Prenatal stress alters brain biogenic amine levels in primates

Stress and the Role of the Gut-Brain Axis in the Pathogenesis of Schizophrenia: A Literature Review

Schizophrenia is a severe neuropsychiatric disorder, and its etiology remains largely unknown. Environmental factors have been reported to play roles in the pathogenesis of schizophrenia, and one of the major environmental factors identified for this disorder is psychosocial stress. Several studies have suggested that stressful life events, as well as the chronic social stress associated with city life, may lead to the development of schizophrenia. The other factor is the gut–brain axis. The composition of the gut microbiome and alterations thereof may affect the brain and may lead to schizophrenia. The main interest of this review article is in overviewing the major recent findings on the effects of stress and the gut–brain axis, as well as their possible bidirectional effects, in the pathogenesis of schizophrenia.

A randomized, controlled pilot study of cognitive analytic therapy for stressed pregnant women with underlying anxiety and depression in a routine health service setting

A pilot study of cognitive analytic therapy (CAT) plus treatment as usual (TAU), versus TAU in stressed pregnant women with anxiety and depression, was undertaken as an essential preliminary to any definitive, randomized controlled trial (RCT). The trial was pragmatic, multicentre, parallel, randomized, controlled, and unblinded. Participants were pregnant women screened using the Hospital Anxiety and Depression Scale (HADS). Treatment was standard 16-session CAT. Main outcome measures were Spielberger State/Trait Anxiety Inventory (STAI) (primary outcome measure) at 24 weeks after randomization, therefore 1 month after therapy for the CAT group; HADS; Clinical Outcomes in Routine Evaluation-Outcome Measure (CORE-OM); Edinburgh Postnatal Depression Scale (EPDS); 36-item Short Form Health Survey (SF-36); and a brief Experiences of Therapy Questionnaire, completed at baseline and on average at 12, 24, 40, and 82 weeks after randomization. Thirty-nine patients (CAT + TAU, n = 20; TAU, n = 19) were randomized with mean baseline STAI State scores of 50.8 (SD 11.4) and 51.1 (SD 13.3), respectively. Sixteen patients had missing primary outcome data leaving 23 (n = 11 and n = 12) patients for analysis. The mean STAI State score was 38.5 (SD 13.8) and 45.7 (SD 16.8) in the CAT and TAU groups respectively at 24 weeks after randomization, with an adjusted difference in means of 7.2 (95% confidence interval [CI]: -7.9 to 20.6). No safety issues were reported. Patient retention for the CAT group was high (18/20; 90% of patients completed therapy). Ten out of 11 (90.9%) respondents 'agreed' or 'strongly agreed' that having CAT had been 'very helpful'. The study demonstrated the feasibility of safely undertaking CAT in this setting. Outcomes showed positive trends compatible with a clinically important effect, although statistically definitive conclusions cannot be drawn in such a study.

Biobehavioral consequences of prenatal exposure to a matrilineal overthrow and relocation in captive infant rhesus (Macaca mulatta) monkeys

There is a general consensus that perinatal experiences help to shape infant behavior; however, relatively little is known about the effects of prenatal experience on postnatal phenotype in non-human primates. The current study sought to take advantage of a naturally occurring incident in a captive population of rhesus monkeys. Following a matrilineal overthrow in an outdoor field cage, pregnant female rhesus macaques were relocated from outdoor to indoor housing. Using data collected from the California National Primate Research Center's Biobehavioral Assessment Program, we assessed infants born to mothers that were in their first or second trimester of pregnancy during the overthrow and relocation, and compared their data with that of animals from two control groups born in the same year: indoor mother raised infants and field cage reared infants. Our results suggest that the experience of an overthrow and relocation during the first trimester elevated postnatal emotional responsiveness, while the same experience in the second trimester resulted in modified HPA axis regulation, elevated glucocorticoid output following maternal separation, and lower hematocrit levels compared to control groups. These data add to a growing body of literature that prenatal experiences represent a significant contribution to postnatal phenotypic variability. Findings such as ours have implications for studies in captive management and the management of captive rhesus monkey populations. Am. J. Primatol. 78:895-903, 2016. © 2016 Wiley Periodicals, Inc.

Psychological Stress, Immunity, and the Effects on Indigenous Microflora

Psychological stress is an intrinsic part of life that affects all organs of the body through direct nervous system innervation and the release of neuroendocrine hormones. The field of PsychoNeuroImmunology (PNI) has clearly demonstrated that the physiological response to psychological stressors can dramatically impact the functioning of the immune system, thus identifying one way in which susceptibility to or severity of diseases are exacerbated during stressful periods. This chapter describes research at the interface between the fields of PNI and Microbial Endocrinology to demonstrate that natural barrier defenses, such as those provided by the commensal microflora, can be disrupted by exposure to psychological stressors. These stress effects are evident in the development of the intestinal microflora in animals born from stressful pregnancy conditions, and in older animals with fully developed microbial populations. Moreover, data are presented demonstrating that exposure to different types of stressors results in the translocation of microflora from cutaneous and mucosal surfaces into regional lymph nodes. When considered together, a scenario emerges in which psychological stressors induce a neuroendocrine response that has the potential to directly or indirectly affect commensal microflora populations, the integrity of barrier defenses, and the internalization of microbes. Finally, a hypothesis is put forth in which stressor-induced alterations of the microflora contribute to the observed stressor-induced increases in inflammatory markers in the absence of overt infection.

Stress In Utero: Prenatal Programming of Brain Plasticity and Cognition

Animal studies confirm earlier anecdotal observations in humans to indicate that early life experience has a profound impact on adult behavior, years after the original experience has vanished. These studies also highlight the role of early life adversaries in the shaping of a disordered brain. Evidence is accumulating to indicate that the epigenome, through which the environment regulates gene expression, is responsible for long-lasting effects of stress during pregnancy on brain and behavior. A possible differential effect of the environment on the epigenome may underlie the observation that only a small fraction of a population with similar genetic background deteriorates into mental disorders. Considerable progress has been made in the untangling of the epigenetic mechanisms that regulate emotional brain development. The present review focuses on the lasting effects of prenatal stress on brain plasticity and cognitive functions in human and rodent models. Although human studies stress the significance of early life experience in functional maturation, they lack the rigor inherent in controlled animal experiments. Furthermore, the analysis of molecular and cellular mechanisms affected by prenatal stress is possible only in experimental animals. The present review attempts to link human and animal studies while proposing molecular mechanisms that interfere with functional brain development.

The influence of early maternal care on perceptual attentional set shifting and stress reactivity in adult rats

Stress influences a wide variety of outcomes including cognitive processing. In the rat, early life maternal care can influence developing offspring to affect both stress reactivity and cognitive processes in adulthood. The current study assessed if variations in early life maternal care can influence cognitive performance on a task, the ability to switch cognitive sets, dependent on the medial prefrontal cortex. Early in life, offspring was reared under High or Low maternal Licking conditions. As adults, they were trained daily and then tested on an attentional set-shifting task (ASST), which targets cognitive flexibility in rodents. Stress-sensitive behavioral and neural markers were assayed before and after the ASST. High and Low Licking offspring performed equally well on the ASST despite initial, but not later, differences in stress axis functioning. These results suggest that early life maternal care does not impact the accuracy of attentional set-shifting in rats. These findings may be of particular importance for those interested in the relationship between early life experience and adult cognitive function.

Is Heart Rate Variability Related to Season of Birth?

BACKGROUND

Season of birth (SOB) has been found to be related to cardiovascular mortality, but the mechanisms are unclear. It is suggested that birth in winter is a protective factor for the circulatory system, and this should be able to be observed using heart rate variability (HRV) measurements. The phenomenon may have a sex difference and is likely to be modulated by climatic factors. This study focused on this problem and investigates healthy school-age children to minimize confounding factors.

HYPOTHESIS

Birth in winter is protective to cardiovascular system via autonomic modulation. There is a gender difference in the relationship between SOB and autonomic activity. Climatic factors are the cause of SOB effects on autonomic system.

METHODS

A total of 381 healthy school-age children were recruited for this study. Their HRV profiles were measured once and climatic information related to their month of birth was gathered. The HRV profiles of the 2 sexes and 4 seasons of birth were compared. Correlation and regression analysis were performed to clarify the relationship between climatic factors and the HRV results.

RESULTS

Boys born in winter have higher high-frequency power (HF) but a lower ratio of low-frequency power to high-frequency power (LF/HF) than do males born in other seasons. This result is not found for girls. Age and the temperature of the SOB are predictive factors for HF among boys. The humidity of SOB is a predictive factor for normalized low-frequency power (LF%) and LF/HF among girls.

CONCLUSIONS

Season of birth is related to both parasympathetic and sympathetic activity among school-age children, especially boys. Temperature and humidity are potential causes of this SOB phenomenon.

Models of stress in nonhuman primates and their relevance for human psychopathology and endocrine dysfunction

Stressful life events have been linked to the onset of severe psychopathology and endocrine dysfunction in many patients. Moreover, vulnerability to the later development of such disorders can be increased by stress or adversity during development (e.g., childhood neglect, abuse, or trauma). This review discusses the methodological features and results of various models of stress in nonhuman primates in the context of their potential relevance for human psychopathology and endocrine dysfunction, particularly mood disorders and dysregulation of the hypothalamic-pituitary-adrenocortical (HPA) system. Such models have typically examined the effects of stress on the animals' behavior, endocrine function (primarily the HPA and hypothalamic-pituitary-gonadal systems), and, in some cases, immune status. Manipulations such as relocation and/or removal of an animal from its current social group or, alternatively, formation of a new social group can have adverse effects on all of these outcome measures that may be either transient or more persistent depending on the species, sex, and other experimental conditions. Social primates may also experience significant stress associated with their rank in the group's dominance hierarchy. Finally, stress during prenatal development or during the early postnatal period may have long-lasting neurobiological and endocrine effects that manifest in an altered ability to cope behaviorally and physiologically with later challenges. Whereas early exposure to severe stress usually results in deficient coping abilities, certain kinds of milder stressors can promote subsequent resilience in the animal. We conclude that studies of stress in nonhuman primates can model many features of stress exposure in human populations and that such studies can play a valuable role in helping to elucidate the mechanisms underlying the role of stress in human psychopathology and endocrine dysfunction.

Is fetal pain a real evidence?

Due to the progress in fetal surgery, it is important to acquire data about fetal pain.

MATERIAL AND METHODS

We performed a Medline research from 1995, matching the following key words: "pain" and "fetus", with the following: "subplate", "thalamocortical", "myelination", "analgesia", "anesthesia", "brain", "behavioral states", "substance p". We focused on: (a) fetal development of nociceptive pathways; (b) fetal electrophysiological, endocrinological and behavioral reactions to stimuli and pain.

RESULTS

We retrieved 217 papers of which 157 were highly informative; some reported similar data or were only case-reports, and were not quoted. Most endocrinological, behavioral and electrophysiological studies of fetal pain are performed in the third trimester, and they seem to agree that the fetus in the 3rd trimester can experience pain. But the presence of fetal pain in the 2nd trimester is less evident. In favor of a 2nd trimester perception of pain is the early development of spino-thalamic pathways (approximately from the 20th week), and the connections of the thalamus with the subplate (approximately from the 23rd week). Against this possibility, some authors report the immaturity of the cortex with the consequent lack of awareness, and the almost continuous state of sleep of the fetus.

CONCLUSIONS

Most studies disclose the possibility of fetal pain in the third trimester of gestation. This evidence becomes weaker before this date, though we cannot exclude its increasing presence since the beginning of the second half of the gestation.

Potential programming of dopaminergic circuits by early life stress

Stress and high levels of glucocorticoids during pre- and early postnatal life seem to alter developmental programs that assure dopaminergic transmission in the mesolimbic, mesocortical, and nigrostriatal systems. The induced changes are likely to be determined by the ontogenetic state of development of these brain regions at the time of stress exposure and their stability is associated with increased lifetime susceptibility to psychiatric disorders, including drug addiction. This article is intended to serve as a starting point for future studies aimed at the attenuation or reversal of the effects of adverse early life events on dopamine-regulated behaviors.

Interactions of lifetime lead exposure and stress: behavioral, neurochemical and HPA axis effects

Lead (Pb) and stress co-occur as risk factors, share biological substrates and produce common adverse effects. We previously found that prenatal restraint stress (PS) or offspring stress (OS) could enhance maternal Pb-induced behavioral, brain neurotransmitter level and HPA axis changes. The current study examined how lifetime Pb exposure, consistent with human environmental exposure, interacts with stress. Dams were exposed to Pb beginning 2 mos prior to breeding (0, 50 or 150ppm in drinking water), PS on gestational days 16 and 17, or the combination. Offspring continued on the same Pb exposure as the dam. A subset of Pb+PS offspring also received 3 additional stress challenges (OS), yielding 9 exposure groups/gender: 0-NS, 0-PS, 0-OS, 50-NS, 50-PS, 50-OS, 150-NS, 150-PS and 150-OS. As with maternal Pb (Virgolini et al., 2008a), lifetime Pb and stress influenced Fixed Interval (FI) behavior primarily in females. Relative to 0-NS control, reductions in postreinforcement pause (PRP) times were seen only with combined Pb+PS (50-PS, 50-OS, 150-PS). Stress increased FI response rates when Pb alone was without effect (150-PS, 150-OS), but gradually mitigated rate increases produced by Pb alone (50-PS, 50-OS), effects that appear to be due primarily to PS, as they were of comparable magnitude in PS and OS groups. Individual subject data suggest that enhanced Pb and PS effects reflect increasing numbers of subjects shifting to the high end of the normal range of FI performance values, consistent with a dose-response type of Pb+stress additivity. Consistent with reports of cortico-striatal mediation of both interval timing (PRP) and FI rates, principal component analyses suggested potential mediation via altered frontal cortex norepinephrine, reduced nucleus accumbens dopaminergic control and enhanced striatal monoamine control. Altered FI performance, whether occurring through changes in response rate, PRP, or both, represent behavioral inefficiency and potentially sub-optimal or even dysfunctional resource/energy use.

Maternal anxiety is related to infant neurological condition, paternal anxiety is not

BACKGROUND

Parental anxiety and stress may have consequences for infant neurological development.

AIMS

To study relationships between parental anxiety or well-being and infant neurological development approximately one year after birth.

STUDY DESIGN

Longitudinal study of a birth cohort of infants born to subfertile couples.

SUBJECTS

206 parent-child dyads.

OUTCOME MEASURES

Infant neurology was assessed with the Touwen Infant Neurological Examination (TINE) at 10 months and a developmental questionnaire at 12 months. Parental measures included trait anxiety measured by the State-Trait Anxiety Inventory (STAI) and well-being measured by the General Health Questionnaire (GHQ).

RESULTS

Maternal trait anxiety was associated with a less optimal neurological condition (r(s)= -0.19, p<0.01) of the infant. This association persisted after adjusting for confounders and results were confirmed by the outcome of the developmental questionnaire. Paternal trait anxiety and parental well-being were not related to the infant's neurodevelopmental outcome.

CONCLUSIONS

Infants of mothers with high trait anxiety have an increased vulnerability to develop a non-optimal nervous system. The association may be mediated in part by early programming of monoaminergic systems. Future research should include an exploration of specific windows of vulnerability to maternal anxiety.

Neonatal exposure to fenoterol and betamethasone: effects on the behavioral development in the rat

We investigated longitudinally the behavioral development in the rat following exposure to beta-agonists and glucocorticoids (GC). Neonatal rats received either 1 mg/kg fenoterol (FEN), 0.3 mg/kg betamethasone (BET), or saline (SAL). Weanling and young adult rats were tested in the open field, the elevated-plus maze, and the water maze. FEN-treated as well as BET-treated animals displayed increased anxiety-like behavior. Furthermore, BET-treated adult animals showed a reduced locomotor activity. An enhanced 24-h memory in the water maze in both treatment groups may be facilitated by emotional arousal due to the increased anxiety levels. The possible neurobiological underpinnings are discussed in detail.

Fetal Magnetoencephalography - Achievements and Challenges in the Study of Prenatal and Early Postnatal Brain Responses: A Review

Fetal magnetoencephalography (fMEG) is the only non-invasive method for investigating evoked brain responses and spontaneous brain activity generated by the fetus in utero. Fetal auditory as well as visual evoked fields have been successfully recorded in basic stimulus-response studies. Moreover, paradigms investigating precursors for cognitive development, such as habituation and mismatch response have been applied successfully with fMEG. These and other studies have shown that the prenatal stage of life could be an important indicator for later cognitive development. This review addresses the achievements of fMEG and constructively discusses its challenges. It concludes with proposals for future studies as well as with designated new applications. Fetal MEG is a promising, and to date it is the only non-invasive approach for the prenatal assessment of precursors for cognitive development. Future fMEG studies might even enable the diagnosis of developmental delays. Furthermore, fMEG could be critical for the implementation and evaluation of fetal intervention programs in at-risk populations.

Effects of elevated circulating cortisol concentrations on maternal behavior in common marmoset monkeys (Callithrix jacchus)

Both acute and chronic stress can impair maternal behavior and increase rates of infant abuse in several species. The mechanisms inducing these effects are unknown, but experimental manipulation of circulating corticosterone levels alters maternal behavior in rats, and circulating or excreted cortisol concentrations have been found to correlate either positively or negatively with maternal behavior in humans and nonhuman primates. In this study, therefore, we experimentally tested the hypothesis that both acute and chronic treatment with exogenous glucocorticoids would alter maternal behavior in a primate, the common marmoset (Callithrix jacchus). Multiparous females, approximately 3-5 weeks postpartum, received daily injections of either cortisol (hydrocortisone sodium succinate and hydrocortisone acetate; N=7) or vehicle (N=7) for 8 days, and maternal behavior was characterized under baseline conditions as well as during exposure to a noise stressor. Cortisol treatment successfully elevated both morning and afternoon plasma cortisol concentrations and suppressed circulating levels of adrenocorticotropic hormone. In home-cage observations, cortisol-treated females carried their infants significantly less than control mothers, and in noise-stressor tests, several hours after the first cortisol or vehicle treatment, cortisol-treated mothers inspected their infants significantly more often than controls. Aggression towards infants was infrequent and mild, and did not differ between treatment groups. These findings provide the first experimental evidence that cortisol elevations can alter maternal behavior in primates. As these effects were limited in scope, however, they suggest that other stress-responsive hormones or neuropeptides may additionally play a role in mediating the effects of stress on maternal behavior.

Contributions of non-human primates to neuroscience research

Non-human primates have a small but important role in basic and translational biomedical research, owing to similarities with human beings in physiology, cognitive capabilities, neuroanatomy, social complexity, reproduction, and development. Although non-human primates have contributed to many areas of biomedical research, we review here their unique contributions to work in neuroscience, and focus on four domains: Alzheimer's disease, neuroAIDS, Parkinson's disease, and stress. Our discussion includes, for example, the role of non-human primates in development of new treatments (eg, stem cells, gene transfer) before phase I clinical trials in patients; basic research on disease pathogenesis; and understanding neurobehavioural outcomes resulting from genotype-environment interactions.

Foster mother care but not prenatal morphine exposure enhances cocaine self-administration in young adult male and female rats

The present study was designed to investigate cocaine self-administration in adult male and female rats exposed prenatally to morphine. Pregnant dams were injected two times a day with either saline, analgesic doses of morphine or no drug at all (controls) on gestation Days 11-18. One day after birth, litters were cross-fostered such that control dams were paired with one another and their litters were crossed; saline- and morphine-treated dams were paired and half of each saline litter was crossed with half of each morphine litter. Thus, each mother (control, saline, and morphine) raised half of her own and half of the adopted litter. At the age of 60 days, males and females were trained first to lever press for sucrose pellets and then for cocaine. Once the lever-pressing behavior was learned and baseline level of this activity was established, animals received a cocaine (.5 mg/kg per infusion) reward for each correct response on the active lever during the next 9-day session. The data demonstrate that adult control, saline- and morphine-exposed male rats self-administer cocaine at a similar rate independent of their prenatal treatment. Adult female rats self-administer cocaine at a higher rate than male rats. Further, saline- and morphine-exposed females in diestrus self-administer more than females in proestrus phase of the estrous cycle, while control females show no such differences. In addition, fostering induces increase in cocaine self-administration in all groups of male rats regardless of prenatal drug exposure. In females, the only fostering-induced increase is in prenatally saline-exposed female rats raised by morphine-treated foster mother. Thus, our results suggest that the prenatal drug exposure does not induce changes in lever-pressing behavior for cocaine reward in adult male and female rats, but it sensitizes the animals to postnatal stimuli such as gonadal hormones and/or rearing conditions that result in increased drug self-administration.

Cerebrospinal fluid monoamine metabolite levels in human newborn infants born in winter differ from those born in summer

An earlier study has shown significant differences in the CSF monoamine metabolite levels in adults born during different seasons of the year. We study here the relationship between season of birth and CSF monoamine metabolite levels in 283 newborn febrile infants without neurological abnormalities, with an age distribution ranging from birth to about 3 months, adjusting for the confounding variables age and time at lumbar puncture, weight at birth, estimated gestational age at birth, gender, race, and medicaid status. Each of the three metabolite levels as well as their ratios HVA/5-HIAA and 5-HIAA/MHPG showed significant month-of-birth variations, but not the ratio HVA/MHPG. For HVA and MHPG levels, the maximum was obtained around the winter birth months November-December, whereas for 5-HIAA level, the maximum was obtained around the summer birth months June-July. The correlations between HVA and 5-HIAA were, in general, significantly positive within the different birth seasons and races. Among summer-born Caucasian infants, MHPG was significantly positively correlated with HVA and with 5-HIAA, whereas among winter-born Black infants, MHPG was significantly positively correlated with HVA. Season of birth is an unspecific environmental factor that may be proxy for several possible seasonally varying environmental circumstances such as the length of photoperiod, temperature, infections, nutrition, stress and lifestyle. Studies relating season of birth to monoaminergic turnover at different stages of life may yield important clues about the gestational and perinatal origins of neurodevelopment.

Prenatal influences on brain dopamine and their relevance to the rising incidence of autism

The incidence of autism has risen 10-fold since the early 1980s, with most of this rise not explainable by changing diagnostic criteria. The rise in autism is paradoxical in that autism is considered to be one of the most genetically determined of the major neurodevelopmental disorders and should accordingly either be stable or even declining. Because a variety of epigenetic influences, particularly those occurring during the prenatal period, can override or masquerade as genetic influences, these should be considered as prime contributors to the recent increase of autism. Prenatal influences on dopamine activity are especially well-documented, including the effects of maternal psychosocial stress, maternal fever, maternal genetic and hormonal status, use of certain medications, urban birth, and fetal hypoxia. All of these factors have been implicated in the genesis of autism, which is characterized by a "hyperdopaminergic" state based on evidence from monkey and human behavioral studies, pharmacological studies in humans, and a left-hemispheric predominance of both dopamine and autistic-like symptoms. Chronically high maternal levels of dopamine caused by the pressures of increasingly urbanized societies and by changing maternal demographics such as increased workforce participation, educational achievement level, and age at first birth, may be especially significant epigenetic contributors to the recent autism rise.

Mid- to late gestational morphine exposure does not alter the rewarding properties of morphine in adult male rats

Prenatal exposure to drugs of abuse often leads to physiological and neurobiological abnormalities including decreased brain and body weight, cognitive deficits and behavioral alterations. A handful of studies showed increased vulnerability to drug abuse in prenatally drug-exposed offspring. Our work also demonstrated that prenatal exposure to analgesic doses of morphine during gestation days 11-18 increases mu-opioid receptor density in the nucleus accumbens and central amygdala of adult male rats. Both the nucleus accumbens and central amygdala play important roles in modulating drug-induced reward via the mesolimbic dopaminergic system. Therefore, two types of behavioral paradigms were used to test the hypothesis that the same prenatal morphine exposure would enhance the rewarding effects of morphine, making drug-exposed offspring more vulnerable to abuse this drug in adulthood. All experiments were performed with adult male offspring of saline-injected, morphine-injected or non-injected (control) dams. (1) The unbiased conditioned place preference (CPP) paradigm was used to investigate whether prenatal morphine exposure sensitizes adult male rats to non-contingent morphine reward. These adult animals were conditioned with 0.1, 0.3, 1, 3 or 5 mg/kg morphine. All control, prenatally saline- and morphine-exposed male rats preferred the morphine-paired compartment relative to the saline-paired compartment. However, the magnitude of morphine CPP in adult male rats was not dependent on the conditioning dose of morphine or prenatal morphine exposure. (2) Intravenous morphine self-administration was used to assess the behavioral response to contingent morphine reward. Each rat self-administered one of four doses of morphine (0.3, 1, 2 or 3 mg/kg/infusion). Morphine self-administration was not altered in prenatally morphine-exposed adult male offspring. Control males self-administered significantly less morphine at the lowest dose of morphine than both prenatally saline- and morphine-exposed males. Although our data show that prenatal exposure to an analgesic dose of morphine during the time of opioid receptor appearance does not enhance morphine CPP or self-administration, they do not exclude the possibility that this prenatal morphine exposure enhances the rewarding properties of other drugs of abuse.

Ontogeny of the human central nervous system: what is happening when?

The present paper reviews current data on the structural development of the human nervous system. Focus is on the timing of ontogenetic events in the telencephalon. Neuronal proliferation and migration especially occur during the first half of gestation; the second half of gestation is the period of the existence of the functionally important transient structure 'subplate' and the major period of glial cell proliferation and programmed cell death. Axon and dendrite sprouting and synapse formation bloom during the last trimester of gestation and the first postnatal year. Major part of telencephalic myelination occurs during the first year after birth. Many developmental processes, such as myelination, synapse formation and synapse elimination continue throughout childhood and adolescence. Evidence is emerging that the peak of synapse elimination occurs between puberty and the onset of adulthood. Neurotransmitter systems are present from early foetal life onwards and their pre- and perinatal development is characterized by periods of transient overexpression. The latter is for instance true for the acetylcholinergic, catecholaminergic and glutamate systems. Thus, the development of the human brain is characterized by a protracted, neatly orchestrated chain of specific ontogenetic events. The continuous changes of the nervous system have consequences for vulnerability to adverse conditions, for diagnostics and for physiotherapeutical intervention.

Antenatal maternal anxiety and stress and the neurobehavioural development of the fetus and child: links and possible mechanisms. A review

A direct link between antenatal maternal mood and fetal behaviour, as observed by ultrasound from 27 to 28 weeks of gestation onwards, is well established. Moreover, 14 independent prospective studies have shown a link between antenatal maternal anxiety/stress and cognitive, behavioural, and emotional problems in the child. This link generally persisted after controlling for post-natal maternal mood and other relevant confounders in the pre- and post-natal periods. Although some inconsistencies remain, the results in general support a fetal programming hypothesis. Several gestational ages have been reported to be vulnerable to the long-term effects of antenatal anxiety/stress and different mechanisms are likely to operate at different stages. Possible underlying mechanisms are just starting to be explored. Cortisol appears to cross the placenta and thus may affect the fetus and disturb ongoing developmental processes. The development of the HPA-axis, limbic system, and the prefrontal cortex are likely to be affected by antenatal maternal stress and anxiety. The magnitude of the long-term effects of antenatal maternal anxiety/stress on the child is substantial. Programs to reduce maternal stress in pregnancy are therefore warranted.

RETRACTED: Maternal adversity, glucocorticoids and programming of neuroendocrine function and behaviour

The fetus may be exposed to increased endogenous glucocorticoid or synthetic glucocorticoid in late gestation. Approximately 7% of pregnant women in Europe and North America are treated with synthetic glucocorticoid to promote lung maturation in fetuses at risk of preterm delivery. Very little is known about the mechanisms by which synthetic glucocorticoid or prenatal stress influence neurodevelopment in the human, or whether specific time windows of increased sensitivity exist. Glucocorticoids are essential for many aspects of normal brain development, but exposure of the fetal brain to excess glucocorticoid can have life-long effects on neuroendocrine function and behaviour. Both endogenous glucocorticoid and synthetic glucocorticoid exposure have a number of rapid effects in the fetal brain, including modification of neurotransmitter systems and transcriptional machinery. Such fetal exposure permanently alters hypothalamo-pituitary-adrenal (HPA) function in prepubertal, postpubertal and aging offspring, in a sex-dependent manner. Prenatal glucocorticoid manipulation also leads to modification of behaviour, brain and organ morphology, as well as altered regulation of other endocrine systems. Permanent changes in endocrine function will impact on health, since elevated cumulative exposure to endogenous glucocorticoid is linked to the premature onset of pathologies associated with aging.

Are maternal smoking and stress during pregnancy related to ADHD symptoms in children?

BACKGROUND

There are some indications that maternal lifestyle during pregnancy (smoking and stress) contributes to symptoms of ADHD in children. We prospectively studied whether prenatal exposure to maternal smoking and/or stress is associated with ADHD symptoms and diagnostic criteria (according to DSM-IV) in 7-year-olds.

METHODS

Nulliparous Scandinavian women were consecutively recruited at their first prenatal health care visit and assessments of smoking and stress were collected at gestational weeks 10, 12, 20, 28, 32, and 36. Children were followed up at 7 years old. We obtained full data for 72% of the sample: ADHD symptoms were rated by 74% of mothers (n=290) and 96% of eligible teachers (n=208). Attrition analyses showed no differences on key variables between participants and non-participants at follow-up.

RESULTS

Results of multiple regression analyses showed prenatal exposure to smoking (beta=.16, p<.01) and stress (beta=.18, p<.01) were independently associated with later symptoms of ADHD. Results of logistic regression analyses showed that fulfillment of the diagnostic criteria for ADHD was related to exposure to prenatal stress (beta=.68, p<.01) especially in boys. The results were not confounded by sociodemographic factors or birth outcomes.

CONCLUSIONS

This study provides evidence that prenatal exposure to stress and smoking is independently associated with later symptoms of ADHD in human children, particularly for boys. Because stress and smoking are relatively common during pregnancy, and yet preventable, these results are of public health significance.

The effects of prenatal stress on temperament and problem behavior of 27-month-old toddlers

AIM

To examine, in a prospective study, the influence of prenatal stress on infant temperament and problem behavior.

METHOD

Self-report data on stress and anxiety, and levels of cortisol in saliva were collected from nulli-parous women during pregnancy. Temperament of the child was measured at 27 months by parent report on the Infant Characteristics Questionnaire. Behavior of the child was assessed by direct observation during the administration of the Bayley Scales of Development 2-30, and by parent report on the Child Behavior Checklist 2-3.

RESULTS

Complete data were available for 103 healthy toddlers. Logistic regression analyses were performed and results were adjusted for possible prenatal, perinatal and postnatal confounders. Perceived stress during pregnancy was a predictor of lower levels of restless/disruptive temperament (OR=0.77), more total behavioral problems (OR=1.17), and more externalizing behavioral problems (OR=1.12) in 2-year-olds. Fear of bearing a handicapped child was a predictor of higher levels of restless/disruptive temperament (OR=1.39) and more attention regulation problems in toddlers (OR=1.46).

CONCLUSIONS

Increased levels of maternal prenatal stress appear to be associated with temperamental and behavioral problems in toddlers.

Social withdrawal behaviors in nonhuman primates and changes in neuroendocrine and monoamine concentrations during a separation paradigm

This study investigated relationships between withdrawal behaviors in rhesus macaques and changes in monoamine metabolite and endocrine concentrations during repeated psychosocial stress. Rhesus monkeys (N = 71) experienced maternal separation in which four separations took place during four consecutive weeks. Behavioral observations were made, as well as plasma concentrations of cortisol and cerebrospinal fluid concentrations of the serotonin, dopamine, and norepinephrine metabolites were obtained. Animals were assigned to high, moderate, and low withdrawal groups, defined using baseline durations of withdrawal behaviors. Highly withdrawn animals showed less reduction than nonwithdrawn animals in serotonin metabolite concentrations over repeated separations. Highly withdrawn macaques also failed to significantly reduce cortisol concentrations across separation weeks. More adaptation in central serotonin functioning and cortisol concentrations was seen in nonwithdrawn primates than in highly withdrawn primates; these findings have implications for increased risk of developing anxiety disorders in highly inhibited children.

Gene-environment interaction in hyperkinetic conduct disorder (HD + CD) as indicated by season of birth variations in dopamine receptor (DRD4) gene polymorphism

Recently, an interaction between season of birth and the expression of candidate genes has been suggested. Season of birth variations in tryptophan hydroxylase (TPH), the serotonin transporter (5-HTTLPR) and the dopamine D4 receptor (DRD4) gene polymorphisms are different for affective disorders and schizophrenia. The DRD4 gene has been postulated as a candidate gene for attention-deficit-hyperactivity disorder (ADHD), equivalent to hyperkinetic disorder (HD). The seven-repeat long variant of this gene (DRD4*7) in comparison to the short repeat variants of the DRD4 gene polymorphism, has been found to be associated with ADHD. A seasonal pattern of birth has also been proposed for different subtypes of ADHD. Therefore, in a subgroup of children with HD and conduct disorder (CD) and in healthy controls, we investigated a possible association between the DRD4*7 allele and HD + CD in association with the season of birth. Supporting this hypothesis, we found an interaction between the seasons of birth and the expression of the DRD4 candidate gene in children with HD + CD as well as in controls, which differ significantly from each other. Depending on the season of birth, children carrying the DRD4*7R allele showed different relative risks for developing HD + CD.

Moderate level alcohol during pregnancy, prenatal stress, or both and limbic-hypothalamic-pituitary-adrenocortical axis response to stress in rhesus monkeys

This study examined the relationship between moderate-level prenatal alcohol exposure, prenatal stress, and postnatal response to a challenging event in 6-month-old rhesus monkeys. Forty-one rhesus monkey (Macaca mulatta) infants were exposed prenatally to moderate level alcohol, maternal stress, or both. Offspring plasma cortisol and adrenocorticotrophic hormone (ACTH) were determined from blood samples before maternal separation and after separation. Behavioral observations were made repeatedly across separation. Moderate-level prenatal alcohol exposure was associated with significantly higher plasma ACTH response to maternal separation. Offspring exposed to prenatal alcohol, prenatal stress, and prenatal alcohol and stress showed reduced behavioral adaptation to stress compared with controls. Baseline, 2-hr, and 26-hr plasma ACTH levels were intercorrelated and predicted behavior during separation.

High Antenatal Maternal Anxiety Is Related to ADHD Symptoms, Externalizing Problems, and Anxiety in 8- and 9-Year-Olds

Associations between antenatal maternal anxiety, measured with the State Trait Anxiety Inventory, and disorders in 8- and 9-year-olds were studied prospectively in 71 normal mothers and their 72 firstborns. Clinical scales were completed by the mother, the child, the teacher, and an external observer. Hierarchical multiple regression analyses showed that maternal state anxiety during pregnancy explained 22%, 15%, and 9% of the variance in cross-situational attention deficit hyperactivity disorder symptoms, externalizing problems, and self-report anxiety, respectively, even after controlling for child's gender, parents' educational level, smoking during pregnancy, birth weight, and postnatal maternal anxiety. Anxiety at 12 to 22 weeks postmenstrual age turned out to be a significant independent predictor whereas anxiety at 32 to 40 weeks was not. Results are consistent with a fetal programming hypothesis.

Prenatal stress alters bacterial colonization of the gut in infant monkeys

OBJECTIVE

The hypothesis that prenatal stress lowers the levels of protective microflora and increases the risk for postpartum Gram-negative pathogens was tested in infant monkeys.

METHODS

Female monkeys were left undisturbed or were stressed during pregnancy using an acoustical startle paradigm for 6 weeks either early or late in their 24-week gestation. Several types of intestinal microflora were repeatedly enumerated by fecal culture while infants were reared normally by their mothers.

RESULTS

Significant changes in microflora concentrations occurred during the first 6 months of life. The profile of total aerobes and facultative anaerobes was biphasic, with peak concentrations occurring between 2 and 16 weeks of age. The numbers of bifidobacteria and lactobacilli were low at 2 days after birth but rapidly increased to a peak between 8 and 16 weeks of age. Although similar temporal patterns were evident in all infants, prenatal stress reduced the overall numbers of bifidobacteria and lactobacilli.

CONCLUSIONS

Moderate disturbance during pregnancy was sufficient to alter the intestinal microflora in the newborn infant. These alterations could result in enhanced susceptibility to infection and suggest a mechanism for some effects of maternal pregnancy conditions on infant health.

Prenatal stress and risk for psychopathology: specific effects or induction of general susceptibility?

This review focuses on prenatal stress as a risk factor for psychopathology. Evidence from animal studies is summarized, and the relevance of prenatal stress models in animals for human studies is discussed. In the offspring of prenatally stressed animals, overactivity and impaired negative feedback regulation of the hypothalamic-pituitary-adrenal axis are consistent findings and may reflect a pathophysiological mechanism involved in the development of psychopathology. Reduced activity of the opioid GABA/benzodiazepine, serotonin, and dopamine systems and increased activity of the sympathico-adrenal system have been found as well. These alterations have been linked to a diverse spectrum of psychopathology. Therefore, the evidence supports the view that exposure to prenatal stress may result in a general susceptibility to psychopathology, rather than exerting a direct effect on a specific form of psychopathology.

Clinical and service implications of a cognitive analytic therapy model of psychosis

Cognitive analytic therapy (CAT) is an integrative, interpersonal model of therapy predicated on a radically social concept of self, developed over recent years in the UK by Anthony Ryle. A CAT-based model of psychotic disorder has been developed much more recently based on encouraging early experience in this area. The model describes and accounts for many psychotic experiences and symptoms in terms of distorted, amplified or muddled enactments of normal or 'neurotic' reciprocal role procedures (RRPs) and of damage at a meta-procedural level to the structures of the self. Reciprocal role procedures are understood in CAT to represent the outcome of the process of internalization of early, sign-mediated, interpersonal experience and to constitute the basis for all mental activity, normal or otherwise. Enactments of maladaptive RRPs generated by early interpersonal stress are seen in this model to constitute a form of 'internal expressed emotion'. Joint description of these RRPs and their enactments (both internally and externally) and their subsequent revision is central to the practice of CAT during which they are mapped out through written and diagrammatic reformulations. This model may usefully complement and extend existing approaches, notably recent CBT-based interventions, particularly with 'difficult' patients, and generate meaningful and helpful understandings of these disorders for both patients and their treating teams. We suggest that use of a coherent and robust model such as CAT could have important clinical and service implications in terms of developing and researching models of these disorders as well as for the training of multidisciplinary teams in their effective treatment.

Prenatal stress and cognitive development and temperament in infants

Studies in rodents and nonhuman primates indicate that maternal stress during pregnancy can influence the developing fetus, resulting in delay of motor and cognitive development and impaired adaptation to stressful situations. These effects may be mediated by the hypothalamic-pituitary-adrenal (HPA) axis. We examined whether stress during pregnancy predicted developmental outcome of human infants in a prospective design. Self-report data about daily hassles and pregnancy-specific anxiety and salivary cortisol levels were collected in nulliparous pregnant women. Dependent measures were scores on the Bayley Scales of Infant Development and on temperamental questionnaires at 3 and 8 months. Pregnancy-specific anxiety in mid pregnancy predicted lower mental and motor developmental scores at 8 months. Early morning values of cortisol in late pregnancy were negatively related to both mental and motor development at 3 months and motor development at 8 months. Pregnancy-specific anxiety explained 7% of the variance of test-affectivity and goal-directedness at 8 months. Increased maternal stress during pregnancy seems to be one of the determinants of temperamental variation and delay of development of infants and may be a risk factor for developing psychopathology later in life.

Maternal separation at birth and schizophrenia--a long-term follow-up of the Finnish Christmas Seal Home Children

OBJECTIVE

Problems in the early mother-infant relation pose a hypothetical risk factor of schizophrenia. We studied the association between very early separation and later development of schizophrenia or other psychoses in a unique data set.

METHOD

The index cohort consisted of 3020 subjects born in 1945-1965 in Finland who were temporarily isolated from their family immediately after birth to adequate nursing homes due to tuberculosis in the family. The average separation time was 7 months. For every index subject, two reference subjects were matched for sex, year of birth and place of birth. The Finnish Hospital Discharge Register was used to identify subjects with schizophrenia and other psychoses arising from childhood to middle age, between January 1, 1971 and December 31, 1998.

RESULTS

The 28-year cumulative incidence of schizophrenia was 1.6% both in the index cohort and in the reference cohort (rate ratio 1.01, 95% CI 0.75-1.37). The incidences of other psychotic disorders were 1.5% and 1.3% (RR 1.11, 95% CI 0.79-1.58), respectively.

CONCLUSION

Separation at birth was not found to be associated with either schizophrenia or other psychotic illness. Temporary placement to adequate nursing homes in the first year of life is unlikely to increase the risk for schizophrenia or other psychoses.

Effects of prenatal stress on cellular and humoral immune responses in neonatal pigs

In the present study, we investigated the effects of a daily 5 min restraint stress of pregnant sows in the last five gestational weeks on the development and reactivity of the immune system of the offspring. Maternal stress resulted in significant decreased serum immunoglobulin G (IgG) concentrations in suckling piglets at 1 and 3 days of age. Furthermore, the stress treatment of the sows had an immunosuppressive effect on lymphocyte proliferation in response to the T-cell mitogen concanavalin A (ConA) at postnatal days 1 and 7. A suppressive effect was also found in response to the B-cell mitogens lipopolysaccharid (LPS) at days 1 and 35 and pokeweed mitogen (PWM) at day 1 of life, whereas natural killer (NK) cell cytotoxicity was not altered by prenatal stress. The relative thymus weights were significantly reduced in prenatally stressed piglets on the first and 35th day of life and the morbidity and mortality during the suckling period were significantly increased in prenatally stressed litters, as shown by a higher frequency of diseased and died piglets per litter. In addition, the ConA-, LPS- and PWM-stimulated lymphocyte proliferation at the age of 7, 21 and 35 days, and the NK cell cytotoxicity at the age of 21 and 35 days decreased in prenatally stressed and in control piglets 1h after a corticotropin (ACTH) injection. However, the cellular immunity was always higher in the control piglets which might be a result of the weaker stress hormone reactivity in prenatally stressed animals. In conclusion, the results provide first experimental evidence that prenatal maternal stress during late gestation is able to impair both humoral and cellular immune function in suckling piglets. The data also suggest that gestational stress in pigs may affect the ontogeny of the foetal immune system with consequences on the susceptibility to diseases and immune responsiveness to stressful stimuli of the offspring.

The role of prenatal stress in the etiology of developmental behavioural disorders

Substantial evidence from preclinical laboratory studies indicates that prenatal stress (PS) affects the hormonal and behavioural development of offspring. In the following review, the effects of PS in rodents and non-human primates on hypothalamic-pituitary-adrenal (HPA) reactivity to stress, morphological changes in the brain, motor behaviour and learning are surveyed. PS has been found to alter baseline and stress-induced responsivity of the HPA axis and levels and distribution of regulatory neurotransmitters, such as norepinepherine, dopamine, serotonin and acetylcholine and to modify key limbic structures. In rodents and non-human primates, PS affected learning, anxiety and social behaviour. The relevance of these findings to humans is discussed with respect to (a) the effect of administration of exogenous corticosteroids in pregnancy and (b) maternal state and trait anxiety during gestation and its relation to foetal autonomic regulation as putative predisposing factors in the pathogenesis of behavioural developmental delays in children.

Selective chronic stress-induced in vivo ERK1/2 hyperphosphorylation in medial prefrontocortical dendrites: implications for stress-related cortical pathology?

Stress has been shown to affect brain structural plasticity, promote long-term changes in multiple neurotransmitter systems and cause neuronal atrophy. However, the mechanisms involved in these stress-related neural alterations are still poorly understood. Mitogen-activated protein kinase (MAPK) cascades play a crucial role in the transduction of neurotrophic signal from the cell surface to the nucleus and are implicated in the modulation of synaptic plasticity and neuronal survival. An intriguing possibility is that stress might influence brain plasticity through its effects on selective members of such intracellular signalling cascades responsible for the transduction of neurotrophin signals. Here, we have investigated the effects of stress on the expression of three members of the MAPK/extracellular-regulated kinase (ERK) pathway such as phospho-ERK1, phospho-ERK2 and phospho-cAMP/calcium-responsive element-binding protein (CREB) in the adult rat brain. Male rats were subjected to mild footshocks and the patterns of protein expression were analysed after 21 consecutive days of stress. We found that chronic stress induced a pronounced and persistent ERK1/2 hyperphosphorylation in dendrites of the higher prefrontocortical layers (II and III) and a reduction of phospho-CREB expression in several cortical and subcortical regions. We hypothesized that defects in ERK signalling regulation combined with a reduced phospho-CREB activity may be a crucial mechanism by which sustained stress may induce atrophy of selective subpopulations of vulnerable cortical neurons and/or distal dendrites. Thus, ERK-mediated cortical abnormalities may represent a specific path by which chronic stress affects the functioning of cortical structures and causes selective neural network defects.

Effects of cocaine/polydrug exposure and maternal psychological distress on infant birth outcomes

To assess teratogenic effects of cocaine exposure and maternal psychological distress on birth outcomes, we conducted a longitudinal prospective study of 415 infants (218 cocaine-exposed--CE, 197 nonexposed--NE). Drug exposure was determined through a combination of maternal self-report, urine, and meconium screens. Maternal psychological distress postpartum was evaluated through a standardized, normative, self-report assessment. An extensive set of confounding variables was controlled, including severity of exposure to alcohol, tobacco, marijuana and other drugs, maternal age, race, parity, number of prenatal care visits, educational, marital, and socioeconomic status, and verbal and nonverbal intelligence. CE infants were smaller on all birth parameters and more likely to be preterm, small for gestational age, and microcephalic than NE infants. Forty-one percent of cocaine users had clinically significant psychological symptoms, compared to 20% of a high-risk comparison group of noncocaine users. Consistent with a teratologic model, cocaine exposure independently predicted offspring birthweight, length, and head circumference. Maternal psychological distress self-reported postnatally also independently predicted head circumference. Tobacco, alcohol, and marijuana exposures were also significant independent predictors of some fetal growth parameters. In addition, maternal distress symptoms, which may be reflective of maternal mental health disorders or responses to stress, added significantly to the risk for poorer fetal growth.

The impact of prenatal stress, fetal alcohol exposure, or both on development: perspectives from a primate model

The question of whether psychosocial stress during pregnancy (alone or in combination with fetal alcohol exposure) has negative consequences for offspring has not been clearly established in human studies. In this article, we present an overview of three prospective longitudinal studies. Using rhesus monkeys as subjects, a noise or hormone stressor, alone or in combination with moderate level alcohol solution, was presented daily during different stages of pregnancy. Prenatal stress resulted in lighter birth weights in two of three studies, and males from the alcohol plus noise stress condition had reduced birth weights. There were no significant effects of any of the prenatal treatments on gestation duration. Both prenatal stress and moderate fetal alcohol exposure reduced attention span and neuromotor capabilities of offspring during the first month of life, while early gestation prenatal stress, during the period of neuronal migration, emerged as a period of enhanced vulnerability for these effects. Under conditions of challenge, prenatally stressed monkeys showed more disturbance behaviors and reduced locomotion and exploration as well as altered hypothalamic-pituitary-adrenal (HPA) axis reactivity to stress. Fetal alcohol exposed monkeys also showed increased HPA axis activity in response to stressful conditions. Finally, altered patterns of alcohol consumption during adolescence were associated with prenatal stress.

Depression as a spreading adjustment disorder of monoaminergic neurons: a case for primary implication of the locus coeruleus

A model for the pathophysiology of depression is discussed in the context of other existing theories. The classic monoamine theory of depression suggests that a deficit in monoamine neurotransmitters in the synaptic cleft is the primary cause of depression. More recent elaborations of the classic theory also implicitly include this postulate, other theories of depression frequently prefer to depart from the monoamine-based model altogether. We suggest that the primary defect emerges in the regulation of firing rates in brainstem monoaminergic neurons, which brings about a decrease in the tonic release of neurotransmitters in their projection areas, an increase in postsynaptic sensitivity, and concomitantly, exaggerated responses to acute increases in the presynaptic firing rate and transmitter release. It is proposed that the initial defect involves, in particular, the noradrenergic innervation from the locus coeruleus (LC). Dysregulation of the LC projection activities may lead in turn to dysregulation of serotonergic and dopaminergic neurotransmission. Failure of the LC function could explain the basic impairments in the processing of novel information, intensive processing of irrational beliefs, and anxiety. Concomitant impairments in the serotonergic neurotransmission may contribute to the mood changes and reduction in the mesotelencephalic dopaminergic activity to loss of motivation, and anhedonia. Dysregulation of CRF and other neuropeptides such as neuropeptide Y, galanin and substance P may reinforce the LC dysfunction and thus further weaken the adaptivity to stressful stimuli.

Prenatal stress alters early neurobehavior, stress reactivity and learning in non-human primates: a brief review

In this paper we review three prospective longitudinal studies from our laboratory examining the effects of prenatal stress on early neuro behavior, stress reactivity and learning performance in rhesus monkeys. Either a noise stressor or ACTH treatment was administered to pregnant monkeys during specific periods of pregnancy and offspring were examined repeatedly across development. In all three studies, the prenatally stressed monkeys showed reduced attention and impaired neuromotor functioning during the first month of life compared to controls from undisturbed pregnancies. When the monkeys were separated from their mothers or peers at 6-8 months of age, prenatally stressed monkeys exhibited more disturbance behavior and showed hypothalamic-pituitary-adrenal axis dysregulation. During adolescence, they exhibited impairments in learning, compared to controls.

Neurobehavioral outcomes of cocaine-exposed infants

The present study investigated the neurobehavioral outcomes of fetal cocaine exposure. Attempts were made to control, by design or statistical analysis, for significant confounders. Timing and amount of drug exposures were considered, and biologic measures of exposure were quantified to classify exposure severity. One hundred sixty-one non-cocaine and 158 cocaine-exposed (82 heavily and 76 lightly exposed) infants were seen at a mean-corrected age of 43 weeks post-conception and administered the Neurobehavioral Assessment (NB Assessment). Heavily cocaine-exposed infants had more jitteriness and attentional problems than lightly and non-exposed infants. They also had more movement and tone abnormalities, and sensory asymmetries than non-exposed infants. Heavily exposed infants were more likely to be identified with an abnormality than non-exposed infants and there was a trend toward heavily exposed infants being more likely to be identified with an abnormality than lightly exposed infants. Furthermore, there was a trend for heavily exposed infants to be less likely to be testable than non-exposed infants. After the confounding and mediating factors were considered, heavily cocaine-exposed infants were four times as likely to be jittery and nearly twice as likely to demonstrate any abnormality than lightly and non-exposed infants, but all other effects were no longer significant. Higher concentrations of the cocaine metabolites of cocaine, cocaethylene, and benzoylecgonine (BZE) were related to higher incidence of movement and tone abnormalities, jitteriness, and presence of any abnormality. Higher cocaethylene levels were related to attentional abnormalities and higher meta-hydroxybenzoylecgonine (m-OH-BZE) was related to jitteriness. Drug effects on attention were mediated by maternal psychological distress, suggesting that this factor should be considered in future studies of drug exposure effects.