Altered reward and effort processing in children with maltreatment experience: a potential indicator of mental health vulnerability

From movement to motivation: a proposed framework to understand the antidepressant effect of exercise

Depression is the leading cause of disability worldwide, exerting a profound negative impact on quality of life in those who experience it. Depression is associated with disruptions to several closely related neural and cognitive processes, including dopamine transmission, fronto-striatal brain activity and connectivity, reward processing and motivation. Physical activity, especially aerobic exercise, reduces depressive symptoms, but the mechanisms driving its antidepressant effects are poorly understood. Here we propose a novel hypothesis for understanding the antidepressant effects of exercise, centred on motivation, across different levels of explanation. There is robust evidence that aerobic exercise decreases systemic inflammation. Inflammation is known to reduce dopamine transmission, which in turn is strongly implicated in effort-based decision making for reward. Drawing on a broad range of research in humans and animals, we propose that by reducing inflammation and boosting dopamine transmission, with consequent effects on effort-based decision making for reward, exercise initially specifically improves 'interest-activity' symptoms of depression-namely anhedonia, fatigue and subjective cognitive impairment - by increasing propensity to exert effort. Extending this framework to the topic of cognitive control, we explain how cognitive impairment in depression may also be conceptualised through an effort-based decision-making framework, which may help to explain the impact of exercise on cognitive impairment. Understanding the mechanisms underlying the antidepressant effects of exercise could inform the development of novel intervention strategies, in particular personalised interventions and boost social prescribing.

Social experience in adolescence shapes prefrontal cortex structure and function in adulthood

During adolescence, the prefrontal cortex (PFC) undergoes dramatic reorganization. PFC development is profoundly influenced by the social environment, disruptions to which may prime the emergence of psychopathology across the lifespan. We investigated the neurobehavioral consequences of isolation experienced in adolescence in mice, and in particular, the long-term consequences that were detectable even despite normalization of the social milieu. Isolation produced biases toward habit-like behavior at the expense of flexible goal seeking, plus anhedonic-like reward deficits. Behavioral phenomena were accompanied by neuronal dendritic spine over-abundance and hyper-excitability in the ventromedial PFC (vmPFC), which was necessary for the expression of isolation-induced habits and sufficient to trigger behavioral inflexibility in socially reared controls. Isolation activated cytoskeletal regulatory pathways otherwise suppressed during adolescence, such that repression of constituent elements prevented long-term isolation-induced neurosequelae. Altogether, our findings unveil an adolescent critical period and multi-model mechanism by which social experiences facilitate prefrontal cortical maturation.

The impact of childhood trauma exposure on social functioning in schizophrenia: the moderated mediation role of oxytocin and oxytocin receptor gene polymorphisms

BACKGROUND

Childhood trauma has been linked to increased risk of schizophrenia and social dysfunction, and oxytocin and its receptor gene have been implicated in regulating social behavior. This study investigated the potential role of oxytocin and oxytocin receptor gene (OXTR) in mediating the effects of childhood trauma on social functioning in schizophrenia.

METHODS

The study consisted of 382 patients with schizophrenia and 178 healthy controls who were assessed using the Taiwanese version of the Childhood Trauma Questionnaire (CTQ-SF), the Social Functioning Scale (SFS), and plasma oxytocin levels. DNA was extracted to genotype the OXTR and ten single-nucleotide polymorphisms (SNPs; rs2254298, rs237885, rs237887, rs237899, rs53576, rs9840864, rs13316193, rs7632287, rs1042778, and rs237895) were selected.

RESULTS

Patients with schizophrenia showed higher CTQ-SF scores (t = 12.549, p < 0.001), lower SFS scores (t = -46.951, p < 0.001), and lower plasma oxytocin levels (t = -5.448, p < 0.001) compared to healthy controls. The study also found significant differences in OXTR SNPs between both groups, with risk alleles being more prevalent in patients with schizophrenia (t = 2.734, p = 0.006). Results indicated a significant moderated mediation effect, with oxytocin and the OXTR SNPs partially mediating the relationship between childhood trauma exposure and social functioning in patients with schizophrenia (index of mediation = 0.038, 95% CI [0.033-0.044]).

CONCLUSIONS

The findings suggest that oxytocin and its receptor gene may be promising targets for interventions aimed at improving social functioning in patients with a history of childhood trauma and schizophrenia. However, further research is needed to fully understand these effects and the potential of oxytocin-based interventions in this population.

The contribution of childhood maltreatment to the incidence of heavy cannabis use in Iran (IRNS-CCI): A multicenter, matched-pairs, nested, case-control study

BACKGROUND

Previous studies have shown the role of the interaction between the endocannabinoid system (ECS) and life's adversities in the formation of addiction, including alcohol abuse.

OBJECTIVE

Our objective was to identify childhood maltreatment (CM) patterns with the strongest impact on the probability of heavy cannabis use (THCCOOH concentrations ≥150 ng/mL) in Iran.

PARTICIPANTS AND SETTING

Using survivor sampling, 350 adult participants were selected, and they were then allocated to three categories based on an optimal algorithm: 1) Sexual abuse, 2) Physical abuse, and 3) Physical neglect.

METHODS

From 1 September 2019 to 1 May 2023, we implemented a multicenter, matched-pairs, nested, case-control study based on the wave 3-wave 6 data of a longitudinal, multicenter, cohort study. The cases and controls (n = 350 men) were defined according to the severity of CM. The THC potency was evaluated with the delta-9 carboxy tetrahydrocannabinol (THC-COOH) levels in urine using gas chromatography/mass spectrometry (GC/MS). We calculated the population attributable fractions (PAFs) to identify the patterns of maltreatment associated with the highest odds of high-potency cannabis use.

RESULTS

Accumulating CM, including sexual abuse, physical abuse, and physical neglect, carried more than three times the risk of heavy cannabis use (OR 3.4 95 % CI 2.9-4.1), and the combination of the three indicators of maltreatment and a high BMI (25-29.9) carried more than four times the risk of heavy cannabis use (OR 4.7 95 % CI 2.7-4.1) compared to the controls. We estimated that in the case of zero CM for each of the three indicators, over 20 % of new cases of heavy cannabis use can be prevented.

CONCLUSIONS

The findings show the significance of CM as a predicator of heavy cannabis use in adulthood and in the abstinence phase.

Heightened response to positive facial cues as a potential marker of resilience following childhood adversity

Background: Childhood maltreatment profoundly influences social and emotional development, increasing psychiatric risk. Alterations in the implicit processing of threat-related cues following early abuse and neglect represent a marker of mental health vulnerability. Less is known about how early adversity influences the perception of positive social cues, despite their central role in establishing and maintaining social interactions and their association with better mental health outcomes.Methods: The sample consisted of 42 children and adolescents with substantiated childhood maltreatment experiences and 32 peers (mean age 13.3), matched on age, pubertal status, gender, socioeconomic status, ethnicity, and cognitive ability. A computerised experimental task assessed the perceived emotional intensity of positive (happy) and negative (fearful) facial expressions. Mental health symptoms were measured via self- and parental reports, and perceived social support was self-reported.Results: The experience of abuse and neglect was associated with heightened perceived intensity of positive facial cues. Cross-sectional post-hoc moderation and mediation analyses, employing a model-building approach, revealed that in maltreatment-exposed participants: (i) their increased response to positive facial cues was associated with lower symptoms; (ii) the presence of social support accounted for their heightened perceived intensity of positive facial cues; (iii) the presence of social support putatively contributed to lower symptoms by increasing the perceived intensity of positive facial cues. No group differences in perceived intensity of negative expressions were observed.Conclusions: These findings provide fresh insight into how positive faces are processed following maltreatment experience in childhood. Maltreatment experience was found to be associated with heightened perceived intensity of happy faces, which in turn was associated with better mental health and greater levels of social support. This suggests that heightened saliency of positive emotions acts protectively in children with maltreatment experience.

Atypical Interpersonal Problem-Solving and Resting-state Functional Connectivity in Adolescents with Maltreatment Experience

BACKGROUND

Childhood maltreatment is associated with altered neurocognitive functioning, which is thought to reflect, in part, adaptation to early adverse environmental experiences. However, we continue to lack a precise mechanistic understanding linking atypical neurocognitive processing with social functioning and psychiatric outcomes following early adversity.

OBJECTIVE

The present work investigated interpersonal problem-solving, resting-state functional connectivity (rsFC), and mental health symptoms in adolescents with documented maltreatment experience and explored whether altered neural function contributes in part to poorer social functioning.

METHODS

Forty adolescents (aged 12-17) with documented experiences of abuse or neglect and a carefully matched group of 42 non-maltreated peers participated in this study that measured task-based interpersonal problem-solving skills and rsFC.

RESULTS

Adolescents with maltreatment experience showed poorer interpersonal problem-solving performance, which partly accounted for their elevated mental health symptoms. Resting-state seed-based analyses revealed that adolescents with maltreatment experience showed a significant increase in rsFC between medial Default Mode Network (DMN) hubs, the medial prefrontal cortex (mPFC), with a posterior cluster, including the posterior cingulate cortex (PCC), precuneus (PCu), retrosplenial cortex (RSC), and lingual gyrus (LG). Moderation analyses revealed that maltreatment-related increased DMN rsFC partly accounted for poorer performance in interpersonal problem-solving.

CONCLUSION

Poorer interpersonal problem-solving, partly accounted for by atypical coupling between DMN medial hubs, was associated with maltreatment exposure. Interventions tailored to enhance interpersonal problem-solving represents a promising avenue to promote resilience and reduce the likelihood of mental health disorder following maltreatment experience.

Does reward processing moderate or mediate the link between childhood adversity and psychopathology: A longitudinal study

Childhood adversity is common and associated with elevated risk for transdiagnostic psychopathology. Reward processing has been implicated in the link between adversity and psychopathology, but whether it serves as a mediator or moderator is unclear. This study examined whether alterations in behavioral and neural reward processing function as a mechanism or moderator of psychopathology outcomes following adversity experiences, including threat (i.e., trauma) and deprivation. A longitudinal community sample of 10-15-year-old youths was assessed across two waves (Wave 1: n = 228; Wave 2: n = 206). Wave 1 assessed adverse experiences, psychopathology symptoms, reward processing on a monetary incentive delay task, and resting-state fMRI. At Wave 2, psychopathology symptoms were reassessed. Greater threat experiences were associated with blunted behavioral reward sensitivity, which, in turn, predicted increases in depression symptoms over time and mediated the prospective association between threat and depression symptoms. In contrast, reward sensitivity moderated the association between deprivation experiences and prospective externalizing symptoms such that the positive association of deprivation with increasing externalizing symptoms was absent for children with high levels of reward sensitivity.

Preventing mental illness in children that experienced maltreatment the efficacy of REThink online therapeutic game

Exposure to child maltreatment (CM) is considered to predispose children to devastating consequences in terms of mental health. Thus, it is a public health priority to provide these children with early preventive interventions that are accessible on a large scale, adapted to their needs, and effective in supporting their mental health. Here we report a randomized control trial to test the efficacy of the REThink online therapeutic game, as compared with a Care as Usual (CAU) control group in the prevention of mental illness in maltreated children. Out of 439 children aged 8-12 that were recruited, 294 children with self-reported maltreatment histories were included in the current study, and were allocated, 146 participants in the REThink group and 148 participants in the CAU group. All children completed pre- and post-intervention assessments measuring mental health, emotion regulation, and irrational cognitions. We also tested potential moderators for these effects, such as the severity of CM and the security of parent attachment. Our results show that children receiving the REThink game intervention outperform the CAU group at post-test, showing a significantly lower level of emotional problems, mental health difficulties, use of maladaptive emotion-regulation strategies such as catastrophizing, rumination, and self-blame, and irrational cognitions. Moreover, children with higher CM severity benefit the most from the REThink game, while children with lower parent attachment security benefit the least. Future research is needed, to investigate the long-term efficacy of the REThink game in promoting the mental health of children exposed to CM.

Neural activations to loss anticipation mediates the association between difficulties in emotion regulation and screen media activities among early adolescent youth: A moderating role for depression

BACKGROUND

Screen media activities (SMAs; e.g., watching videos, playing videogames) have become increasingly prevalent among youth as ways to alleviate or escape from negative emotional states. However, neural mechanisms underlying these processes in youth are incompletely understood.

METHOD

Seventy-nine youth aged 11-15 years completed a monetary incentive delay task during fMRI scanning. Neural correlates of reward/loss processing and their associations with SMAs were explored. Next, brain activations during reward/loss processing in regions implicated in the processing of emotions were examined as potential mediating factors between difficulties in emotion regulation (DER) and engagement in SMAs. Finally, a moderated mediation model tested the effects of depressive symptoms in such relationships.

RESULT

The emotional components associated with SMAs in reward/loss processing included activations in the left anterior insula (AI) and right dorsolateral prefrontal cortex (DLPFC) during anticipation of working to avoid losses. Activations in both the AI and DLPFC mediated the relationship between DER and SMAs. Moreover, depressive symptoms moderated the relationship between AI activation in response to loss anticipation and SMAs.

CONCLUSION

The current findings suggest that DER link to SMAs through loss-related brain activations implicated in the processing of emotions and motivational avoidance, particularly in youth with greater levels of depressive symptoms. The findings suggest the importance of enhancing emotion-regulation tendencies/abilities in youth and, in particular, their regulatory responses to negative emotional situations in order to guide moderate engagement in SMAs.

Preferences for seeking effort or reward information bias the willingness to work

Research suggests that the temporal order in which people receive information about costs and benefits whilst making decisions can influence their choices. But, do people have a preference for seeking information about costs or benefits when making effort-based decisions, and does this impact motivation? Here, participants made choices about whether to exert different levels of physical effort to obtain different magnitudes of reward, or rest for low reward. Prior to each effort-based choice, they also had to decide which information they wanted to see first: how much physical effort would be required, or how large the reward would be. We found no overall preference for seeking reward or effort information first, but motivation did change when people saw reward or effort information first. Seeking effort information first, both someone's average tendency to do so and their choice to see effort first on a given trial, was associated with reductions in the willingness to exert higher effort. Moreover, the tendency to prefer effort information first was associated with reduced vigorous exercise and higher levels of fatigue in everyday life. These findings highlight that preferences for seeking effort information may be a bias that reduces people's willingness to exert effort in the lab and in everyday life.