Neurobiology of prenatal cocaine exposure effect on developing monoamine systems

Animal Models of the Impact of Social Stress on Cocaine Use Disorders

Cocaine use disorders are strongly influenced by the social conditions prior, during, and after exposure to cocaine. In this chapter, we discuss how social factors such as early life stress, social rank stress, and environmental stress impact vulnerability and resilience to cocaine. The discussion of each animal model begins with a brief review of examples from the human literature, which provide the psychosocial background these models attempt to capture. We then discuss preclinical findings from use of each model, with emphasis on how social factors influence cocaine-related behaviors and how sex and age influence the behaviors and neurobiology. Models discussed include (1) early life social stress, such as maternal separation and neonatal isolation, (2) social defeat stress, (3) social hierarchies, and (4) social isolation and environmental enrichment. The cocaine-related behaviors reviewed for each of these animal models include cocaine-induced conditioned place preference, behavioral sensitization, and self-administration. Together, our review suggests that the degree of psychosocial stress experienced yields robust effects on cocaine-related behaviors and neurobiology, and these preclinical findings have translational impact for the future of cocaine use disorder treatment.

Developmental consequences of fetal exposure to drugs: what we know and what we still must learn

Most drugs of abuse easily cross the placenta and can affect fetal brain development. In utero exposures to drugs thus can have long-lasting implications for brain structure and function. These effects on the developing nervous system, before homeostatic regulatory mechanisms are properly calibrated, often differ from their effects on mature systems. In this review, we describe current knowledge on how alcohol, nicotine, cocaine, amphetamine, Ecstasy, and opiates (among other drugs) produce alterations in neurodevelopmental trajectory. We focus both on animal models and available clinical and imaging data from cross-sectional and longitudinal human studies. Early studies of fetal exposures focused on classic teratological methods that are insufficient for revealing more subtle effects that are nevertheless very behaviorally relevant. Modern mechanistic approaches have informed us greatly as to how to potentially ameliorate the induced deficits in brain formation and function, but conclude that better delineation of sensitive periods, dose-response relationships, and long-term longitudinal studies assessing future risk of offspring to exhibit learning disabilities, mental health disorders, and limited neural adaptations are crucial to limit the societal impact of these exposures.

Prenatal substance abuse: short- and long-term effects on the exposed fetus

Prenatal substance abuse continues to be a significant problem in this country and poses important health risks for the developing fetus. The primary care pediatrician's role in addressing prenatal substance exposure includes prevention, identification of exposure, recognition of medical issues for the exposed newborn infant, protection of the infant, and follow-up of the exposed infant. This report will provide information for the most common drugs involved in prenatal exposure: nicotine, alcohol, marijuana, opiates, cocaine, and methamphetamine.

Increased "default mode" activity in adolescents prenatally exposed to cocaine

Prenatal cocaine exposure (PCE) is associated with attention/arousal dysregulation and possible inefficiencies in some cognitive functions. However, the neurobiological bases of these teratogenic effects have not been well characterized. Because activities in the default mode network (DMN) reflect intrinsic brain functions that are closely associated with arousal regulation and cognition, alterations in the DMN could underlie cognitive effects related to PCE. With resting-state and task activation functional magnetic resonance imaging (fMRI), this study investigated the possible PCE related changes in functional brain connectivity and brain activation in the DMN. In the resting state, the PCE group was found to have stronger functional connectivity in the DMN, as compared to the nonexposed controls. During a working memory task with emotional distracters, the PCE group exhibited less deactivation in the DMN and their fMRI signal was more increased by emotional arousal. These data revealed additional neural effects related to PCE, and consistent with previous findings, indicate that PCE may affect behavior and functioning by increasing baseline arousal and altering the excitatory/inhibitory balancing mechanisms involved in cognitive resource allocation.

Perinatal risk factors in the development of aggression and violence

Over the past several decades, the relative contribution of both environmental and genetic influences in the development of aggression and violence has been explored extensively. Only fairly recently, however, has it become increasingly evident that early perinatal life events may substantially increase the vulnerability toward the development of violent and aggressive behaviors in offspring across the lifespan. Early life risk factors, such as pregnancy and birth complications and intrauterine exposure to environmental toxins, appear to have a profound and enduring impact on the neuroregulatory systems mediating violence and aggression, yet the emergence of later adverse behavioral outcomes appears to be both complex and multidimensional. The present chapter reviews available experimental and clinical findings to provide a framework on perinatal risk factors that are associated with altered developmental trajectories leading to violence and aggression, and also highlights the genetic contributions in the expression of these behaviors.

Impaired regulation of arousal in 3-month-old infants exposed prenatally to cocaine and other drugs

This study investigated relations between drug exposure, particularly cocaine, and infants' regulation of arousal in response to novelty. Sixty-three infants — 36 cocaine exposed and 27 non-cocaine exposed — participated at 3 months of age in a novel-repeat stimulus presentation procedure. Arousal was operationalized in terms of infant behavioral state, affective expressiveness, and attention to the stimulus. Infants were tested and infant behaviors were scored by experimenters blind to the drug exposure status of the infant. There were no differences between the two groups in baseline behavioral state or affective expression before the presentation of novel stimuli. Compared to the non-cocaine-exposed group, infants exposed prenatally to cocaine and other drugs were more likely to exhibit a crying state and to display negative affect on novel stimulus presentations. There were no group differences in the amount of looking toward the stimulus. Both groups showed less crying and negative affect when stimuli were presented a second time, but decrements were consistently greater for the cocaine-exposed group. These results obtained when group differences were controlled for sociodemographic and perinatal variables. Sources of differences in the regulation of arousal in cocaine-exposed and non-cocainc-exposed infants are discussed, and impairments in the regulation of arousal in cocaine-exposed infants are considered in a framework of predictive implications for children's social and cognitive development.

Preventing Child Maltreatment and Crime with Prenatal and Infancy Support of Parents: The Nurse-Family Partnership

Pregnancy and the early years of the child's life offer an opportune time to prevent a host of adverse maternal and child outcomes that are important in their own right, but that also have significant implications for the development of criminal behaviour. This paper summarizes a 30-year programme of research that has attempted to improve the health and development of mothers and infants and their future life prospects with prenatal and infancy home visiting by nurses. The programme, known today as the Nurse-Family Partnership, is designed for low-income mothers who have had no previous live births. The home visiting nurses have three major goals: to improve the outcomes of pregnancy by helping women improve their prenatal health; to improve the child's health and development by helping parents provide more sensitive and competent care of the child; and to improve parental life-course by helping parents plan future pregnancies, complete their educations, and find work. Given consistent effects on prenatal health behaviours, parental care of the child, child abuse and neglect, child health and development, maternal life-course, and criminal involvement of the mothers and children, the programme is now being offered for public investment throughout the United States, where careful attention is being given to ensuring that the programme is being conducted in accordance with the programme model tested in the randomized trials. The programme also is being adapted, developed, and tested in five countries outside of the US: the Netherlands, Germany, England, Australia, and Canada, where programmatic adjustments are being made to accommodate different populations served and health and human service contexts. We believe it is important to test this programme in randomized controlled trials in these new settings before it is offered for public investment.

Reactivity and regulation in children prenatally exposed to cocaine

Children prenatally exposed to cocaine may be at elevated risk for adjustment problems in early development because of greater reactivity and reduced regulation during challenging tasks. Few studies have examined whether cocaine-exposed children show such difficulties during the preschool years, a period marked by increased social and cognitive demands and by rapid changes in reactivity and regulation. The authors addressed this question by examining frustration reactivity and regulation of behavior during a problem-solving task in cocaine-exposed and -unexposed preschoolers. Participants were 174 4.5-year-olds (M age = 4.55 years, SD = 0.09). Frustration reactivity was measured as latency to show frustration and number of disruptive behaviors, whereas regulation was measured as latency to approach and attempt the problem-solving task and number of problem-solving behaviors. Results indicated that cocaine-exposed children took longer to attempt the problem-solving task but that cocaine-exposed boys showed the most difficulties: They were quicker to express frustration and were more disruptive. Effect sizes were relatively small, suggesting both resilience and vulnerabilities.

The nurse-family partnership: An evidence-based preventive intervention

Pregnancy and the early years of the child's life offer an opportune time to prevent a host of adverse maternal, child, and family outcomes that are important in their own right, but that also reflect biological, behavioral, and social substrates in the child and family that affect family formation and future life trajectories. This article summarizes a 27-year program of research that has attempted to improve early maternal and child health and future life options with prenatal and infancy home visiting by nurses. The program is designed for low-income mothers who have had no previous live births. The home-visiting nurses have three major goals: to improve the outcomes of pregnancy by helping women improve their prenatal health, to improve the child's health and development by helping parents provide more sensitive and competent care of the child, and to improve parental life course by helping parents plan future pregnancies, complete their education, and find work. The program has been tested in three separate large-scale, randomized controlled trials with different populations living in different contexts. Results from these trials indicate that the program has been successful in achieving two of its most important goals: (a) the improvement of parental care of the child as reflected in fewer injuries and ingestions that may be associated with child abuse and neglect and better infant emotional and language development; and (b) the improvement of maternal life course, reflected in fewer subsequent pregnancies, greater work-force participation, and reduced dependence on public assistance and food stamps. The impact on pregnancy outcomes is equivocal. In the first trial, the program also produced long-term effects on the number of arrests, convictions, emergent substance use, and promiscuous sexual activity of 15-year-old children whose nurse-visited mothers were low-income and unmarried when they registered in the study during pregnancy. In general, the impact of the program was greater on those segments of the population at greater risk for the particular outcome domain under examination. Since 1996, the program has been offered for public investment outside of research contexts. Careful attention has been given to ensuring that organizational and community contexts are favorable for development of the program, to providing excellent training and guidance to the nurses in their use of the program's visit-by-visit guidelines, to monitoring the functioning of the program with a comprehensive clinical information system, and to improving the performance of the programs over time with continuous improvement strategies.

Cocaine Exposure Is Associated With Subtle Compromises of Infants' and Mothers' Social-Emotional Behavior and Dyadic Features of Their Interaction in the Face-to-Face Still-Face Paradigm

Prenatal cocaine and opiate exposure are thought to subtly compromise social and emotional development. The authors observed a large sample of 236 cocaine-exposed and 459 nonexposed infants (49 were opiate exposed and 646 nonexposed) with their mothers in the face-to-face still-face paradigm. Infant and maternal behaviors were microanalytically coded. No opiate-exposure effects were detected. However, mothers of cocaine-exposed infants showed more negative engagement than other mothers. The cocaine-exposed dyads also showed higher overall levels of mismatched engagement states than other dyads, including more negative engagement when the infants were in states of neutral engagement. Infants exposed to heavier levels of cocaine showed more passive-withdrawn negative engagement and engaged in more negative affective matching with their mothers than other infants. Although effect sizes were small, cocaine exposure, especially heavy cocaine exposure, was associated with subtly negative interchanges, which may have a cumulative impact on infants' later development and their relationships with their mothers.

Similar and functionally typical kinematic reaching parameters in 7- and 15-month-old in utero cocaine-exposed and unexposed infants

This study examined the effects of intrauterine cocaine exposure on the reaches of 19 exposed and 15 unexposed infants at 7 and 15 months using kinematic measures. Infants sat at a table and reached for a rattle, a toy doll, and a chair. Videotaped reaches were digitized using the Peak Performance system. Kinematic movement variables were extracted (e.g., reach duration, peak velocity, movement units, path length) and ratios computed (e.g., path length divided by number of movement units). Regardless of exposure status, reaches of older infants were faster, more direct, had fewer movement units, and covered more distance with the first movement unit. Exposed infants covered more distance per movement unit than unexposed infants, but there were no other significant differences. Reaches of exposed and unexposed infants were essentially similar. Importantly, reach parameters for these high-risk infants were similar to reach parameters for infants at lower social and biological risk.

Severity of prenatal cocaine exposure and child language functioning through age seven years: a longitudinal latent growth curve analysis

The current study estimates the longitudinal effects of severity of prenatal cocaine exposure on language functioning in an urban sample of full-term African-American children (200 cocaine-exposed, 176 noncocaine-exposed) through age 7 years. The Miami Prenatal Cocaine Study sample was enrolled prospectively at birth, with documentation of prenatal drug exposure status through maternal interview and toxicology assays of maternal and infant urine and infant meconium. Language functioning was measured at ages 3 and 5 years using the Clinical Evaluation of Language Fundamentals--Preschool (CELF-P) and at age 7 years using the Core Language Domain of the NEPSY: A Developmental Neuropsychological Assessment. Longitudinal latent growth curve analyses were used to examine two components of language functioning, a more stable aptitude for language performance and a time-varying trajectory of language development, across the three time points and their relationship to varying levels of prenatal cocaine exposure. Severity of prenatal cocaine exposure was characterized using a latent construct combining maternal self-report of cocaine use during pregnancy by trimesters and maternal and infant bioassays, allowing all available information to be taken into account. The association between severity of exposure and language functioning was examined within a model including factors for fetal growth, gestational age, and IQ as intercorrelated response variables and child's age, gender, and prenatal alcohol, tobacco, and marijuana exposure as covariates. Results indicated that greater severity of prenatal cocaine exposure was associated with greater deficits within the more stable aptitude for language performance (D = -0.071, 95% CI = -0.133, -0.009; p = 0.026). There was no relationship between severity of prenatal cocaine exposure and the time-varying trajectory of language development. The observed cocaine-associated deficit was independent of multiple alternative suspected sources of variation in language performance, including other potential responses to prenatal cocaine exposure, such as child's intellectual functioning, and other birth and postnatal influences, including language stimulation in the home environment.

Developmental trajectories of cocaine-and-other-drug-exposed and non-cocaine-exposed children

Few data are available concerning the trajectories of mental and motor development across time for cocaine-exposed children compared with others. Findings are presented from individual group curve analyses of the mental and motor development measured by the Bayley Scales of Infant Development-II (BSID-II) on repeated visits from 3 through 36 months of a group of prenatally cocaine-and-other-drug-exposed children (n = 265) compared with those exposed to no drugs (n = 129) or no-cocaine-but-other-drugs (n = 66), including alcohol and/or tobacco. Across time, there was a general decline in motor performance but cocaine-exposed-infants showed a trend toward a greater decrease than children in the other two comparison groups. For mental performance, there was also a decline across age but only through 24 months and no differences in the trajectory of the cocaine-exposed group compared to the other two. And, across all assessment ages, cocaine-exposed-infants showed lower BSID-II mental performance compared to both non-drug and non-cocaine-exposed children. Results suggest that prenatally cocaine-exposed children show delayed developmental indices, particularly in their mental performance, but their trajectories across time are similar to those from impoverished, non-cocaine-exposed groups.

Influence of prenatal cocaine exposure on early language development: longitudinal findings from four months to three years of age

The influence of prenatal cocaine exposure on children's language functioning was evaluated longitudinally at six time points from 4 months to 3 years of age. The Miami Prenatal Cocaine Study prospectively enrolled 476 full-term African-American infants at birth, categorized as cocaine-exposed (n = 253) or non-cocaine-exposed (n = 223) by maternal self-report and bioassays (maternal/infant urine, meconium). The Bayley Scales of Infant Development, scored using the Kent Scoring Adaptation for language, was administered at 4, 8, 12, 18, and 24 months. The Clinical Evaluation of Language Fundamentals-Preschool was administered at 3 years. In longitudinal analyses using Generalized Estimating Equations, cocaine-exposed children had lower overall language skills than non-cocaine-exposed children (D = -0.151; 95% CI = -0.269, -0.033; p =.012). Longitudinal findings remained stable after evaluation of potential confounding influences including other prenatal substance exposures and sociodemographic factors. Preliminary evidence also indicated possible mediation through an intermediary effect involving cocaine-associated deficits in fetal growth.

Prenatal drug exposure and the conceptualization of long-term effects

This paper discusses several factors affecting the development of children prenatally exposed to drugs. In the "first generation" of research in this field a main factor model of disease formed the basis for a belief in the feasibility of detecting the direct pharmacological or teratogenic effects of drug exposure on long-term child development. However, the clustering of confounding variables has constituted a major problem in identifying these effects. In the last few years a "second generation" of research in this field has emerged, and investigators have moved beyond simple main-effect models. The importance of controlling for confounding variables has been underscored. However, prenatal substance exposure is still often studied within a teratology model where the main goal is the search for unique effects of a specific drug or substance. Based on this review it is suggested that an appropriate model for understanding the development of drug-exposed children cannot be based on a main-effect perspective. Rather, such a model must evolve from a contextual perspective, and it is suggested that a transactional model, where both potential risk factors and protective factors are considered, should replace the traditional teratology model in this field.

The intersection of stress, drug abuse and development

Use or abuse of licit and illicit substances is often associated with environmental stress. Current clinical evidence clearly demonstrates neurobehavioral, somatic growth and developmental deficits in children born to drug-using mothers. However, the effects of environmental stress and its interaction with prenatal drug exposure on a child's development is unknown. Studies in pregnant animals under controlled conditions show drug-induced long-term alterations in brain structures and functions of the offspring. These cytoarchitecture alterations in the brain are often associated with perturbations in neurotransmitter systems that are intimately involved in the regulation of the stress responses. Similar abnormalities have been observed in the brains of animals exposed to other adverse exogenous (e.g., environmental stress) and/or endogenous (e.g., glucocorticoids) experiences during early life. The goal of this article is to: (1) provide evidence and a perspective that common neural systems are influenced during development both by perinatal drug exposure and early stress exposure; and (2) identify gaps and encourage new research examining the effects of early stress and perinatal drug exposure, in animal models, that would elucidate how stress- and drug-induced perturbations in neural systems influence later vulnerability to abused drugs in adult offspring.

Longitudinal investigation of task persistence and sustained attention in children with prenatal cocaine exposure

The present study estimates the longitudinal effects of prenatal cocaine exposure on indicators of sustained attention processing at 3, 5 and 7 years of age in an urban sample of full-term African-American children (235 cocaine-exposed, 207 noncocaine-exposed). The sample was enrolled prospectively at birth, with documentation of prenatal drug exposure status through maternal interview, urine and meconium toxicology assays. Sustained attention was measured at age 3 years using a standardized measure of task persistence during a challenging task [G.A. Morgan, N.A. Busch-Rossnagel, C.A. Maslin-Cole and R.J. Harmon, Individualized Assessment of Mastery Motivation: Manual for 15-36 Month Old Children, 1992.], and at ages 5 and 7 years using omission error scores from computerized continuous performance tasks (CPT) [L. Greenberg, R. Leark, T. Dupuy, C. Corman, C. Kindschi, M. Cenedela, Test of Variables of Attention (T.O.V.A. and T.O.V.A.-A.), 22, Universal Attention Disorders, Los Alamitos, CA, 1996; C.K. Conners, Conners' Continuous Performance Test (CPT), second ed., Multi-Health Systems, Canada, 1995.]. Findings from longitudinal GLM/GEE analyses of the three measured time points support a stable influence of prenatal cocaine exposure on indicators of sustained attention, after controlling for prenatal exposure to alcohol, marijuana, tobacco and over 20 additional medical and social-demographic covariates drawn from potentially confounding influences assessed at birth and later assessment visits (D=0.21; 95% CI=0.04, 0.38; P=.017). This effect was not mediated by fetal growth or gestational age and remained highly stable with increasing levels of covariate control. Separately, using the age 7 data, a structural equations model (SEM) was constructed combining all available self-report and bioassay data to measure magnitude of cocaine exposure in relationship to attention task performance. Results indicated a gradient of influence, with each standard deviation increase in the level of prenatal cocaine exposure relating to a 16% standard deviation increase in omission error scores at age 7. Overall findings support a stable cocaine-specific effect on indicators of sustained attention processing during the early childhood years. Results are discussed within the context of neurobiological and behavioral research linking prenatal cocaine exposure to long-lasting disruption of the brain systems subserving arousal and attention.

Influence of prenatal cocaine exposure on full-term infant neurobehavioral functioning

This study investigated infant neurobehavioral functioning during the newborn period in 334 full-term, African American neonates (187 cocaine exposed, 147 non-cocaine exposed) enrolled prospectively at birth, with documentation of drug exposure status through maternal interview and urine and meconium toxicology assays. Infants were assessed using the Brazelton Neonatal Behavioral Assessment Scale (BNBAS) during the newborn period (0-6 postnatal days). Findings from multivariate profile analyses support a consistent, modest effect of prenatal cocaine exposure on neurobehavioral functioning in full-term neonates. All of the BNBAS cluster scores, with the exception of abnormal reflexes, were similarly affected, sharing a common slope (D=-0.14; 95% CI=-0.27, -0.003; P=.046) representing a -0.14 point difference between cocaine-exposed and non-cocaine-exposed infants after controlling for prenatal exposure to alcohol, tobacco, and marijuana (ATM); maternal age, education, employment, primigravida status, and prenatal care visits; and infant sex and postnatal age in days. Fetal growth was also related to neurobehavioral functioning and, in part, mediated the relationship between cocaine exposure and the BNBAS cluster scores. Cocaine exposure during each trimester similarly influenced infant neurobehavioral profiles, with cocaine-associated deficits most pronounced in infants with exposure in all three trimesters. Results from qualitative and quantitative urine and meconium bioassay indicators further substantiated these results. Findings, while significant, represent modest effect sizes in full-term infants.

Developmental outcomes and environmental correlates of very low birthweight, cocaine-exposed infants

Fetal cocaine exposure may have differentially adverse effects on developmental outcomes of very low birthweight (VLBW) infants. As part of a longitudinal study, 31 cocaine-positive very low birthweight infants, and age, race and socioeconomic status matched VLBW controls enrolled at birth were followed. Neonatal maternal-child interactions, concurrent maternal psychological characteristics and environmental factors conceptualized as important for child outcome were assessed as well as standard developmental outcomes at 3 years. In the neonatal period, cocaine-exposed VLBW infants who remained in maternal custody tended to be rated as less responsive and their mothers as less nurturing, less emotionally available and with a tendency to use more maladaptive coping mechanisms than nonexposed VLBW infants. At follow-up, cocaine-exposed VLBW children were delayed in cognitive, motor and language development compared to controls. Almost half (45%) of the exposed children scored in the range of mental retardation compared to 16% of the comparison VLBW children. The persistent cognitive, motor and language delays of the cocaine-exposed VLBW children, combined with the poorer behavioral interactions of cocaine-using women with their infants in the neonatal period, indicate a need for increased developmental surveillance of cocaine-exposed VLBW infants with a focus on maternal drug treatment and parenting interventions.

Adverse effects of fetal cocaine exposure on neonatal auditory information processing

BACKGROUND

Studies with animals have shown that in utero exposure to cocaine interferes with fetal brain development by disrupting the processes of neuronal proliferation, differentiation, and migration, often leading to subsequent neurobehavioral deficits. However, studies with humans have produced inconsistent findings. Although neurobehavioral abnormalities have been observed among cocaine-exposed infants in several studies and in some cases dose-response effects have been found, the specific neurobehaviors affected vary from one study to the next. Researchers studying the effects of fetal cocaine-exposure are faced with many difficult challenges. For example, women who use cocaine typically use other substances in addition to cocaine, many of the methods available for identifying cocaine-exposed neonates are not reliable, and the available methods for assessing cocaine-exposed newborns may not be sufficiently sensitive to detect the subtle effects of cocaine on the developing central nervous system. Despite these difficulties, there is a growing body of research that suggests that fetal cocaine exposure is associated with subsequent language deficits among children exposed in utero. However, it is virtually impossible to disentangle the effects of the impoverished environments in which these children are often raised from the effect, if any, of fetal cocaine exposure. To determine the effects of fetal cocaine exposure independent of postnatal environmental effects, cocaine-exposed neonates would ideally be tested within the first few weeks of birth, and to identify early risks for subsequent language delay, well-researched auditory information processing measures could be used.

OBJECTIVE

The purpose of the present study was to assess the effects of fetal cocaine exposure on neonatal auditory information processing ability. To overcome limitations of some previous studies on the neuroteratogenic effects of cocaine, such as unreliable subject identification techniques, inadequate control over confounding variables, and questionable measures of central nervous system integrity, a valid measure of auditory information processing was used in a rigorous, case-control design.

METHOD

Newborn information processing was assessed using habituation and recovery of head-turning toward an auditory stimulus across the 3 phases of the procedure: familiarization, novelty, and dishabituation. During the familiarization phase, the infant orients and habituates to a repeated word; during the novelty phase, the infant recovers head-turning to a novel word and subsequently habituates to this word; and during the dishabituation phase the infant displays renewed head-turning to the return of the original stimulus. Testing takes approximately 20 minutes. This procedure has been shown previously to discriminate among infants at high-, moderate-, and low-risk for subsequent developmental delay. Twenty-five cocaine-exposed and 25 nonexposed control neonates, identified by meconium analysis, urine analysis, and/or maternal self-report, were tested on the auditory information processing procedure. The majority of infants were tested within the first few days of birth. Cocaine-exposed and control neonates were matched on birth weight, gestational age, Apgar scores, age at testing, and socioeconomic status as reflected by household income. Mothers were matched on age, weight gain, cigarette smoking, and alcohol consumption.

RESULTS

Fetal cocaine exposure was associated with impaired auditory information processing. Both cocaine-exposed and nonexposed control neonates oriented to the familiarization stimulus, but cocaine-exposed neonates displayed impaired habituation. Moreover, cocaine-exposed neonates did not recover or habituate to the novel stimulus or dishabituate to the return of the familiarization stimulus. (ABSTRACT TRUNCATED)

NEONATAL VISUAL INFORMATION PROCESSING IN COCAINE-EXPOSED AND NON-EXPOSED INFANTS

This study investigated early neonatal visual preferences in 267 poly drug exposed neonates (131 cocaine-exposed and 136 non-cocaine exposed) whose drug exposure was documented through interviews and urine and meconium drug screens. Infants were given four visual recognition memory tasks comparing looking time to familiarized stimuli of lattices and rectangular shapes to novel stimuli of a schematic face and curved hourglass and bull's eye forms. Cocaine-exposed infants performed more poorly, after consideration of confounding factors, with a relationship of severity of cocaine exposure to lower novelty score found for both self-report and biologic measures of exposure, Findings support theories which link prenatal cocaine exposure to deficits in information processing entailing attentional and arousal organizational systems. Neonatal visual discrimination and attention tasks should be further explored as potentially sensitive behavioral indicators of teratologic effects.

Incidence of passive exposure to crack/cocaine and clinical findings in infants seen in an outpatient service

OBJECTIVES

Passive exposure to crack/cocaine and the associated clinical symptoms may present a significant health risk to very young infants and children. This study was designed to determine the incidence of cocaine exposure, presumed to be passive, in ill infants younger than 1 year of age, using a threshold of detection for cocaine and/or its major metabolite, benzoylecognine (BE), that is lower than the current National Institute on Drug Abuse standard. The study also investigates the morbidity associated with passive cocaine exposure in this population.

METHODS

We prospectively obtained 124 samples of urine from 122 children younger than 1 year of age for routine clinical indications from the emergency department at Yale-New Haven Hospital. Samples were analyzed by radioimmunoassay (RIA) for cocaine, with cross-reactivity for BE. The presence of BE in a portion of the RIA-positive samples also was detected in additional analyses by enzyme-multiplied immunoassay technique or by gas chromatography-mass spectrometry. A chart review was conducted on all 122 patients by reviewers blind to the urine toxicology results. Presenting complaints, symptoms, vital signs, and diagnosis were obtained for all visits before the first birthday. Birth history, including maternal drug history and birth weight, demographics, and number of medical visits in the first year, were recorded as well.

RESULTS

Of the 124 samples, 45 (36.3%) were positive (>/=50 ng/mL of BE equivalents) for cocaine and/or cocaine metabolite by RIA testing. The positive results, determined by RIA, were highly correlated with patients who had lower and upper respiratory symptoms and sought medical care more often.

CONCLUSIONS

The incidence of unsuspected, passive cocaine exposure in ill infants seeking medical care primarily through an emergency service may be as high as 1 in 3 to 6 infants from our predominantly inner city population. Current immunoassay methods, specific for BE, and their routine threshold of detection (200 to 300 ng/mL) may not be sensitive enough to detect cocaine and BE in the urine samples of children younger than 1 year of age who are exposed passively. The development of upper and lower respiratory symptoms is correlated significantly with positive urine results in this study. The increased use of health care resources correlated with passive cocaine exposure in this sample may serve as an indirect marker for the increased medical needs of these infants.

Child development: vulnerability and resilience

Many of the challenges facing children now are a function of changing times, including increase in urbanization, political violence, changing family forms, and in some areas decreased supplies of adequate food. This review focuses particularly on those changes in which children are the victims and which induce new threats for them, rather than on problems such as child disability or mental illness. The outcome variables of interest in this paper are dimensions of children's psychosocial development, including cognitive development, psychological adjustment and aggression, whereas the companion paper in this issue (Caldwell P., Child survival: vulnerability and resilience in adversity in the European past and the contemporary Third World, Soc. Sci. Med.) [1] focuses on physical aspects of children's development. The risks that are hurdles in the process of development of a young child begin from conception and carry on into later life. To address them all would be impossible; thus, in order to do justice to the issues at hand, we have chosen those risks that, in our view, are important in a child's psychosocial development in developing countries. This paper will thus provide a discussion of the concepts of risk and resilience, then apply these concepts to the analysis of three examples of risk faced by children today: nutritional threats (e.g. malnutrition due to decline in breastfeeding); family dynamics and types of family forms (e.g. child fostering and non-traditional families); and experiences of violence (domestic or political). In each case, the same four questions will be addressed: what are the consequences of the risk factor for children, what are the etiologies and conditions of risk, are there any children who seem to cope with the risk factor successfully and what are some of the protective factors, and what interventions or programs would help support these children?