novel treatments lying along a continuum relating to clinical impact of the disorder and the intensity of clinical management required. We review cognitive training, which involves the lowest risk and may be applicable for problems with mild to moderate impact; psychotherapy, which includes a higher level of clinical involvement and may be sufficient for problems with moderate impact; and brain stimulation, which has the highest potential risks and is therefore most appropriate for problems with high impact. For each treatment, we review the specific underlying cognitive, emotional, and brain circuit mechanisms that are being targeted, whether treatments modify those underlying mechanisms, and efficacy in reducing symptoms. We conclude by highlighting future directions, including the importance of work that leverages developmental windows of high brain plasticity to time interventions to the specific epochs in childhood that have the largest and most enduring life-long impact.

Incremental validity of ERP correlates of self-referential processing in predicting emerging depressive symptoms in late childhood: Evidence from a community-dwelling sample

Depressogenic self-referential processing (e.g., self-schemas reflecting shallower processing of positive, and deeper processing of negative, self-descriptive words) is an established cognitive vulnerability to depression. Alterations of event-related potentials (ERPs) during self-referential processing have been observed in adolescents with depression risk or clinical depression. However, no study has examined ERPs associated with self-referential processing in typical-risk youth with emerging depressive symptoms during late childhood, a high-risk period for depression. It is also unclear to what extent ERPs provide incremental validity in predicting symptoms beyond performance on self-referential processing tasks. Sixty-five community-dwelling children (38 girls; mean age/SD = 11.02/1.59 years) completed a self-referent encoding task (SRET) with EEG recorded. Children showed a larger P2 and a larger late positive potential (LPP) in response to positive SRET stimuli versus negative stimuli. Hierarchical regression showed that in the positive condition only, including ERP correlates (P1, P2, LPP) and interactions between the ERPs and positive SRET score increased the explained variation in depressive symptoms beyond behavioral SRET performance. The LPP in response to positive words was associated with lower depressive symptoms. The P1 and P2 in response to positive words interacted with positive SRET score, such that the association between positive SRET score and symptoms was significant in children with greater P1 but smaller P2. We provide novel evidence supporting the incremental validity of ERPs beyond behavioral makers in predicting emerging depressive symptoms in children. Our findings also highlight the moderating role of ERP activity in strengthening the association between behavioral markers of self-schemas and depressive outcomes.

Deficits in doors P300 amplitude during adolescence associated with preschool-onset depression

The psychophysiological underpinnings of preschool-onset depression (PO-MDD) remain underexplored. Moreover, there is currently a limited understanding of the potential impact that PO-MDD might have on neurobiological functions later in development such as general cognitive domains and reward processing. Thus, the current study sought to examine potential neurophysiological differences, measured via electroencephalography (EEG), in adolescents with and without a history of PO-MDD. Participants and their caregivers (N = 138) from a large longitudinal study completed semi-structured clinical interviews at a baseline visit (ages 3-7) to determine PO-MDD status. At a follow-up visit approximately 11 years later, adolescents (ages 13-19) completed the doors gambling task while EEG was recorded to measure event-related potentials (ERPs) elicited by both the doors and feedback stimuli, to index cognitive and reward processing functions (i.e., doors-P300, gain/loss feedback-P300, and RewP). Adolescents with a history of PO-MDD exhibited significantly smaller doors-P300 compared with adolescents with no history of PO-MDD, whereas there were no group differences in gain/loss feedback-P300 or RewP. Additionally, reduced doors-P300 was independently associated with lower baseline income-to-needs ratio, older age, and female gender. The current study suggests that reduced doors-P300 amplitude during adolescence might reflect impaired neurophysiological development related to PO-MDD. Thus, the P300 derived from the doors stimuli might be a valuable neural measure to further our understanding of potential neurophysiological differences associated with early-onset childhood depression.

Neural responsiveness to reward and suicidal ideation in social anxiety and major depression before and after psychotherapy

Suicidality is prevalent in Social Anxiety Disorder (SAD) and Major Depressive Disorder (MDD). Limited data indicate the reward positivity (RewP), a neurophysiological index of reward responsivity, and subjective capacity for pleasure may serve as brain and behavioral assays for suicide risk though this has yet to be examined in SAD or MDD in the context of psychotherapy. Therefore, the current study tested whether suicidal ideation (SI) relates to RewP and subjective capacity for anticipatory and consummatory pleasure at baseline and whether Cognitive Behavioral Therapy (CBT) impacts these measures. Participants with SAD (n = 55) or MDD (n = 54) completed a monetary reward task (gains vs. losses) during electroencephalogram (EEG) before being randomized to CBT or supportive therapy (ST), a comparator common factors arm. EEG and SI data were collected at baseline, mid-treatment, and post-treatment; capacity for pleasure was collected at baseline and post-treatment. Baseline results showed participants with SAD or MDD were comparable in SI, RewP, and capacity for pleasure. When controlling for symptom severity, SI negatively corresponded with RewP following gains and SI positively corresponded with RewP following losses at baseline. Yet, SI did not relate to subjective capacity for pleasure. Evidence of a distinct SI-RewP association suggests RewP may serve as a transdiagnositic brain-based marker of SI. Treatment outcome revealed that among participants with SI at baseline, SI significantly decreased regardless of treatment arm; also, consummatory, but not anticipatory, pleasure increased across participants regardless of treatment arm. RewP was stable following treatment, which has been reported in other clinical trial studies.

Environmental Conditions to Promote Healthy Childhood Brain/Behavioral Development: Informing Early Preventive Interventions for Delivery in Routine Care

Environmental experiences early in life have strong and enduring consequences for cognitive, emotional, and neurobiological development and related physical and mental health trajectories. The powerful influence of early caregiver nurturance and stimulation on promoting positive neurodevelopmental outcomes has been demonstrated across species. These findings elucidate the environmental conditions known to facilitate healthy neurodevelopment and underscore the potential for modifiable psychosocial factors in the environment to be harnessed to inform early preventive interventions to promote health and adaptive development. A framework for early preventive interventions to enhance nurturing and responsive caregiving for implementation during early sensitive periods of brain development delivered within existing health or educational infrastructures is proposed. Emotional development during sensitive periods is an important, under-recognized, and abundantly modifiable predictor of mental and physical health outcomes that warrants investment of resources and integration of interventions into public health infrastructure for children worldwide. Future studies are needed to further clarify whether and when sensitive periods are present for key developmental domains to inform the optimal timing and targets of these interventions. Numerous available empirically supported early interventions may be modified and applied in briefer and more feasible modalities of delivery to broader populations of developing children. As well established in growth and development across species, essential environmental inputs that are particularly important at specified developmental periods facilitate optimal growth trajectories. Such principles hold great potential in application to early child neurodevelopment to facilitate a thriving and resilient human population.

Neural correlates of emotional reactivity predict response to cognitive-behavioral therapy in obsessive-compulsive disorder

BACKGROUND

Examining predictive biomarkers to identify individuals who will likely benefit from a specific treatment is important for the development of targeted interventions. The late positive potential (LPP) is a neural marker of attention and elaborated stimulus processing, and increased LPP responses to negative stimuli are characteristic of pathological anxiety. The present study investigated whether LPP reactivity would prospectively predict response to cognitive-behavioral therapy (CBT), the first-line treatment for obsessive-compulsive disorder (OCD).

METHODS

To this end, the LPP in response to negative as compared to neutral pictures was examined in 45 patients with OCD, who underwent CBT in a naturalistic outpatient setting. LPP amplitudes were used as predictors of symptom reduction after CBT.

RESULTS

We found that higher LPP amplitudes to negative relative to neutral stimuli were predictive of lower self-reported OCD symptoms after completion of CBT, controlling for pre-treatment symptoms. Further, LPP reactivity was negatively correlated with self-reported habitual use of suppression in everyday life.

LIMITATIONS

Some participants had already begun treatment at the time of study participation. Overall, results need further replication in larger samples and standardized therapy settings.

CONCLUSIONS

The current findings suggest that patients with increased emotional reactivity benefit more from CBT, possibly through less avoidance of anxiety-provoking stimuli during exposure with response prevention, a crucial component in CBT for OCD. Although its clinical utility still needs to be evaluated further, the LPP constitutes a promising candidate as a prognostic marker for CBT response in OCD.

Cortical Development Mediates Association of Prenatal Maternal Depressive Symptoms and Child Reward Sensitivity: A Longitudinal Study

OBJECTIVE

Maternal depression during pregnancy has long-term impacts on offspring. This study used neuroimaging and behavioral data from children aged 4 to 6 years and investigated whether prenatal maternal depressive symptoms (pre-MDS) associated with child cortical morphological development and subsequent reward-related behaviors in preschoolers.

METHOD

Pre-MDS was measured using the Edinburgh Postnatal Depression Scale at 26 weeks of pregnancy. Children (n = 130) underwent structural magnetic resonance imaging (MRI) at both 4 and 6 years of age. Child sensitivity to reward and punishment was reported by mothers when children were 6 years of age. Linear mixed-effect models examined pre-MDS associations with child cortical thickness and surface area. Mediation analysis examined whether cortical development mediated associations between pre-MDS and child sensitivity to reward and punishment.

RESULTS

The 3-way interactions of pre-MDS, age, and sex on cortical thickness and surface area were not statistically significant. We found a significant interaction of pre-MDS with sex on the cortical surface area but not on thickness or their growth from 4 to 6 years, adjusting for ethnicity, socioeconomic status, baseline age, and postnatal MDS as covariates. Higher pre-MDS scores were associated with larger surface areas in the prefrontal cortex, superior temporal gyrus, and superior parietal lobe (SPL) in boys, whereas the opposite pattern was seen in girls. The SPL surface area mediated the relationship between pre-MDS and sensitivity to reward in girls.

CONCLUSION

Prenatal maternal depression alters the cortical morphology of pre-schoolers in a sex-dependent manner.

Win, lose, or draw: Examining salience, reward memory, and depression with the reward positivity

The reward positivity (RewP) is a putative biomarker of depression. Careful control of stimulus properties and manipulation of both stimulus valence and salience could facilitate interpretation of the RewP. RewP interpretation could further be improved by investigating functional outcomes of a blunted RewP in depression, such as reduced memory for rewarding outcomes. This study sought to advance RewP interpretation first by advancing task design through use of neutral (i.e., draw) control trials and counterbalanced feedback stimuli. Second, we examined the RewP's association with memory and the impact of depression. Undergraduates completed self-report measures of depression and anhedonia prior to a modified doors task in which words were displayed in colored fonts that indicated win, loss, or draw feedback. Memory of the feedback associated with each word (i.e., source memory) was tested. Results showed that RewP response to wins was more positive than to losses, which was more positive than to draws. The RewP was not associated with depression or anhedonia. The low depression group showed a source memory advantage for win words, but the high depression group did not. Source memory showed small relations to the RewP, but these did not survive Bonferroni correction. Results suggest the RewP is sensitive to salience and highlight challenges in detecting an association between the RewP and depression in modified doors tasks. Findings indicate that depression is related to dysfunctional source memory for reward but not loss and that future research should probe the possible associations between the RewP and memory in depression.

I, robot: depression plays different roles in human-human and human-robot interactions

Socially engaging robots have been increasingly applied to alleviate depressive symptoms and to improve the quality of social life among different populations. Seeing that depression negatively influences social reward processing in everyday interaction, we investigate this influence during simulated interactions with humans or robots. In this study, 35 participants with mild depression and 35 controls (all from nonclinical populations) finished the social incentive delay task with event-related potential recording, in which they received performance feedback from other persons or from a robot. Compared to the controls, the mild depressive symptom (MDS) group represented abnormalities of social reward processing in the human feedback condition: first, the MDS group showed a lower hit rate and a smaller contingent-negative variation (correlated with each other) during reward anticipation; second, depression level modulated both the early phase (indexed by the feedback-related negativity (FRN)) and the late phase (indexed by the P3) of reward consumption. In contrast, the effect of depression was evident only on FRN amplitude in the robot feedback condition. We suggest that compared to human-human interaction, the rewarding properties of human-robot interaction are less likely to be affected by depression. These findings have implications for the utilization of robot-assisted intervention in clinical practice.