Executive function in preschool children prenatally exposed to methadone or buprenorphine

Prefrontal cortical microglial transcriptome relates to mouse offspring executive function deficits after perinatal opioid exposure in a sex-dependent manner

Opioid use during pregnancy affects over 7% of pregnancies in the United States. While efforts have been directed at mitigating effects of prenatal opioid exposure acutely in the neonatal period, long-term neurodevelopmental studies in humans remain challenging. Using a preclinical model, we previously found that perinatal morphine (MO) exposure induces sex-dependent executive function deficits in adult offspring, and sexually divergent shifts in microglia phenotype. Therefore, this study used transcriptional profiling to test whether perinatal MO exposure would cause sex-specific transcriptional changes in microglia that would relate to offspring executive function outcomes in BXD F1 mice. Female C57BL/6 mice were given MO via the drinking water or saccharin only (SCH) one week prior to mating with DBA males, throughout gestation, and lactation until offspring were weaned. Offspring executive function was assessed in adulthood using the 5-choice serial reaction time task (5CSRTT), and microglia from the PFC were isolated and characterized via RNA-seq. In the 5CSRTT, male MO-exposed offspring had reduced accuracy and female MO-exposed offspring had increased inattentive behavior. There were a similar number of genes altered in female vs. male microglia, but only 3 differentially expressed genes were evident in both sexes. Further, hierarchical clustering analysis and WGCNA identified genes that related to behavioral deficits. Together, our data identify individual genes and pathways in microglia within each sex that may relate to executive function deficits observed after perinatal opioid exposure, even though the transcriptional profiles are highly divergent between the sexes.

Early parent-child interaction and home environments of children exposed prenatally to opioids: A comparison of biological mothers and out-of-home caregivers

Children born to mothers with opioid use disorder (OUD) are at increased risk of maltreatment and out-of-home care (OOHC) placement. This study examines the parent-child interaction quality and home environments of 92 New Zealand children with prenatal opioid exposure (OE) and 106 non-opioid-exposed (NE) children. Experiences for those in maternal care versus OOHC were of particular interest. Biological mothers completed a lifestyle interview during late pregnancy/at birth. At 18 months, parent-child interaction observations, maternal/primary caregiver interviews, and the Home Observation for Measurement of the Environment were completed during a home visit. At age 4.5, children underwent developmental assessment. By 18 months, 20% of OE children were in OOHC. Mothers with OUD who were younger, less cooperative, and had increased polysubstance use during pregnancy were more likely to have lost custody of their child. OE children in their mother's care experienced less positive parenting and lower-quality home environments than NE children. OE children in OOHC had similarly resourced environments to NE children, yet experienced lower levels of parental warmth and responsiveness. Early parenting predicted child cognition, language, and behavior 3 years later, underscoring the critical importance of supporting the parenting and psychosocial needs of OE children's parents/caregivers to improve long-term outcomes.

Opioid receptor signaling throughout ontogeny: Shaping neural and behavioral trajectories

Due to the recent and ongoing opioid crisis in the United States, exposure to opioid drugs in utero is becoming more common, including during medication-assisted therapy used to treat opioid use disorder. As such, careful consideration of opioidergic signaling in utero and beyond, as well as alterations to this signaling via introduction of exogenous opioids, is warranted. This review explores the ontogeny and function of the Mu, Kappa and Delta opioid receptor systems throughout the lifespan, highlighting their importance in guiding neurobehavioral development. We argue for a paradigm shift in conceptualization of opioids as not only contributors within their own system, but also vital regulators of a multitude of downstream neurodevelopmental processes.

Maternal exposure to buprenorphine, but not methadone, during pregnancy reduces social play behavior across two generations of offspring

RATIONALE

The prevalence of newborns exposed to medications for opioid use disorder (MOUD), such as methadone or buprenorphine, during pregnancy is increasing. The opioid system plays a crucial role in regulating and shaping social behavior, and children prenatally exposed to opioids face an increased risk of developing behavioral problems. However, the impact of prenatal exposure to MOUD on offspring's social behavior during adolescence and adulthood, as well as potential intergenerational effects, remains largely unexplored.

OBJECTIVES

Our study employed a translationally relevant animal model to investigate how maternal (F0) exposure to MOUD during pregnancy affects social behavior in young and adult rats across the first (F1) and second (F2) generation of offspring.

METHODS

Female Sprague-Dawley rats were implanted with an osmotic minipump delivering methadone (10 mg/kg/day), buprenorphine (1 mg/kg/day), or sterile water, prior to mating with drug-naïve males. Adult F1 females were mated with treatment-matched F1 males to generate F2 offspring. We assessed social play behavior in juvenile offspring, and social interaction behavior in a three-chamber social interaction test in young adults of the F1 and F2 generations.

RESULTS

Maternal exposure to buprenorphine, but not methadone, during pregnancy reduced social play behavior in both F1 and F2 offspring, expressed by a reduced number of pounces and pins, which are the two most characteristic parameters of social play in rats. Adult social interactions were unaffected by prenatal MOUD exposure across both generations.

CONCLUSIONS

Maternal exposure to buprenorphine during pregnancy may have adverse effects on social play behavior across two generations of offspring.

Cognitive function among methadone assisted treatment patient in Malaysia

BACKGROUND

The use of non-medical opioids has reached 60 million in 2021. Methadone-assisted treatment (MAT) is a widely used harm-reduction strategy for opioid addiction. However, methadone can cause cognitive impairment, which can impede treatment.

METHODS

This cross-sectional study was conducted between July 1st and July 31, 2023. A total of 114 participants, comprising 76 MAT patients and 38 healthy subjects (controls), were recruited. Sociodemographic questionnaire, DSM-5 and neuropsychiatric cognitive (NUCOG) assessments were used. A general linear model was used to examine cognitive function between the MMT and control groups while controlling for all possible confounders.

RESULTS

The MAT group performed significantly lower on the NUCOG total score (p < .001) and visuoconstructional (p < .001), memory (p < .001), executive (p = .016), and language (p < .001) scores than the control group. No significant differences were found between the groups in terms of the attention score (p = .457). Adjusted confounders included age, education level, income, and marital status.

CONCLUSIONS

Patients on MAT demonstrated cognitive impairment, particularly in the visuoconstructional, memory, executive, and language domains, compared to the control group. However, there are confounding factors that needs to be addressed in order to come with better treatment and intervention strategies.

A protocol for enhancing the diagnostic accuracy and predictive validity of neonatal opioid withdrawal syndrome: The utility of non-invasive clinical markers

Every 15 minutes in the US, an infant exposed to opioids is born. Approximately 50% of these newborns will develop Neonatal Opioid Withdrawal Syndrome (NOWS) within 5 days of birth. It is not known which infants will develop NOWS, therefore, the current hospital standard-of-care dictates a 96-hour observational hold. Understanding which infants will develop NOWS soon after birth could reduce hospital stays for infants who do not develop NOWS and decrease burdens on hospitals and clinicians. We propose noninvasive clinical indicators of NOWS, including newborn neurobehavior, autonomic biomarkers, prenatal substance exposures, and socioeconomic environments. The goals of this protocol are to use these indicators shortly after birth to differentiate newborns who will be diagnosed with NOWS from those who will have mild/no withdrawal, to determine if the indicators predict development at 6 and 18 months of age, and to increase NOWS diagnostic sensitivity for earlier, more accurate diagnoses.

Trans-generational effects of parental exposure to drugs of abuse on offspring memory functions

Recent evidence reported that parental-derived phenotypes can be passed on to the next generations. Within the inheritance of epigenetic characteristics allowing the transmission of information related to the ancestral environment to the offspring, the specific case of the trans-generational effects of parental drug addiction has been extensively studied. Drug addiction is a chronic disorder resulting from complex interactions among environmental, genetic, and drug-related factors. Repeated exposures to drugs induce epigenetic changes in the reward circuitry that in turn mediate enduring changes in brain function. Addictive drugs can exert their effects trans-generally and influence the offspring of addicted parents. Although there is growing evidence that shows a wide range of behavioral, physiological, and molecular phenotypes in inter-, multi-, and trans-generational studies, transmitted phenotypes often vary widely even within similar protocols. Given the breadth of literature findings, in the present review, we restricted our investigation to learning and memory performances, as examples of the offspring's complex behavioral outcomes following parental exposure to drugs of abuse, including morphine, cocaine, cannabinoids, nicotine, heroin, and alcohol.

Neural and behavioral indicators of cognitive control in preschoolers with and without prenatal opioid exposure

Prenatal opioid exposure is one consequence of the opioid epidemic, but effects on child development remain poorly understood. There is emerging evidence that children exposed to opioids in utero exhibit elevated emotional and behavioral problems, which may be partially due to alterations in cognitive control. Using multiple methods (i.e., neuropsychological, behavioral, and event-related potential [ERP] assessments), the present study examined differences in emotional, behavioral, and cognitive control difficulties in preschool-aged children with (n = 21) and without (n = 23) prenatal opioid exposure (Mage = 4.30, SD = 0.77 years). Child emotional and behavioral problems were measured with a caregiver questionnaire, indicators of cognitive control were measured using developmentally appropriate behavioral (i.e., delay discounting, Go/No-Go) and neuropsychological (i.e., Statue) tasks, and electroencephalogram was recorded to error and correct responses in a Go/No-Go task. ERP analyses focused on the error-related negativity (ERN), an ERP that reflects error monitoring, and correct-response negativity (CRN), a component reflecting performance monitoring more generally. Opioid exposure was associated with elevated difficulties across domains and a blunted ERN, reflecting altered cognitive control at the neural level, but groups did not significantly differ on behavioral measures of cognitive control. These result replicate prior studies indicating an association between prenatal opioid exposure and behavioral problems in preschool-aged children. Further, our findings suggest these differences may be partially due to children with prenatal opioid exposure exhibiting difficulties with cognitive control at the neural level. The ERN is a potential target for future research and intervention efforts to address the sequelae of prenatal opioid exposure.

Perinatal morphine but not buprenorphine affects gestational and offspring neurobehavioral outcomes in mice

Within the national opioid epidemic, there has been an increase in the number of infants exposed to opioids in utero. Additionally, opioid agonist medications are the standard of care for women with opioid use disorder during pregnancy. Buprenorphine (BUP), a partial µ -opioid receptor agonist, has been successful in improving gestational and neonatal outcomes. However, in utero exposure has been linked to childhood cognitive and behavioral problems. Therefore, we sought to compare offspring cognitive and behavioral outcomes after prenatal exposure to a clinically relevant low dose of BUP compared to morphine (MO), a full µ -opioid receptor agonist and immediate metabolite of heroin. We used a mouse model to assess gestational and offspring outcomes. Mouse dams were injected once daily s.c. with saline (SAL, n = 12), MO (10 mg/kg, n = 15), or BUP (0.1 mg/kg, n = 16) throughout pre-gestation, gestation, and lactation until offspring were weaned on postnatal day (P)21. Offspring social interaction and exploratory behavior were assessed, along with executive function via the touchscreen 5 choice serial reaction time task (5CSRTT). We then quantified P1 brain gene expression in the frontal cortex and amygdala (AMG). Perinatal MO but not BUP exposure decreased gestational weight gain and was associated with dystocia. In adolescent offspring, perinatal MO but not BUP exposure increased social exploration in males and grooming behavior in females. In the 5CSRTT, male MO exposed offspring exhibited increased impulsive action errors compared to male BUP offspring. In the AMG of P1 MO exposed offspring, we observed an increase in gene expression of targets related to activity of microglia. Importantly, both MO and BUP caused acute hyperlocomotion in the dams to a similar degree, indicating that the selected doses are comparable, in accordance with previous dose comparisons on analgesic and reward efficacy. These data suggest that compared to MO, low dose BUP improves gestational outcomes and has less of an effect on the neonatal offspring brain and later adolescent and adult behavior.

Molecular and long-term behavioral consequences of neonatal opioid exposure and withdrawal in mice

Introduction

Infants exposed to opioids in utero are at high risk of exhibiting Neonatal Opioid Withdrawal Syndrome (NOWS), a combination of somatic withdrawal symptoms including high pitched crying, sleeplessness, irritability, gastrointestinal distress, and in the worst cases, seizures. The heterogeneity of in utero opioid exposure, particularly exposure to polypharmacy, makes it difficult to investigate the underlying molecular mechanisms that could inform early diagnosis and treatment of NOWS, and challenging to investigate consequences later in life.

Methods

To address these issues, we developed a mouse model of NOWS that includes gestational and post-natal morphine exposure that encompasses the developmental equivalent of all three human trimesters and assessed both behavior and transcriptome alterations.

Results

Opioid exposure throughout all three human equivalent trimesters delayed developmental milestones and produced acute withdrawal phenotypes in mice reminiscent of those observed in infants. We also uncovered different patterns of gene expression depending on the duration and timing of opioid exposure (3-trimesters, in utero only, or the last trimester equivalent only). Opioid exposure and subsequent withdrawal affected social behavior and sleep in adulthood in a sex-dependent manner but did not affect adult behaviors related to anxiety, depression, or opioid response.

Discussion

Despite marked withdrawal and delays in development, long-term deficits in behaviors typically associated with substance use disorders were modest. Remarkably, transcriptomic analysis revealed an enrichment for genes with altered expression in published datasets for Autism Spectrum Disorders, which correlate well with the deficits in social affiliation seen in our model. The number of differentially expressed genes between the NOWS and saline groups varied markedly based on exposure protocol and sex, but common pathways included synapse development, the GABAergic and myelin systems, and mitochondrial function.

Enhanced heroin analgesic effect in male offspring of sires who self-administered heroin

Introduction: A growing body of evidence suggests that parental substance abuse, even prior to conception, may induce phenotypic changes in offspring. Parental opioid exposure has been shown to affect developmental processes, induce memory deficits, and lead to psycho-emotional disorders in offspring. However, how parental, especially paternal, chronic drug exposure affects offspring remains unexplored. Methods: Adult male rats were subjected to 31 days of heroin self-administration followed by mating with naïve females. Litter size and body weight of F1 offspring were recorded. Object-based attention tests, cocaine self-administration tests, and hot plate tests were used to test for potential effects of chronic paternal heroin seeking on cognition, reward, or analgesic sensitivity in the offspring. Results: Body weight and litter size of the heroin F1 generation were not altered compared to the saline F1 generation. Furthermore, paternal chronic heroin self-administration experience had no significant effect on object-based attention tests or cocaine self-administration behavior in either sex. However, in the hot plate test, although no difference in basal latency was found between the two groups in either sex, a significant increase in the analgesic effect of heroin was observed in the male heroin F1 generation. Conclusions: Taken together, these data provide evidence that paternal chronic heroin self-administration experience could sex-dimorphically increase the analgesic effect of heroin in male offspring, but had no significant effect on response to cocaine reinforcement or attentional behavior.

Neonatal Opioid Withdrawal Syndrome: An Update on Developmental Outcomes

Infants and children with prenatal opioid exposure generally have development within the normal range; however, they seem to be at risk for behavioral problems and for lower scores on cognitive, language, and motor assessments than children without prenatal opioid exposure. It is as of yet unclear whether prenatal opioid exposure itself causes issues with development and behavior, or whether it is simply correlated, due to other confounding factors.

Prenatal exposure to opioids and neurodevelopment in infancy and childhood: A systematic review

Aim

This systematic review aims to estimate the relationship between prenatal exposure to opioids and neurodevelopmental outcomes and examines potential sources of heterogeneity between the studies.

Methods

We searched four databases through May 21st, 2022: PubMed, Embase, PsycInfo and the Web of Science according to a specified search strings. Study inclusion criteria include: (1) cohort and case-control peer-reviewed studies published in English; (2) studies comparing neurodevelopmental outcomes among children with prenatal opioid-exposure (prescribed or used non-medically) vs. an unexposed group. Studies investigating fetal alcohol syndrome or a different primary prenatal exposure other than opioids were excluded. Two main performed data extraction using "Covidence" systematic review platform. This systematic review was conducted in accordance with PRISMA guidelines. The Newcastle-Ottawa-Scale was used for quality assessment of the studies. Studies were synthesized based on the type of neurodevelopmental outcome and the instrument used to assess neurodevelopment.

Results

Data were extracted from 79 studies. We found significant heterogeneity between studies due to their use of different instruments to explore cognitive skills, motor, and behavioral outcomes among children of different ages. The other sources of heterogeneity included: procedures to assess prenatal exposure to opioids; period of pregnancy in which exposure was assessed; type of opioids assessed (non-medical, medication used for opioid use dis-order, prescribed by health professional), types of co-exposure; source of selection of prenatally exposed study participants and comparison groups; and methods to address lack of comparability between exposed and unexposed groups. Cognitive and motor skills as well as behavior were generally negatively affected by prenatal opioid exposure, but the significant heterogeneity precluded a meta-analysis.

Conclusion

We explored sources of heterogeneity in the studies assessing the association between prenatal exposure to opioids and neurodevelopmental outcomes. Sources of heterogeneity included different approaches to participant recruitment as well as exposure and outcome ascertainment methods. Nonetheless, overall negative trends were observed between prenatal opioid exposure and neuro-developmental outcomes.

Body size and brain volumetry in the rat following prolonged morphine administration in infancy and adulthood

Background

Prolonged morphine treatment in infancy is associated with a high incidence of opioid tolerance and dependence, but our knowledge of the long-term consequences of this treatment is sparse. Using a rodent model, we examined the (1) short- and (2) long-term effects of prolonged morphine administration in infancy on body weight and brain volume, and (3) we evaluated if subsequent dosing in adulthood poses an increased brain vulnerability.

Methods

Newborn rats received subcutaneous injections of either morphine or equal volume of saline twice daily for the first two weeks of life. In adulthood, animals received an additional two weeks of saline or morphine injections before undergoing structural brain MRI. After completion of treatment, structural T2-weigthed MRI images were acquired on a 7 T preclinical scanner (Bruker) using a RARE FSE sequence. Total and regional brain volumes were manually extracted from the MRI images using ITK-SNAP (v.3.6). Regions of interest included the brainstem, the cerebellum, as well as the forebrain and its components: the cerebral cortex, hippocampus, and deep gray matter (including basal ganglia, thalamus, hypothalamus, ventral tegmental area). Absolute (cm³) and normalized (as % total brain volume) values were compared using a one-way ANOVA with Tukey HSD post-hoc test.

Results

Prolonged morphine administration in infancy was associated with lower body weight and globally smaller brain volumes, which was not different between the sexes. In adulthood, females had lower body weights than males, but no difference was observed in brain volumes between treatment groups. Our results are suggestive of no long-term effect of prolonged morphine treatment in infancy with respect to body weight and brain size in either sex. Interestingly, prolonged morphine administration in adulthood was associated with smaller brain volumes that differed by sex only in case of previous exposure to morphine in infancy. Specifically, we report significantly smaller total brain volume of female rats on account of decreased volumes of forebrain and cortex.

Conclusions

Our study provides insight into the short- and long-term consequences of prolonged morphine administration in an infant rat model and suggests brain vulnerability to subsequent exposure in adulthood that might differ with sex.

Perceived Clinical Characteristics of Children With History of Opioid Exposure: A Speech-Language Pathology Perspective

PURPOSE

This research was conducted to describe the clinical characteristics of children with a history of opioid exposure as perceived by the speech-language pathologists (SLPs) treating them.

METHOD

Three focus groups were conducted. Participants consisted of 20 SLPs working in the schools in West Virginia who had experienced working with children with a confirmed or suspected history of opioid exposure. A thematic, qualitative analysis was conducted, whereby focus group sessions were transcribed verbatim and information was coded, organized into themes, and interpreted.

RESULTS

Themes of perceived clinical characteristics (speech, language, executive function, and other developmental delays) are reported to address the research question. Additionally, themes derived from the data regarding perceived significant differentiators (greater severity/needs, inconsistent performance, and atypical manifestation) and perceived confounding characteristics (safety and well-being, aspects of home environment, and effects on school environment) that are often reported in children with a history or suspected history of opioid exposure are presented.

CONCLUSIONS

Perceived clinical characteristics of this population, both intrinsic and situational, highlight the complex profile of this population and demonstrate the importance of considering each child from a multidimensional perspective. Additional research is needed to represent the profile of these children more completely and to identify successful supports that will improve their speech and language outcomes, educational achievement, and their overall quality of life.

Buprenorphine Compared with Methadone in Pregnancy: A Systematic Review and Meta-Analysis

INTRODUCTION

Illicit opioid use in pregnancy is associated with adverse maternal, neonatal, and childhood outcomes. Opioid substitution is recommended, but whether methadone or buprenorphine is the optimal agent remains unclear.

METHODS

We searched EMBASE, PubMed, Web of Science, Scopus, Open Gray, CINAHL and the Cochrane Central Registry of Controlled Trials (CENTRAL) from inception to April 2020 for randomized controlled trials (RCTs) and cohort studies comparing methadone and buprenorphine treatment for opioid-using mothers. Included studies assessed maternal and or neonatal outcomes. We used random-effects meta-analyses to estimate summary measures for outcomes and report these separately for RCTs and cohort studies.

RESULTS

Of 408 abstracts screened, 20 papers were included (4 RCTs, 16 cohort, 223 and 7028 participants respectively). All RCTs (4/4) had a high risk of bias and median (IQR) Newcastle Ottawa Scale for cohort studies was 7.5 (6-9). In both RCTs and cohort studies, buprenorphine was associated with; greater offspring birth weight (weighted mean difference [WMD] 343 g (95% CI: 40-645 g) in RCT and 184 g (95% CI: 121-247 g) in cohort studies); body length at birth (WMD 2.28 cm (95% CI: 1.06-3.49 cm) in RCTs and 0.65 cm (95% CI: 0.31-0.98 cm) in cohort studies); and reduced risk of prematurity (risk ratio [RR] 0.41 (95% CI: 0.18-0.93) in RCTs and 0.63 [95% CI: 0.53-0.75] in cohort studies) when compared to methadone. All other clinical outcomes were comparable.

CONCLUSIONS

Compared to methadone, buprenorphine was consistently associated with improved birthweight and gestational age, however given potential biases, results should be interpreted with caution.

Consequences of Parental Opioid Exposure on Neurophysiology, Behavior, and Health in the Next Generations

Substance abuse and the ongoing opioid epidemic represents a large societal burden. This review will consider the long-term impact of opioid exposure on future generations. Prenatal, perinatal, and preconception exposure are reviewed with discussion of both maternal and paternal influences. Opioid exposure can have long-lasting effects on reproductive function, gametogenesis, and germline epigenetic programming, which can influence embryogenesis and alter the developmental trajectory of progeny. The potential mechanisms by which preconception maternal and paternal opioid exposure produce deleterious consequences on the health, behavior, and physiology of offspring that have been identified by clinical and animal studies will be discussed. The timing, nature, dosing, and duration of prenatal opioid exposure combined with other important environmental considerations influence the extent to which these manipulations affect parents and their progeny. Epigenetic inheritance refers to the transmission of environmental insults across generations via mechanisms independent of the DNA sequence. This topic will be further explored in the context of prenatal, perinatal, and preconception opioid exposure for both the maternal and paternal lineage.

Prenatal methadone exposure and child developmental outcomes in 2-year-old children

AIM

To examine the developmental outcomes of children born to opioid-dependent females enrolled in methadone maintenance and identify pre- and postnatal factors that place these children at developmental risk.

METHOD

Ninety-nine methadone-maintained females and their 100 infants (42 females, 58 males, mean gestational age 38.8wks) were recruited during pregnancy/at birth and studied to age 2 years alongside a regionally representative comparison group of 108 non-methadone-maintained females and their 110 infants (62 females, 48 males, mean gestational age 39.2wks). Information about perinatal exposure was collected from medical records, maternal urine and infant meconium toxicological analysis, maternal interviews (at birth and at 18mo), and a home visit (at 18mo). At age 2 years, child neuromotor function, cognition, language, and emotional/behavioral dysregulation were assessed.

RESULTS

Opioid-exposed children achieved lower motor, cognitive, and language scores and had poorer self, emotional, eating/feeding, and sensory processing regulation than unexposed children. After adjustment for maternal education and other substance use in pregnancy, between-group differences in child motor, cognitive, and overall dysregulation remained. Postnatal parental and family factors explained a further 40% to 52% of between-group differences in child outcomes.

INTERPRETATION

These children and families are extremely high-risk and need antenatal and postnatal support. Children exposed to opioids during pregnancy have pervasive developmental difficulties by age 2 years. These challenges are largely explained by adverse pregnancy and socio-environmental exposures, emphasizing the importance of specialist prenatal care and postnatal intervention support. What this paper adds Children born to opioid-dependent females are at high risk of pervasive developmental problems. These problems span a range of functional domains, including motor, cognitive, language, and behavioral/emotional dysregulation. Contributing factors include other adverse pregnancy exposures, postnatal environmental factors, and the direct effects of prenatal opioid exposure.

Prenatal methadone exposure impairs adolescent cognition and GABAergic neurodevelopment in a novel rat model of maternal methadone treatment

Methadone maintenance treatment (MMT) is the most common treatment for opioid-dependent pregnant women worldwide. Despite its widespread use, MMT is associated with a variety of adverse neurodevelopmental outcomes in exposed offspring, particularly cognitive impairments. The neurobiological abnormalities underlying these cognitive impairments are, however, poorly understood. This is, in part, due to a lack of animal models that represents the standard of care that methadone is administered in the clinic, with inconsistencies in the timing, doses and durations of treatment. Here we describe the characterisation of a clinically relevant rat model of MMT in which the long-term behavioural and neurobiological effects of prenatal methadone exposure can be assessed in adolescent offspring. Female Sprague-Dawley rats were treated orally with an ascending methadone dosage schedule (5, 10, 15, 20, 25 and 30 mg/kg/day), self-administered in drinking water prior to conception, throughout gestation and lactation. Pregnancy success, maternal gestational weight gain, litter survival and size were not significantly altered in methadone-exposed animals. Methadone-exposed offspring body and brain weights were significantly lower at birth. Novel object recognition tests performed at adolescence revealed methadone-exposed offspring had impaired recognition memory. Furthermore, the rewarded T-maze alternation task demonstrated that methadone-exposed female, but not male, offspring also exhibit working memory and learning deficits. Immunoblots of the adolescent prefrontal cortex and hippocampus showed methadone-exposed offspring displayed reduced levels of mature BDNF, in addition to the GABAergic proteins, GAD67 and parvalbumin, in a sex- and brain region-specific fashion. This rat model closely emulates the clinical scenario in which methadone is administered to opioid-dependent pregnant woman and provides evidence MMT can cause cognitive impairments in adolescent offspring that may be underlined by perturbed neurodevelopment of the GABAergic system.

Longitudinal Health Care Utilization of Medicaid-Insured Children with a History of Neonatal Abstinence Syndrome

OBJECTIVE

To describe longitudinal health care utilization of Medicaid-insured children with a history of neonatal abstinence syndrome (NAS) compared with similar children without NAS.

STUDY DESIGN

Retrospective, longitudinal cohort study. Data were extracted from the Medicaid Analytic eXtract files for all available states and DC from 2003-2013. Subjects were followed up to 11 years. In total, 17 229 children with NAS were identified using the International Classification of Diseases, Ninth Revision code 779.5. Children without NAS, matched on demographic and health variables, served as the comparison group. Outcomes were number of claims for inpatient, outpatient, and emergency department encounters, numbers of prescription claims, and costs associated with these services. Linked claims were identified for each subject using a unique, within-state ID.

RESULTS

Children with NAS had increased claims for inpatient admissions (marginal effect [ME] 0.49; SE 0.01) and emergency department visits (ME 0.30; SE 0.04) through year 1; increased prescriptions (ME 1.45; SE 0.08, age 0) (ME 0.69; SE 0.11, age 1 year) through year 2; and increased outpatient encounters (ME 20.13; SE 0.54, age 0) (ME 3.95; SE 0.62, age 1 year) (ME 2.90; SE 1.11, age 2 years) through year 3 after adjusting for potential confounders (P < .01 for all). Beyond the third year, health care utilization was similar between those with and without NAS.

CONCLUSIONS

Children with a diagnosis of NAS have greater health care utilization through the third year of life. These differences resolve by the fourth year. Our results suggest resolution of disparities may be due to shifts in developmental health management in school-age children and inability to track relevant diagnoses in a health care database.

Affective decision-making in children prenatally exposed to opioids

Although opioid maintenance therapy (OMT) is currently recommended for pregnant opioid-dependent women, potential effects on children's long-term development are still largely unknown. The current study assessed the long-term cognitive development of children born to women in OMT. Particularly, children's decision-making performance was assessed with a child-friendly version of the Iowa Gambling Task. Using a prospective longitudinal design, a cohort of children was followed from birth to middle childhood. Data were collected in Norway between 2005 and 2017. Participants included 41 children (aged 9-11 years), 20 of whom had histories of prenatal methadone or buprenorphine exposure. Background data were collected from personal interviews and medical records in 2005-2006. Children's affective decision-making was assessed in 2016-2017. Results showed no main effect of group on the net scores in the gambling task, F(1, 39) = 1.44, p = 0.24, η² = 0.04, demonstrating no group differences in decision-making performance. A main effect of group was found on sensitivity to punishment, with children in the control group choosing the doors with the infrequent, but high punishment more often compared to children in the OMT group, F(1, 39) = 4.90, p = 0.03, η²  = 0.11. No main effect of group on decision-making speed was found, although results showed a significant interaction effect between group and gain, F(1, 8,194) = 4.09, p = 0.04, η²  = 0.001. Children prenatally exposed to opioids were found to have normal decision-making performance on an affective decision-making task and were able to consider future consequences when making decisions.

Prenatal opioid exposure and vulnerability to future substance use disorders in offspring

The heightened incidence of opioid use during pregnancy has resulted in unprecedented rates of neonates prenatally exposed to opioids. Prenatal opioid exposure (POE) results in significantly adverse medical, developmental, and behavioral outcomes in offspring. Of growing interest is whether POE contributes to future vulnerability to substance use disorders. The effects of POE on brain development is difficult to assess in humans, as the timing, dose, and route of drug exposure together with complex genetic and environmental factors affect susceptibility to addiction. Preclinical models of POE have allowed us to avoid methodological difficulties and confounding factors of POE in humans. Here, we review the effects of maternal opioid exposure on the developing brain with an emphasis on the neurobiological basis of drug addiction and on preclinical models of POE and their limitations. These studies have indicated that POE increases self-administration of drugs, reward-driven behaviors in the conditioned place paradigm, and locomotor sensitization. While addiction is multifaceted and vulnerability to drug addiction is still inconclusive in human studies of prenatally exposed infants, animal studies do provide a noteworthy corroboration of negative behavioral outcomes.

Neuroimaging in infants with prenatal opioid exposure: Current evidence, recent developments and targets for future research

Prenatal opioid exposure (POE) has shown to be a risk factor for adverse long-term cognitive and behavioral outcomes in offspring. However, the neural mechanisms of these outcomes remain poorly understood. While preclinical and human studies suggest that these outcomes may be due to opioid-mediated changes in the fetal and early postnatal brain, other maternal, social, and environmental factors are also shown to play a role. Recent neuroimaging studies reveal brain alterations in children with POE. Early neuroimaging and novel methodology could provide an in vivo mechanistic understanding of opioid mediated alterations in developing brain. However, this is an area of ongoing research. In this review we explore recent imaging developments in POE, with emphasis on the neonatal and infant brain, and highlight some of the challenges of imaging the developing brain in this population. We also highlight evidence from animal models and imaging in older children and youth to understand areas where future research may be targeted in infants with POE.

Prenatal Opioid Exposure and ADHD Childhood Symptoms: A Meta-Analysis

To systematically investigate the association between prenatal opioid exposure (POE) and attention-deficit hyperactivity disorder (ADHD) symptoms in children 2-18 years old, studies were searched using PubMed, CINAHL, PsycINFO, and Web of Science from January of 1950 to October of 2019. Inclusion criteria were observational studies reporting ADHD symptoms of children with POE compared with non-exposed children or normative data. The study protocol was registered with PROSPERO: CRD42018115967. Two independent reviewers extracted data on hyperactivity/impulsivity, inattention symptoms, ADHD combined subscale symptoms, and sample characteristics. Of 223 articles screened, seven met the inclusion criteria. Data represent 319 children with POE and 1308 non-exposed children from 4.3 to 11.2 mean years from five countries. POE was positively associated with childhood hyperactivity/impulsivity (d = 1.40; 95% CI, 0.49-2.31; p = 0.003), inattention (d = 1.35; 95% CI, 0.69-2.01; p < 0.0001), and combined ADHD symptoms scores (d = 1.27; 95% CI = 0.79-1.75; p < 0.0001). POE was positively associated with ADHD combined symptom scores at preschool (d = 0.83, 95% CI, 0.57, 1.09; p < 0.0001) and school age (d = 1.45, 95% CI, 0.85 to 2.04; p < 0.0001). Results suggest increased risk of ADHD symptoms during school age. Future research is needed to clarify the relationship between biological, social, and environmental risk and ADHD symptoms for children who experienced POE.

Medication-assisted treatment vs. detoxification for women who misuse opioids in pregnancy: Associations with dropout, relapse, neonatal opioid withdrawal syndrome (NOWS), and childhood sexual abuse

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A professional organization does not recommend opioid detoxification in pregnancy.

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Medically-assisted treatment (MAT) is recommended to reduce relapse and dropout.

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We sampled 55 pregnant women who misused opioids who chose detoxification or MAT.

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There was no dropout in either group and more relapse with MAT than detoxification.

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Replication and follow-up are needed to assess relative rates of relapse postpartum.

The American College of Obstetricians and Gynecologists recommends medication-assisted treatment (MAT) for pregnant women who misuse opioids rather than detoxification because of possible relapse and dropout from treatment (ACOG, 2017). In a prospective study, fifty-five pregnant women with an opioid use disorder were offered a choice of MAT or detoxification. Ethical concerns precluded random assignment. We assessed dropout, treatment outcome, relapse, other illicit drug use, infant neonatal opioid withdrawal syndrome (NOWS), and childhood sexual abuse. Of 55 women, 13 initially chose MAT and 42 women chose detoxification. All women received behavioral support. No one dropped out of treatment prior to delivery. All women who chose MAT initially remained on MAT. Of women who chose detoxification, 23% switched to MAT, 30% tapered below initial MAT doses, and 45% fully detoxified by delivery. There was a significant difference in opioid relapse between women on MAT (26%) and those who detoxified (0%), but no differences for other illicit drug use. Infants of women on MAT were more likely to have neonatal NOWS (91%) than infants of women who tapered below initial MAT doses but did not fully detoxify (62%). Infants of mothers who tapered (62%) were more likely to have NOWS than infants of women who fully detoxified (0%). Women on MAT reported significantly lower sexual abuse severity than did women who tapered or detoxified. It is critical to replicate the current findings and to follow up with mothers and their infants postpartum to ascertain the long-term impact of tapering or detoxification during pregnancy.

Longitudinal Outcomes of Children Exposed to Opioids In-utero: A Systematic Review

PURPOSE

The purpose was to summarize evidence of long-term outcomes of children, 2 years and older, exposed to opioids in-utero.

DESIGN

This was a systematic review. Studies were identified by searching the following electronic databases: PubMed, EBSCO HOST/Medline, and Web of Science. Articles were published between 1979 and 2019.

METHODS

This systematic review was reported according to the Preferred Reporting Items for Systematic Review and Meta-Analysis. Two sets of two independent reviewers extracted data and assessed study quality according to National Institutes of Health quality assessment tools.

RESULTS

Forty-three articles met inclusion criteria. Synthesis of articles identified trends toward worse outcomes for children with in-utero opioid exposure in all areas, most notably related to academic success, behavior, cognition, hospitalizations, and vision.

CONCLUSIONS

Findings reinforce the necessity of continued research in this area with improved study design. Despite limitations in the current body of evidence, findings from this review are vital knowledge for clinicians, because children exposed to opioids in-utero are clearly vulnerable to a wide variety of suboptimal health and developmental outcomes.

CLINICAL RELEVANCE

Recognition of all outcomes across childhood associated with in-utero opioid exposure will inform improved identification and interventions tailored to the most pressing needs of affected children. Despite the need for continued research, there is sufficient evidence to necessitate close, individualized follow-up throughout childhood.

Resting state functional MRI in infants with prenatal opioid exposure-a pilot study

PURPOSE

Exposure to prenatal opioids may adversely impact the developing brain networks. The aim of this pilot study was to evaluate alterations in amygdalar functional connectivity in human infants with prenatal opioid exposure.

METHODS

In this prospective IRB approved study, we performed resting state functional MRI (rs-fMRI) in 10 infants with prenatal opioid exposure and 12 infants without prenatal drug exposure at < 48 weeks corrected gestational age. Following standard preprocessing, we performed seed-based functional connectivity analysis with the right and left amygdala as the regions of interest after correcting for maternal depression and infant sex. We compared functional connectivity of the amygdala network between infants with and without prenatal opioid exposure.

RESULTS

There were significant differences in connectivity of the amygdala seed regions to the several cortical regions including the medial prefrontal cortex in infants who had prenatal opioid exposure when compared with opioid naïve infants.

CONCLUSION

This finding of increased amygdala functional connectivity in infants with in utero opioid exposure suggests a potential role of maternal opioid exposure on infants' altered amygdala function. This association with prenatal exposure needs to be replicated in future larger studies.

Prenatal exposure to methadone or buprenorphine impairs cognitive performance in young adult rats

BACKGROUND

Concerns have been raised about the use of opioid maintenance treatment (OMT) during pregnancy and negative effects for the offspring. While neonatal outcomes and short-term effects are relatively well described, studies examining long-term effects in adolescents and adults are absent. The aim of the present study was to examine effects on learning and memory in young adult rats prenatally exposed to methadone or buprenorphine.

METHODS

Female rats were implanted with a 28-day osmotic minipump delivering methadone (10 mg/kg/day), buprenorphine (1 mg/kg/day) or vehicle 5 days prior to mating. To examine possible effects on cognitive functioning, young adult offspring were included in three different behavioral tests that examine recognition memory, nonspatial, and spatial learning and memory. In addition, offspring growth and maternal behavior after birh were investigated.

RESULTS

Prenatal exposure to methadone or buprenorphine caused impaired recognition memory and nonspatial reference learning and memory in young adult rats compared with the vehicle-treated group. Methadone-exposed offspring, but not the buprenorphine-exposed, also showed reduced long-term spatial memory. We did not observe any changes in maternal behavior or offspring growth after prenatal exposure to methadone or buprenorphine, suggesting that the impaired cognitive functioning is due to the opioid exposure rather than reduced maternal caregiving.

CONCLUSION

The present findings of long-term cognitive impairments in methadone- and buprenorphine-exposed offspring points to a negative impact of OMT on neurobiological development.

Neurodevelopmental Outcomes of Children Born to Opioid-Dependent Mothers: A Systematic Review and Meta-Analysis

BACKGROUND

Children born to opioid-dependent mothers are at risk of adverse neurodevelopment. The magnitude of this risk remains inconclusive.

OBJECTIVE

To conduct a meta-analysis of studies that assessed neurodevelopmental outcomes of children aged 0 to 12 years born to opioid-dependent mothers, compared with children born to nonopioid-dependent mothers, across general cognitive, language, motor, and social-emotional domains.

DATA SOURCES

PubMed, CINAHL, PsycINFO, and Google Scholar databases.

STUDY ELIGIBILITY CRITERIA

English-language publications between January 1993 and November 2018, including prenatally opioid-exposed and nonopioid-exposed comparison children, reporting outcomes data on standardized assessments.

STUDY APPRAISAL AND SYNTHESIS METHODS

Two reviewers independently extracted data. Pooled standardized mean differences (SMDs) were analyzed using random effects models. Risk of bias was assessed with the Newcastle-Ottawa Quality Assessment Scale.

RESULTS

Across 16 studies, individual domain outcomes data were examined for between 93 to 430 opioid-exposed and 75 to 505 nonopioid-exposed infants/children. Opioid-exposed infants and children performed more poorly than their nonopioid-exposed peers across all outcomes examined, demonstrated by lower infant cognitive (SMD = 0.77) and psychomotor scores (SMD = 0.52), lower general cognition/IQ (SMD = 0.76) and language scores (SMD = 0.65-0.74), and higher parent-rated internalizing (SMD = 0.42), externalizing (SMD = 0.66), and attention problems (SMD = 0.72).

LIMITATIONS

Most studies examined early neurodevelopment; only 3 reported school-age outcomes thereby limiting the ability to assess longer-term impacts of prenatal opioid exposures.

CONCLUSIONS AND IMPLICATIONS OF FINDINGS

Children born to opioid-dependent mothers are at modest- to high-risk of adverse neurodevelopment at least to middle childhood. Future studies should identify specific clinical and social factors underlying these challenges to improve outcomes.

Prenatal exposure to methadone or buprenorphine and long-term outcomes: A meta-analysis

AIM

To combine meta-analyses of multiple long-term outcomes in children prenatally exposed to methadone or buprenorphine through their mothers' Opioid maintenance therapy (OMT) with a systematic review of similar outcomes in experimental animals.

METHOD

The Medline, Embase, Web of Science, CINAHL, Cochrane and Epistemonikos databases were searched through August 30, 2018. Clinical studies measuring effects on cognitive, behavioral or visual outcomes in 3 months or older children prenatally exposed to OMT and control group(s) were included for meta-analyses. Experimental animal studies with similar exposures and outcomes were included in a systematic review. The three authors independently performed abstract screenings and full-text reviews, and extracted the data. One author performed the meta-analyses.

RESULTS

The pooled results of the meta-analyses showed worse cognitive, psychomotor, behavioral, attentional and executive functioning, and affected vision in children born to mothers who were in OMT during pregnancy compared to children without prenatal drug exposure (overall effect size = 0.49, 95% confidence interval = 0.38, 0.59, p < 0.00001). Many of the experimental animal studies showed impaired outcomes after prenatal exposure to methadone or buprenorphine. The clinical results may be biased, e.g., with the OMT group having more concurrent risk factors than the unexposed comparison group. There are few studies of older children.

CONCLUSION

Children born to mothers in OMT show worse outcomes for a number of different behaviors and impaired vision compared to children born to nonusers. Experimental animal studies indicate that there might be a causal relationship between prenatal methadone or buprenorphine exposure and subsequent negative outcomes.

Prenatal opioid exposure: The next neonatal neuroinflammatory disease

The rates of opioid use disorder during pregnancy have more than quadrupled in the last decade, resulting in numerous infants suffering exposure to opioids during the perinatal period, a critical period of central nervous system (CNS) development. Despite increasing use, the characterization and definition of the molecular and cellular mechanisms of the long-term neurodevelopmental impacts of opioid exposure commencing in utero remains incomplete. Thus, in consideration of the looming public health crisis stemming from the multitude of infants with prenatal opioid exposure entering school age, we undertook an investigation of the effects of perinatal methadone exposure in a novel preclinical model. Specifically, we examined the effects of opioids on the developing brain to elucidate mechanisms of putative neural cell injury, to identify diagnostic biomarkers and to guide clinical studies of outcome and follow-up. We hypothesized that methadone would induce a pronounced inflammatory profile in both dams and their pups, and be associated with immune system dysfunction, sustained CNS injury, and altered cognition and executive function into adulthood. This investigation was conducted using a combination of cellular, molecular, biochemical, and clinically translatable biomarker, imaging and cognitive assessment platforms. Data reveal that perinatal methadone exposure increases inflammatory cytokines in the neonatal peripheral circulation, and reprograms and primes the immune system through sustained peripheral immune hyperreactivity. In the brain, perinatal methadone exposure not only increases chemokines and cytokines throughout a crucial developmental period, but also alters microglia morphology consistent with activation, and upregulates TLR4 and MyD88 mRNA. This increase in neuroinflammation coincides with reduced myelin basic protein and altered neurofilament expression, as well as reduced structural coherence and significantly decreased fractional anisotropy on diffusion tensor imaging. In addition to this microstructural brain injury, adult rats exposed to methadone in the perinatal period have significant impairment in associative learning and executive control as assessed using touchscreen technology. Collectively, these data reveal a distinct systemic and neuroinflammatory signature associated with prenatal methadone exposure, suggestive of an altered CNS microenvironment, dysregulated developmental homeostasis, complex concurrent neural injury, and imaging and cognitive findings consistent with clinical literature. Further investigation is required to define appropriate therapies targeted at the neural injury and improve the long-term outcomes for this exceedingly vulnerable patient population.

Health and Neurodevelopment of Children Born to Opioid-Dependent Mothers at School Entry

OBJECTIVE

To examine the school readiness of a regional cohort of prenatally methadone-exposed children across 5 domains and to examine factors contributing to impairment risk.

METHODS

Data were drawn from a single-center, prospective longitudinal study. One hundred children born to women in methadone maintenance treatment and 110 randomly identified non-methadone-exposed children were studied from birth (2003-2008) to age 4.5 years. At 4.5 years, children underwent comprehensive assessment of their physical/motor development, social-emotional skills, approaches to learning, language development, and cognitive functioning. Predictors of children's overall school readiness were examined, including the extent of prenatal substance exposure (number and quantity of different substances), social risk, maternal mental health, infant clinical factors, and the quality of the home environment at age 18 months Home Observation for Measurement of the Environment (HOME) score.

RESULTS

Methadone-exposed children had higher rates of delay/impairment across all outcome domains (odds ratios 4.0-5.3), with 72% impaired in at least 1 domain. Multiple problems were also common, affecting 48% of methadone-exposed children compared with 15% of control children. The mean number of school readiness domains impaired increased, with increasing prenatal substance exposure (rate ratio [RR] = 1.05 [1.01-1.11]), higher social risk (RR = 1.35 [1.20-1.53]), male sex (RR = 1.69 [1.27-2.25]), and lower HOME scores indicating a poorer quality postnatal environment (RR = 0.96 [0.94-0.99]).

CONCLUSION

Children born to opioid-dependent mothers are at high risk of impaired school readiness, with multiple domain problems being common. Impaired school readiness was associated with greater maternal prenatal substance use, higher social risk, male sex, and lower-quality caregiving environments.

Neonatal Abstinence Syndrome: Review of Epidemiology, Care Models, and Current Understanding of Outcomes

The incidence of neonatal abstinence syndrome owing to prenatal opioid exposure has grown rapidly in recent decades and it disproportionately affects rural, non-white, and public insurance-dependent populations. Treatment consists of pharmacologic and nonpharmacologic interventions with wide variability in approaches across the United States. Standardizing clinical assessment, minimizing unnecessary interruptions, and prioritizing nonpharmacologic and family-centered care seems to improve hospital outcomes. Neonatal abstinence syndrome may have long-term developmental and biological effects, but understanding is limited owing in part confounding biosocial factors. Early intervention and longitudinal support of the infant and family promote better outcomes.

Mental health in youth prenatally exposed to opioids and poly-drugs and raised in permanent foster/adoptive homes: A prospective longitudinal study

BACKGROUND

Little is known about the mental health of prenatally opioid- and polydrug-exposed youth raised in foster/adoptive families.

AIM

To compare mental health problems among two groups of youth, one prenatally drug-exposed group with participants who were mainly placed in permanent foster or adoptive homes in early infancy and a group without known prenatal risk factors who were raised by their birth parents.

METHODS

The sample consisted of 45 drug-exposed and 48 nonexposed youth between 17 and 22 years old from an original sample of 136 followed since birth. An extended version of the Mini International Neuropsychiatric Interview was used to assess lifetime psychiatric disorder, and participants completed the Achenbach Adult Self-Report form and Cantril's Ladder of Life Satisfaction Scale.

RESULTS

A higher proportion of the youth in the drug-exposed group had lifetime experiences with major depressive episodes, alcohol abuse and attention deficit, hyperactivity disorder (OR > 3, p ≤ .030). They scored higher on the aggressive behavior scale, had more sexual partners and were younger at their sexual debut (p ≤ .030). There were no group differences in current self-reported satisfaction with life.

CONCLUSION

Youth exposed to drugs prenatally continue to represent a risk group despite early placement in permanent foster and adoptive homes. The factors contributing to this elevated risk may be multifaceted and involve adverse prenatal conditions including but not limited to drug exposure, genetics, and postnatal environmental conditions. The results highlight the need for longitudinal follow-up in the transition to adulthood as well as qualified service provision for these youth and their families.

Educational achievement at age 9.5 years of children born to mothers maintained on methadone during pregnancy

Recent research shows that preschool children born to opioid-dependent mothers are at increased risk for cognitive, psychomotor, attention, and social-emotional adjustment problems. But very little is known about their school-age functioning, particularly their educational achievement. This analysis examined the educational outcomes of a regional cohort of 100 prenatally methadone-exposed children who were prospectively studied from birth to age 9.5 years alongside a comparison group of 110 randomly identified non-exposed children born between 2003 and 2008. At age 9.5, as part of a comprehensive neurodevelopmental evaluation, children's teachers rated their achievement across the school curriculum, and children completed the Woodcock Johnson-III Tests of Achievement (WJ-III). Detailed information about the birth mother's social background, pregnancy substance use, and mental health was also collected during pregnancy/at term. Infant clinical data were collected after birth. Methadone-exposed children performed less well than non-exposed children across seven school curriculum areas rated by teachers (ps ≤.001), performed less well than non-exposed children on all reading and mathematics subtests of the WJ-III, and had higher rates of any educational delay on the WJ-III (57% vs. 15%), OR = 7.47 (3.71-15.02). Results were similar when children with severe intellectual impairment were excluded. After adjusting for confounding factors, methadone-exposed children had increased odds of educational delay, but this was only marginally significant (OR = 3.62, [1.01-13.01], p = .049). Maternal educational attainment level (OR = 0.69, [0.50-0.89], p = .006), and maternal benzodiazepine use during pregnancy (OR = 2.70 [1.03-7.12], p = .044) were also associated with later educational risk. Findings suggest that children born to opioid-dependent women enrolled in methadone maintenance are at high risk of educational delay by age 9.5 years. Children's academic difficulties appeared to reflect the effects of both adverse prenatal exposures and postnatal social risk.

Salivary cortisol levels relate to cognitive performance in children prenatally exposed to methadone or buprenorphine

Opioid maintenance therapy (OMT) is generally recommended for pregnant opioid-dependent women. However, much is still unknown about the potential long-term effects of prenatal methadone and buprenorphine exposure. This study explored the long-term effects of prenatal methadone and buprenorphine exposure in a cohort (n = 41) of children, aged 9-11 years, using the Wechsler Abbreviated Scale of Intelligence (WASI) to measure cognitive development and salivary cortisol samples to measure HPA-axis activity. Prenatally exposed children scored significantly lower on all four subtests of WASI (vocabulary, similarities, block design, and matrix reasoning), compared to a comparison group (all p < .05). No group differences were found for salivary cortisol levels or cortisol reactivity levels (all p > .05). Cortisol levels significantly predicted matrix reasoning scores for the OMT group, β = -65.58, t(20) = 15.70, p = .02. Findings suggest that prenatal exposure to methadone or buprenorphine does not have long-term effects on children's HPA-axis functioning. However, since children of women in OMT scored significantly lower on tasks of cognitive function, careful follow-up throughout the school years and across adolescence is recommended.

Cognitive and Behavioral Impact on Children Exposed to Opioids During Pregnancy

The developmental impact of opioid use during pregnancy is a subject of ongoing debate. Short-term neonatal outcomes, such as lower birth weight and neonatal abstinence syndrome, are the most well-recognized outcomes. However, knowledge gaps exist regarding longer-term neurocognitive and mental health outcomes. In this article, we summarize an expert panel discussion that was held in April 2018 by the Substance Abuse and Mental Health Services Administration and attended by national experts in the field of perinatal opioid exposure and its impact on child development. Despite the challenges with research in this area, there is emerging literature revealing an association between neonates exposed to opioids in utero and longer-term adverse neurocognitive, behavioral, and developmental outcomes. Although adverse sequalae may not be apparent in the neonatal period, they may become more salient as children develop and reach preschool and school age. Multiple variables (genetic, environmental, and biological) result in a highly complex picture. The next steps and strategies to support families impacted by opioid use disorder are explored. Model programs are also considered, including integrated care for the child and mother, parenting supports, and augmentations to home visiting.

Association between prenatal opioid exposure, neonatal opioid withdrawal syndrome, and neurodevelopmental and behavioral outcomes at 5-8 months of age

BACKGROUND

While use of prescription opioids and medication assisted therapy (MAT) for opioid use disorder in pregnancy, as well as the incidence of neonatal opioid withdrawal syndrome (NOWS) continue to rise, little is known about outcomes for children with NOWS beyond the newborn period.

METHODS

We examined 1) prenatal MAT exposure vs. unexposed healthy controls [HC]; and 2) treatment for NOWS and NOWS severity on infant neurodevelopmental and behavioral outcomes at 5-8 months of age in 78 maternal-infant pairs from the ENRICH prospective cohort study. Data were obtained from 3 study visits: prenatal, delivery, and neurodevelopmental evaluation at 5-8 months of age. Neurodevelopmental outcomes included the Bayley Scales of Infant Development [BSID-III], caregiver questionnaires (Parenting Stress Index [PSI-SF], Infant Behavior Questionnaire [IBQ-R], Sensory Profile), and the experimental Still-Face Paradigm (SFP).

RESULTS

No differences in the BSID-III, PSI-SF, or IBQ-R scores were observed between MAT and HC groups; however, MAT-exposed and HC infants differed with respect to SFP self-regulation (β = -18.9; p = 0.01) and Sensory Profile sensation seeking (OR = 4.87; 95% CI: 1.55; 15.30) after adjusting for covariates. No significant differences between Treated-for-NOWS vs. not-Treated-for-NOWS were observed. Shorter timing to NOWS treatment initiation was associated with higher Total Stress (β = -9.08; p = 0.035), while longer hospitalization was associated with higher Parent-child dysfunctional interaction (p = 0.018) on PSI-SF.

CONCLUSIONS

Our results provide additional evidence of little-to-no effect of MAT and pharmacological treatment of NOWS on infant neurodevelopmental and behavioral outcomes at 5-8 months of age. However, prolonged hospitalization might increase family psychosocial stress and requires further examination.

Neonatal abstinence syndrome

Neonatal abstinence syndrome refers to the signs and symptoms attributed to the cessation of prenatal exposure (via placental transfer) to various substances. This Primer focuses on neonatal abstinence syndrome caused by opioid use during pregnancy - neonatal opioid withdrawal syndrome (NOWS). As the global prevalence of opioid use has alarmingly increased, so has the incidence of NOWS. NOWS can manifest with varying severity or not at all, for unknown reasons, but is likely to be associated with multiple factors, both maternal (for example, smoking and additional substance exposures) and neonatal (gestational age, sex and genetics). Care for the infant with NOWS begins with addressing the issues experienced by pregnant women with opioid use disorder. Co-occurring mental illness, economic hardship, intimate partner violence, infectious diseases and limited access to care are common in these women and can result in poor maternal and neonatal outcomes. Although there is no consensus regarding optimal NOWS management, non-pharmacological interventions (such as breastfeeding and rooming-in of the mother and the baby) have become a priority, as they can ameliorate symptoms without the need for further opioid exposure. Untreated NOWS can be associated with morbidity in early infancy, and the long-term consequences of fetal opioid exposure are only beginning to be understood.

ERP correlates of cognitive control in children prenatally exposed to methadone or buprenorphine

Much is still unknown about the potential long-term effects of prenatal methadone and buprenorphine exposure. We examined neural correlates of cognitive control in 19 prenatally methadone and buprenorphine exposed and 21 nondrug exposed children, aged 9-11 years. Children performed a modified version of the Eriksen Flanker task, which taps into selective attention, conflict response, and response inhibition mechanisms. We investigated behavioral responses and the ERP components N1, P2, N2, P3, and the late positive component (LPC). Children in the exposed group showed normal cognitive control function. However, an atypical ERP response related to perceptual and attention allocation processes was found in the exposed group.

Expression of kappa opioid receptors in developing rat brain - Implications for perinatal buprenorphine exposure

Buprenorphine, a mu opioid receptor partial agonist and kappa opioid receptor (KOR) antagonist, is an emerging therapeutic agent for maternal opioid dependence in pregnancy and neonatal abstinence syndrome. However, the endogenous opioid system plays a critical role in modulating neurodevelopment and perinatal buprenorphine exposure may detrimentally influence this. To identify aspects of neurodevelopment vulnerable to perinatal buprenorphine exposure, we defined KOR protein expression and its cellular associations in normal rat brain from embryonic day 16 to postnatal day 23 with double-labelling immunohistochemistry. KOR was expressed on neural stem and progenitor cells (NSPCs), choroid plexus epithelium, subpopulations of cortical neurones and oligodendrocytes, and NSPCs and subpopulations of neurones in postnatal hippocampus. These distinct patterns of KOR expression suggest several pathways vulnerable to perinatal buprenorphine exposure, including proliferation, neurogenesis and neurotransmission. We thus suggest the cautious use of buprenorphine in both mothers and infants until its impact on neurodevelopment is better defined.

Functional MRI in prenatally opioid-exposed children during a working memory-selective attention task

BACKGROUND

Opioid induced cerebral changes may contribute to neuropsychological difficulties, like attention problems, frequently reported in prenatally opioid-exposed children. Reduced regional brain volumes have been shown after prenatal opioid exposure, but no study to date has explored the possible impact of prenatal opioids on brain activation patterns.

MATERIALS AND METHODS

A hospital-based sample of prenatally opioid-exposed school-aged children (n = 11) and unexposed controls (n = 12) underwent functional magnetic resonance imaging (fMRI) during a combined working memory-selective attention task. Within-group- and between-group analyses of blood-oxygen-level-dependent (BOLD) activation were performed using the SPM12 software package and group differences in task performance were analyzed using Cox proportional hazards modeling.

RESULTS

Overall, similar patterns of task related parietal and prefrontal BOLD activations were found in both groups. The opioid-exposed group showed impaired task performance, and during the most cognitive demanding versions of the working memory-selective attention task, increased activation in prefrontal cortical areas was found in the opioid-exposed group compared to controls.

CONCLUSION

Our findings suggest that prenatal opioids affect later brain function, visible through changes in BOLD activation patterns. However, results should be considered preliminary until replicated in larger samples better suited to control for potential confounding factors.

Early inhibitory control and working memory abilities of children prenatally exposed to methadone

BACKGROUND

Methadone maintenance is the most common method of treating opioid-dependent pregnant women. However, little is known about the impact of prenatal methadone exposure on child neurocognitive development.

AIMS

To examine the early executive functioning of children born to methadone-maintained mothers, and to assess relations between executive functioning and later emotional and behavioral adjustment.

STUDY DESIGN

Prospective longitudinal study.

PARTICIPANTS

The sample consisted of 68 methadone-exposed children and 88 non-methadone-exposed children.

OUTCOME MEASURES

At age 2years, children's inhibitory control and working memory were assessed using the Snack Delay and Three Boxes tasks. At 2 and 4.5years, their emotional and behavioral adjustment was assessed using the caregiver-completed Strengths and Difficulties Questionnaire.

RESULTS

Methadone-exposed children had poorer inhibitory control than non-exposed children (p<0.0001). These differences were explained by maternal education and prenatal benzodiazepine use. With respect to working memory, although both groups performed similarly on the first trial set, non-exposed children significantly improved their performance on the second trial set (p=0.002), while methadone-exposed children did not (p=0.92). Inhibitory control at age 2years was predictive of higher conduct (p=0.001), hyperactivity (p=0.0001), peer relationship (p=0.02), and total (p<0.0001) problems at 4.5years even after adjustment for behavioral problems at 2years.

CONCLUSIONS

Methadone-exposed children demonstrate difficulties with inhibitory control and possibly sustained attention/learning. These difficulties were explained by factors correlated with maternal prenatal methadone use. Longer-term follow-up of these children is needed to understand the effects of prenatal methadone exposure and related maternal factors on executive functioning and behavioral adjustment.

Brain morphology in school-aged children with prenatal opioid exposure: A structural MRI study

BACKGROUND

Both animal and human studies have suggested that prenatal opioid exposure may be detrimental to the developing fetal brain. However, results are somewhat conflicting. Structural brain changes in children with prenatal opioid exposure have been reported in a few studies, and such changes may contribute to neuropsychological impairments observed in exposed children.

AIM

To investigate the association between prenatal opioid exposure and brain morphology in school-aged children.

STUDY DESIGN

A cross-sectional magnetic resonance imaging (MRI) study of prenatally opioid-exposed children and matched controls.

SUBJECTS

A hospital-based sample (n=16) of children aged 10-14years with prenatal exposure to opioids and 1:1 sex- and age-matched unexposed controls.

OUTCOME MEASURES

Automated brain volume measures obtained from T1-weighted MRI scans using FreeSurfer.

RESULTS

Volumes of the basal ganglia, thalamus, and cerebellar white matter were reduced in the opioid-exposed group, whereas there were no statistically significant differences in global brain measures (total brain, cerebral cortex, and cerebral white matter volumes).

CONCLUSIONS

In line with the limited findings reported in the literature to date, our study showed an association between prenatal opioid exposure and reduced regional brain volumes. Adverse effects of opioids on the developing fetal brain may explain this association. However, further research is needed to explore the causal nature and functional consequences of these findings.

Behavior and Attention Problems in Eight-Year-Old Children with Prenatal Opiate and Poly-Substance Exposure: A Longitudinal Study

Multiple studies have found that children born to mothers with opioid or poly-substance use during pregnancy have more behavior and attention problems and lower cognitive functioning than non-exposed children. The present study aimed to investigate whether behavior and attention problems are more prominent than general cognitive deficits in this risk group and whether the problems wane or increase over time. This prospective longitudinal cross-informant study compared 72 children who were prenatally exposed to heroin and multiple drugs with a group of 58 children without known prenatal risk factors. Group differences in caregivers' and teachers' reports of the children's behavior and attention problems based on the Child Behavior Check List and the ADHD Rating Scale were compared based on group differences in general cognitive functioning at 4 ½ and 8 ½ years of age. Both parent and teacher reports suggest that the exposed group has significantly more problems in several behavioral areas than the comparison group, particularly with regard to attention problems. The preschool teachers had already reported these problems when the children were 4 ½ years old, whereas the caregivers reported these problems mainly when the children were 8 ½ years old. The group differences in behavioral and attentional problems were not significantly greater and some were even significantly smaller than the group differences in general cognitive abilities. These findings suggest that children subject to prenatally drug exposure have increasing problems in multiple areas related to behavior from preschool age to 8 ½ years but that these problems do not seem to be specific; i.e., they are not more severe than the problems with general cognitive abilities found for this group.