Relationship between behaviour problems and perceived parenting practices in Korean youth

BACKGROUND

Parenting practices have been accepted as powerful risk factors for behaviour problems, even though previous studies have suffered from significant methodological problems, such as small, non-representative samples, cross-sectional study designs, poor control for confounders, and minimal consideration of paternal parenting. This study examined whether three, specific maternal and paternal parenting practices are associated with internalizing and externalizing behavioural problems in youth.

METHODS

A prospective, longitudinal, cohort study was conducted among 1641 seventh- and eighth-grade students from representative sample of middle school students. The measurements were the Korean Youth Self Report and the Childrearing Behavior Questionnaire (measuring three dimensions of parenting practice: warmth-acceptance, rejection-restriction and permissiveness-non-intervention). Descriptive and logistic regression analyses were performed.

RESULTS

Maternal rejection-restriction increased risks for internalizing problems (OR = 1.112), whereas paternal control-rejection increased risks for externalizing behavioural problem (OR = 1.125).

CONCLUSIONS

Specific parenting practices showed differential associations with youth behaviour problems. These results suggest that further studies are necessary to understand the importance of unique and shared parenting practices as well as their interactions with other factors in the aetiology of youth behaviour problems. In the meantime, these findings point to therapeutic opportunities for both parents and their children.

Transmission disequilibrium testing of arginine vasopressin receptor 1A (AVPR1A) polymorphisms in autism

Impairment in social reciprocity is a central component of autism. In preclinical studies, arginine vasopressin (AVP) has been shown to increase a range of social behaviors, including affiliation and attachment, via the V(1a) receptor (AVPR1A) in the brain. Both the behavioral effects of AVP and the neural distribution of the V1a receptor vary greatly across mammalian species. This difference in regional receptor expression as well as differences in social behavior may result from a highly variable repetitive sequence in the 5' flanking region of the V1a gene (AVPR1A). Given this comparative evidence for a role in inter-species variation in social behavior, we explored whether within our own species, variation in the human AVPR1A may contribute to individual variations in social behavior, with autism representing an extreme form of social impairment. We genotyped two microsatellite polymorphisms from the 5' flanking region of AVPR1A for 115 autism trios and found nominally significant transmission disequilibrium between autism and one of the microsatellite markers by Multiallelic Transmission/Disequilibrium test (MTDT) that was not significant after Bonferroni correction. We also screened approximately 2 kb of the 5' flanking region and the coding region and identified 10 single nucleotide polymorphisms.

Transmission disequilibrium mapping at the serotonin transporter gene (SLC6A4) region in autistic disorder

The serotonin transporter gene (SLC6A4, MIM 182138) is a candidate gene in autistic disorder based on neurochemical, neuroendocrine studies and the efficacy of potent serotonin transporter inhibitors in reducing ritualistic behaviors and related aggression. An insertion/deletion polymorphism (5-HTTLPR) in the promoter region and a variable number of tandem repeat polymorphism (VNTR) in the second intron, were previously identified and suggested to modulate transcription. Six previous family-based association studies of SLC6A4 in autistic disorder have been conducted, with four studies showing nominally significant transmission disequilibrium and two studies with no evidence of nominally significant transmission disequilibrium. In the present study, TDT was conducted in 81 new trios. A previous finding of transmission disequilibrium between a haplotype consisting of the 5-HTTLPR and intron 2 VNTR was replicated in this study, but not preferential transmission of 5-HTTLPR as an independent marker. Because of inconsistent transmission of 5-HTTLPR across studies, SLC6A4 and its flanking regions were sequenced in 10 probands, followed by typing of 20 single nucleotide polymorphisms (SNPs) and seven simple sequence repeat (SSR) polymorphisms in 115 autism trios. When individual markers were analyzed by TDT, seven SNP markers and four SSR markers (six SNPs, 5-HTTLPR and the second intron VNTR from promoter 1A through intron 2 of SLC6A4, one SSR from intron 7 of SLC6A4, one SNP from the bleomycin hydrolase gene (BLMH, MIM 602403) and one SSR telomeric to BLMH) showed nominally significant evidence of transmission disequilibrium. Four markers showed stronger evidence of transmission disequilibrium (TDT(max) P = 0.0005) than 5-HTTLPR.

Multisite, double-blind, placebo-controlled trial of porcine secretin in autism

OBJECTIVE

To examine the efficacy of intravenous porcine secretin for the treatment of autistic disorder.

METHOD

Randomized, double-blind, placebo-controlled, crossover design. Fifty-six subjects with autistic disorder received either a secretin or placebo infusion at baseline and the other substance at week 4. Subjects were given the Autism Diagnostic Observation Schedule (ADOS) and other pertinent developmental measures at baseline and at weeks 4 and 8 to assess drug effects.

RESULTS

For the primary efficacy analysis, change of ADOS social-communication total score from week 0 to week 4, no statistically significant difference was obtained between placebo (-0.8 +/- 2.9) and secretin groups (-0.6 +/- 1.4; t54 = 0.346, p < .73). The other measures showed no treatment effect for secretin compared with placebo.

CONCLUSION

There was no evidence for efficacy of secretin in this randomized, placebo-controlled, double-blind trial.

Double-blind, placebo-controlled study of amantadine hydrochloride in the treatment of children with autistic disorder

OBJECTIVE

To test the hypothesis that amantadine hydrochloride is a safe and effective treatment for behavioral disturbances--for example, hyperactivity and irritability--in children with autism.

METHOD

Thirty-nine subjects (intent to treat; 5-19 years old; IQ > 35) had autism diagnosed according to DSM-IV and ICD-10 criteria using the Autism Diagnostic Interview-Revised and the Autism Diagnostic Observation Schedule-Generic. The Aberrant Behavior Checklist-Community Version (ABC-CV) and Clinical Global Impressions (CGI) scale were used as outcome variables. After a 1-week, single-blind placebo run-in, patients received a single daily dose of amantadine (2.5 mg/kg per day) or placebo for the next week, and then bid dosing (5.0 mg/kg per day) for the subsequent 3 weeks.

RESULTS

When assessed on the basis of parent-rated ABC-CV ratings of irritability and hyperactivity, the mean placebo response rate was 37% versus amantadine at 47% (not significant). However, in the amantadine-treated group there were statistically significant improvements in absolute changes in clinician-rated ABC-CVs for hyperactivity (amantadine -6.4 versus placebo -2.1; p = .046) and inappropriate speech (-1.9 versus 0.4; p = .008). CGI scale ratings were higher in the amantadine group: 53% improved versus 25% (p = .076). Amantadine was well tolerated.

CONCLUSIONS

Parents did not report statistically significant behavioral change with amantadine. However, clinician-rated improvements in behavioral ratings following treatment with amantadine suggest that further studies with this or other drugs acting on the glutamatergic system are warranted. The design of these and similar drug trials in children with autistic disorder must take into account the possibility of a large placebo response.

Clinical and neurochemical effects of fenfluramine in children with autism

Fifteen children with autism were treated with 60 mg d,l-fenfluramine (FEN) or placebo in a double-blind A-B-A protocol followed immediately by double-blind placebo-controlled crossover administration of FEN (total duration 62 weeks). Both biochemical and clinical outcomes were examined. Biochemically, FEN led to an increase in dihydroxyphenylacetic acid (DOPAC) and decreases in whole-blood serotonin (5-HT), plasma norepinephrine (NE), and plasma 3-methoxy-4-hydroxyphenylglycol (MHPG). The decrease in whole-blood 5-HT was seen only during treatment with FEN. However, NE levels did not return to baseline as long as 8 weeks after the first FEN treatment period. Increases in DOPAC were greater during the second FEN treatment period than the first. Persistent changes in catecholamine regulation may be related to previously reported long-term effects on central nervous system 5-HT after FEN. Clinically, FEN led to a modest decrease in parent, but not teacher, ratings of hyperactivity and to a small reduction in sensorimotor abnormalities. Abnormal social and affectual responses also decreased, but this was not directly related to FEN treatment. Effects on cognition were equivocal. Hyperserotonemic subjects did not differ from normoserotonemic subjects in clinical response. Overall, no significant advantage for the use of FEN could be established.

Autistic children and their first-degree relatives: relationships between serotonin and norepinephrine levels and intelligence

Whole-blood serotonin (5-HT) and plasma norepinephrine (NE) were studied in 16 autistic children, 21 siblings of autistic children, and 53 parents of autistic children. Both plasma NE and whole-blood 5-HT were negatively correlated with vocabulary performance. Whole-blood 5-HT and plasma NE did not differ between autistic children with or without histories of self-injurious behavior or decreased pain sensitivity. Eighteen subjects were hyperserotonemic (whole-blood 5-HT greater than 270 ng/ml). For these subjects, plasma NE was significantly higher than for subjects without hyperserotonemia. Seven of 10 families with one hyperserotonemic member had two or more hyperserotonemic members. Observations of familiarity of whole-blood 5-HT suggest that larger-scale and more focused study of whole-blood 5-HT as a possible genetic marker may be productive.

Genomic organization of the SLC1A1/EAAC1 gene and mutation screening in early-onset obsessive-compulsive disorder

The first genome scan conducted in early-onset obsessive-compulsive disorder used a non-parametric analysis to identify a peak in a region of chromosome 9 containing the gene SLC1A1, which codes for the neuronal and epithelial glutamate transporter EAAC1. Interaction between the glutamatergic and serotonergic systems within the striatum suggests EAAC1 as a functional candidate in OCD as well. We determined the genomic organization of SLC1A1 primarily by using primers designed from cDNA sequence to amplify from adaptor-ligated genomic DNA restriction fragments. In order to confirm SLC1A1 as a positional candidate in early-onset OCD, common single nucleotide polymorphisms (SNPs) were identified that enabled mapping of SLC1A1 within the region of the lod score peak. Based on the linkage evidence, the coding region was sequenced in the probands of the seven families included in the genome scan. No evidence was found for a functional mutation, but several SNPs were identified. Capillary electrophoresis SSCP typing of a haplotype consisting of two common SNPs within EAAC1 revealed no significant linkage disequilibrium.

Quantifying the phenotype in autism spectrum disorders

Twin and family studies suggest that familial transmission in autism extends to a spectrum of social and behavioral deficits that characterize individuals who have significant impairments within the autism spectrum, but do not meet formal criteria for autistic disorder. Standardized diagnostic instruments, including the Autism Diagnostic Interview-Revised (ADI-R) and the Autism Diagnostic Observation Schedule (ADOS-WPS Edition), offer the opportunity to quantify deficits across the autism spectrum, controlling effects of language and cognitive delay, in individuals with significant impairments. It is suggested that quantitative measures of social reciprocity and repetitive behaviors and interests, with separate quantification of expressive language level and nonverbal intelligence, most accurately reflect the range of behavioral phenotypes in autism spectrum disorders.

The autism diagnostic observation schedule-generic: a standard measure of social and communication deficits associated with the spectrum of autism

The Autism Diagnostic Observation Schedule-Generic (ADOS-G) is a semistructured, standardized assessment of social interaction, communication, play, and imaginative use of materials for individuals suspected of having autism spectrum disorders. The observational schedule consists of four 30-minute modules, each designed to be administered to different individuals according to their level of expressive language. Psychometric data are presented for 223 children and adults with Autistic Disorder (autism), Pervasive Developmental Disorder Not Otherwise Specified (PDDNOS) or nonspectrum diagnoses. Within each module, diagnostic groups were equivalent on expressive language level. Results indicate substantial interrater and test-retest reliability for individual items, excellent interrater reliability within domains and excellent internal consistency. Comparisons of means indicated consistent differentiation of autism and PDDNOS from nonspectrum individuals, with some, but less consistent, differentiation of autism from PDDNOS. A priori operationalization of DSM-IV/ICD-10 criteria, factor analyses, and ROC curves were used to generate diagnostic algorithms with thresholds set for autism and broader autism spectrum/PDD. Algorithm sensitivities and specificities for autism and PDDNOS relative to nonspectrum disorders were excellent, with moderate differentiation of autism from PDDNOS.

Deletion polymorphism in the coding region of the human NESP55 alternative transcript of GNAS1

NESP55, a novel member of the chromogranins, was originally implicated as a precursor of a peptide LSAL with 5-HT1B receptor antagonist activity. In humans, NESP55 (MIM 139320) is encoded by an alternative transcript of GNAS1, the gene encoding the guanine nucleotide-binding alpha subunit of G(S). As a result of the potential relevance of NESP55 to serotoninergic neurotransmission, we screened its sequence using genomic DNA pools from autistic disorder, obsessive-compulsive disorder (OCD) probands and control subjects. Six single nucleotide polymorphisms (SNPs) were identified and the allele frequencies of those SNPs were determined. In addition, a 24-bp in-frame deletion in the coding region was found in one of the OCD probands. To further investigate its pattern of inheritance and the relevance to studied phenotypes, we genotyped 123 total subjects from autism, OCD and attention deficit hyperactivity disorder (ADHD) families. The deletion was detected only in one OCD family and followed Mendelian inheritance. All subjects with the deletion were heterozygous. However, there are no specific behavioural or physical alterations in the subjects with this deletion variant. The physiological role of NESP55 in serotoninergic neurotransmission as well as the effect of the deletion on its function should be evaluated in future studies.

The autism diagnostic observation schedule-generic: a standard measure of social and communication deficits associated with the spectrum of autism

The Autism Diagnostic Observation Schedule-Generic (ADOS-G) is a semistructured, standardized assessment of social interaction, communication, play, and imaginative use of materials for individuals suspected of having autism spectrum disorders. The observational schedule consists of four 30-minute modules, each designed to be administered to different individuals according to their level of expressive language. Psychometric data are presented for 223 children and adults with Autistic Disorder (autism), Pervasive Developmental Disorder Not Otherwise Specified (PDDNOS) or nonspectrum diagnoses. Within each module, diagnostic groups were equivalent on expressive language level. Results indicate substantial interrater and test-retest reliability for individual items, excellent interrater reliability within domains and excellent internal consistency. Comparisons of means indicated consistent differentiation of autism and PDDNOS from nonspectrum individuals, with some, but less consistent, differentiation of autism from PDDNOS. A priori operationalization of DSM-IV/ICD-10 criteria, factor analyses, and ROC curves were used to generate diagnostic algorithms with thresholds set for autism and broader autism spectrum/PDD. Algorithm sensitivities and specificities for autism and PDDNOS relative to nonspectrum disorders were excellent, with moderate differentiation of autism from PDDNOS.

Mutation screening of human 5-HT(2B)receptor gene in early-onset obsessive-compulsive disorder

The serotonin receptor 2B gene (HTR2B; MIM 601122) is a pharmacological and positional candidate gene in early-onset obsessive-compulsive disorder. Sequences of a putative promoter region and splice regions were first elucidated, then sequenced along with HTR2B coding regions. Probands from seven families included in a previous genome scan in which one of the strongest linkage findings was to a region including HTR2B, along with two genomic DNA pools of 10 unrelated control subjects and 10 unrelated autism probands were screened. One single nucleotide polymorphism was found in intron 1, that may be useful as a marker in genetic linkage and association studies. It does not appear likely to affect splicing. No evidence for functional mutation was found in the sequenced regions of HTR2B.

Physical mapping of the serotonin 5-HT(7) receptor gene (HTR7) to chromosome 10 and pseudogene (HTR7P) to chromosome 12, and testing of linkage disequilibrium between HTR7 and autistic disorder

The gene encoding the serotonin 5-HT(7) receptor (HTR7) has been considered as a candidate locus in several neuropsychiatric disorders, based on pharmacological evidence and ligand-binding studies. After determining over 3 kb of previously unpublished sequence from introns 1 and 2 of HTR7, a single base (C/T) polymorphism in the second intron of HTR7 was found. Allele-specific PCR was used to genotype the HTR7 marker in 53 trios consisting of subjects with autistic disorder and both parents. Using the transmission disequilibrium test (TDT), no evidence of preferential transmission of either allele was found (TDT chi(2) = 0.252, p = 0.602). Sequence data obtained from both intron 1 and intron 2 of HTR7, and from the 5-HT(7) pseudogene (HTR7P), was used to confirm localization of HTR7 to 10q23 and HTR7P to 12p13 using radiation hybrid analyses.

Mutation screening of the UBE3A/E6-AP gene in autistic disorder

Previous reports of individuals with autistic disorder with maternal duplications of 15q11-q13, the Prader-Willi/Angelman syndrome region, suggest this area as a source of candidate genes in autistic disorder. Maternal truncation mutations in UBE3A, which encodes for E6-AP ubiquitin-protein ligase, have been shown to cause Angelman syndrome, which can also result from the absence of maternal chromosomal material from this region. Despite showing no evidence for imprinting in other tissues, this gene was recently discovered to be preferentially maternally expressed in human brain and expressed solely from the murine maternal chromosome in the hippocampus and cerebellar Purkinje cells, regions implicated in the neuropathology of autism. Based on this evidence, the coding region and a putative promoter region were sequenced in ten autistic subjects. Several polymorphisms were detected, but no evidence was found for a functional mutation. Evidence for likely altered regulation of UBE3A expression in maternal 15q11-q13 duplications suggests further investigation of the regulatory regions of this gene in autistic disorder.

Molecular screening for proximal 15q abnormalities in a mentally retarded population

Paternal or maternal deletions in the 15q11.2-q13 region are known to result in Prader-Willi syndrome (PWS) or Angelman syndrome (AS), respectively. Maternal duplications in 15q11.2-q13 have been found in patients with autism. A population of adults with moderate to profound mental retardation was studied to examine the usefulness of PCR based molecular methods in screening for proximal chromosome 15 abnormalities. Two hundred and eighty-five subjects were initially screened at five microsatellite markers with average heterozygosity values of 0.74 (range 0.54-0.82). Of these subjects, four had a single allele at all five loci, suggestive of a deletion or uniparental isodisomy. The four samples were further screened with additional markers located within 15q11.2-q13 as well as markers telomeric to this region. One subject had uniparental disomy (UPD) and three subjects had a deletion. To determine the parental origin of the 15q11-q13 region containing the single haplotype, samples were analysed with a newly developed methylation specific PCR technique at the SNRPN locus. Each of the four subjects showed presence of the paternal allele and absence of the maternal allele. All cases had a phenotype consistent with Angelman syndrome as expected for the level of mental retardation, but the subject with UPD was distinct from the other subjects with an absence of a history of seizures and presence of bilateral undescended testes and Parkinsonism. Although Angelman syndrome has an estimated population prevalence of 0.008%, at least 1.4% of the moderately to profoundly mentally retarded subjects screened were found to have Angelman syndrome.

Linkage-disequilibrium mapping of autistic disorder, with 15q11-13 markers

Autistic disorder is a complex genetic disease. Because of previous reports of individuals with autistic disorder with duplications of the Prader-Willi/Angelman syndrome critical region, we screened several markers across the 15q11-13 region, for linkage disequilibrium. One hundred forty families, consisting predominantly of a child with autistic disorder and both parents, were studied. Genotyping was performed by use of multiplex PCR and capillary electrophoresis. Two children were identified who had interstitial chromosome 15 duplications and were excluded from further linkage-disequilibrium analysis. Use of the multiallelic transmission-disequilibrium test (MTDT), for nine loci on 15q11-13, revealed linkage disequilibrium between autistic disorder and a marker in the gamma-aminobutyric acidA receptor subunit gene, GABRB3 155CA-2 (MTDT 28.63, 10 df, P=.0014). No evidence was found for parent-of-origin effects on allelic transmission. The convergence of GABRB3 as a positional and functional candidate along with the linkage-disequilibrium data suggests the need for further investigation of the role of GABRB3 or adjacent genes in autistic disorder.

Serotonin transporter and seasonal variation in blood serotonin in families with obsessive-compulsive disorder

The serotonin transporter (HTT) is a candidate gene for obsessive-compulsive disorder (OCD) that has been associated with anxiety-related traits. The long (l) and short (s) variants of the HTT promoter have different transcriptional efficiencies. HTT promoter genotype and blood 5-HT concentration were examined in 70 subjects from 20 families ascertained through children and adolescents with a DSM-III-R diagnosis of OCD. The HTT promoter variant had a significant effect on blood 5-HT content. Subjects with the l/l and l/s genotypes had significantly higher blood 5-HT levels than did those with the s/s genotype. There was a significant interaction between HTT promoter genotype and seasonal variation in blood 5-HT content, with significant seasonal differences in 5-HT occurring only in the subjects with the l/l genotype. Further studies of the regulation of HTT gene expression are indicated.

Maternal smoking during pregnancy and the risk of conduct disorder in boys

BACKGROUND

Previous animal and human studies have indicated that prenatal exposure to nicotine is associated with adverse reproductive outcomes, including altered neural structure and functioning, cognitive deficits, and behavior problems in the offspring. Our study extends previous research on humans by controlling a broad range of correlates of maternal smoking during pregnancy to determine if smoking is associated with behavior problems in the offspring severe enough to qualify for DSM-III-R diagnosis.

METHODS

Subjects were 177 clinic-referred boys, ages 7 to 12 years at the time of the first assessment, who underwent longitudinal assessment for 6 years using annual structured diagnostic interviews. Correlates of maternal smoking during pregnancy and previously identified demographic, parental, perinatal, and family risk factors for the disruptive behavior disorders were controlled in logistic regression analyses.

RESULTS

Mothers who smoked more than half a pack of cigarettes daily during pregnancy were significantly more likely to have a child with conduct disorder (odds ratio, 4.4; P = .001) than mothers who did not smoke during pregnancy. This association was statistically significant when controlling for socioeconomic status, maternal age, parental antisocial personality, substance abuse during pregnancy, and maladaptive parenting.

CONCLUSIONS

Maternal smoking during pregnancy appears to be a robust independent risk factor for conduct disorder in male offspring. Maternal smoking during pregnancy may have direct adverse effects on the developing fetus or be a marker for a heretofore unmeasured characteristic of mothers that is of etiologic significance conduct disorder.

Evidence of linkage between the serotonin transporter and autistic disorder

The serotonin transporter gene (HTT) is a primary candidate in autistic disorder based on efficacy of potent serotonin transporter inhibitors in reducing rituals and routines. We initiated a candidate gene study of HTT in trios consisting of probands with autistic disorder and both parents. Preliminary transmission/disequilibrium test (TDT) analysis with 86 families revealed no evidence for linkage or linkage disequilibrium between autistic disorder and a polymorphism in the second intron of HTT. However, preferential transmission of a short variant of the HTT promoter was found in the same 86 trios (TDT chi 2 = 4.69, 1 d.f., P = 0.030). In further analyses, we considered haplotypes of the HTT promoter variant and second intron locus as alleles in a multiallelic TDT. Results confirmed the significance of the effect of this region (TDT chi 2 = 11.85, 4 d.f., P = 0.018). This provides preliminary evidence of linkage and association between HTT and autistic disorder.

Autism or atypical autism in maternally but not paternally derived proximal 15q duplication

Duplications of proximal 15q have been found in individuals with autistic disorder (AD) and varying degrees of mental retardation. Often these abnormalities take the form of a supernumerary inverted duplicated chromosome 15, more properly described as an isodicentric chromosome 15, or idic(15). However, intrachromosomal duplications also have been reported. In a few cases, unaffected mothers, as well as their affected children, carry the same duplications. During the course of the genotyping of trios of affected probands with AD and their parents, at the positional candidate locus D15S122, an intrachromosomal duplication of proximal 15q was detected by microsatellite analysis in a phenotypically normal mother. Microsatellite and methylation analyses of the pedigree in the following report show that, among three children, the two with autism or atypical autism have maternal inheritance of a 15q11-q13 duplication whereas the third child, who is unaffected, did not inherit this duplication. Their mother's 15q11-q13 duplication arose de novo from her father's chromosomes 15. This finding documents, for the first time, the significance of parental origin for duplications of 15q11-q13. In this family, paternal inheritance leads to a normal phenotype, and maternal inheritance leads to autism or atypical autism.

The serotonin system in autism

The serotonin system has been implicated as a factor in some cases of autism since the finding in 1961 of elevated serotonin (5-hydroxytryptamine) levels in the blood of patients with autism. This has been clarified as elevation in the platelet content of serotonin. Subjects with elevated whole blood serotonin levels have been shown to have elevated platelet serotonin transport into platelets and decreased serotonin 5-HT2 receptor binding. Most individuals with autism who are treated with potent serotonin transporter inhibitors have a reduction in ritualistic behavior and aggression. Reduction of central nervous system serotonin, induced by acute tryptophan depletion, causes a worsening of stereotyped behavior. Recent developments in the molecular biology of serotonin receptors are reviewed.

Behavioral and cognitive effects of methylxanthines. A meta-analysis of theophylline and caffeine

BACKGROUND

Theophylline has been extensively studied as a treatment of asthma. However, some studies have suggested that theophylline may precipitate adverse behavioral and cognitive effects on children. Other reports have evaluated the effects of caffeine, another commonly used methylxanthine, as a treatment of attention-deficit hyperactivity disorder.

OBJECTIVE

To present a meta-analysis of research on the behavioral and cognitive effects of methylxanthines in children.

METHODS

The meta-analyses were conducted on 12 studies of theophylline and nine studies of caffeine that met inclusion criteria.

RESULTS

In contrast to popular beliefs and earlier scientific reports, meta-analyses of controlled studies did not indicate that either theophylline or caffeine resulted in significant deleterious effects on cognition or behavior. In fact, there was a small, positive effect on parental report of externalizing behavior for both methylxanthines.

CONCLUSIONS

There is little evidence to suggest that methylxanthines have adverse cognitive or behavioral effects on children. Questions remain with regard to the identification and determinants of either responsive or sensitive subgroups, dose-response relationships, and the effects of parent-teacher expectancies on behavioral ratings.

Attention deficit hyperactivity disorder and whole-blood serotonin levels: effects of comorbidity

Whole-blood serotonin (5-hydroxytryptamine, 5-HT) levels were measured in children with attention deficit hyperactivity disorder (ADHD) with and without comorbid conduct disorder (CD) or oppositional-defiant disorder (ODD). It was hypothesized that the whole-blood 5-HT levels of ADHD probands would be significantly correlated with the whole-blood 5-HT levels of their mothers. Fifty-two children who met DSM-III-R criteria for ADHD were selected consecutively from an ADHD clinic (47 males--35 Caucasians, 10 African-Americans, and 2 Hispanics; 10 females--all Caucasians). Whole-blood 5-HT was assayed by high performance liquid chromatography and compared between ADHD children with and without comorbid CD or ODD. The familiality of whole-blood 5-HT levels was studied by Spearman's rank-order correlation. There were no significant age, race, or sex effects. There was no significant difference in whole-blood 5-HT levels between children with ADHD only (n = 22; 190 +/- 45 ng/ml) and ADHD with CD or ODD (n = 30; 212 +/- 67). However, 7 out of 30 (23%) children with ADHD+CD/ODD had whole-blood 5-HT levels > 270 ng/ml, while none of the ADHD-only children had whole-blood 5-HT levels > 270 ng/ml, a statistically significant difference. Whole-blood 5-HT levels showed significant positive correlations between 36 children with disruptive behavior disorders and their biological mothers (rs = 0.47). There was no difference in mean levels of whole-blood 5-HT between subgroups of children with ADHD with or without comorbid CD or ODD.(ABSTRACT TRUNCATED AT 250 WORDS)

Association of attention-deficit disorder and the dopamine transporter gene

Attention-deficit hyperactivity disorder (ADHD) has been shown to be familial and heritable, in previous studies. As with most psychiatric disorders, examination of pedigrees has not revealed a consistent Mendelian mode of transmission. The response of ADHD patients to medications that inhibit the dopamine transporter, including methylphenidate, amphetamine, pemoline, and bupropion, led us to consider the dopamine transporter as a primary candidate gene for ADHD. To avoid effects of population stratification and to avoid the problem of classification of relatives with other psychiatric disorders as affected or unaffected, we used the haplotype-based haplotype relative risk (HHRR) method to test for association between a VNTR polymorphism at the dopamine transporter locus (DAT1) and DSM-III-R-diagnosed ADHD (N = 49) and undifferentiated attention-deficit disorder (UADD) (N = 8) in trios composed of father, mother, and affected offspring. HHRR analysis revealed significant association between ADHD/UADD and the 480-bp DAT1 allele (chi 2 7.51, 1 df, P = .006). When cases of UADD were dropped from the analysis, similar results were found (Chi 2 7.29, 1 df, P = .007). If these findings are replicated, molecular analysis of the dopamine transporter gene may identify mutations that increase susceptibility to ADHD/UADD. Biochemical analysis of such mutations may lead to development of more effective therapeutic interventions.

Fluoxetine effects on cerebral glucose metabolism

In a counterbalanced, double-blind, placebo-controlled trial, 40 mg of fluoxetine was administered to four healthy adult volunteers (three men, one woman; age range 20-39 years), 90 min before injection of 6-7.5 mCi of [18F]-2-deoxyglucose to measure cerebral metabolic rate of glucose (CMRglu). Subjects were engaged in a visual monitoring task shortly before and during scanning with a PETT-VI tomograph. Global CMRglu did not differ when placebo (8.93 +/- 0.96 mg 100 g-1 min-1) was compared to fluoxetine (8.22 +/- 0.86 mg 100 g-1 min-1; paired t-test = 0.82, df = 3, p < 0.48). However, statistical parametric mapping of differences in CMRglu between placebo and fluoxetine conditions revealed regional effects of fluoxetine shown by decreased metabolism in the amygdaloid complex, hippocampal formation and ventral striatum, and by increased metabolism centered in the right superior parietal lobe (Brodmann area 7). Parametric mapping for use in PET studies of glucose metabolism represents a significant new tool for studying drug effects in humans.

Primary structure of the human platelet serotonin 5-HT2A receptor: identify with frontal cortex serotonin 5-HT2A receptor

Previous radioligand binding studies have demonstrated human platelet serotonin2A (5-HT2A) receptor binding sites. Pharmacological similarities between platelet and frontal cortex 5-HT2A receptor binding parameters have been demonstrated. However, it is not clear whether the platelet 5-HT2A receptor primary structure is identical to that of the brain receptor. Three overlapping cDNAs were obtained to span completely the coding region of the 5-HT2A receptor. These clones were sequenced with external and internal primers. The nucleotide sequence of human platelet 5-HT2A cDNA was identical to that reported for the human frontal cortex 5-HT2A receptor, except for nucleotide 102 (T-->C), which has been reported to represent a normal DNA polymorphism that does not alter the amino acid sequence. This finding may have implications in the study of neuropsychiatric disorders for which altered platelet 5-HT2A receptor binding has been demonstrated.

Depressive and obsessive-compulsive symptoms in hyperserotonemic parents of children with autistic disorder

Because of previous findings that parents of children with autistic disorder may be at increased risk for anxiety disorders and/or mood disorders, the Center for Epidemiological Studies-Depression (CES-D) Scale and the Modified Maudsley Obsessive-Compulsive Inventory (MMOCI) were administered to parents of children with autistic disorder and parents of children with Down's syndrome. Parents with normal whole blood serotonin levels who had children with autistic disorder and parents of children with Down's syndrome had significantly lower CES-D depression scores than parents with elevated whole blood serotonin levels who had children with autistic disorder. Hyperserotonemic parents of children with autistic disorder had significantly higher MMOCI scores than parents of children with Down's syndrome.

Autistic disorder and post-traumatic stress disorder

The present case study examined an adolescent boy who initially was evaluated at our clinic and was found to meet DSM-III-R criteria for autistic disorder. After placement in a residential school using Daily Life Therapy for autistic disorder, the subject reported being physically abused by a staff member. Additional psychiatric evaluation revealed post-traumatic stress disorder (PTSD) including symbolic anxiety and repetition of the trauma. The diagnosis of PTSD should be considered in children with autistic disorder and other severe developmental disorders who have experienced physical and sexual abuse. Furthermore, parents, professionals, educators, and child care workers struggle with emotional reactions to children with severe developmental disorders and may have difficulty accepting the reality of the child rather than the fantasy of the "wished-for child." The disappointment of this fantasy and the equating of the child's weaknesses as one's own may lead to personal devaluation and increase the risk of abusive behavior.

Receptor inhibition by immunoglobulins: specific inhibition by autistic children, their relatives, and control subjects

Forty-two parents of children with autistic disorder, 15 children with autistic disorder, 17 siblings of children with autistic disorder, and 12 unrelated normal adult controls were studied to determine if immunoglobulins isolated from their plasma would inhibit binding of the 5HT1A agonist, [3H]-8-hydroxy-N,N-dipropyl-2-aminotetralin (DPAT) to 5HT1A receptors in human hippocampal membranes. There were no significant differences among the means of percentage inhibition of DPAT binding of parents, children with autistic disorder, siblings, or unrelated controls. In addition, there were no differences in the proportion of subjects with > 15% DPAT inhibition among autistic children, their parents, their siblings, or unrelated controls. Immunoglobulin inhibition was not specific for the 5HT1A receptor binding site, since immunoglobulins inhibited binding to 5HT2, D1, D2, and alpha 2-adrenergic binding sites. The immunoglobulins isolated from normal controls inhibited [3H]-rauwolscine binding at alpha 2-adrenergic sites less than immunoglobulins of children with autistic disorder and their parents and siblings. This study did not support the hypothesis that autoantibodies to 5HT1A or 5HT2 receptors are characteristic of autistic disorder.

Platelet serotonin studies in hyperserotonemic relatives of children with autistic disorder

Platelet serotonin (5-HT) studies were conducted with 12 hyperserotonemic and 12 normoserotonemic age-, sex-, and relationship-matched relatives of autistic probands. Each group consisted of 7 mothers, 4 fathers, and 1 sister of autistic children and adolescents. The density (Bmax) of platelet 5-HT2 receptor binding sites, labelled with [3H]-lysergic acid diethylamide (LSD), was significantly lower in 11 hyperserotonemic subjects compared to 12 normoserotonemic subjects (40.9 +/- 13.5 fmol/mg protein, 59.6 +/- 13.2; p < 0.004). The affinity (Kd) for [3H]-LSD binding did not differ. Although the density (Bmax) of [3H]-paroxetine binding did not differ between groups, there was a small difference in the affinity (Kd) for [3H]-paroxetine binding (hyperserotonemic 47.6 +/- 9.0 pM, normoserotonemic 54.8 +/- 12.1; p < 0.05). There were no significant differences in platelet 5-HT uptake, or in thrombin-stimulated 5-HT release. Basal, 5-HT-stimulated, and arginine-vasopressin (AVP)-stimulated inositol phosphate production, as well as basal, prostaglandin E1 (PGE1)-, and forskolin-stimulated cAMP production did not differ. There were significant correlations between whole blood 5-HT levels and LSD Bmax (rs = -0.63, N = 23, p < 0.002) and whole blood 5-HT levels and 5-HT uptake Vmax (rs = 0.56, N = 18, p < 0.02). However, [3H]-LSD labelled 5-HT2 binding and 5-HT uptake were not correlated with each other. Hyperserotonemia of autism may be heterogeneous with one subgroup of subjects with increased 5-HT uptake and another subgroup with decreased 5-HT2 binding.

Clonidine treatment of hyperactive and impulsive children with autistic disorder

Many autistic children have associated problems of inattention, impulsivity, and hyperactivity that limit the effectiveness of educational and behavioral interventions. Few controlled psychopharmacologic trials have been conducted in autistic children to determine which agents may be effective for these associated features. Eight male children (8.1 +/- 2.8 years) with autistic disorder, diagnosed by DSM-III-R criteria, completed a placebo-controlled, double-blind crossover trial of clonidine. Subjects were included in the study if they had inattention, impulsivity, and hyperactivity that was excessive for their developmental level. Subjects had not tolerated or responded to other psychopharmacologic treatments (neuroleptics, methylphenidate, or desipramine). Teacher ratings on the Aberrant Behavior Checklist irritability, stereotypy, hyperactivity, and inappropriate speech factors were lower during treatment with clonidine than during treatment with placebo. Attention deficit disorder with hyperactivity: Comprehensive Teacher's Rating Scale ratings were not significantly improved during the study, except for oppositional behavior. Parent Conners Abbreviated Parent-Teacher Questionnaire ratings significantly improved during clonidine treatment. Clonidine led to increased ratings of the side effects of drowsiness and decreased activity. Clinician ratings (Children's Psychiatric Rating Scale Autism, Hyperactivity, Anger and Speech Deviance factors; Children's Global Assessment Scale; Clinical Global Impressions efficacy) of videotaped sessions were not significantly different between clonidine and placebo. Clonidine was modestly effective in the short-term treatment of irritability and hyperactivity in some children with autistic disorder.

Fluoxetine treatment of children and adults with autistic disorder and mental retardation

An open trial of pharmacological treatment with fluoxetine, ranging from 20 mg every other day to 80 mg per day, led to a significant improvement in Clinical Global Impressions ratings of Clinical Severity in 15 of 23 subjects with autistic disorder and 10 of 16 subjects with mental retardation. Six of 23 patients with autistic disorder and 3 of 16 patients with mental retardation had side effects which significantly interfered with function, consisting predominantly of restlessness, hyperactivity, agitation, decreased appetite, or insomnia. Double-blind studies of the efficacy of pharmacological agents that potently inhibit 5-HT uptake in the treatment of mental retardation coexisting with Axis I psychiatric disorders (especially obsessive-compulsive disorder) and autistic disorder are warranted.

Platelet 5-HT2 serotonin receptor binding sites in autistic children and their first-degree relatives

We examined platelet serotonin2 [5-hydroxytryptamine2 (5-HT2)] receptor binding sites, whole blood serotonin (5-HT), and plasma norepinephrine (NE) in male autistic children and their first-degree relatives. Saturation studies utilizing 125I-spiroperidol labeled the 5-HT2 sites with an affinity of 224.6 +/- 84.4 pmol/L (Kd). No group differences, i.e., autistic (n = 12), siblings (n = 6), parents (n = 22), control (adult; n = 7: child; n = 10), were seen for either the Kd or the total number of sites (Bmax: 14.3 +/- 10.9 fmol/mg protein). No correlations were found in any group between binding parameters (Kd or Bmax) and whole blood 5-HT. For the parental group, inverse correlations were found between NE and Bmax (standing NE, rs = -0.67, n = 21, p = 0.001; supine NE, rs = -0.49, n = 22, p = 0.021). In the autistic group, no correlation was seen between plasma NE and Bmax. A correlation between the autistic boys' Bmax and their fathers' Bmax was observed (rs = 0.79, n = 11, p = 0.004). These findings suggest (1) circulating NE may be involved in heterologous regulation of 5-HT2 receptors in the platelet and (2) genetic (paternal-filial) factors may play a role in the expression of 5-HT2 binding sites in the platelet. These preliminary findings are discussed in relation to heterologous receptor regulation. The relationships between these findings and either the pathophysiology of autism or hyperserotonemia in autism are unknown.

Relationships of whole blood serotonin and plasma norepinephrine within families

Whole blood serotonin (5HT) and plasma norepinephrine (NE) levels were determined in 47 families of autistic probands to study relationships within families of these measures. Whole blood 5HT, but not plasma NE, was significantly positively correlated between autistic children and their mothers, fathers, and siblings. Twenty-three of the 47 families studied had at least 1 hyperserotonemic member. Of these 23 families, 10 (43.5%) had 2 or more hyperserotonemic members; 5 families were identified in which each family member studied had hyperserotonemia (whole blood 5HT greater than 270 ng/ml). If the autistic child of a family was hyperserotonemic, the first-degree relatives were 2.4 times more likely to be hypersertonemic than if the autistic child was not hyperserotonemic. Mean whole blood 5HT levels were higher in autistic subjects than their parents or siblings. Siblings were found to have lower plasma NE than autistic probands. This study replicates a previous study showing familial relationships of hyperserotonemia within families with autistic children.

Serotonin and measured intelligence

Blood serotonin (5HT) has been shown to be elevated in 30% of autistic children and 50% of severely mentally retarded children. Ninety-eight normal adult subjects were studied to determine if there was an inverse relationship between whole blood 5HT in normal adults of average and above-average intelligence. There was a trend toward a negative correlation between whole blood 5HT and Vocabulary scores that would not account for hyperserotonemia in autistic or mentally retarded individuals. Female subjects had significantly greater whole blood 5HT than male subjects. There was no difference in whole blood 5HT collected before and after volume depletion of 450 ml, providing further evidence of the intraindividual stability of whole blood serotonin levels. There was no relationship between age and whole blood 5HT in a group of normal adult subjects.

Down's syndrome with mania

Sovner et al (1985) proposed that the presence of Down's Syndrome (DS) precludes the possibility of concomitant mama, and this is not a new claim, since Earl (1961) had stated that neither cyclothymia nor manic-depressive psychosis occurred in the mentally retarded. While Sovner et al conceded that cases of mania in individuals with DS may simply have gone unrecognised or unpublished, they felt this to be unlikely. However, lest this suggestion enter the canon, we present a previously unreported case of a young adult with both DS and recurrent mania.