This study examines the relationship between prenatal cocaine exposure and parent-reported child behavior problems at age 7 years.
Data are from 407 African-American children (210 cocaine-exposed, 197 non-cocaine-exposed) enrolled prospectively at birth in a longitudinal study on the neurodevelopmental consequences of in utero exposure to cocaine. Prenatal cocaine exposure was assessed at delivery through maternal self-report and bioassays (maternal and infant urine and infant meconium). The Achenbach Child Behavior Checklist (CBCL), a measure of childhood externalizing and internalizing behavior problems, was completed by the child’s current primary caregiver during an assessment visit scheduled when the child was seven years old.
Structural equation and GLM/GEE models disclosed no association linking prenatal cocaine exposure status or level of cocaine exposure to child behavior (CBCL Externalizing and Internalizing scores or the eight CBCL sub-scale scores).
This evidence, based on standardized ratings by the current primary caregiver, fails to support hypothesized cocaine-associated behavioral problems in school-aged children with in utero cocaine exposure. A next step in this line of research is to secure standardized ratings from other informants (e.g., teachers, youth self-report).
cocaine; prenatal exposure; child behavior
The negative effects of prenatal substance exposure on neurobiological and psychological development and of early adversity are clear, but little is known about their combined effects. In this study, multilevel analyses of the effects of prenatal substance exposure and early adversity on the emergence of neurobehavioral disinhibition in adolescence were conducted. Neurobehavioral disinhibition has previously been observed to occur frequently in multiproblem youth from high-risk backgrounds. In the present study, neurobehavioral disinhibition was assessed via behavioral dysregulation and poor executive function composite measures. Data were drawn from a prospective longitudinal investigation of prenatal substance exposure that included 1073 participants followed from birth through adolescence. The results from latent growth modeling analyses showed mean stability but significant individual differences in behavioral dysregulation and mean decline with individual differences in executive function difficulties. Prior behavioral dysregulation predicted increased executive function difficulties. Prenatal drug use predicted the emergence and growth in neurobehavioral disinhibition across adolescence (directly for behavioral dysregulation and indirectly for executive function difficulties via early adversity and behavioral dysregulation). Prenatal drug use and early adversity exhibited unique effects on growth in behavioral dysregulation; early adversity uniquely predicted executive function difficulties. These results are discussed in terms of implications for theory development, social policy, and prevention science.
To examine the impact of prenatal cocaine exposure and maternal behavioral health (recent drug use and psychological functioning) on child behavior at age 5 years.
In this longitudinal investigation, maternal report of child behavior was assessed using the Achenbach Child Behavior Checklist (CBCL) in 140 cocaine-exposed and 181 noncocaine-exposed (61 alcohol, tobacco, and/or marijuana-exposed, and 120 nondrug-exposed) low-income, African American children. Structural equation modeling was used to estimate suspected causal relationships between indicators of maternal behavioral health at 5-year follow-up, according to self-report on a modified Addiction Severity Index (ASI) and CBCL scores.
Prenatal cocaine exposure was not related to child behavior at age 5. Recent maternal drug use and psychological functioning had relationships with CBCL Internalizing and Externalizing scores. However, when considered within a combined model, only maternal psychological functioning remained significant.
Findings highlight the importance of maternal functioning in the behavioral outcome of children exposed prenatally to cocaine.
prenatal cocaine exposure; child behavior; CBCL
Our prospective cohort study of nonsmoking African-American and Dominican
mothers and children in New York City is evaluating the role of prenatal
exposure to urban pollutants, including polycyclic aromatic hydrocarbons (PAHs), environmental tobacco smoke (ETS), and pesticides, in
the pathogenesis of neurobehavioral disorders. We used the Bayley Scales
of Infant Development to evaluate the effects on child mental and
psychomotor development of prenatal exposure to airborne PAHs monitored
during pregnancy by personal air sampling. Behavioral development was
assessed by the Child Behavior Checklist. We adjusted for potential
confounders including sociodemographic factors and prenatal exposure to
ETS and chlorpyrifos. Prenatal exposure to PAHs was not associated with
psychomotor development index or behavioral problems. However, high
prenatal exposure to PAHs (upper quartile) was associated with lower
mental development index at age 3 [β= –5.69; 95% confidence interval (CI), –9.05 to –2.33; p < 0.01]. The odds of cognitive developmental delay were also
significantly greater for children with high prenatal exposure (odds
ratio = 2.89; 95% CI, 1.33 to 6.25; p = 0.01). General estimated equation analysis showed a significant
age × PAH effect on mental development (p = 0.01), confirming the age-specific regression findings. Further
adjustment for lead did not alter the relationships. There were no
differences in effect sizes by ethnicity. The results require confirmation
but suggest that environmental PAHs at levels recently encountered
in New York City air may adversely affect children’s cognitive
development at 3 years of age, with implications for school performance.
air pollution; neurodevelopment; polycyclic aromatic hydrocarbons; prenatal
To examine risk and protective factors associated with behavioural problems of children and adolescents following prenatal alcohol exposure.
A total of 73 children and adolescents with foetal alcohol spectrum disorders (FASD) were assessed for internalizing, externalizing and total behavioural problems using the Child Behavior Checklist. Linear regression models were used to determine the effects of diagnostic and environmental risk and protective factors on behaviour, while controlling for age, sex and IQ.
Length of time spent in residential care was the most pervasive risk factor associated with internalizing, externalizing and total behavioural problems. A low dysmorphology score was related to more internalizing and total problems.
Children and adolescents prenatally exposed to alcohol faced greater risk of substantive behavioural problems (i) if they were less visibly alcohol affected and (ii) the longer time they had spent in residential care. The results underscore the clinical importance of appropriate services and care for less visibly affected children with FASD and highlight the need to attend to children with FASD being raised in institutions.
Behavioural problems; Foetal alcohol spectrum disorders; Prenatal alcohol; Risk factors
In this longitudinal study of prenatal cocaine exposure (PCE), school-age physical and cognitive development and behavioral characteristics were examined, while controlling for other factors that affect child development. At this follow-up phase, children were on average 7.2 years old, and their caregivers were 33.7 years old, had 12.5 years of education, and 48% were African American. During the first trimester, 20% of the women were frequent cocaine users (≥ 1 line/day). First trimester cocaine exposure predicted decreased weight and height at 7 years. There was no significant relationship between PCE and the cognitive and neuropsychological measures. Third trimester cocaine use predicted more total and externalizing behavior problems on the Child Behavior Checklist  and the Teacher Report Form , and increased activity, inattention, and impulsivity on the Routh Activity  and SNAP scales . Children who were exposed to cocaine throughout pregnancy had more mother- and teacher-rated behavior problems compared to children of women who stopped using early in pregnancy or who never used cocaine prenatally. These detrimental effects of PCE on behavior are consistent with other reports in the literature and with the hypothesis that PCE affects development through changes in neurotransmitter systems. These school-age behaviors may be precursors of later adolescent behavior problems.
prenatal cocaine exposure; school age; growth; cognitive development; behavior problems
The relationship between prenatal cocaine use and preschooler’s physical and cognitive development and behavioral characteristics was examined, controlling for other influences on child development. On average, children were 38.5 months old, women were 29.4 years old, had 12.3 years of education, and 47% were African American. During the first trimester, 18% of the women were frequent cocaine users (≥ 1 line/day). First trimester cocaine exposure predicted decreased head circumference at 3 years and lower scores on the short-term memory subscale of the Stanford-Binet Intelligence Scale (SBIS) . There was no significant relationship between prenatal cocaine use and the other SBIS scales. First trimester cocaine use also predicted more total, internalizing, and externalizing behavior problems on the Child Behavior Checklist  and higher scores on the fussy/difficult scale of the Infant Characteristics Questionnaire . Children who were exposed to cocaine throughout pregnancy had more behavior problems and were more fussy compared to children of women who never used cocaine prenatally. A repeated measures analysis showed that children of first trimester cocaine users became more fussy over time. These detrimental effects on growth and behavior are consistent with other reports in the literature and with the hypothesis that prenatal cocaine exposure affects development through changes in neurotransmitter systems.
prenatal cocaine exposure; preschool age; growth; cognitive development; temperament; behavior problems
To examine the relationship between early parenting stress and later child behavior in a high risk sample and measure the effect of drug exposure on the relationship between parenting stress and child behavior.
A subset of child-caregiver dyads (n = 607) were selected from the Maternal Lifestyle Study, which is a large sample of children (n = 1388) with prenatal cocaine exposure and a comparison sample unexposed to cocaine. Of the 607 dyads, 221 were prenatally exposed to cocaine and 386 were unexposed to cocaine. Selection was based on the presence of a stable caregiver at 4 and 36 months with no evidence of change in caregiver between those time points.
Parenting stress at 4 months significantly predicted child externalizing behavior at 36 months. These relations were unaffected by cocaine exposure suggesting the relationship between parenting stress and behavioral outcome exists for high-risk children regardless of drug exposure history.
These results extend the findings of the relationship between parenting stress and child behavior to a sample of high-risk children with prenatal drug exposure. Implications for outcome and treatment are discussed.
disruptive behavior; parenting stress; high-risk children; prenatal drug exposure; cocaine
We previously reported an association between prenatal cocaine exposure (PCE) and childhood behavior problems as observed by the parent or caretaker. However, these behavior problems may not manifest in a structured environment, such as a school setting.
We determined whether there is an association between PCE and school behavior problems and whether ratings of behavior problems from the teacher differ from those noted by the parent or caretaker.
The Maternal Lifestyle Study, a multicenter study, enrolled 1388 children with and without PCE at one month of age for longitudinal assessment. Teachers masked to prenatal drug exposure status completed the Teacher Report Form (TRF/6-18) when children were 7, 9, and 11 years old. We also administered the Child Behavior Checklist-parent report (CBCL) to the parent/caretaker at same ages and then at 13 years. We performed latent growth curve modeling to determine whether high PCE will predict externalizing, internalizing, total behavior, and attention problems at 7 years of age and whether changes in problems' scores over time differ between those exposed and non-exposed from both teacher and parent report. Besides levels of PCE as predictors, we controlled for the following covariates, namely: site, child characteristics (gender and other prenatal drug exposures), family level influences (maternal age, depression and psychological symptomatology, continuing drug use, exposure to domestic violence, home environment, and socioeconomic status), and community level factors (neighborhood and community violence).
The mean behavior problem T scores from the teacher report were significantly higher than ratings by the parent or caretaker. Latent growth curve modeling revealed a significant relationship between intercepts of problem T scores from teacher and parent ratings; i.e., children that were rated poorly by teachers were also rated poorly by their parent/caretaker or vice versa. After controlling for covariates, we found high PCE to be a significant predictor of with higher externalizing behavior problem T scores from both parent and teacher report at 7 years (p=0.034 and p=0.021, respectively) in comparison to non-PCE children. These differences in scores from either teacher or caregiver were stable through subsequent years or did not change significantly over time. Boys had higher T scores than girls on internalizing and total problems by caretaker report; they also had significantly higher T scores for internalizing, total, and attention problems by teacher ratings; the difference was marginally significant for externalizing behavior (p=0.070). Caretaker postnatal use of tobacco, depression, and community violence were significant predictors of all behavior problems rated by parent/caretaker, while lower scores on the home environment predicted all behavior outcomes by the teacher report.
Children with high PCE are likely to manifest externalizing behavior problems; their behavior problem scores at 7 years from either report of teacher or parent remained higher than scores of non-exposed children on subsequent years. Screening and identification of behavior problems at earlier ages could make possible initiation of intervention, while considering the likely effects of other confounders.
The authors examined 223 children at age 4 years for the effects of prenatal cocaine exposure, exposure to other substances, maternal and environmental risk factors, and neonatal medical problems on IQ, externalizing problems, and internalizing problems. Regression analyses showed that maternal verbal IQ and low environmental risk predicted child IQ. Cocaine exposure negatively predicted children’s overall IQ and verbal reasoning scores, but only for boys. Cocaine exposure also predicted poorer short-term memory. Maternal harsh discipline, maternal depressive symptoms, and increased environmental risk predicted externalizing problems. In contrast, only maternal depressive symptoms predicted internalizing problems. These findings indicate that early exposure to substances is largely unrelated to subsequent IQ or adjustment, particularly for girls.
This study examined the effects of prenatal cocaine exposure, environmental risk, and maternal verbal intelligence on children's cognitive ability. Gender and age were examined as moderators of potential cocaine exposure effects. The Stanford-Binet IV intelligence test was administered to 231 children (91 cocaine exposed, 140 unexposed) at 4, 6, and 9 years of age. Neonatal medical risk and other prenatal exposures (alcohol, cigarettes, and marijuana) were also examined for their unique effects on child IQ. Mixed models analysis indicated that prenatal cocaine exposure interacted with gender as cocaine exposed boys had lower composite IQ scores. Age of assessment did not moderate this relation, indicating that cocaine exposed boys had lower IQs across this age period. A stimulating home environment and high maternal verbal IQ also predicted higher composite IQ scores. Cocaine exposed boys had lower scores on the Abstract/Visual Reasoning subscale, with trends for lower scores on the Short-term Memory and Verbal Reasoning subscales, as exposure effects were observed across domains. The findings indicate that cocaine exposure continues to place children at risk for mild cognitive deficits into preadolescence. Possible mechanisms for the exposure by gender interaction are discussed.
prenatal cocaine exposure; environmental risk; gender differences; intelligence
In this prospective study, teenager mothers (mean age = 16; range = 12–18; 70% African American) were interviewed about their tobacco use during pregnancy. When their children were ten, mothers reported on their child’s behavior and the children completed a neuropsychological battery. We examined the association between prenatal cigarette smoke exposure (PCSE) and offspring neurobehavioral outcomes on data from the ten-year phase (n = 336). Multivariate regression analyses were conducted to test if PCSE predicted neurobehavioral outcomes, adjusting for demographic characteristics, maternal psychological characteristics, prenatal exposure to other substances, and exposure to environmental tobacco smoke. Independent effects of PCSE were found. Exposed offspring had more delinquent, aggressive and externalizing behaviors (CBCL). They were more active (Routh, EAS, SNAP) and impulsive (SNAP), and had more problems with peers (SNAP). On the Stroop test, deficits were observed in both baseline response processing measures and on the more complex interference task that requires both selective attention and response inhibition. The significant effects of PCSE on neurobehavioral outcomes were found for exposure to as few as 10 cigarettes per day. These results are consistent with results from an earlier assessment when the children were age 6, demonstrating that the effects of prenatal tobacco exposure can be identified early and are consistent through middle childhood.
prenatal smoking; neurobehavioral; teenage mothers; children
Abuse of drugs by pregnant women both in the United States and worldwide has raised many questions regarding the effects of prenatal drug exposure on the developing fetus and subsequent child outcomes. Studies using the neurobehavioral teratology model have been undertaken to determine specific prenatal drug effects on cognitive and behavioral development. Here we summarize the findings of studies that have investigated the developmental effects of prenatal exposure to tobacco, marijuana, stimulants, and opiates. These studies consider the timing and amount of prenatal exposure; other drug exposures; maternal characteristics; and other health, nutritional, and environmental factors. We review treatment options for pregnant, substance-dependent women and therapeutic interventions for exposed children.
To assess 6-year-old cocaine- and noncocaine-exposed children's mental health outcomes controlling for potential confounders.
The sample consisted of 322 children [169 cocaine exposed (CE) and 153 noncocaine exposed (NCE)] enrolled in a longitudinal study since birth. At age 6, children were assessed for mental health symptoms using the Dominic Interactive (DI), a child self-report measure, and the Child Behavior Checklist (CBCL), a caregiver report of behavioral problems.
CE children were more likely to self-report symptoms in the probable clinical range for oppositional defiant disorder (ODD) and attention deficit hyperactivity disorder (ADHD). In contrast, prenatal cocaine exposure was not related to child behavior based on the CBCL. After control for exposure, CE children in adoptive or foster care were rated as having more problems with aggression, externalizing behaviors, and total behavioral problems than NCE children and CE children in maternal or relative care. Also, CE children in adoptive or foster care self-reported more externalizing symptoms than CE children in maternal or relative care and NCE children. Findings could not be attributed to caregiver intelligence or depressive symptoms, or to the quality of the home environment.
CE children report more symptoms of ODD and ADHD than nonexposed children. Adoptive or foster caregivers rated their CE children as having more behavioral problems than did maternal or relative caregivers of CE children or parents of NCE children. Although further studies are needed to understand the basis for the more negative ratings by adoptive or foster caregivers of their CE children, the self-report of CE children indicates a need for psychological interventions.
ADHD; adoptive or foster care; CBCL; Dominic Interactive; mental health outcomes; oppositional defiant disorder; prenatal cocaine exposure
The importance of genetic and environmental influences on children’s behavioral and emotional problems may vary as a function of environmental exposure. We previously reported that 12-year-olds with divorced parents showed more internalizing and externalizing problems than children with married parents, and that externalizing problems in girls precede and predict later parental divorce. The aim of the current study was to investigate as to whether genetic and environmental influences on internalizing and externalizing problems were different for children from divorced versus non-divorced families.
Maternal ratings on internalizing and externalizing problems were collected with the Child Behavior Checklist in 4,592 twin pairs at ages 3 and 12 years, of whom 367 pairs had experienced a parental divorce between these ages. Variance in internalizing and externalizing problems at ages 3 and 12 was analyzed with biometric models in which additive genetic and environmental effects were allowed to depend on parental divorce and sex. A difference in the contribution of genetic and environmental influences between divorced and non-divorced groups would constitute evidence for gene–environment interaction.
For both pre- and post-divorce internalizing and externalizing problems, the total variances were larger for children from divorced families, which was mainly due to higher environmental variances. As a consequence, heritabilities were lower for children from divorced families, and the relative contributions of environmental influences were higher.
Environmental influences become more important in explaining variation in children’s problem behaviors in the context of parental divorce.
Gene–environment interaction; Internalizing; Externalizing; Twins
Substance abuse during pregnancy results in persistent affective and behavioral deficits in drug-exposed children, and increased rates of substance abuse have been observed in young adults prenatally exposed to drugs of abuse. Animal models of prenatal cocaine exposure have yielded differing results depending on the behavioral method used to assess drug potency.
The effects of cocaine, the dopamine D1 agonists SKF-81297 and SKF-82958, and the D2 agonist quinpirole on intracranial self-stimulation were measured in adult Swiss-Webster mice exposed to cocaine in utero (40 mg/kg/day) and vehicle controls using the curve-shift method of brain stimulation-reward (BSR) threshold determination.
The reward-potentiating effects of cocaine (0.3-30 mg/kg i.p.) and SKF-82958, but not SKF-81297, on BSR were increased in adult male but not female mice following prenatal cocaine exposure. Quinpirole exerted biphasic effects on BSR, both elevating (0.1-0.3 mg/kg i.p.) and lowering (1.0-10 mg/kg i.p.) reward thresholds. Both effects of quinpirole were also enhanced in adult male mice following prenatal cocaine exposure.
Prenatal cocaine exposure results in increased reward-potentiating potency of cocaine on BSR in adult mice in a sexually-dimorphic manner. This augmented rewarding effect of cocaine is also associated with increased sensitivity to both D1- and D2-selective agonists.
In utero; gestation; psychostimulant; intracranial self-stimulation; ICSS; brain stimulation-reward; BSR
Predictors of caregiver-reported behavior problems for 3-year-olds with prenatal cocaine exposure (PCE) and matched controls were examined using structural equation modeling. We tested whether PCE had a direct effect on child behavior problems in a model that included other prenatal drug exposure, child sex, caregiver depression, and the quality of the child’s home environment. The sample (N = 256) was drawn from a longitudinal, prospective study of children of (predominantly crack) cocaine-using women and controls matched on race, socioeconomic status, parity, and pregnancy risk. Child Behavior Problems was modeled as a latent variable composed of the 48-item Conners’ Parent Report Scale Conduct Problem and Impulsive-Hyperactive scales and the Eyberg Child Behavior Inventory Intensity scale. Caregiver depression was the only significant predictor of Child Behavior Problems. Mean levels of caregiver self-reported depression and reported child behavior problems did not differ between groups. Mean depression scores were well above the recommended clinical cutoff while mean child behavior problems scores were within normal limits. The model explained 21% of the variance in caregiver-reported child behavior problems in our sample of rural African American, low SES youngsters. Non-maternal caregivers of cocaine-exposed children had significantly lower mean depression scores and mean child behavior problems ratings for 2 of 3 scales used in the study compared to biological mothers of children with PCE and controls. For all groups, much larger proportions of children were rated as having clinically significant behavior problems than would be expected based on the prevalence of behavior problems in the general population.
An objective in current research on children with fetal alcohol spectrum disorders (FASD) is to determine neurobehavioral profiles to identify affected individuals. Deficits observed when children with FASD are compared to typically developing controls may be confounded by lower IQ scores in the subjects with FASD. To determine if prenatal alcohol exposure is associated with neurobehavioral deficits after controlling for IQ differences, multivariate analyses were conducted to compare alcohol-exposed (ALC) subjects to a comparison group closely matched on IQ (IQC). The initial analysis included a broad neuropsychological battery with measures of language, executive function, visual–motor integration, motor ability, and academic achievement. Additional, in depth comparisons focused on visual sustained attention, verbal learning and memory and parent/guardian-reported behavior problems. Group differences (ALC < IQC) were found on verbal learning and parent-rated behavior problems. Group differences were marginally significant (measures within the broad neuropsychological comparison) or not significant (visual attention, retention of verbal material) on the remaining comparisons. Therefore, some deficits (e.g., verbal learning and behavior problems) in children with heavy prenatal alcohol exposure cannot be explained by the lower FSIQ observed in the population. These areas of relative weakness could be useful in distinguishing children with FASD from other children with lowered IQ.
Fetal alcohol spectrum disorders; Fetal alcohol syndrome; IQ-matched control group; Neurobehavioral profile; Intelligence; Teratology
Children prenatally exposed to cocaine may be at increased risk for behavioral problems due to disruptions of monaminergically regulated arousal systems and/or environmental conditions.
To assess behavioral outcomes of cocaine (CE) and non-cocaine exposed (NCE) children, 4 through 10 years old, controlling for other prenatal drug exposures and environmental factors.
Low socioeconomic status (SES), primarily African-American children (n = 381 (193 (CE), 188 (NCE)) were recruited from birth. Generalized Estimating Equation (GEE) analyses were used to assess the predictive relationship of prenatal cocaine exposure to odds of caregiver reported clinically elevated behavioral problems at 4, 6, 9 and 10 years of age, controlling for confounders.
Prenatal cocaine exposure was associated with increased rates of caregiver reported delinquency (OR=1.93, CI: 1.09-3.42, p<.02). A significant prenatal cocaine exposure by sex interaction was found for delinquency indicating that only females were affected (OR=3.57, CI: 1.67-7.60, p<.001). There was no effect of cocaine on increased odds of other CBCL subscales. Higher prenatal tobacco exposure was associated with increased odds of externalizing symptoms at 4, 9 and 10 years of age. For CE children, those in foster or adoptive care were rated as having more behavior problems than those in biologic mother or relative care. Greater caregiver psychological distress was associated with increased behavioral problems. There were no independent effects of elevated blood lead level on increased behavior problems after control for prenatal drug exposure and other environmental conditions.
Prenatal cocaine and tobacco exposure were associated with greater externalizing behavior after control for multiple prenatal drug exposures, other environmental and caregiving factors and lead exposure from 4 through 10 years of age. Greater caregiver psychological distress negatively affected caregiver ratings of all CBCL domains. Since cocaine and tobacco use during pregnancy and maternal psychological distress have the potential to be altered through prenatal educational, drug treatment and and mental health interventions, they warrant attention in efforts to reduce rates of problem behaviors in children.
behavior; delinquency; prenatal cocaine-exposure; lead exposure; longitudinal
Heavy prenatal alcohol exposure can cause alterations to the developing brain. The resulting neurobehavioral deficits seen following this exposure are wide-ranging and potentially devastating and, therefore, are of significant concern to individuals, families, communities, and society. These effects occur on a continuum, and qualitatively similar neuropsychological and behavioral features are seen across the spectrum of effect. The term fetal alcohol spectrum disorders (FASD) has been used to emphasize the continuous nature of the outcomes of prenatal alcohol exposure, with fetal alcohol syndrome (FAS) representing one point on the spectrum. This paper will provide a comprehensive review of the neuropsychological and behavioral effects of heavy prenatal alcohol exposure, including a discussion of the emerging neurobehavioral profile. Supporting studies of lower levels of exposure, brain-behavior associations, and animal model systems will be included when appropriate.
fetal alcohol syndrome (FAS); fetal alcohol spectrum disorders (FASD); neuropsychological outcome; behavior; neurobehavioral profile; behavioral teratology
Children exposed to cocaine during gestation have a higher incidence of neurobehavioral deficits. The neurochemical bases of these deficits have not been determined, but the pharmacology of cocaine and the nature of the abnormalities suggest that disruptions in catecholaminergic systems may be involved. In the current study, we used a rat model of prenatal cocaine exposure to examine the impact that this exposure has on the locus coeruleus (LC) noradrenergic system in offspring. Pregnant rats received twice-daily intravenous injections of cocaine (3 mg/kg) or saline between gestational days 10 and 20, and progeny were tested as juveniles. Exposure to a mild stressor elevated an index of norepinephrine turnover in the prefrontal cortex and also increased Fos expression in tyrosine hydroxylase-positive LC neurons in rats exposed to prenatal cocaine but not in rats exposed to prenatal saline. No change in the number of tyrosine hydroxylase-positive neurons in the LC was observed between the two prenatal treatment groups. Specific binding of [125I]-para-iodoclonidine, a radioligand with specificity for high affinity α2A-adrenergic receptors, was decreased in the LC of rats exposed to prenatal cocaine compared to prenatal saline controls. As α2-adrenergic receptors on LC norepinephrine neurons function as autoreceptors, their down-regulation by prenatal cocaine exposure provides a plausible mechanism for the observed heightened reactivity of norepinephrine neurons in these animals. These data indicate that prenatal cocaine exposure results in lasting changes to the regulation and responsivity of rat LC norepinephrine neurons. A similar dysregulation of LC norepinephrine neurons may occur in children exposed to cocaine during gestation, and this may explain, at least partly, the increased incidence of cognitive deficits that have been observed in these subjects.
alpha-2 adrenergic receptor; ADHD, Fos; prefrontal cortex; stress; tyrosine hydroxylase
Accumulating evidence in experimental animals over the past three decades suggests that mammalian brain development and differentiation of the central nervous system are influenced by perinatal exposure to sex hormones. Hence, changes in human behavioral patterns may be associated with prenatal exposure to estrogenic substances such as diethylstilbestrol (DES). This paper reviews relevant studies from a series of laboratories and finds that no clear-cut differences can be demonstrated to date between unexposed and DES-exposed women in gender-related behavior, although the physical and psychological impact of the problems associated with exposure to DES are well documented. If both prenatal and postnatal influences such as social, economic, and environmental factors are taken into consideration, individual variation is more apparent than differences in gender-related behavior between unexposed and DES-exposed women. In summary, gender-related behavior is determined by a complex array of interacting factors, and prenatal influences are only one of many developmental events. More studies are needed using larger populations with carefully controlled selection criteria to suggest a direct role of prenatal DES exposure on subsequent gender-related behavior.
To evaluate the impact of prenatal cocaine exposure and small-for-gestational-age (SGA) status on childhood growth.
Cocaine exposure was defined by history or meconium metabolites. Hierarchical linear modeling was used to examine cocaine exposure and SGA status on growth, while controlling for exposure to other drugs and alcohol use.
At birth cocaine-exposed infants (n=364) had significantly lower growth parameters compared to non-exposed children (n=771). At 6 years, weight was similar between exposed and unexposed children. SGA infants continued to be growth impaired. There was a significant interaction between prenatal cocaine exposure and SGA status at 6 years. The negative effects of cocaine on weight and height were greater among non-SGA than SGA children (432 vs. 280 gm, and 0.7 and 0.5 cm, respectively) while negative effects of SGA status on weight and height were larger in non-cocaine exposed compared to the exposed children (2.3 kg vs.1.6 kg and 2.2 and 1.0 cm).
Children exposed to prenatal cocaine were similar in weight to non-exposed children at 6 years of age. Cocaine had an unexplained greater detrimental effect on non-SGA than SGA children. SGA status at birth has an independent detrimental effect on childhood growth.
Prenatal cocaine exposure; small for gestational age; childhood growth
To determine in a representative sample of full-term urban newborns of English-speaking mothers whether an immediate or late dose-response effect could be demonstrated between prenatal cocaine exposure and newborn neurobehavioral performance, controlling for confounding factors.
The Neonatal Behavioral Assessment Scale (NBAS) was administered by masked examiners to a total sample of 251 clinically healthy, full-term infants at 2 days and/or 17 days. Three in utero cocaine exposure groups were defined: heavily exposed (n = 44, >75th percentile self-reported days of use during pregnancy and/or >75th percentile of meconium benzoylecognine concentration); lightly exposed (n = 79, less than both 75th percentiles); and unexposed (n = 101, no positive biological or self-report marker). At the 3-week examination there were 38 heavily exposed, 73 lightly exposed, and 94 unexposed infants. Controlling for infant birth weight, gestational age, infant age at the time of examination, mothers’ age, perinatal risk, obstetric medication, and alcohol, marijuana, and cigarette use, a regression analysis evaluated the effects of levels of cocaine exposure on NBAS performance.
No neurobehavioral effects of exposure on the newborn NBAS cluster scores or on the qualifier scores were found when confounders were controlled for at 2 to 3 days of age. At 3 weeks, after controlling for covariates, a significant dose effect was observed, with heavily exposed infants showing poorer state regulation and greater excitability.
These findings demonstrate specific dose-related effects of cocaine on 3-week neurobehavioral performance, particularly for the regulation of arousal, which was not observed in the first few days of life.
cocaine exposure and newborn neurobehavior; neurobehavioral effects of prenatal cocaine exposure; dose-related cocaine effects on newborn neurobehavior; prenatal cocaine impairment of newborn regulation of arousal; Brazelton Scale; behavior of cocaine-exposed newborns
Genetic and environmental contributions to the observed correlations among DSM-IV ADHD problems [inattentive (INATT) and hyperactive/impulsive (HYP/IMP) behaviors], conduct problems (CDP) and alcohol problems (AlcProb) were examined by fitting multivariate structural equation models to data from the Missouri Adolescent Female Twin Study [N=2892 twins (831 monozygotic pairs, 615 dizygotic pairs)]. Based on results of preliminary regression models, we modified the structural model to jointly estimate (i) the regression of each phenotype on significant familial/prenatal predictors, and (ii) genetic and environmental contributions to the residual variance and covariance. Results suggested that (i) parental risk factors, such as parental alcohol dependence and regular smoking, increase risk for externalizing behavior; (ii) prenatal exposures predicted increased symptomatology for HYP/IMP (smoking during pregnancy), INATT and CDP (prenatal alcohol exposure); (iii) after adjusting for measured familial/prenatal risk factors, genetic influences were significant for HYP/IMP, INATT, and CDP; however, similar to earlier reports, genetic effects on alcohol dependence symptoms were negligible; and (iv) in adolescence, correlated liabilities for conduct and alcohol problems are found in environmental factors common to both phenotypes, while covariation among impulsivity, inattention, and conduct problems is primarily due to genetic influences common to these three behaviors. Thus, while a variety of adolescent problem behaviors are significantly correlated, the structure of that association may differ as a function of phenotype (e.g., comorbid HYP/IMP and CDP vs. comorbid CDP and AlcProb), a finding that could inform different approaches to treatment and prevention.
ADHD; alcoholism; conduct disorder; genetics; twin studies; prenatal substance exposure; parental alcoholism