Difficult Temperament Research Articles

Security and closeness with mothers and fathers in the transition to adolescence: Differences by temperament.

Relations between parental (mother and father) sensitivity and opportunity for productive activity during early and middle childhood and fifth graders' perceptions of security and closeness to each parent were examined for 771 children. In addition, differential susceptibility to parental sensitivity and opportunity for productive activity was examined for children with difficult temperaments. Perceived security with respect to both mothers and fathers was related to both parental sensitivity and opportunity for productive activity. In the case of opportunity for productive activity, relations were stronger for children with difficult temperaments. By contrast, productive activity was the only significant predictor of perceived closeness; and it was significant only for mothers. However, the productive activity by child temperament interaction was significant for both mothers and fathers. Overall, the findings are consistent with the idea that parent-child relationships often undergo transformations during the transition to adolescence. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Hostile, Quick-Tempered, and Exposed to Dangerous Environments: Exploring the Link Between Temperament and the Street Code Adherence

Although Elijah Anderson’s code of the street thesis has received a great deal of scholarly attention, fewer studies have examined the characteristics associated with its adoption. Existing evidence is supportive of Anderson’s initial observations, however, less is known about the association between personality and emotional characteristics and adopting street code norms. The current study assesses the role of DeLisi and Vaughn’s difficult temperament index in the adoption of the street code among a sample of juvenile justice-involved youth. Results indicated youth with more difficult temperaments, characterized by lower levels of effortful control and higher levels of negative emotionality, were more likely to report greater street code adherence. Implications for juvenile justice policy and future research are discussed.

The Link between Individual Personality Traits and Criminality: A Systematic Review.

In addition to social and environmental factors, individual personality traits have intricately linked with maladaptive behaviour. Thus, the purpose of this article was to review the link between individual personality traits and criminality. A systematic review was conducted to obtain information regarding the link between individual personality traits with criminal behaviour in the Sage, Web of Science, APA PsycNet, Wiley Online Library, and PubMed databases. The results indicate that individual personality traits that contribute towards criminality are (i) psychopathy; (ii) low self-control; and (iii) difficult temperament. As an overall impact, the review is expected to provide in-depth understanding of the link between individual personality traits and criminality; hence, greater consideration will be given to the dimension of personality as a notable risk factor of criminal behaviour.

Parity moderates the effect of delivery mode on maternal ratings of infant temperament.

ObjectiveCesarean section (CS) rates are rising rapidly around the world but no conclusive evidence has been obtained about the possible short- and long-term effects of CS on child behavior. We evaluated prospectively the association between CS and infant temperament across the first 9 postpartum months, controlling for indications for CS and investigating parity and infant sex as moderators.MethodsThe sample consisted of mothers and their healthy infants. Infant temperament was measured using the Infant Characteristics Questionnaire completed by the mothers at 6 weeks (n = 452) and 9 months (n = 258) postpartum. Mode of birth was classified into spontaneous vaginal birth (n = 347 for 6 weeks sample; 197 for 9 months sample), CS planned for medical reasons (n = 55; 28) and emergency CS (n = 50; 33).ResultsMultiple regression analysis revealed no main effects of birth mode, but showed a significant interaction between birth mode and parity indicating that emergency CS in firstborn infants was associated with more difficult temperament at 6 weeks. There were no significant associations between indications for CS and infant temperament, although breech presentation predicted difficult temperament at 9 months.ConclusionWe largely failed to support the association between CS and infant temperament. Although our results suggest that emergency CS may be associated with temperament in firstborns, further research is needed to replicate this finding, preferably using observational measures to assess child temperament.

Early-Life Environmental and Child Factors Associated with the Presence of Disruptive Behaviors in Seven-Year-Old Children with Autistic Traits in the Avon Longitudinal Study of Parents and Children

We studied the association of early-life environmental and child factors with disruptive behaviors in children with autistic traits around age 7, in the Avon Longitudinal Study of Parents and Children (n = 6,401). Logistic regression with the least absolute shrinkage and selection operator indicated that disruptive behaviors were associated with prenatal smoking, no seafood-consumption during pregnancy, breech presentation at delivery, neonatal feeding problems, low social-economic situation, suboptimal preschool family environment, maternal depression, maternal antisocial behavior, male sex, and difficult child temperament. Compared to controls, male sex, maternal depression, and suboptimal preschool family environment were related to autistic traits without disruptive behaviors. Thus, there may be a difference in early-life factors related to autism spectrum disorder with and without disruptive behaviors.

Risk Factors for Postpartum Depression in Active Duty Women

Postpartum depression (PPD) is a common perinatal complication. Risk factors previously found to correlate with PPD in civilians include prenatal depression, childcare stress, limited social support, difficult infant temperament, and maternity blues. Previously identified risk factors in military spouses include spouse deployment/redeployment cycles. It is unclear if these previously identified risk factors are also a risk factor for AD women or if the additional stressors associated with being on active duty (AD) are risk factors for PPD. The purpose of this review is to determine if civilian risk factors have been found to put AD women at risk for PPD and to identify unique risk factors for PPD in AD women. A scoping literature review was performed using PubMed, Defense Technical Information Center, and PsychINFO. The searches were conducted using relevant medical subject headings and keywords. The inclusion criteria included articles published since 1948 (the year women were legally allowed to join the military) that reference risk factors for postpartum/peripartum depression in AD women serving in the U.S. military. The following exclusion criteria were also applied: in a language other than English, opinion papers, and/or not published in a peer-reviewed journal. Articles meeting criteria were evaluated and mapped to stressors previously identified in the literature for civilian and military spouses with PPD with novel stressors identified as mapping outside this framework. Only two articles met the inclusion criteria. The first study included 87 AD women. The second study, a cohort study between 2001 and 2008, included 1660 AD women. Unique risk factors identified in AD women include previous deployments, serving in the Army, smoking status, alcohol use, and low self-esteem. Few studies have investigated the risk factors for PPD in AD women. It appears that AD women share many risk factors, or variants of those risk factors, for PPD as their civilian and AD spouse counterparts, but there are also unique risks to consider. More work is needed to improve screening and prevention efforts.

541 Cognitive Hyperarousal, Sleep Problems and Temperament Linked to Impaired Maternal-Infant Bonding

Abstract Introduction Emerging evidence links maternal and infant sleep problems to impairments in the mother-to-infant bond, but the independence and directionality of these associations remain unclear. The present study characterized concurrent and prospective effects of maternal sleep disturbances and poor infant sleep on the mother-infant relationship. As common sequalae of problematic sleep, nocturnal cognitive hyperarousal and daytime sleepiness were investigated as facilitating mechanisms. Methods Sociodemographic information and clinical symptoms were measured prenatally then weekly across the first two postpartum months in 67 women. Participants reported insomnia symptoms, sleep duration, snoring, daytime sleepiness, nocturnal cognitive arousal (broadly focused and perinatal-specific), perseverative thinking, depression, infant colic, infant sleep quality, and mother-infant relationship quality. Mixed effects models were conducted to test hypotheses. Results Prenatal snoring and weak maternal-fetal attachment augured poorer postpartum bonding. Poor infant sleep was associated with increased odds for maternal insomnia and short sleep. Impairments in the mother-to-infant bond were linked to maternal insomnia, nocturnal perinatal-focused rumination, daytime sleepiness, depression, and poor infant sleep. Postnatal insomnia predicted future decreases in mother-infant relationship quality, and nocturnal cognitive hyperarousal partially mediated this association. Conclusion Both maternal and infant sleep problems were associated with impairments in mother-to-infant bonding, independent of the effects of maternal depression and difficult infant temperament. Perseverative thinking at night, particularly on infant-related concerns, was linked to impaired bonding, rejection and anger, and infant-focused anxiety. Improving maternal and infant sleep, as well as maternal cognitive-emotional regulation, may improve the maternal-to-infant bond. Support (if any) This work was funded by the American Academy of Sleep Medicine (198-FP-18, PI: Kalmbach). Dr. Cheng’s effort was supported by the National Heart, Lung, and Blood Institute (K23 HL138166, PI: Cheng).

The association of infant temperament and maternal sensitivity in preterm and full-term infants.

Infants who experience sensitive caregiving are at lower risk for numerous adverse outcomes. This is especially true for infants born preterm, leading them to be more susceptible to risks associated with poorer quality caregiving. Some research suggests that preterm and full-term infants differ on temperament, which may contribute to these findings. This study aimed to investigate associations between infant temperament (negative emotionality, positive affectivity/surgency, and orienting/regulatory capacity) and maternal sensitivity among infants born preterm (M=30.2weeks) and full term. It was hypothesized that mothers of infants born preterm and mothers of infants with more difficult temperaments would display lower sensitivity, indicated by lower responsiveness to nondistress, lower positive regard, and higher intrusiveness. Videotaped play interactions and a measure of temperament (Infant Behavior Questionnaire) were coded for 18 preterm and 44 full-term infants at 9 months (corrected) age. Results suggest that mothers of preterm and full-term infants differed significantly in responding to their infants, but these results cannot be explained by infant temperament. Preterm status and sociodemographic risk emerged as correlates of maternal behavior, such that mothers of infants born preterm and mothers with greater sociodemographic risk displayed lower levels of maternal sensitivity.

Impact of maternal age on infants' emotional regulation and psychomotor development.

Maternal age has progressively increased in industrialized countries. Most studies focus on the consequences of delayed motherhood for women's physical and mental health, but little is known about potential effects on infants' neurodevelopment. This prospective study examines the association between maternal age and offspring neurodevelopment in terms of both psychomotor development (Ages & Stages Questionnaires-3) and emotional competences (Early Childhood Behavior Questionnaire). We evaluated a cohort of healthy pregnant women aged 20-41 years and their offspring, assessed at 38 weeks gestation (n = 131) and 24 months after birth (n = 101). Potential age-related variables were considered (paternal age, education level, parity, social support, maternal cortisol levels, and maternal anxiety and depressive symptoms). Bayesian ordinal regression models were performed for each neurodevelopmental outcome. Maternal age was negatively associated with poor child development in terms of personal-social skills [odds ratio (OR) -0.13, 95% confidence interval (CI) 0.77-0.99] and with difficult temperament in terms of worse emotional regulation (OR -0.13, 95% CI 0.78-0.96) and lower positive affect (OR 0.16, 95% CI 0.75-0.95). As for age-related variables, whereas maternal anxiety symptoms and cortisol levels were also correlated with poor child development and difficult temperament, maternal social support and parental educational level were associated with better psychomotor and emotional competences. Increasing maternal age may be associated with child temperament difficulties and psychomotor delay in terms of social interaction skills. Early detection of neurodevelopment difficulties in these babies would allow preventive psychosocial interventions to avoid future neuropsychiatric disorders.

Tantrums, toddlers and technology: Temperament, media emotion regulation, and problematic media use in early childhood

Parents regularly use media to help regulate their child's difficult emotions, particularly for those with a more difficult temperament. However, no research has examined how this may be related to the development of problematic (or addictive-like) media use in early childhood. The purpose of the study was to examine associations between temperament, parental media emotion regulation, and problematic media use in young children, using both questionnaires and observational data. Participants included 269 toddlers (2–3 years old) and their parents, who completed several observational tasks and questionnaires. Analyses revealed that higher levels of media emotion regulation was associated with more problematic media use and more extreme emotions when media was removed in toddlers. Additionally, temperament (specifically negative affect and surgency) was related to problematic media and extreme emotions and was mediated by media emotion regulation. Parents should avoid using media as a primary way of regulating their children's emotions as this may be related to the development of problematic media strategies during infancy.

US fathers' reports of bonding, infant temperament and psychosocial stress based on family sleep arrangements.

Background and objectivesEvolutionary-grounded sleep research has been critical to establishing the mutual dependence of breastfeeding and nighttime sleep proximity for mothers and infants. Evolutionary perspectives on cosleeping also often emphasize the emotional motivations for and potential benefits of sleep proximity, including for parent-infant bonding. However, this potential link between infant sleep location and bonding remains understudied for both mothers and fathers. Moreover, in Euro-American contexts bedsharing has been linked to family stress and difficult child temperament, primarily via maternal reports. We know relatively little about whether paternal psychosocial dynamics differ based on family sleep arrangements, despite fathers and other kin often being present in the cosleeping environment across cultures. Here, we aim to help address some of these gaps in knowledge pertaining to fathers and family sleep arrangements.MethodologyDrawing on a sample of Midwestern U.S. fathers (N=195), we collected sociodemographic and survey data to analyze links between infant nighttime sleep location, paternal psychosocial well-being, father-infant bonding, and infant temperament. From fathers’ reports, families were characterized as routinely solitary sleeping, bedsharing, or roomsharing (without bedsharing).ResultsWe found that routinely roomsharing or bedsharing fathers, respectively, reported stronger bonding than solitary sleepers. Bedsharing fathers also reported that their infants had more negative temperaments and also tended to report greater parenting-related stress due to difficulties with their children.ConclusionsThese cross-sectional results help to highlight how a practice with deep phylogenetic and evolutionary history, such as cosleeping, can be variably expressed within communities with the potential for family-dependent benefits or strains.

Empathy, Self-control, Callous-Unemotionality, and Delinquency: Unique and Shared Developmental Antecedents.

The current investigation tested childhood developmental antecedents of adolescent empathy, self-control, callous-unemotionality, and delinquency, namely difficult temperament, positive socialization experiences, and intelligence; it also tested potential mediation effects of temperament via socialization. Data were collected as part of the National Institute of Child Health and Human Development Early Child Care and Youth Development Study, which followed N = 1364 children from birth through 15years (51% female, 80% European American). Early positive socialization (maternal sensitivity, secure attachment, and quality home environment) and temperament variables were assessed from 1 to 36months, intelligence at age 9, and self-control, empathy, callous-unemotionality, and delinquency at age 15. Based on structural equation modeling hypothesis tests, early positive socialization positively predicted self-control and empathy, and negatively predicted callous-unemotionality and delinquency. Intelligence uniquely and positively predicted empathy. Difficult infant temperament indirectly predicted each of the four traits through early positive socialization. Important research and practical implications are discussed.

Maternal parentification history impacts evaluative cognitions about self, parenting, and child.

Parentification occurs when children are unfairly charged with fulfilling parental instrumental and emotional needs. Parentification is associated with risk to evaluative self cognitions from childhood to emerging adulthood, but this association has not yet been studied among parents. The transition to parenthood is typically characterized by declines in self-esteem, suggesting it is a critical period for understanding the risk parentification history poses to evaluative self-cognitions and evaluative cognitions about children. The present study addresses these gaps using longitudinal data (N=374 first-time mothers) to examine the influence of maternal parentification history domains (emotional and instrumental caregiving, role unfairness) on trajectories of maternal evaluative cognitions about the self (self-esteem, parenting self-efficacy) and about the child (difficult child temperament, dissatisfaction with child contributions to relationships) in early parenthood. A spillover model was also examined such that evaluative cognitions about the self were examined as potential mediators between parentification history and evaluative cognitions about children. Results support associations between the role unfairness domain of parentification and each domain of maternal evaluative cognitions and a significant indirect effect of unfairness on risk to maternal evaluative cognitions about child contributions via parenting self-efficacy. Implications for mother-child relationships and processes of intergenerational transmission of parentification are discussed.

Infant temperament, early-childhood parenting, and early-adolescent development: Testing alternative models of Parenting × Temperament interaction.

Here we evaluate whether infant difficult temperament (6 months) functions as a vulnerability or more general plasticity factor when investigating effects of early-childhood parenting (8-42 months) on both positive and negative early-adolescent socioemotional development (age 8-11 years). Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC, N = 14,541) and a re-parameterized model-testing approach to distinguish alternative person × environment conceptual models, results indicated that temperament × parenting interacted in predicting externalizing (i.e., hyperactivity, conduct problems), but not other behavior (i.e., emotional symptoms, peer problems), in a (weak) differential susceptibility manner. While more and less supportive parenting predicted, respectively, fewer and more behavior problems, it did so more strongly for children who were more difficult as infants.

Relationship between subjective and objective measures of anticipatory anxiety prior to extraction procedures in 8- to 12-year-old children.

BackgroundThis study assessed anticipatory dental anxiety levels among 8- to 12-year-old children based on subjective and physiological measures and their correlation. The variations in anxiety based on sex, age, temperament, and academic performance were evaluated.MethodsAn observational study was conducted in 60 children recruited from the waiting room over a 6-month period. The operator recorded subjective anxiety in the children using a novel visual facial anxiety scale. The operator also noted the demographic details and child's temperament using the nine dimensions of the Thomas and Chess criteria, and graded children as “easy,” “slow to warm-up,” and “difficult.” The academic performance of the children was graded (parental ratings) on a five-point Likert scale. Physiological variables (heartrate [HR], oxygen saturation[SpO2], and blood pressure [BP]) were recorded by another evaluator. The correlation between anxiety levels and physiological variables was also assessed. The effects of age, sex, temperament, and academic performance on anxiety were evaluated.ResultsThe study included 60 children aged 8–12 years, including 36 boys and 24 girls. Seventy percent of children had mild to moderate levels of pre-extraction anxiety, while 30% of children demonstrated high anxiety. A significant positive correlation was noted between anxiety levels and HR (rs = 0.477, P < 0.001*) and systolic BP (rs = 0.294, P < 0.05), while a significant but inverse correlation was observed with SpO2 (rs = −0.40, P < 0.05). Anxiety did not influence diastolic BP. Children with difficult temperament and poor academic performance had significantly higher anxiety.ConclusionA high percentage (70%) of children aged 8–12 years had mild to moderate anxiety prior to the extraction procedure. Increased HR, systolic BP, and reduced SpO2 were significantly associated with high levels of anticipatory dental anxiety. Pre-extraction anxiety was significantly related to the temperament and scholastic performance.

Okul Öncesi Dönemdeki Çocukların Fiziksel ve İlişkisel Saldırganlıklarının Mizaç Özellikleriyle İlişkisinin İncelenmesi

Çocuğun hayatında sürekli hale gelebilecek saldırganlık yönelimi ve saldırganlık davranışının temeli okul öncesi dönemde başlamaktadır. Bu dönemde çocuk saldırganlık yönelimi göstermekte ve bunu kalıcı hale getirmektedir. Çocukların saldırgan davranışlar göstermelerinde çocukların mizaçsal özellikleri de bir risk faktörüdür. Mizaç biyolojik temelli bir özelliktir. Yürümeye başlayan çocuğun saldırgan davranışında, çocuğun zor mizacı ve zayıf sosyalleşme ortamları önemli rol oynar. Çocukta zor bir mizaç; sert, tutarsız ve olumsuz sosyalleşme davranışlarını ortaya çıkartır ve bu davranışlar agresif veya yıkıcı davranışlara dönüşebilir. Saldırgan davranışlar üzerinde etkili olan mizaç, bireyler arasında farklılık gösteren ve biyolojik etkilerle ortaya çıkan duygusal ve davranışsal özelliklerdir. Bununla birlikte, erken çocukluk müdahaleleri bu riskleri önlemede etkilidir. Bu çalışmada çocukların fiziksel ve ilişkisel saldırgan davranışları ile mizaç özellikleri arasındaki ilişkiyi incelemek amaçlanmıştır. Araştırmanın örneklemini İstanbul’da resmi iki anaokulunda okul öncesi eğitime devam eden 48-72 ay arasındaki 231 çocuk oluşturmuştur. Araştırmada veriler “Kişisel Bilgi Formu”, “Sosyal Davranış Ölçeği” ve “Çocuklar İçin Kısa Mizaç Ölçeği” kullanılarak toplanmıştır. Araştırmanın sonucuna göre cinsiyet ve yaş fiziksel saldırganlıkta anlamlı farklılık oluştururken, kardeş sayısı, okula devam süresi anlamlı farklılık oluşturmamıştır. İlişkisel saldırganlıkta ise yaş ve kardeş sayısı gruplar arasında anlamlı farklılık oluştururken cinsiyet ve okula devam süresi anlamlı farklılık oluşturmamıştır. Saldırganlığın mizaç özellikleri ilişkisinde ise fiziksel saldırganlık ile sebatkarlık mizaç özelliği arasında negatif yönde hafif düzeyde, tepkisel mizaç özelliğiyle pozitif yönde hafif düzeyde anlamlı ilişki, İlişkisel saldırganlık boyutunda ise ritmiklik ile ilişkisel saldırganlık arasında negatif yönde hafif düzeyde anlamlı ilişki bulunmuştur.

The relationship between preschoolers’ sensory regulation and temperament: implications for parents and early childhood caregivers

ABSTRACT With a non-clinical sample of pre-schoolers, we used partial least squares regression to assess the extent to which children's seven sensory regulatory factors (X) account for variations in the three temperament factors (Y) and Y explains variations in X. The results suggested predicting temperament factors from sensory processing factors receive better outcomes. Finally, multiple regression analyses using the sensory processing measures to predict each of the three temperamental variables showed that (1) significant predictors of negative affectivity included difficulties in tactile sensitivity, taste/smell sensitivity, and low energy; (2) surgency was predicted by underresponsive/seeks sensation, auditory filtering, tactile sensitivity, and movement sensitivity; and (3) effortful control was predicted by low energy and auditory filtering. The hypothesis supported children's sensory processing preferences form the basis for the manifestation of temperament. Parents and educators need to notice environmental stimuli can cause challenges for children with sensory processing difficulties and manifesti difficult temperament.

The Impact of Perinatal Life Stress on Infant Temperament and Child Development: A 2-Year Follow-Up Cohort Study.

Accumulating evidence suggests a persistent impact of perinatal exposure to maternal stress on the infant. In utero, the fetus is particularly vulnerable to maternal stress and mental health complications with various long-term consequences. This study examines the prospective relationship of subclinical maternal perinatal life stress based on individual responses to stressful life events and infant temperament and child development. Data were derived from the Akershus Birth Cohort, a longitudinal cohort study including 3,752 women scheduled to give birth at Akershus University Hospital, Norway. Psychometric measures pertained to perinatal life stress, maternal perinatal depression (Edinburgh Postnatal Depression Scale), difficult infant temperament at 8 weeks (Infant Characteristics Questionnaire), and child development 2 years after birth (Ages & Stages Questionnaire). Perinatal life stress predicted difficult infant temperament at 8 weeks and challenges in social-emotional development at 2 years above and beyond demographics, pregnancy, and childbirth-related and postpartum factors. Life events perceived as severely distressing in the peripartum period pose a burden on mothers and may have potentially detrimental long-term effects on neurobiological and social-emotional child development. Our findings highlight the need for person-centered perinatal care and support of mothers facing difficult life events. Clinical awareness of in utero development and its relationship to maternal psychological health is warranted to intervene effectively. Future research should consider the timing of in utero exposure and neurobiological and environmental mechanisms pertaining to the relationship between maternal perinatal life stress and child development.

Determinants of child resilience in poverty: findings from the Taiwan Birth Cohort Study

Abstract Background Poverty has adverse effects on child health. While children in poverty face greater health challenges, some still achieve positive health outcomes. This is in part due to their resilience when facing adversity. Identifying the factors that foster child resilience can aid in developing strategies to promote child resilience and reduce the harmful effects of child poverty. This study aims to identify the biological and social factors of resilience among children in poverty from birth to age 12. Methods Data for the analysis came from the Taiwan Birth Cohort Study, a nationally representative sample of 17,354 children who completed six waves of interview surveys between 2005 and 2017. Our sample included 4,570 children who experienced poverty from birth to age 12. The primary outcome variable was child resilience, defined as impoverished children who maintained good health outcomes over the 12-year survey period. Multiple logistic regression was used to examine the factors of child resilience. Results Of the 4,570 children, 36.1% always had good health despite experiencing poverty before the age of 12. An easy temperament (OR = 2.5, 95% CI: 1.9-3.0), female (OR = 1.1, 95% CI: 1.0-1.3), a birth weight greater than 2,500 grams (OR = 1.6, 95% CI: 1.2-2.1), having a foreign-born mother (OR = 1.5, 95% CI: 1.2-1.7), receiving breast milk after birth (OR = 1.3, 95% CI: 1.1-1.5), and good parent-child interaction at 3 years of age (OR = 1.4, 95% CI: 1.2-1.7) were associated with child resilience. Early parent-child interactions can moderate the effect of children's birth weight on later resilience. Conclusions Our findings indicated the factors associated with child resilience in the context of poverty, suggesting that supporting breastfeeding and nurturing parent-child relationships are effective public health actions to foster child resilience. Future research is needed to unravel the underlying mechanisms of biological factors associated with child resilience. Key messages Breastfeeding after birth and high-quality parent-child interaction can lead to positive adaptations to child poverty. Children with difficult temperaments, boys and those born at low birthweight are more vulnerable to poverty and should be targeted for building resilience against poverty.

A person-centered approach examining longitudinal associations betweenmaternal prenatal stress-related factors and infant difficult temperament

A person-centered approach examining longitudinal associations betweenmaternal prenatal stress-related factors and infant difficult temperament