Quantitative autistic traits ascertained in a national survey of 22 529 Japanese schoolchildren.

OBJECTIVE: Recent epidemiologic studies worldwide have documented a rise in prevalence rates for autism spectrum disorders (ASD). Broadening of diagnostic criteria for ASD may be a major contributor to the rise in prevalence, particularly if superimposed on an underlying continuous distribution of autistic traits. This study sought to determine the nature of the population distribution of autistic traits using a quantitative trait measure in a large national population sample of children. METHOD: The Japanese version of the Social Responsiveness Scale (SRS) was completed by parents on a nationally representative sample of 22 529 children, age 6-15. RESULTS: Social Responsiveness Scale scores exhibited a skewed normal distribution in the Japanese population with a single-factor structure and no significant relation to IQ within the normal intellectual range. There was no evidence of a natural 'cutoff' that would differentiate populations of categorically affected children from unaffected children. CONCLUSION: This study provides evidence of the continuous nature of autistic symptoms measured by the SRS, a validated quantitative trait measure. The findings reveal how paradigms for diagnosis that rest on arbitrarily imposed categorical cutoffs can result in substantial variation in prevalence estimation, especially when measurements used for case assignment are not standardized for a given population.

Infants later diagnosed with autism have lower canonical babbling ratios in the first year of life.

BACKGROUND: Canonical babbling-producing syllables with a mature consonant, full vowel, and smooth transition-is an important developmental milestone that typically occurs in the first year of life. Some studies indicate delayed or reduced canonical babbling in infants at high familial likelihood for autism spectrum disorder (ASD) or who later receive an ASD diagnosis, but evidence is mixed. More refined characterization of babbling in the first year of life in infants with high likelihood for ASD is needed. METHODS: Vocalizations produced at 6 and 12 months by infants (n = 267) taking part in a longitudinal study were coded for canonical and non-canonical syllables. Infants were categorized as low familial likelihood (LL), high familial likelihood diagnosed with ASD at 24 months (HL-ASD) or not diagnosed (HL-Neg). Language delay was assessed based on 24-month expressive and receptive language scores. Canonical babble ratio (CBR) was calculated by dividing the number of canonical syllables by the number of total syllables. Generalized linear (mixed) models were used to assess the relationship between group membership and CBR, controlling for site, sex, and maternal education. Logistic regression was used to assess whether canonical babbling ratios at 6 and 12 months predict 24-month diagnostic outcome. RESULTS: No diagnostic group differences in CBR were detected at 6 months, but HL-ASD infants produced significantly lower CBR than both the HL-Neg and LL groups at 12 months. HL-Neg infants with language delay also showed reduced CBR at 12 months. Neither 6- nor 12-month CBR was significant predictors of 24-month diagnostic outcome (ASD versus no ASD) in logistic regression. LIMITATIONS: Small numbers of vocalizations produced by infants at 6 months may limit the reliability of CBR estimates. It is not known if results generalize to infants who are not at high familial likelihood, or infants from more diverse racial and socioeconomic backgrounds. CONCLUSIONS: Lower canonical babbling ratios are apparent by the end of the first year of life in ASD regardless of later language delay, but are also observed for infants with later language delay without ASD. Canonical babbling may lack specificity as an early marker when used on its own.

Genetic counseling as preventive intervention: toward individual specification of transgenerational autism risk.

BACKGROUND: Although autism spectrum disorders (ASD) are among the most heritable of all neuropsychiatric syndromes, most affected children are born to unaffected parents. Recently, we reported an average increase of 3-5% over general population risk of ASD among offspring of adults who have first-degree relatives with ASD in a large epidemiologic family sample. A next essential step is to investigate whether there are measurable characteristics of individual parents placing them at higher or lower recurrence risk, as this information could allow more personalized genetic counseling. METHODS: We assembled what is to our knowledge the largest collection of data on the ability of four measurable characteristics of unaffected prospective parents to specify risk for autism among their offspring: (1) sub clinical autistic trait burden, (2) parental history of a sibling with ASD, (3) transmitted autosomal molecular genetic abnormalities, and (4) parental age. Leveraging phenotypic and genetic data in curated family cohorts, we evaluate the respective associations between these factors and child outcome when autism is present in the family in the parental generation. RESULTS: All four characteristics were associated with elevation in offspring risk; however, the magnitude of their predictive power-with the exception of isolated rare inherited pathogenic variants -does not yet reach a threshold that would typically be considered actionable for reproductive decision-making. CONCLUSIONS: Individual specification of risk to offspring of adults in ASD-affected families is not straightforwardly improved by ascertainment of parental phenotype, and it is not yet clear whether genomic screening of prospective parents in families affected by idiopathic ASD is warranted as a clinical standard. Systematic screening of affected family members for heritable pathogenic variants, including rare sex-linked mutations, will identify a subset of families with substantially elevated transmission risk. Polygenic risk scores are only weakly predictive at this time but steadily improving and ultimately may enable more robust prediction either singly or when combined with the risk variables examined in this study.

Language delay aggregates in toddler siblings of children with autism spectrum disorder.

BACKGROUND: Language delay is extremely common in children with autism spectrum disorder (ASD), yet it is unclear whether measurable variation in early language is associated with genetic liability for ASD. Assessment of language development in unaffected siblings of children with ASD can inform whether decreased early language ability aggregates with inherited risk for ASD and serves as an ASD endophenotype. METHODS: We implemented two approaches: (1) a meta-analysis of studies comparing language delay, a categorical indicator of language function, and language scores, a continuous metric, in unaffected toddlers at high and low familial risk for ASD, and (2) a parallel analysis of 350 unaffected 24-month-olds in the Infant Brain Imaging Study (IBIS), a prospective study of infants at high and low familial risk for ASD. An advantage of the former was its detection of group differences from pooled data across unique samples; an advantage of the latter was its sensitivity in quantifying early manifestations of language delay while accounting for covariates within a single large sample. RESULTS: Meta-analysis showed that high-risk siblings without ASD (HR-noASD) were three to four times more likely to exhibit language delay versus low-risk siblings without ASD (LR-noASD) and had lower mean receptive and expressive language scores. Analyses of IBIS data corroborated that language delay, specifically receptive language delay, was more frequent in the HR-noASD (n = 235) versus LR-noASD group (n = 115). IBIS language scores were continuously and unimodally distributed, with a pathological shift towards decreased language function in HR-noASD siblings. The elevated inherited risk for ASD was associated with lower receptive and expressive language scores when controlling for sociodemographic factors. For receptive but not expressive language, the effect of risk group remained significant even when controlling for nonverbal cognition. CONCLUSIONS: Greater frequency of language delay and a lower distribution of language scores in high-risk, unaffected toddler-aged siblings support decreased early language ability as an endophenotype for ASD, with a more pronounced effect for receptive versus expressive language. Further characterization of language development is warranted to refine genetic investigations of ASD and to elucidate factors influencing the progression of core autistic traits and related symptoms.

Shape mapping of the hippocampus in young children with autism spectrum disorder.

BACKGROUND AND PURPOSE: We hypothesized the occurrence of characteristic hippocampal-shape alterations in young children with autistic spectrum disorder (ASD) who also exhibit deficits on neuropsychologic tests of medial temporal lobe (MTL) function. MATERIALS AND METHODS: Coronal 3D MR images were acquired from 3- to 4-year-old children with ASD (n = 45) and age-matched children with typical development (n = 13). Children with ASD were further subclassified into those with autism disorder (AD, n = 29) or pervasive developmental disorder-not otherwise specified (PDD-NOS) (n = 16). Variations in hippocampal shape were evaluated by using large-deformation high-dimensional brain mapping. RESULTS: Hippocampal shape measures distinguished children with ASD from those with typical development; within the ASD sample, children with AD were distinguished from those with PDD-NOS. Hippocampal-shape alterations in children with ASD were correlated with degree of mental retardation and performance deficits on tests of MTL function. CONCLUSIONS: Children with ASD exhibited an alteration of hippocampal shape consistent with inward deformation of the subiculum. This pattern of hippocampal-shape deformations in the children with ASD was accentuated in the more severely affected subgroup of children with AD and was associated with deficits on neuropsychologic tests of MTL but not prefrontal function. Hippocampal-shape deformation in the children with ASD was observed to be similar to a pattern of hippocampal shape deformation previously reported in adults with MTL epilepsy. Although the children with ASD, and those with AD in particular, PDD-NOS are at high risk for epilepsy as they enter adolescence, the specificity and causal relationship of this pattern of hippocampal-shape deformation to the development of seizures is not yet known.

Family psychiatric history, cerebrospinal fluid monoamine metabolites, and temperament in infants.

BACKGROUND: Variations in cerebrospinal fluid (CSF) levels of the monoamine metabolites 5-hydroxyindoleacetic acid, 3-methoxy-4-hydroxyphenylglycol, and homovanillic acid have been associated with behavioral abnormalities in nonhuman primates, and with psychopathology in studies of children and adults. METHODS: We assayed monoamine metabolites in "left-over" spinal fluid from 167 neurologically normal newborn infants (0-3 months of age), and later (at age 18-21 months of age) obtained their family psychiatric histories and assessed their temperament using the Colorado Childhood Temperament Inventory (CCTI). RESULTS: Family history of antisocial personality disorder predicted significantly lower scores for soothability (p = .003) at 18-21 months. There were no statistically significant associations between newborn monoamine metabolite levels and any aspect of temperament on the CCTI. CONCLUSIONS: These findings suggest complex relationships between genetic liability for psychiatric disorders and CSF monoamine metabolite levels; those relationships do not seem to be mediated by infant temperament. It appears likely that interindividual differences in monoamine metabolite levels change over the course of development in humans.

Genetic structure of reciprocal social behavior.

OBJECTIVE: The study examined the genetic structure of deficits in reciprocal social behavior in an epidemiologic sample of male twins. METHOD: Parents of 232 pairs of 7-15-year-old male twins completed the Social Reciprocity Scale to provide data on their children's reciprocal social behavior. Scale scores were analyzed by using structural equation modeling. RESULTS: Intraclass (twin-twin) correlations for scores on the Social Reciprocity Scale were 0.73 for monozygotic twins (N=98 pairs) and 0.37 for dizygotic twins (N=134 pairs). The best fitting model of causal influences on reciprocal social behavior incorporated additive genetic influences and unique environmental influences. CONCLUSIONS: For school-age boys in the general population, reciprocal social behavior is highly heritable, with a genetic structure similar to that reported for autism in clinical samples. Continuous measures of reciprocal social behavior may be useful for characterizing the broader autism phenotype and may enhance the statistical power of genetic studies of autism.

CSF 5-HIAA and family history of antisocial personality disorder in newborns.

OBJECTIVE: The relationship between genetic liability for antisocial behavior and CSF 5-hydroxyindoleacetic acid (5-HIAA) in newborns was explored. METHOD: The authors assayed 5-HIAA in "leftover" CSF from 193 neurologically normal newborns and obtained family psychiatric histories of the newborns' first- and second-degree relatives. RESULTS: Levels of 5-HIAA were significantly lower in the infants with family histories of antisocial personality disorder than in the newborns without such family histories. CONCLUSIONS: These findings support the possibility that serotonin mediates one component of genetic liability to antisocial outcome, but the magnitude of that component may be less than what has been inferred from previously published reports.

Testosterone and aggression in children.

OBJECTIVE: A link between serum testosterone and aggressive behavior, which has been demonstrated in numerous animal studies and suggested in several studies of adult men, has never been investigated in children before the time of puberty. METHOD: We measured serum testosterone, sex hormone binding globulin (SHBG), dehydroepiandrosterone (DHEA), and dehydroepiandrosterone sulfate (DHEAS) in 18 highly aggressive prepubertal boys, ages 4 to 10, hospitalized for violent or unmanageable behavior at a state children's psychiatric facility in New York City (the Bronx). We compared them with a group of age and race matched controls from the same demographic area, screened negative for aggressive behavior problems. All the aggressive subjects met DSM-III-R criteria for conduct disorder and scored higher than the 98th percentile on the aggression subscale of the Child Behavior Checklist (mean T = 80 for the group). RESULTS: There were no significant differences between aggressive and nonaggressive children for T, SHBG, DHEA, DHEAS, or ratios of combinations of these variables. CONCLUSIONS: These findings raise questions about inferences from adult studies that testosterone may play a causal role in the development of human aggression. Testosterone does not appear to be a useful biological marker for aggressivity in early childhood.

Monoamine metabolites in 'leftover' newborn human cerebrospinal fluid--a potential resource for biobehavioral research.

Although variations in monoamine neurotransmission have been implicated in a variety of psychopathologic outcomes in man, little is known about how monoamines influence or are affected by developmental processes early in childhood. In this study, assays for 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), and 3-methoxy-4-hydroxyphenylglycol (MHPG) were obtained from leftover cerebrospinal fluid (CSF) of 119 human newborns. The levels of these monoamine metabolites were in keeping with pre-existing 'normative' data from two small previously published studies. The levels were largely unaffected by variations in the infants' physiologic condition at the time of lumbar puncture, and exhibited evidence for circadian rhythms. Among 32 infants (8 neurologically normal, 24 neurologically compromised) for whom more than one CSF sample was obtained during the first year of life, the correlations between baseline and follow-up measurements for 5-HIAA and HVA were on the order of 0.75. Correlations between twins (four sets) were significantly higher than those between unrelated individuals for 5-HIAA and HVA. At 9-month follow-up, neurologically normal infants in the lower extreme 15% of the distribution for 5-HIAA exhibited a trend toward lower scores for sociability on the Colorado Childhood Temperament Inventory (maternal report) than their counterparts at the upper extreme of the 5-HIAA distribution. Leftover CSF is a readily available resource for measurements of monoamine metabolites (and possibly other CSF constituents) in population-based samples of human newborns.

Serotonin and externalizing behavior in young children.

Considerable evidence suggests that there is a relationship between pathologic aggressive behavior and low cerebrospinal fluid (CSF) concentrations of the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) in both humans and non-human primates. The purpose of this investigation is to examine the relationship between CSF concentrations of human newborn 5-HIAA and subsequent aggressive behavior observed at 30 months of age. Leftover portions of culture negative CSF drawn from febrile infants (age, birth to 3 months) were assayed for 5-HIAA. Family environment and child behavior were assessed at 30 months by parent report. Subjects with 5-HIAA levels below the median of the distribution had higher externalizing behavior scores at 30 months than did subjects whose 5-HIAA levels fell above the median (P = 0.02). While it is likely that serotonin mediates one component of genetic liability to antisocial outcome, the magnitude of that component may be less than what has been inferred from previously published reports.

Effects of serotonin reuptake inhibitors on aggressive behavior in psychiatrically hospitalized adolescents: results of an open trial.

Low concentrations of the neurotransmitter serotonin and its 5-hydroxyindoleacetic acid metabolite in the central nervous system have been associated with increased aggressive behavior in animals and humans. Controlled clinical trials of serotonin agonists in depressed adults have suggested that aggressive behavior is less likely during treatment with these medications than with placebo, but there have been no previous studies of selective serotonin reuptake inhibitors (SSRIs) and aggression in children. We prospectively followed the course of aggressive behavior in 19 psychiatrically hospitalized adolescents (not selected for aggressiveness) who received open clinical trials of fluoxetine, paroxetine, or sertraline. The patients received standard doses (equivalent to fluoxetine 10-40 mg daily) for a minimum of 5 weeks. The starting dose was 15 +/- 5 mg, and dosages were raised at a mean rate of 5 mg every 4 days up to a mean dose of 25 +/- 10 mg daily. Results from trials of the three SSRIs were clustered because the sample sizes were not sufficient for separate analyses. Overall, there were no statistically meaningful improvements in the level of aggressive behavior, as measured on a modified version of the Overt Aggression Scale, over the course of these patients' SSRI trials. Symptoms of physical aggression toward others or self were manifest in 12 of the 19 patients while on SSRIs. Of the 19 patients, 13 were assessed both on and off SSRIs: verbal aggression (p = 0.04), physical aggression toward objects (p = 0.05), and physical aggression toward self (p < 0.02) occurred significantly more frequently on SSRIs than off; no increase was observed in physical aggression toward others. Patients with the highest baseline aggressivity scores did not show greater improvement during SSRI treatment. Further research is warranted, particularly to explore whether SSRIs may have therapeutic effects on aggression at higher (or lower) doses than were administered in this open trial.

Early relationships and the development of aggression in children.

The development of abnormally aggressive human behavior is complex and multifactorial. Aggressive patterns of behavior often begin early in life and, once established, are notorious for their resistance to change, which has led some to believe that environmental interventions offer little hope for significant reductions in the prevalence of violent behavior in our society. Recent findings from research in the field of developmental psychopathology, however, have shed some new light on this very old problem. This paper specifically reviews the attachment literature and interprets it in the context of what has already been learned from research in epidemiology and behavioral genetics on environmental contributions to aggression over the life span. Environmental factors may influence the development of aggression by affecting children's early relationships with primary caregivers or by limiting opportunities for children to engage in positive relationships with caring adult figures. Longitudinal studies directly correlating early attachment relationships with levels of aggression in later childhood have been limited in number but suggest that insecure early attachment relationships may predispose children to the development of abnormally aggressive behavior, particularly when such relationships represent the entirety of their early social experience. Interventions aimed at either enhancing parent-child relationships or providing opportunities for alternative relationships with caring adult figures, particularly in high-risk settings, may help to prevent abnormally aggressive behavioral outcome.

Intergenerational aspects of the development of aggression: a preliminary report.

Across studies in a variety of environmental settings, secure attachment relationships early in life are associated with a lower rate of abnormally aggressive patterns of behavior later in childhood. The quality of an attachment relationship can be predicted by a recently developed measure of parents' mental representations of their own early childhood relationships, the Adult Attachment Interview (AAI). AAI classifications of single parents of abnormally aggressive preschoolers (n = 10) from two low income day care centers were compared with those of single parents of age-, race-, sex-, and center-matched controls (n = 10). All abnormally aggressive children had parents classified as insecure on the AAI; parents of all but one of the nonaggressive controls were classified as secure (p < .001). The AAI may be a useful intergenerational predictor of antisocial and resilient outcomes among children for whom a single caregiver is the only resource for longstanding attachment relationships. Efforts to enhance the constellation of children's early attachment relationships may serve to prevent antisocial outcome.

Reciprocal social behavior in children with and without pervasive developmental disorders.

An invariant feature of pervasive developmental disorders (PDDs) is a relative deficit in the capacity for reciprocal social behavior (RSB). The authors acquired teacher reports of RSB in 287 schoolchildren and parent reports of RSB in 158 child psychiatric patients using a new research instrument, the Social Reciprocity Scale. Total scores on this measure of RSB were continuously distributed in all groups of subjects; children with PDDs scored significantly higher for the degree of deficits in RSB than did clinical or nonclinical controls. Latent class analysis and factor analysis failed to demonstrate separate categories of deficiency for core autistic symptomatology and more general impairments in RSB, consistent with the notion of a "broader autism phenotype." Assessments of RSB on a continuous scale may be useful clinically for characterizing the behavior of children whose social deficits fall below the threshold for a full diagnosis of autism. They may also be useful in genetic-linkage studies of autistic spectrum disorders.

Supplementation of urban home visitation with a series of group meetings for parents and infants: results of a "real-world" randomized, controlled trial.

OBJECTIVE: Home visitation has been shown to be effective in reducing rates of child maltreatment and in enhancing psychosocial outcomes in children and their parents. Even when available, however, it is underutilized by parents in some urban settings. We tested a supplemental 10-session group intervention for its ability to increase active participation in home visitation, enhance the quality of caregiving behavior of parents, and improve social developmental outcome in children. METHOD: A randomized controlled design was utilized, involving two separate cohorts of parents of 3- to 18-month old infants, totaling 148 parent-child dyads. The intervention focused on practical experience in promoting parent-infant attachment relationships. RESULTS: At 6 months follow-up, there was a substantial increase in the proportion of intervention group parents participating in home visitation, compared to parents in the control group (Fisher's exact p = .008). Parents in the intervention group exhibited a trend for improvement in their capacity to appropriately interpret infants' emotional cues (p = .08), independent of the effects of home visitation itself. Attrition in both the treatment and control groups was inversely associated with income and level of education. CONCLUSIONS: Group meetings may constitute an effective means of engaging stressed urban families in home visitation.

Pediatric emergencies in children with psychiatric conditions.

This article reviews special considerations for children with psychiatric conditions when they present with pediatric emergencies. The review spans a variety of scientific disciplines and attempts to integrate information that is not usually available to the emergency practitioner from a single source; the intent is not to be exhaustive on any particular topic but to organize what is most relevant to pediatric emergency care. Topics that are discussed include: 1) a brief review of true psychiatric emergencies, 2) side effects of psychotropic medications that have direct implications for emergency assessment and management, 3) neurologic disorders that present with psychiatric manifestations, and 4) psychiatric disorders that present with somatic manifestations.