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Biomedical subjects

Richard E Tremblay

Publications and source records attributed to Richard E Tremblay.

At least 19 recordsLinked to original sources
PubMed2007

Gender differences in physical aggression: A prospective population-based survey of children before and after 2 years of age.

There has been much controversy over the past decades on the origins of gender differences in children's aggressive behavior. A widely held view is that gender differences emerge sometime after 2 years of age and increase in magnitude thereafter because of gender-differentiated socialization practices. The objective of this study was to test for (a) gender differences in the prevalence of physical aggression in the general population of 17-month-old children and (b) change in the magnitude of these differences between 17 and 29 months of age. Contrary to the differential socialization hypothesis, the results showed substantial gender differences in the prevalence of physical aggression at 17 months of age, with 5% of boys but only 1% of girls manifesting physically aggressive behaviors on a frequent basis. The results suggest that there is no change in the magnitude of these differences between 17 and 29 months of age.

Aggression↗
PubMed2006

Do early difficult temperament and harsh parenting differentially predict reactive and proactive aggression?

The goal of this study was to examine the links between difficult temperament (i.e., negative emotionality) and harsh parental discipline during toddlerhood, and reactive and proactive aggression in kindergarten. These links were assessed on a longitudinal population-based study of 1516 boys and girls followed longitudinally from the age of 17 months through the age of 72 months. Two possible models were tested to examine the interplay between negative emotionality and harsh parenting in predicting later reactive aggression compared to proactive aggression. The first was an additive model where both aspects make unique contributions in predicting later reactive aggression. The second model was an interactive model where harsh parenting exacerbates the link between negative emotionality and reactive aggression. Results showed a specific contribution of negative emotionality to reactive aggression. The results relative to harsh parenting are more mixed but nonetheless in line with developmental models stressing different pathways to reactive and proactive aggression.

Aggression↗
PubMed2006

Salivary testosterone and aggression, delinquency, and social dominance in a population-based longitudinal study of adolescent males.

Testosterone (T) has been found to have a stimulating effect on aggressive behavior in a wide range of vertebrate species. There is also some evidence of a positive relationship in humans, albeit less consistently. In the present study we investigated the relationship between T and aggression, dominance and delinquency over time, covering a period from early adolescence to adulthood. From a large population-based sample (n = 1.161) a subgroup of 96 boys was selected whose behavior had been assessed repeatedly by different informants from age 12 to 21 years, and who had provided multiple T samples over these years of assessment. On the whole, a decrease in aggressive and delinquent behavior was observed in a period in which T rises dramatically. Boys who developed a criminal record, had higher T levels at age 16. In addition, positive associations were observed between T and proactive and reactive aggression and self-reported delinquent behavior. Over the pubertal years different forms of aggressive and delinquent behavior were positively related to T, which may indicate that specific positive links are dependent on the social setting in which this relationship is assessed.

Adolescent↗
PubMed2006

The dopamine D4 receptor gene and moderation of the association between externalizing behavior and IQ.

BACKGROUND: Dopaminergic neurotransmission is implicated in externalizing behavior problems, such as aggression and hyperactivity. Externalizing behavior is known to be negatively associated with cognitive ability. Activation of dopamine D4 receptors appears to inhibit the functioning of the prefrontal cortex, a brain region implicated in cognitive ability. The 7-repeat allele of the dopamine D4 receptor gene produces less efficient receptors, relative to other alleles, and this may alter the effects of dopamine on cognitive function. OBJECTIVE: To examine the influence of a polymorphism in the third exon of the dopamine D4 receptor gene on the association between externalizing behavior and IQ. DESIGN: In 1 community sample and 2 clinical samples, the presence or absence of the 7-repeat allele was examined as a moderator of the association between externalizing behavior and IQ; the strength of this effect across samples was estimated meta-analytically. PATIENTS: Eighty-seven boys from a longitudinal community study, 48 boys referred clinically for aggression, and 42 adult males diagnosed with attention-deficit/hyperactivity disorder. MAIN OUTCOME MEASURES: IQ scores and observer ratings of externalizing behavior were taken from existing data sets. RESULTS: Among individuals lacking the 7-repeat allele, externalizing behavior was negatively correlated with IQ (mean r = -0.43; P<.001). Among individuals having at least 1 copy of the 7-repeat allele, externalizing behavior and IQ were uncorrelated (mean r = 0.02; P = .45). The difference between these correlations was significant (z = -2.99; P<.01). CONCLUSIONS: Allelic variation of the dopamine D4 receptor gene appears to be a genetic factor moderating the association between externalizing behavior and cognitive ability. This finding may help to elucidate the adaptive value of the 7-repeat allele.

Adolescent↗
PubMed2006

Prediction of early-onset deviant peer group affiliation: a 12-year longitudinal study.

CONTEXT: Deviant peer group involvement is strongly related to onset, aggravation, and persistence of conduct problems during adolescence. OBJECTIVE: To identify early childhood behavioral profiles that predict early-onset deviant peer group involvement. DESIGN: A 12-year longitudinal study of behavioral development. SETTING: Fifty-three inner-city elementary schools in a large Canadian city. PARTICIPANTS: A total of 1037 boys in kindergarten from low socioeconomic neighborhoods. MAIN OUTCOME MEASURES: Annual self-reported deviant peer group involvement from 11 to 17 years of age. RESULTS: Kindergarten boys were at highest risk of following an early adolescence trajectory of deviant peer group affiliation if they were hyperactive, fearless, and low on prosocial behaviors but much less at risk if they scored high on only 2 of these dimensions. Family adversity had no main effect but substantially increased the risk of following an early adolescence trajectory of deviant peer group affiliation for boys with a profile of hyperactivity, fearlessness, and low prosocial behaviors. CONCLUSIONS: Kindergarten boys from low socioeconomic areas who are hyperactive, fearless, infrequently prosocial, and raised in adverse family environments are at much heightened risk of engaging in deviant peer groups early in their development. Boys at high risk can be identified as early as kindergarten and should be targeted for preventive intervention.

Adolescent↗
PubMed2006

The development of physical aggression from toddlerhood to pre-adolescence: a nation wide longitudinal study of Canadian children.

The objectives of the study were to model the developmental trajectories of physical aggression (PA) from toddlerhood to pre-adolescence and to identify risk factors that distinguish typical (normative) from atypical developmental patterns. Ten cohorts of approximately 1,000 children (n = 10,658) drawn form a nationally representative (Canadian) sample were followed over 6 years. Using a group based trajectory approach, we identified three groups of children with distinct developmental trajectories between 2 and 11 years of age. One third of the children (31.1%) followed a low desisting trajectory, reflected in infrequent use of PA in toddlerhood and virtually no PA by pre-adolescence. The majority of children (52.2%) followed a moderate desisting trajectory, reflected in occasional use of PA in toddlerhood and infrequent use by pre-adolescence. One sixth of the children (16.6%) followed a high stable trajectory of PA. Multivariate logistic regression indicated that children in the high PA trajectory group were more likely to be boys (OR: 1.67; CI: 1.5-1.87), from low income families (OR: 1.4; CI; 1.27-1.67), from families where the mother had not completed high school (OR: 1.20; CI: 1.05-1.38) and who reported using hostile/ineffective parenting strategies (OR: 1.16; CI: 1.14-1.18). In sum, the results indicate that the typical developmental pattern of PA was one of occasional and declining use over time. However, about one sixth of children, mostly boys from disadvantaged families, exhibited an atypical developmental pattern reflected in more frequent and stable use of PA. The results suggest that most children learned relatively well to inhibit PA by the end of childhood and that a minority failed to do so. Family risks traditionally found to be associated with antisocial behaviors during adolescence appear to interfere with the socialization of PA during early and middle childhood.

Aggression↗
PubMed2006

Intoxicated behavioral disinhibition and the heart rate response to alcohol.

This study examined the association between the heart rate (HR) response to alcohol intoxication, which is thought to reflect sensitivity to alcohol-induced reward and alcohol-induced behavioral disinhibition. High- and low-HR responders to alcohol participated in a go/no-go task, under sober and intoxicated conditions. Errors of commission on this task have previously been related to behavioral disinhibition. High-HR responders made more intoxicated commission errors as compared with low-HR responders. High-HR responders also reported increased alcohol consumption, and controlling for the latter did not alter the significant association between high-HR responders and increased intoxicated errors of commission. These results are consistent with previous findings of an increased risk for addictive and disinhibited behavioral propensities in individuals with a high-HR response to alcohol intoxication.

Alcoholic Intoxication↗
PubMed2006

Development of male proactive and reactive physical aggression during adolescence.

BACKGROUND: Different developmental courses have been postulated for proactive and reactive aggression. OBJECTIVE: Investigated the developmental course of proactive and reactive aggression in a large sample of adolescent boys from low socioeconomic areas. METHOD: A dual group-based joint trajectory method was used to identify distinct trajectories as well as similarities and differences in intra-individual changes. RESULTS: The trajectories for proactive and reactive aggression were similar: the majority of individuals followed infrequent and desisting trajectories. Contrary to expectations, very few adolescents followed trajectories of increasing proactive aggression. Reactive aggression was more common than proactive aggression. The overlap in trajectory group membership of individuals following trajectories of high peaking proactive and reactive aggression was nearly 100%. Across a period of 5 years, the boys on the high peaking trajectories were twice as likely to have affiliated with gangs. CONCLUSIONS: The developmental courses of proactive and reactive aggression are similar during adolescence. Males who tend to frequently use one form of aggression throughout adolescence also tend to frequently use the other and are at an increased risk for contemporaneous delinquent lifestyles.

Adolescent↗
PubMed2006

Heart rate response to alcohol and intoxicated aggressive behavior.

BACKGROUND: This study examined the elevated heart rate (HR) response to alcohol intoxication, thought to reflect an increased sensitivity to alcohol-induced reward, as a potential factor in the increased likelihood of alcohol-induced aggression. METHODS: Three groups, intoxicated high (n=37) and low (n=37) HR responders and sober controls (n=73), participated in a laboratory measure of physical aggression, the Taylor Aggression Paradigm. RESULTS: Results revealed that intoxicated high HR responders were more aggressive than the intoxicated low HR responders and sober controls. CONCLUSIONS: These findings are interpreted within a hypothetical model relating increased alcohol-induced aggression to a dysregulation in the motivational system responding to rewards.

Adult↗
PubMed2006

Neuropsychological characteristics of adolescent boys differing in risk for high blood pressure.

BACKGROUND: Individuals with established hypertension have been found to display deficits in a number of neuropsychological abilities. In general, these are probably due to structural changes in the brain produced by sustained high blood pressure. However, a potentially important line of research suggests that some of these deficits may extend to younger individuals with less severe elevations of blood pressure, perhaps even children, and thus be related more to risk for hypertension than hypertension per se. PURPOSE: The objective was to examine the relationships between neuropsychological function and risk for hypertension in children. METHODS: Measurements of blood pressure and parental history of hypertension were obtained in 88 French-Canadian 14-year-old boys and used to predict performance on a neuropsychological battery. RESULTS: Boys at greater risk of hypertension by virtue of having a parental history of high blood pressure and normatively elevated systolic blood pressure had significantly lower scores on a verbal learning factor score compared to boys at lower risk. Boys with normatively elevated systolic blood pressure also had significantly lower scores on a spatial learning and memory factor score compared to boys with lower blood pressure. The results could not be attributed to differences in family socioeconomic status. CONCLUSIONS: Using a younger sample than typically employed in the area, the results support previous suggestions that some of the neuropsychological characteristics displayed by hypertensive individuals may predate the development of clinically elevated blood pressure and could be associated with risk for the disorder.

Adolescent↗
PubMed2006

Development and prediction of hyperactive symptoms from 2 to 7 years in a population-based sample.

OBJECTIVES: Children with hyperactive symptoms are often referred to mental health services. Given the frequency and persistent nature of hyperactivity, it is important to better understand its developmental course. This study identified the different developmental trajectories of hyperactive symptoms from 2 to 7 years and tested early predictors of high-level and persistent hyperactivity. These data may lead to earlier detection of at-risk children and to more effective interventions that take into account developmental considerations. PARTICIPANTS: Four data-collection cycles of a nationwide survey of Canadian children were used to track the early development of hyperactivity. Children were 0 to 23 months at the first cycle in 1994 and 6 to 7 years at the fourth cycle in 2000. OUTCOME MEASURES: Hyperactivity data were gathered from mothers on a biennial basis beginning when children were 24 months old. Information on potential prenatal and postnatal predictors was gathered from mothers at the first cycle. DESIGN: Group-based semiparametric mixture modeling was used to estimate developmental trajectories, and logistic-regression analysis identified predictors of hyperactivity. RESULTS: Four trajectories of hyperactive symptoms were identified: very low, low, moderate, and high. Statistically significant predictors for high and persistent hyperactivity, after controlling for all other factors, were maternal prenatal smoking, child male gender, maternal depression, and hostile parenting. CONCLUSIONS: For the majority of children, the frequency of hyperactive symptoms decreased or remained low from 2 to 7 years. However, 7 children in 100 were classified as having high initial levels of hyperactive symptoms that persisted over time. Several prenatal and early postnatal risk factors identified these children, although additional variables will need to be identified to accurately predict high and persistent hyperactivity. Findings suggest that preventive interventions could target high-risk families during pregnancy and early childhood.

Age of Onset↗
PubMed2005

Joint trajectories of gambling, alcohol and marijuana use during adolescence: a person- and variable-centered developmental approach.

The usefulness of Moffitt's (1993) [Moffitt, T. E. (1993). Adolescence-limited and life-course-persistent antisocial behavior: A developmental taxonomy. Psychological Review, 100, 674-701.] theory of antisocial behavior was examined regarding gambling, alcohol and marijuana use. We assessed 903 Caucasian boys' developmental trajectories of these behaviors annually from age 11 through age 16. Severity of problems with these behaviors were assessed at ages 17 and 23. As correlates of these behaviors, teacher-rated personality and self-reported parenting were assessed at age 10. Self-reported autonomy was measured at ages 11 and 14. A cluster analysis on the correlates yielded two clusters. Membership in the cluster without adult problems was associated with either late onset of gambling and/or alcohol use trajectories or consistently low involvement in each of the behaviors. This cluster may correspond to Moffitt's adolescence-limited group and uninvolved adolescents, respectively. Membership in the cluster with subsequent adult problems was associated with early initiation of at least one of the three behaviors and involvement in each of them during adolescence. This cluster may correspond to Moffitt's life-course-persistent group. Findings indicate that early assessment of correlates used in the cluster analysis may be useful for screening and preventive purposes.

Adolescent↗
PubMed2005

Can teachers' behavior ratings be used to screen early adolescent boys for psychiatric diagnoses?

The present study examined if a short, 22-item teacher rating questionnaire could be used to screen young adolescent boys for psychiatric diagnoses. Subjects were 239 12-year-old boys from a community sample of low socioeconomic status families. Child and parent versions of the Diagnostic Interview Schedule for Children were used to provide DSM-III-R diagnoses. Results show a low to moderate screening value for the Short Social Behavior Questionnaire (S-SBQ) scales, with best results for externalizing disorders. The method used to establish the diagnoses had an impact on the screening efficacy of the S-SBQ, higher prevalence rates resulting in a lower proportion of false-positives for the same cutoff point. Additional research is needed to assess the screening efficacy of the S-SBQ across ages and gender, but results suggest that teacher ratings with the S-SBQ could be used to screen boys with externalizing disorders at the end of elementary school.

Child↗
PubMed2005

Bed-wetting and its association with developmental milestones in early childhood.

OBJECTIVE: To evaluate the relationship between bed-wetting and various developmental milestones in a large and representative sample of young children. DESIGN: A randomized 3-level stratified survey design. SETTING: Data were collected by questionnaires, and interviews were scheduled at home with the mother. PARTICIPANTS: A representative sample of children born from 1997 to 1998 in Quebec. A complete set of data on bed-wetting was obtained for 1666 children at the ages of 29, 41, and 53 months. MAIN OUTCOME MEASURES: Percentage of children who bed-wet and developmental factors associated with bed-wetting. RESULTS: Approximately 10% of the children were bed-wetting at the age of 53 months. Bed-wetting cessation occurred for most children studied between the ages of 29 and 41 months. Motor skills were achieved by fewer boys who bed-wet compared with boys who did not (had sat up without support for 10 minutes at 5 months, P = .05; and had started crawling at 5 months, P<.01). More girls who bed-wet were prematurely born and had hyperactivity and inattention (P<.01 for all) compared with those who did not. Language milestones were achieved by fewer children who bed-wet compared with those who did not (boys: P = .04; girls: P = .02). No between-group difference was found for physical growth and sleep variables. CONCLUSIONS: These findings show an association between bed-wetting and developmental milestones in early childhood. This study supports that bed-wetting could be indicative of a possible delay in the development of the central nervous system and could act as a noticeable indicator for parents and pediatricians.

Age Distribution↗
PubMed2005

Factors associated with fragmented sleep at night across early childhood.

OBJECTIVE: To identify the factors most strongly associated with sleeping less than 6 consecutive hours at night for children aged 5, 17, and 29 months. DESIGN, SETTING, AND PARTICIPANTS: A randomized survey design used a representative sample of infants born in 1997-1998 in the Canadian province of Quebec. Data were collected by questionnaires and interviews. Interviews were scheduled at home with the mothers. The number of consecutive hours slept at night by 1741 children aged 5, 17, and 29 months was assessed from parental reports. Factors associated with fragmented sleep were investigated for each age in a cross-sectional design. RESULTS: At 5 months of age, 23.5% of children did not sleep 6 consecutive hours. Of the children who did not sleep 6 consecutive hours at night at 5 months or 17 months of age, 32.9% were still not sleeping 6 consecutive hours at night at 29 months of age. The factor most strongly associated with not sleeping at least 6 consecutive hours per night at 5 months of age was feeding the child after an awakening. Parental presence until sleep onset was the factor most strongly associated with not sleeping at least 6 consecutive hours per night at 17 months and 29 months of age. CONCLUSIONS: Sleep consolidation evolves rapidly in early childhood. Parental behaviors at bedtime and in response to a nocturnal awakening are highly associated with the child's sleep consolidation. The effects are probably bidirectional and probably create a long-term problem. Early interventions could possibly break the cycle.

Bottle Feeding↗
PubMed2005

Multilevel correlates of childhood physical aggression and prosocial behavior.

The study identified independent individual, family, and neighborhood correlates of children's physical aggression and prosocial behavior. Participants were 2,745 2-11-year olds nested in 1,982 families, which were themselves nested in 96 Canadian neighborhoods. Hierarchical linear modeling showed that the total variation explained by the three-level model was 28.03% for physical aggression and 17.57% for prosocial behavior. For both childhood behaviors, approximately 66% of this explained variance was between individuals and up to 30% was between families. The smallest amount of observed variation was between neighborhoods. Significant individual-level predictors common to both childhood behaviors were child's sex and maternal hostility toward the target child. Specifically, boys had more mother-reported physical aggression and less prosocial behavior. Children who experienced greater-than-average maternal hostility (compared to siblings) were more physically aggressive and less prosocial. At the family level, significant common predictors were mother depressed mood and punitive parenting. Children had higher levels of physical aggression and lower levels of prosocial behavior in families where mothers had greater depressed mood and used more punitive parenting practices. At the neighborhood level, greater perceived problems and lower poverty level were associated with higher levels of physical aggression. Results are discussed with reference to past and future studies of multilevel effects on children's socialization.

Aggression↗
PubMed2005

The genetic-environmental etiology of parents' perceptions and self-assessed behaviours toward their 5-month-old infants in a large twin and singleton sample.

BACKGROUND: Given the importance of parenting for the child's early socio-emotional development, parenting perceptions and behaviours, and their correlates, should be assessed as early as possible in the child's life. The goals of the present study were 1) to confirm, in two parallel population-based samples, including a large sample of twins, the factor structure of a new self-administered questionnaire assessing both parents' specific parenting perceptions and behaviours toward their 5-month-old infants (i.e., parental self-efficacy, perceived parental impact, parental hostile-reactive behaviours and parental overprotection), 2) to identify the specific risk factors associated with the negative side of these parenting dimensions, 3) to document the genetic-environmental etiology of these parenting dimensions through the twin method. METHODS: Parents (2,122 mothers and 1,829 fathers) of 5-month-old infants, and parents of 5-month-old infant twins (510 families) completed the questionnaire (28 items). The data were submitted to a series of confirmatory factor analyses. The contribution to parenting of a variety of risk factors was examined in the two samples using regression analyses. A series of quantitative genetic analyses were performed to quantify the different sources of variation in parenting. RESULTS: A consistent factor structure was found across informants and across samples. There were significant mean differences in parenting between mothers and fathers, as well as between parents of twins and parents of singletons. A differentiated pattern of association with risk factors was found for each dimension of parenting. The twin analyses revealed that shared environment accounted for each parenting dimension. Maternal hostile-reactive behaviours were also moderately related to genetic factors in the child and this association was mainly mediated by the infant difficultness. CONCLUSIONS: The overall pattern of results was consistent with Belsky's (1984) view of parenting as multiply determined. The longitudinal follow-up of these families should provide the means for testing developmental models about the determinants and outcomes of these parenting dimensions.

Adult↗