Research Review: A systematic review and meta-analysis of infant and toddler temperament as predictors of childhood attention-deficit/hyperactivity disorder

One year respiratory and neurodevelopmental outcome of premature neonates after exposure to plasticizers in the neonatal intensive care unit - A prospective cohort study

BACKGROUND

Premature neonates have an increased risk of long-term effects, including impaired respiratory and neurodevelopment. During NICU admission, they are exposed to endocrine-disrupting phthalates and alternative plasticizers. The objective was to study the association between cumulative NICU-based plasticizer exposure and respiratory and neurodevelopmental outcome during the first year of life.

METHODS

Premature neonates (gestational age <31 weeks and/or birth weight <1500 g) were prospectively enrolled at the Antwerp University Hospital, Belgium. Outcome was assessed at 12 months corrected age, using the Bayley Scales of Infant and Toddler Development-III and validated questionnaires for respiratory outcome. Urinary concentrations of plasticizers' biomarkers were measured weekly during NICU stay. Weighted quantile sum regression was utilized to assess associations between plasticizer biomarkers' mixtures and outcome.

RESULTS

Exposure of premature neonates (n = 110) to specific plasticizer mixtures correlated with worse fine motor (ß -0.96; 95%-CI -1.76, -0.15; p = 0.02) and receptive language development (ß -0.77; 95%-CI -1.23, -0.32; p = 0.001), and better gross motor (ß 2.24; 95%-CI 0.62, 3.86; p = 0.01) and expressive language development (ß 1.50; 95%-CI 0.33, 2.67; p = 0.02). NICU exposure to different plasticizer mixtures was associated with eczema (aOR 3.12; 95%-CI 1.23, 9.11; p = 0.02), repeated ear infections (aOR 5.53; 95%-CI 1.87, 23.14; p = 0.01), and respiratory-related healthcare visits during the first year of life (aOR 8.50; 95%-CI 2.05-55.91; p = 0.01).

CONCLUSIONS

Cumulative NICU exposure to phthalates and alternative plasticizers was associated with increased respiratory morbidity and eczema during the first year of life. Exposure to specific plasticizer mixtures correlated with worse or better neurodevelopment at one year of age.

Neonatal neurobehavior and infant temperament amongst offspring born to parents with and without ADHD

Attention-deficit/hyperactivity disorder (ADHD) is the most common neurodevelopmental condition of childhood. Identification of signals of emerging ADHD before the onset of symptoms is a necessary first step to intervening early and preventing associated impairments. The current study examined the relation between neonatal neurobehaviors infant temperament traits known to be associated with childhood ADHD. Neonates (43-49 weeks postmenstrual age; N = 78), half with increased likelihood of childhood ADHD based on parental ADHD, were assessed using the NeoNatal Neurobehavioral Scale (NNNS-II). Parents later reported on infant temperament using the Infant Behavior Questionnaire at 7-10 months of age. Offspring born to parents with and without ADHD did not differ on neonatal neurobehavior.Infants of parents with ADHD had less effortful control and greater negative affect.Greater non-optimal reflexes and central nervous system stress abstinence signs were associated with less effortful control in infancy. Whereas greater neonatal selfregulation was associated with more negative affect in infancy. Very early neurobehavioral signals of risk for behavioral and emotional dysregulation associated with later attentional problems to be detectable as early as the neonatal period. Longitudinal follow-up to the age at which ADHD can be clinically assessed is needed to examine these neurobehavioral presentations as predictors of childhood ADHD.

Effects of Peruvian mothers' experiences of violence, resilience, and posttraumatic stress on infant temperament: A longitudinal path model

Worldwide, research has demonstrated that maternal experiences of violence can adversely affect infant development, but moderating and mediating effects on this pathway are less understood, particularly within low- and middle-income countries. Using longitudinal structural equation modeling, the present study analyzed data from 251 Peruvian mothers during the prenatal and postpartum periods. We evaluated the relations between mothers' experiences of childhood violence (CV), prenatal intimate partner violence (IPV), posttraumatic stress symptoms (PTSS), and resilience, and how these factors influenced domains of their infants' temperament (i.e., surgency, negative affectivity, and regulatory capacity). Consistent with hypotheses, analyses revealed that mothers' CV exposure was associated with increased prenatal IPV and PTSS, and prenatal IPV was linked to increased prenatal PTSS and lower resilience. Prenatal PTSS was linked to lower infant regulatory capacity. Maternal prenatal resilience was negatively associated with prenatal PTSS. High postpartum maternal resilience mitigated the adverse effects of maternal CV on infant regulatory capacity. Inconsistent with hypotheses, postpartum PTSS was associated with higher infant regulatory capacity, though sensitivity testing suggested this finding may be spurious. Findings underscore the need for violence prevention and prenatal mental health interventions to reduce maternal PTSS and bolster resilience to support positive infant outcomes in Peru.

Temperament and executive functioning correlates of ADHD symptom severity during early versus middle childhood

BACKGROUND

This study investigated associations among temperament, executive functioning (EF), and attention-deficit/hyperactivity disorder (ADHD) symptom severity at two developmental stages.

METHODS

Participants were 61 4-year-old children and 165 8-11-year-old children (126 ADHD, 39 typically developing [TD]). Caregivers reported on temperament (effortful control [EC], negative affect, and surgency), and ADHD symptoms. Three aspects of EF (working memory, inhibitory control, and processing speed) were measured with neuropsychological tests.

RESULTS

Among 4-year-olds, variance in ADHD symptom severity was only explained by the temperament variables. EC was not significantly correlated with any of the EFs in this cohort. Among school-aged children, low EC, high surgency, high negative affect, and reduced working memory were associated with greater ADHD symptom severity. EC was significantly and positively correlated with processing speed in the school-aged children.

CONCLUSIONS

Results are consistent with a neurodevelopmental model of ADHD, wherein dysregulated temperament is associated with ADHD in young children, while both dysregulated temperament and cognitive skills are associated with ADHD in middle childhood. Results could inform the selection of clinical tools for diagnostic evaluation of pediatric ADHD symptoms and clinical follow-up.

Genetic and phenotypic evidence of the predictive validity of preschool parent reports of hyperactivity/impulsivity and inattention

To determine the validity of parent reports (PRs) of ADHD in preschoolers, we assessed hyperactivity/impulsivity (HI) and inattention (IN) in 1114 twins with PRs at 1.5, 2.5, 4, 5, 14, 15, and 17 years, and teacher-reports at 6, 7, 9, 10, and 12. We examined if preschool PRs (1) predict high HI/IN trajectories, and (2) capture genetic contributions to HI/IN into adolescence. Group-based trajectory analyses identified three 6-17 years trajectories for both HI and IN, including small groups with high HI (N = 88, 10.4%, 77% boys) and IN (N = 158, 17.3%, 75% boys). Controlling for sex, each unit of HI PRs starting at 1.5 years and at 4 years for IN, increased more than 2-fold the risk of belonging to the high trajectory, with incremental contributions (Odds Ratios = 2.5-4.5) at subsequent ages. Quantitative genetic analyses showed that genetic contributions underlying preschool PRs accounted for up to a quarter and a third of the heritability of later HI and IN, respectively. Genes underlying 1.5-year HI and 4-year IN contributed to 6 of 8 later HI and IN time-points and largely explained the corresponding phenotypic correlations. Results provide phenotypic and genetic evidence that preschool parent reports of HI and IN are valid means to predict developmental risk of ADHD.

Temperament Profiles at Age 18 Months as Distinctive Predictors of Elevated ASD- and ADHD-Trait Scores and Their Co-Occurrence at Age 8-9: HBC Study

Autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) can be traced back to specific early childhood temperament patterns. However, no unique pattern has been identified for their co-occurrence. Given that children with both traits often require more clinical attention, this study aimed to discover such patterns by examining three temperament domains measured during early childhood-Surgency/Extraversion (SE), Negative Affectivity (NA), and Effortful Control (EC)-and their association with group membership defined as being above the cut-off points for either ASD- or ADHD-trait scores or their co-occurrence at school age. We enrolled 814 children from a birth cohort, assessing temperament at 18 months using the Early Childhood Behavior Questionnaire, and ASD- and ADHD-trait scores at ages 8-9 using the Social Responsiveness Scale-2 and ADHD-Rating Scale. Group membership was determined by clinically significant symptoms, defined as + 1 SD after standardizing scores by age and sex. Multinomial regression analyses examined associations between temperament domain scores and group membership (ASD-dominant, ADHD-dominant, co-occurring, neither-ASD-nor-ADHD). The co-occurring group showed a unique temperament profile, with higher scores in both NA and EC (OR in NA = 1.48, 95% confidence interval (CI): 1.11 to 1.96 and OR in EC = 1.61, 95% CI: 1.18 to 2.20), distinct from the patterns shown by the ASD-dominant and ADHD-dominant groups. The combination of high NA and EC scores uniquely characterizes the co-occurring group, highlighting the need for early temperament assessments to identify children potentially requiring clinical attention for both ASD and ADHD traits.

The utility of multiple assessments in infancy and toddlerhood to predict middle childhood ADHD symptoms: Temperamental, behavioral, and genetic contributions

BACKGROUND

Early intervention is effective for reducing ADHD symptoms and related impairments, yet methods of identifying young children in need of services are lacking. Most early predictors of ADHD previously identified are of limited clinical utility. This study examines several theoretically relevant predictors of ADHD in infancy and toddlerhood and whether assessment at multiple time points improves prediction. We also examine whether links between early risk factors and middle childhood ADHD are driven by shared genetic and/or environmental mechanisms to identify potential early intervention targets.

METHOD

614 twins (52.12 % female, 58.50 % non-Hispanic White) participated in a larger study on genetic and environmental contributions to mental health outcomes. Caregiver-reported attention and behavior problems in infancy (M = 12.67 months) and toddlerhood (M = 32.18 months) and caregiver-reported temperament (attentional focusing, impulsivity, inhibitory control) in toddlerhood were used to predict caregiver-reported ADHD symptoms in middle childhood (M = 8.78 years).

RESULTS

Only behavior problems in infancy and toddlerhood were robust predictors of caregiver-reported ADHD symptoms in middle childhood. Using multiple timepoints did not improve predictive ability. The relationship between infant behavior problems and caregiver reported middle childhood ADHD symptoms was explained by both environmental and genetic influences, whereas environmental influences almost entirely explained the relationship between toddler behavior problems and caregiver-reported middle childhood ADHD symptoms.

IMPLICATIONS

Behavior problems in toddlerhood showed the strongest predictive utility, and links to later ADHD were largely driven by environmental factors, suggesting that psychosocial interventions modifying the child's environment may be particularly effective for reducing ADHD risk.

Greater Frontoparietal Connectivity During Task Engagement Among Toddlers With Parent-Reported Inattention

Attention-deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder with lifelong impairments. ADHD-related behaviors have been observed as early as toddlerhood for children who later develop ADHD. Children with ADHD have disrupted connectivity in neural circuitry involved in executive control of attention, including the prefrontal cortex (PFC) and dorsal attention network (DAN). It is not known if these alterations in connectivity can be identified before the onset of ADHD. Children (N = 51) 1.5-3 years old were assessed using functional near-infrared spectroscopy while engaging with a book. The relation between mother-reported ADHD-related behaviors and neural connectivity, computed using robust innovation-based correlation, was examined. Task engagement was high across the sample and unrelated to ADHD-related behaviors. Observed attention was associated with greater connectivity between the right lateral PFC and the right temporal parietal junction (TPJ). Children with greater ADHD-related behaviors had greater frontoparietal connectivity, particularly between the PFC bilaterally and the right TPJ. Toddlers at risk for developing ADHD may require increased frontoparietal connectivity to sustain attention. Future work is needed to examine early interventions that enhance developing attention and their effect on neural connectivity between the PFC and attention networks.

Effect of an early music intervention on emotional and neurodevelopmental outcomes of preterm infants at 12 and 24 months

Background

Few studies have found long-term effects of early musical environmental enrichment in the NICU on preterm infant's development. This study examines how early music enrichment affects emotional development and effortful control abilities in 12- and 24-month-old very preterm (VPT) infants.

Methods

One hundred nineteen newborns were recruited, including 83 VPTs and 36 full-term (FT) infants. The VPT infants were randomly assigned to the music intervention (44 VPT-Music) or control (39 VPT-control) groups. VPT-Music infants listened specifically designed music intervention from the 33rd week of gestation until hospital discharge. At 12 and 24 months, children were clinically evaluated using the Bayley-III Scales of Infant and Toddler Development and the Laboratory Temperament Assessment Battery, and at 24 months, with 3 additional episodes of the Effortful Control Battery.

Results and discussion

Our analysis showed that during a fear eliciting task, the VPT-Music group expressed lower level of fear reactivity and higher positive motor actions than VPT-controls and FT infants. At 24 months, the VPT-music group had lower scores for negative motor actions in the joy task, compared to both VPT-control and FT groups. In addition, both FT and VPT-music had higher scores of sustained attention compared to VPT-controls, but the contrasts were not significant. No significant effects on mental, language and motor outcomes were identified and for all three dimensions of the ECBQ.

Conclusion

The present study suggests that an early music intervention in the NICU might influence preterm children's emotional processing at 12 and 24 months. Limitations and suggestions for future research are highlighted.

Influence of temperament on early neurodevelopmental disorders: a systematic review protocol

INTRODUCTION

Several studies have highlighted the role of temperament as a relevant construct to understand the wide variability observed in neurodevelopmental disorders (NDDs) such as autism spectrum disorder and attention deficit hyperactivity disorder. Some studies have pointed to temperamental traits such as strained control as possible precursors to the development of these disorders. In addition, how temperament influences high-risk populations, as well as intervention programmes aimed at families, has been investigated.

METHODS AND ANALYSIS

This paper presents the protocol that will be followed to carry out a systematic review, the objective of which is to know how child temperament is related to the different domains of development in children with NDD or the risk of suffering from it. The search strategy will be implemented in Web of Science (WoS Core Collection), PubMed, ERIC, PsycINFO and Cochrane databases. The risk of bias will be measured by the Newcastle-Ottawa Scale to carry out the integration of the results obtained to synthesis without meta-analysis will be used. This systematic review aims to improve scientific evidence for institutions and professionals and enhance the effectiveness of early care programmes for children with NDD and their families.

ETHICS AND DISSEMINATION

No express approval has been sought from any ethics committee because there is no primary data involved and no access to confidential patient information.

PROSPERO REGISTRATION NUMBER

CRD42023445173.

Prenatal Gut Microbiota Predicts Temperament in Offspring at 1-2 Years

The purpose of this study was to explore whether prenatal gut microbiota (GM) and its functions predict the development of offspring temperament. A total of 53 mothers with a 1-year-old child and 41 mothers with a 2-year-old child were included in this study using a mother-infant cohort from central China. Maternal fecal samples collected during the third trimester were analyzed using 16S rRNA V3-V4 gene sequences. Temperament of the child was measured by self-reported data according to the primary caregiver. The effects of GM in mothers on offspring's temperament were evaluated using multiple linear regression models. The results demonstrated that the alpha diversity index Simpson of prenatal GM was positively associated with the activity level of offspring at 1 year (adj. P = .036). Bifidobacterium was positively associated with high-intensity pleasure characteristics of offspring at 1 year (adj. P = .031). Comparatively, the presence of Bifidobacterium found in the prenatal microbiome was associated with low-intensity pleasure characteristics in offspring at 2 years (adj. P = .031). There were many significant associations noted among the functional pathways of prenatal GM and temperament of offspring at 2 years. Our findings support the maternal-fetal GM axis in the setting of fetal-placental development with subsequent postnatal neurocognitive developmental outcomes, and suggest that early childhood temperament is in part associated with specific GM in the prenatal setting.

Using the Infant Sibling-Design to Explore Associations Between Autism and ADHD Traits in Probands and Temperament in the Younger Siblings

The purpose of the current study was to use the infant sibling design to explore whether proband traits of autism and ADHD could provide information about their infant sibling's temperament. This could help us to gain information about the extent to which infant temperament traits are differentially associated with autism and ADHD traits. We used parent-ratings of autistic traits and ADHD traits (CRS-3) in older siblings diagnosed with autism (age range 4 to 19 years), and their infant siblings' temperament traits (IBQ) at 9 months of age in 216 sibling pairs from two sites (BASIS, UK, and EASE, Sweden) to examine associations across siblings. We found specific, but modest, associations across siblings after controlling for sex, age, developmental level and site. Proband autistic traits were specifically related to low levels of approach in the infant siblings, with infant developmental level explaining part of the variance in infant approach. Proband ADHD traits were specifically related to high levels of infant activity even after controlling for covariates. Our findings suggest that proband traits of autism and ADHD carry information for infant sibling's temperament, indicating that inherited liability may influence early emerging behaviours in infant siblings. The impact of sex, age, developmental level and site are discussed.

Substance use disorders in adults with attention-deficit/hyperactivity disorder: The role of affective temperament

OBJECTIVE

Substance Use Disorders (SUD) are common in adults with Attention-Deficit/Hyperactivity Disorder (ADHD). Although predictors of SUD in this population are relevant for prevention and treatment, they need further clarification. Affective temperaments potentially associated with SUD in adult ADHD patients were explored.

METHODS

ADHD patients with and without SUD were compared for sociodemographic, clinical, and psychological characteristics through: Adult ADHD Self-Report Scale; Wender Utah Rating Scale; Temperament Evaluation Memphis for Pisa, Paris, and San Diego-Autoquestionnaire. Logistic regression investigated factors associated with SUD.

RESULTS

We included one-hundred and thirty-six ADHD patients with (n = 51, 37.5 %) and without SUD (n = 85, 62.5 %). The presence of SUD was associated with irritable temperament (p = 0.009), as well as more frequent school failure (p = 0.038), legal problems (p = 0.039), and lifetime suicide attempts (p = 0.014).

LIMITATIONS

The cross-sectional design, the relatively small sample size, and the use of self-administered questionnaires.

CONCLUSIONS

This study confirms the greater overall severity of adult ADHD-SUD compared with ADHD-only patients and suggests the potential role of irritable temperament as a predictor of substance-related problems.

Exploring the impact of antenatal micronutrients used as a treatment for maternal depression on infant temperament in the first year of life

Antenatal depression and maternal nutrition can influence infant temperament. Although broad-spectrum-micronutrients (BSM: vitamins and minerals) given above Recommended Dietary Allowances during pregnancy can mitigate symptoms of antenatal depression, their associated effects on infant temperament are unknown. One hundred and fourteen New Zealand mother-infant dyads (45 infants exposed to BSM during pregnancy (range of exposure during pregnancy: 12-182 days) to treat antenatal depressive symptoms (measured by Edinburgh Postnatal Depression Scale) and 69 non-exposed infants) were followed antenatally and for 12 months postpartum to determine the influence of in utero BSM exposure on infant temperament. The Infant Behavior Questionnaire-Revised: Very Short-Form assessed temperament at 4 (T1), 6 (T2) and 12 (T3) months postpartum via online questionnaire. Latent growth curve modeling showed BSM exposure, antenatal depression and infant sex did not statistically significantly predict initial levels or longitudinal changes in orienting/regulatory capacity (ORC), positive affectivity/surgency (PAS) or negative affectivity (NEG). Higher gestational age was positively associated with initial PAS, and smaller increases between T1 and T3. Breastfeeding occurrence was positively associated with initial NEG. Although not significant, BSM exposure exerted small, positive effects on initial NEG (β = -0.116) and longitudinal changes in ORC (β = 0.266) and NEG (β = -0.235). While BSM exposure did not significantly predict infant temperament, it may mitigate risks associated with antenatal depression. BSM-exposed infants displayed temperamental characteristics on par with typical pregnancies, supporting the safety of BSM treatment for antenatal depression.

The Developmental Unfolding of ADHD Symptoms from Early Childhood Through Adolescence: Early Effects of Exuberant Temperament, Parenting and Executive Functioning

Temperament, parenting, and executive functioning (EF) are individual and contextual factors that have been identified to play a role in the development of Attention-Deficit/Hyperactivity Disorder (ADHD) symptoms. Specifically, exuberant temperament in toddlerhood has been associated with both adaptive and maladaptive outcomes, including ADHD symptoms. Therefore, it is important to understand factors that predict which exuberant children experience increased ADHD symptoms and the specific mechanisms through which early exuberant temperament impacts later ADHD symptoms. Using a multi-method, prospective longitudinal design, this study examined a moderated mediation model wherein the interactive effects of observed exuberance and parenting at age 3 predicted the development of parent-reported ADHD symptoms from childhood through adolescence (age 5, 7, 9, 12, and 15) via child EF (i.e., inhibitory control) at age 4. Parent-child dyads (n = 291) from a longitudinal study on child temperament were included. A piecewise model of ADHD symptom growth demonstrated stability in ADHD symptoms from age 5-9 and a decrease from age 9-15. Results support a moderated mediation model wherein an increase in ADHD symptoms throughout childhood was predicted from early childhood exuberant temperament by way of EF, but only for children whose parents displayed less directive parenting. Findings suggest identifiable early markers of risk, including temperament, parenting, and EF- pointing to possible targets for early intervention/prevention.