Maternal care represents an essential environmental factor during the first post-natal week(s) of rodents and is known to have lasting consequences for neuronal structure, brain function as well as behavioral outcome later in life, including social functions and reward-related processes. Previous experiments have shown that the amount of maternal care received by individual pups varies substantially, even within one litter. During adolescence, mammals display high levels of social play behavior, a rewarding form of social interaction that is of great importance for social and cognitive development. In order to investigate how maternal care influences adaptive social behavior later in life, we here examined whether individual differences in maternal licking and grooming (%LG) received during the first postnatal week affect social play behavior during adolescence. We observed that %LG received by male rats early in life correlates positively with the frequency and duration of pouncing and pinning, the two most characteristic behavioral expressions of social play behavior in rats. The latency to engage in social exploration also correlated with %LG. In female rats we observed no correlation between %LG and any social parameter. The data indicate that subtle variations in maternal care received early in life influence social interactions in male adolescent rats. These changes in social play likely have repercussions for the social development of male rats, suggesting that maternal care can have both direct and indirect effects on the behavioral development of the offspring.

Early life adversity affects hypothalamus-pituitary-adrenal axis activity, alters cognitive functioning and in humans is thought to increase the vulnerability to psychopathology–e.g. depression, anxiety and schizophrenia- later in life. Here we investigated whether subtle natural variations among individual rat pups in the amount of maternal care received, i.e. differences in the amount of licking and grooming (LG), correlate with anxiety and prefrontal cortex-dependent behavior in young adulthood. Therefore, we examined the correlation between LG received during the first postnatal week and later behavior in the elevated plus maze and in decision-making processes using a rodent version of the Iowa Gambling Task (rIGT). In our cohort of male and female animals a high degree of LG correlated with less anxiety in the elevated plus maze and more advantageous choices during the last 10 trials of the rIGT. In tissue collected 2 hrs after completion of the task, the correlation between LG and c-fos expression (a marker of neuronal activity) was established in structures important for IGT performance. Negative correlations existed between rIGT performance and c-fos expression in the lateral orbitofrontal cortex, prelimbic cortex, infralimbic cortex and insular cortex. The insular cortex correlations between c-fos expression and decision-making performance depended on LG background; this was also true for the lateral orbitofrontal cortex in female rats. Dendritic complexity of insular or infralimbic pyramidal neurons did not or weakly correlate with LG background. We conclude that natural variations in maternal care received by pups may significantly contribute to later-life decision-making and activity of underlying brain structures.

The aim of the study was to assess internalizing problems before and during the pandemic with data from Dutch consortium Child and adolescent mental health and wellbeing in times of the COVID-19 pandemic, consisting of two Dutch general population samples (GS) and two clinical samples (CS) referred to youth/psychiatric care. Measures of internalizing problems were obtained from ongoing data collections pre-pandemic (NGS = 35,357; NCS = 4487) and twice during the pandemic, in Apr–May 2020 (NGS = 3938; clinical: NCS = 1008) and in Nov–Dec 2020 (NGS = 1489; NCS = 1536), in children and adolescents (8–18 years) with parent (Brief Problem Monitor) and/or child reports (Patient-Reported Outcomes Measurement Information System®). Results show that, in the general population, internalizing problems were higher during the first peak of the pandemic compared to pre-pandemic based on both child and parent reports. Yet, over the course of the pandemic, on both child and parent reports, similar or lower levels of internalizing problems were observed. Children in the clinical population reported more internalizing symptoms over the course of the pandemic while parents did not report differences in internalizing symptoms from pre-pandemic to the first peak of the pandemic nor over the course of the pandemic. Overall, the findings indicate that children and adolescents of both the general and clinical population were affected negatively by the pandemic in terms of their internalizing problems. Attention is therefore warranted to investigate long-term effects and to monitor if internalizing problems return to pre-pandemic levels or if they remain elevated post-pandemic.

BackgroundThe impact of childhood antisocial behaviour on future maladaptation has been acknowledged. Risk‐taking has been associated with antisocial behaviour in adolescents and adults, but its association with childhood antisocial behaviour is understudied. In this study, we explored the association of children's risk‐taking with antisocial behaviour in mainstream elementary schoolchildren studied longitudinally across 7–11 years.MethodsOne thousand and eighty‐six children (51% boys) were assessed in three annual waves. Antisocial behaviours (aggressive, covert antisocial and oppositional defiant behaviour) were assessed using teacher‐ and peer‐reports. Risk‐taking was measured using the Balloon Analogue Risk Task (BART). The association of antisocial behaviour with risk‐taking was analysed using parallel growth models.ResultsChildren with higher levels of risk‐taking at age 7 showed increased growth in peer‐reported aggression from age 7 to 11. Risk‐taking, that is increased levels at age 7 in boys and increased growth in girls, predicted increased growth in peer‐reported oppositional defiant behaviour. Associations of risk‐taking with teacher‐reported aggression and covert antisocial behaviour were at trend level.ConclusionsResults indicated that already in childhood, among typically developing children, risk‐taking is associated with the development of antisocial behaviour. Future research focused on antisocial behaviour, but also school mental health workers and clinicians should take into account that already in childhood, risk‐taking might affect antisocial behaviour development.

Background The COVID-19 pandemic has had an acute impact on child mental and social health, but long-term effects are still unclear. We examined how child mental health has developed since the start of the COVID-19 pandemic up to two years into the pandemic (April 2022). Methods We included children (age 8-18) from two general population samples (N = 222-1,333 per measurement and N = 2,401-13,362 for pre-covid data) and one clinical sample receiving psychiatric care (N = 334-748). Behavioral questionnaire data were assessed five times from April 2020 till April 2022 and pre-pandemic data were available for both general population samples. We collected parent-reported data on internalizing and externalizing problems with the Brief Problem Monitor and self-reported data on Anxiety, Depressive symptoms, Sleep-related impairments, Anger, Global health, and Peer relations with the Patient-Reported Outcomes Measurement Information System (PROMIS). Results In all samples, parents reported overall increased internalizing problems, but no increases in externalizing problems, in their children. Children from the general population self-reported increased mental health problems from before to during the pandemic on all six PROMIS domains, with generally worst scores in April 2021, and scores improving towards April 2022 but not to pre-pandemic norms. Children from the clinical sample reported increased mental health problems throughout the pandemic, with generally worst scores in April 2021 or April 2022 and no improvement. We found evidence of minor age effects and no sex effects. Conclusions Child mental health in the general population has deteriorated during the first phase of the COVID-19 pandemic, has improved since April 2021, but has not yet returned to pre-pandemic levels. Children in psychiatric care show worsening of mental health problems during the pandemic, which has not improved since. Changes in child mental health should be monitored comprehensively to inform health care and policy.

The association between relational victimization and risk-taking development in children is understudied. Also, it is not clear how the social classroom norm may affect this link. The aim of this study was, therefore, to investigate the link between relational victimization and risktaking behavior in elementary schoolchildren, and the potential moderating role of the classroom norm salience toward risk-taking. We expected that relationally victimized children would show an increase in risk-taking behavior in classrooms that are unfavorable toward risk-taking as a way to provoke and act against the classroom norm. However, alternatively, relationally victimized children could show an increase in risk-taking behavior in classrooms that are favorable toward risk-taking as a way to fortify the feeling of belonging to the classroom. Participants were 1,009 children (50% boys) in 69 classrooms of 13 mainstream elementary schools, followed annually across ages 7-11 (Grade 1-5). Risk-taking was assessed using the Balloon Analogue Risk Task. Relational victimization was assessed using teacher reports. The classroom norm salience toward risk-taking was based on the within-classroom correlation of risk-taking with children's social preference score among peers. Results from multilevel modeling showed that there was no significant main effect of relational victimization on risk-taking behavior. However, the classroom norm salience toward risk-taking significantly moderated the effect of relational victimization on risk-taking. Relational victimization was related to relative increases in risk-taking when classroom norms were unfavorable toward risk-taking. In classrooms where risk-taking was favored, relational victimization was related to relative decreases in risk-taking. These findings suggest that children who are relationally victimized may engage in norm-defying behavior in their classroom. Implications for further research are discussed.

Heightened sensation-seeking is related to the development of delinquency. Moreover, sensation-seeking, or biological correlates of sensation-seeking, are suggested as factors linking victimization to delinquency. Here, we focused on epigenetic correlates of sensation-seeking. First, we identified DNA methylation (DNAm) patterns related to sensation-seeking. Second, we investigated the association between sensation-seeking related DNAm and the development of delinquency. Third, we examined whether victimization was related to sensation-seeking related DNAm and the development of delinquency. Participants (N = 905; 49% boys) came from the Avon Longitudinal Study of Parents and Children. DNAm was assessed at birth, age 7 and age 15–17. Sensation-seeking (self-reports) was assessed at age 11 and 14. Delinquency (self-reports) was assessed at age 17–19. Sensation-seeking epigenome-wide association study revealed that no probes reached the critical significance level. However, 20 differential methylated probes reached marginal significance. With these 20 suggestive sites, a sensation-seeking cumulative DNAm risk score was created. Results showed that this DNAm risk score at age 15–17 was related to delinquency at age 17–19. Moreover, an indirect effect of victimization to delinquency via DNAm was found. Sensation-seeking related DNAm is a potential biological correlate that can help to understand the development of delinquency, including how victimization might be associated with adolescent delinquency.

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