Search

Objective: These days, young children are exposed to a wide range of smart devices and their usage of smart devices is rapidly increasing worldwide. However, the use of smart devices by young children has not been studied in detail yet because smart device is relatively recent. The purpose of this study was to investigate the exposure status of smart devices among 2-5 years old children in Korea., Methods: Four hundred parents of 2- to 5-year-old children were invited to enroll. Data on demographic information and the frequency of media use, time of media use, age at first use of media was self-reported., Results: Among 390 toddlers, 39.3% watched TV almost every day, while 12.0% of children used smartphone on a daily basis. During weekdays, 48% of the children watched TV for over an hour. On weekends, 63.1% of the children watched TV for over an hour. On weekends, 23.4% of children use their smartphones for over an hour. Children using smartphones before 24 months of age were 31.3%., Conclusion: Research has shown that TV and smartphones are the most popular digital devices used by toddlers. Most toddlers began using smart devices at 12-24 months. This study provides comprehensive information on children's contemporary use of media.

Purpose: This study aimed to examine the development of socializing and emotional expressions through vocalizations and joint attention (JA) behaviors in Korean-speaking children with autism spectrum disorder (ASD), compared to those with developmental delay (DD)., Materials and Methods: Video samples were collected from 28 toddlers with ASD and 18 age-matched toddlers with DD, and vocalizations were each coded in detail for the purpose of this retrospective research. In addition to some statistical analysis, Computerized Language Analysis was conducted to obtain the final results., Results: Although they produced a higher number of vocalizations than the DD group, the ASD group did not engage in emotional or social interactions with their caretakers, whereas the DD group did. The children with ASD used more atypical vocalizations and socially unengaged vocalizations than the children with DD did. JA using vocalizations in the ASD group, in particular, was largely dyadic, with triadic types occurring at a significantly lower frequency than those in the DD group., Conclusion: Results from this study indicate the importance of assessing early vocalizations in toddlers with ASD, suggesting that some common symptoms of ASD, such as lack of typical, emotional, and social functions in early vocalizations, could be used to develop screening and intervention programs related to ASD., Competing Interests: The authors have no financial conflicts of interest., (© Copyright: Yonsei University College of Medicine 2018.)

Objective: The purpose of this study was to examine the validity and reliability of the Korean Comprehensive Scale for the Assessment of Challenging Behavior in Developmental Disorders (K-CSCB)., Methods: In total, the parents of 189 patients with autism spectrum disorder (ASD) and 168 controls completed the K-CSCB, the Behavior Problems Inventory (BPI) and Child Behavior Checklist (CBCL). The reliability and validity of the K-CSCB was investigated., Results: The K-CSCB was found to be a reliable instrument (Cronbach's α=0.97). There was a significant difference between the ASD and control groups in all subscale scores. Scores on the K-CSCB subscales were significantly correlated with those on the BPI and CBCL. The diagnostic validity was 97.7%, and the cut-off score with the highest sensitivity and specificity was 12.5 points., Conclusion: The K-CSCB is the first tool in Korean to assess problematic behavior in individuals with ASD, and this study shows that it is a valid and reliable instrument. We expect the K-CSCB to be widely used in clinical and research settings.

Aim: The current cut-off score of the Korean version of the Childhood Autism Rating Scale (K-CARS) does not seem to be sensitive enough to precisely diagnose high-functioning autism. The aim of this study was to identify the optimal cut-off score of K-CARS for diagnosing high-functioning individuals with autism spectrum disorders (ASD)., Methods: A total of 329 participants were assessed by the Korean versions of the Autism Diagnostic Interview - Revised (K-ADI-R), Autism Diagnostic Observation Schedule (K-ADOS), and K-CARS. IQ and Social Maturity Scale scores were also obtained., Results: The true positive and false negative rates of K-CARS were 77.2% and 22.8%, respectively. Verbal IQ (VIQ) and Social Quotient (SQ) were significant predictors of misclassification. The false negative rate increased to 36.0% from 19.8% when VIQ was >69.5, and the rate increased to 44.1% for participants with VIQ > 69.5 and SQ > 75.5. In addition, if SQ was >83.5, the false negative rate increased to 46.7%, even if the participant's VIQ was ≤69.5. Optimal cut-off scores were 28.5 (for VIQ ≤ 69.5 and SQ ≤ 75.5), 24.25 (for VIQ > 69.5 and SQ > 75.5), and 24.5 (for SQ > 83.5), respectively., Conclusion: The likelihood of a false negative error increases when K-CARS is used to diagnose high-functioning autism and Asperger's syndrome. For subjects with ASD and substantial verbal ability, the cut-off score for K-CARS should be re-adjusted and/or supplementary diagnostic tools might be needed to enhance diagnostic accuracy for ASD., (© 2017 The Authors. Psychiatry and Clinical Neurosciences © 2017 Japanese Society of Psychiatry and Neurology.)

Background: Arginine vasopressin has been shown to affect social and emotional behaviors, which is mediated by the arginine vasopressin receptor (AVPR1A). Genetic polymorphisms in the AVPR1A promoter region have been identified to be associated with susceptibility to social deficits in autism spectrum disorder (ASD). We hypothesize that alleles of polymorphisms in the promoter region of AVPR1A may differentially interact with certain transcriptional factors, which in turn affect quantitative traits, such as sociality, in children with autism., Methods: We performed an association study between ASD and polymorphisms in the AVPR1A promoter region in the Korean population using a family-based association test (FBAT). We evaluated the correlation between genotypes and the quantitative traits that are related to sociality in children with autism. We also performed a promoter assay in T98G cells and evaluated the binding affinities of transcription factors to alleles of rs7294536., Results: The polymorphisms-RS1, RS3, rs7294536, and rs10877969-were analyzed. Under the dominant model, RS1-310, the shorter allele, was preferentially transmitted. The FBAT showed that the rs7294536 A allele was also preferentially transmitted in an additive and dominant model under the bi-allelic mode. When quantitative traits were used in the FBAT, rs7294536 and rs10877969 were statistically significant in all genotype models and modes. Luciferase and electrophoretic mobility-shift assays suggest that the rs7294536 A/G allele results in a Nf-κB binding site that exhibits differential binding affinities depending on the allele., Conclusion: These results demonstrate that polymorphisms in the AVPR1A promoter region might be involved in pathophysiology of ASD and in functional regulation of the expression of AVPR1A .

Objective: The majority of studies on the associations between breastfeeding and cognitive functioning have focused on IQ, with only a few investigating learning skills, and none of the latter adjusting for maternal IQ. We examined the association between breastfeeding and learning abilities in school-aged children using a cross-sectional design., Methods: We recruited 868 children, aged 8-11 years and parents completed the Learning Disability Evaluation Scale (LDES). Multivariable linear regression models were used and age, gender, area of residence, annual family income, maternal education, and maternal age at delivery, were included as covariates. Maternal IQ was added to further adjust for the effects of maternal cognitive ability. Path analysis was conducted to investigate the mediation effect of maternal IQ between breastfeeding and learning skills., Results: Children who were ever-breastfed had higher learning quotient scores on the LDES (p = 0.001) as well as higher scores on subscales related to speaking (p = 0.001), reading (p = 0.005), writing (p = 0.004), spelling (p = 0.003), and mathematical calculation (p = 0.003) than the never-breastfed participants. All of these variables remained significant after adjusting for gestational and socioeconomic factors and for maternal IQ as covariates. The path analysis showed that breastfeeding had both indirect and direct effects on the learning quotient., Conclusions: The results suggest that breastfeeding is positively associated with learning skills in school-aged children.

In addition to its classical role as a regulator of telomere length, recent reports suggest that telomerase reverse transcriptase (TERT) plays a role in the transcriptional regulation of gene expression such as β-catenin-responsive pathways. Silencing or over-expression of TERT in cultured NPCs demonstrated that TERT induced glutamatergic neuronal differentiation. During embryonic brain development, expression of transcription factors involved in glutamatergic neuronal differentiation was increased in mice over-expressing TERT (TERT-tg mice). We observed increased expression of NMDA receptor subunits and phosphorylation of α-CaMKII in TERT-tg mice. TERT-tg mice showed autism spectrum disorder (ASD)-like behavioral phenotypes as well as lowered threshold against electrically induced seizure. Interestingly, the NMDA receptor antagonist memantine restored behavioral abnormalities in TERT-tg mice. Consistent with the alteration in excitatory/inhibitory (E/I) ratio, TERT-tg mice showed autism-like behaviors, abnormal synaptic organization, and function in mPFC suggesting the role of altered TERT activity in the manifestation of ASD, which is further supported by the significant association of certain SNPs in Korean ASD patients.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social and communication impairments, as well as repetitive and restrictive behaviors. The phenotypic heterogeneity of ASD has made it overwhelmingly difficult to determine the exact etiology and pathophysiology underlying the core symptoms, which are often accompanied by comorbidities such as hyperactivity, seizures, and sensorimotor abnormalities. To our benefit, the advent of animal models has allowed us to assess and test diverse risk factors of ASD, both genetic and environmental, and measure their contribution to the manifestation of autistic symptoms. At a broader scale, rodent models have helped consolidate molecular pathways and unify the neurophysiological mechanisms underlying each one of the various etiologies. This approach will potentially enable the stratification of ASD into clinical, molecular, and neurophenotypic subgroups, further proving their translational utility. It is henceforth paramount to establish a common ground of mechanistic theories from complementing results in preclinical research. In this review, we cluster the ASD animal models into lesion and genetic models and further classify them based on the corresponding environmental, epigenetic and genetic factors. Finally, we summarize the symptoms and neuropathological highlights for each model and make critical comparisons that elucidate their clinical and neurobiological relevance.

To determine the genetic association between qualitative and quantitative traits of autism spectrum disorder (ASD) and neuregulin 1 (NRG1)-a schizophrenia candidate gene-we examined six single nucleotide polymorphisms (SNPs) in NRG1 using a family-based association test (FBAT) in Korean families with ASD. rs35753505 and rs6994992 SNPs in NRG1 revealed a statistically significant family-based association with three quantitative traits for sociality., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Rubinstein-Taybi syndrome (RSTS) is a rare condition with a prevalence of 1 in 125,000-720,000 births and characterized by clinical features that include facial, dental, and limb dysmorphology and growth retardation. Most cases of RSTS occur sporadically and are caused by de novo mutations. Cytogenetic or molecular abnormalities are detected in only 55% of RSTS cases. Previous genetic studies have yielded inconsistent results due to the variety of methods used for genetic analysis. The purpose of this study was to use whole exome sequencing (WES) to evaluate the genetic causes of RSTS in a young girl presenting with an Autism phenotype. We used the Autism diagnostic observation schedule (ADOS) and Autism diagnostic interview revised (ADI-R) to confirm her diagnosis of Autism. In addition, various questionnaires were used to evaluate other psychiatric features. We used WES to analyze the DNA sequences of the patient and her parents and to search for de novo variants. The patient showed all the typical features of Autism, WES revealed a de novo frameshift mutation in CREBBP and de novo sequence variants in TNC and IGFALS genes. Mutations in the CREBBP gene have been extensively reported in RSTS patients, while potential missense mutations in TNC and IGFALS genes have not previously been associated with RSTS. The TNC and IGFALS genes are involved in central nervous system development and growth. It is possible for patients with RSTS to have additional de novo variants that could account for previously unexplained phenotypes.

We compared the attention-deficit/hyperactivity disorder(ADHD) combined subtype (ADHD-C) to the ADHD inattentive subtype (ADHD-I) in terms of genetic, perinatal, and developmental risk factors as well as clinical and neuropsychological characteristics. A total of 147 children diagnosed with ADHD between the ages of 6 and 15 years participated in this study. The parents of the children completed the structured diagnostic interview, the ADHD Rating Scale-IV, the Children's Behavior Checklist, and structured questionnaires on perinatal risk factors, and the children underwent a neuropsychological test and were genotyped. A total of 502 children without ADHD were recruited from the community as a healthy control group. The ADHD-C children showed more severe externalizing symptoms, showed more deficits in a continuous performance test, and were more likely to have comorbid disorders. Maternal stress during pregnancy, postpartum depression, and changes in the primary caretaker during first 3 years were significantly associated with both ADHD-I and ADHD-C. The ADHD-I group was less likely to have received regular prenatal check-ups and more likely to have had postnatal medical illness than the ADHD-C group. There were no significant differences in the genotype frequencies of the dopamine transporter (DAT1) and the serotonin transporter -linked polymorphic region (5-HTTLPR) polymorphisms between ADHD-I and ADHD-C groups. This study shows that the inattentive subtype of ADHD is different from the combined subtype in many parameters including severity of symptoms, comorbidity, neuropsychological characteristics, and environmental risk factors., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

We examined the association between the norepinephrine transporter (SLC6A2) gene and autism spectrum disorder (ASD) in a Korean population. In addition, we investigated which phenotypes of ASD are best attributed to the genotype of SLC6A2. A total of 184 subjects with ASD, their 156 unaffected siblings and both biological parents were recruited through university hospitals. We used the Autism Diagnostic Interview-Revised, the Aberrant Behaviour Checklist (ABC), the Child Behaviour Checklist (CBCL), the Stroop Colour-Word Interference Test and the Wisconsin Card Sorting Test (WCST) as quantitative measures of the ASD phenotypes. The associations between the quantitative measures and specific single-nucleotide polymorphisms (SNPs) were tested with linear regression analyses. We did not find any evidence of the over-transmission of either allele of the 10SLC6A2 SNPs in the DFAM test. At an empirical p value <0.05, findings that were consistent between the linear regression analyses and the QFAM tests were the positive associations between the A allele of rs36020 and attention problems on the CBCL and stereotypical behaviours on the ABC and between the C allele of rs1814270 and the number of trials required to complete the first WCST category. However, these associations did not remain after correction for multiple testing. The study results of this study do not support the association between the SLC6A2 and the diagnosis or phenotype of ASD. However, the study must be replicated in larger populations and with using more genetic markers.

Objective: Autism spectrum disorders (ASDs) are a group of early childhood-onset neurodevelopmental disorders characterized by deficits in social interaction and language skills, and repetitive behaviors. Brain-derived neurotrophic factor (BDNF) plays a critical role in the differentiation of normal neuronal cells during embryonic and postnatal neuronal development through its neurotrophic effects., Methods: In this study, we performed a family-based association test (FBAT) between single nucleotide polymorphisms (SNPs; rs6265, rs11030101, rs7103411, and rs7103873) or haplotypes in the BDNF gene and affection status or several quantitative traits characterized by ADI-R with151 Korean trios, including a child diagnosed as ASDs., Results: While no significant association was found between SNPs or haplotypes and the ASDs disease status, a quantitative transmission disequilibrium test (QTDT) by using quantitative traits identified associations of the SNPs (rs6265 and rs11030101) with a domain score for "Restricted, Repetitive and Stereotyped patterns of behavior" (C domain), especially at the subdomain scores for "encompassing preoccupation or circumscribed pattern of interest" (C1) (rs6265A allele, dominant model, p-value=0.019; rs11030101 A allele, additive model, p-value=0.015) and "preoccupations with part of objects or non-functional elements of material" (C4) (rs11030101 A allele, additive model, p-value=0.015) within the ADI-R diagnostic algorithm. In addition, significant associations were also identified between the haplotypes and these quantitative traits (C1, p-value=0.016; C4, p-value=0.012)., Conclusion: We conclude that BDNF gene polymorphisms have a possible role in the pathogenesis of ASDs.

Although there is some evidence supporting the existence of an association between prenatal maternal or postnatal child's urine phthalate metabolite concentrations and poor attentional performances, the interaction between urine phthalate metabolite levels and genetic variation for neuropsychological deficit of attention-deficit hyperactivity disorder (ADHD) has not been examined. The aim of this study was to determine whether phthalate metabolites in urine are associated with poor neuropsychological performance in children with ADHD, and whether such association is affected by genotype-phthalate interaction. A cross-sectional examination of urine phthalate metabolite concentrations and the continuous performance test (CPT) were performed in 179 Korean children with ADHD recruited from department of psychiatry of university hospital. Correlations between urine phthalate metabolite concentrations and the CPT scores were investigated, and the interaction of phthalate metabolite levels with the selected polymorphisms at major candidate genes for ADHD, namely dopamine receptor D4 (DRD4), dopamine transporter, α-2A-adrenergic receptor, and norepinephrine transporter genes. For the subjects with the DRD4 4/4 genotype, there were significant associations of the urine phthalate metabolite concentrations with the number of omission errors, the number of commission errors, and the response time variability scores on the CPT. However, for the subjects without the DRD4 4/4 genotype, no significant associations were found. The results of this study suggest a possible association between phthalate metabolite concentrations and poor attentional performances of ADHD as well as a genetic influence on this association. Further prospective and epigenetic studies are needed to investigate causality and pathophysiological mechanisms.

Impaired social functioning is a hallmark feature of autism spectrum disorder (ASD), often requiring treatment throughout the life span. PEERS(®) (Program for the Education and Enrichment of Relational Skills) is a parent-assisted social skills training for teens with ASD. Although PEERS(®) has an established evidence base in improving the social skills of adolescents and young adults with ASD in North America, the efficacy of this treatment has yet to be established in cross-cultural validation trials. The objective of this study is to examine the feasibility and treatment efficacy of a Korean version of PEERS(®) for enhancing social skills through a randomized controlled trial (RCT).The English version of the PEERS(®) Treatment Manual (Laugeson & Frankel, 2010) was translated into Korean and reviewed by 21 child mental health professionals. Items identified as culturally sensitive were surveyed by 447 middle school students, and material was modified accordingly. Participants included 47 teens between 12 and 18 years of age with a diagnosis of ASD and a verbal intelligence quotient (IQ) ≥ 65. Eligible teens were randomly assigned to a treatment group (TG) or delayed treatment control group (CG). Primary outcome measures included questionnaires and direct observations quantifying social ability and problems directly related to ASD. Secondary outcome measures included scales for depressive symptoms, anxiety, and other behavioral problems. Rating scales for parental depressive symptoms and anxiety were examined to detect changes in parental psychosocial functioning throughout the PEERS(®) treatment. Independent samples t-tests revealed no significant differences at baseline across the TG and CG conditions with regard to age (14.04 ± 1.64 and 13.54 ± 1.50 years), IQ (99.39 ± 18.09 & 100.67 ± 16.97), parental education, socioeconomic status, or ASD symptoms (p < 0.05), respectively. Results for treatment outcome suggest that the TG showed significant improvement in communication and social interaction domain scores on the Autism Diagnostic Observation Schedule, interpersonal relationship and play/leisure time on the subdomain scores of the Korean version of the Vineland Adaptive Behavior Scale (p's < 0.01), social skills knowledge total scores on the Test of Adolescent Social Skills Knowledge-Revised (p < 0.01), and decreased depressive symptoms on the Child Depression Inventory following treatment (p < 0.05). Analyses of parental outcome reveal a significant decrease in maternal state anxiety in the TG after controlling for potential confounding variables (p < 0.05). Despite cultural and linguistic differences, the PEERS(®) social skills intervention appears to be efficacious for teens with ASD in Korea with modest cultural adjustment. In an RCT, participants receiving the PEERS(®) treatment showed significant improvement in social skills knowledge, interpersonal skills, and play/leisure skills, as well as a decrease in depressive symptoms and ASD symptoms. This study represents one of only a few cross-cultural validation trials of an established evidence-based treatment for adolescents with ASD., (© 2014 International Society for Autism Research, Wiley Periodicals, Inc.)

Background: Although family education generally is recommended in the treatment of tic disorders, few studies have focused on the relationship between family environment and diagnosis of tic disorders., Methods: Presence of DSM-IV tic disorders was determined in a general population of 921 children in Korea from 2008 to 2009. Clinical risk factors were assessed, including comorbidity with attention-deficit/hyperactivity disorder; family-related factors such as the number of family members and primary caretaker of the child; and socioeconomic factors in the form of paternal education level and household yearly income. Multivariable logistic regression analyses were performed to estimate the association between a list of clinical, familial, and social variables and the odds of developing tic disorders., Results: At Bonferroni corrected thresholds, a higher risk of tic disorders was significantly associated with the number of changes in primary caretaker, whereas a lower risk was associated with increasing number of children in the family., Conclusions: Family-related environmental factors may play a role in the development or exacerbation of tic disorders. The results advocate the importance of family education when treating children with tic disorders, and further research is needed on the contextual risk factors of tic disorders.

Purpose: To evaluate the psychosocial distress of part-time occlusion therapy in intermittent exotropia., Methods: A total of 25 children (15 males and 10 females, aged 3 to 7 years, mean age 4.7 years) with intermittent exotropia were enrolled. Behavioral and psychosocial problems were assessed by the Korean Child Behavior Checklist (K-CBCL), which consists of eight categories of withdrawal, somatic problems, depression/anxiety, social problems, thought problems, attention problems, delinquent behavior, and aggressive behavior, and the Amblyopia Treatment Index (ATI). The ATI was designed to evaluate the three factors of compliance, adverse effect, and social stigma. The Parenting Stress Index (PSI) is a parent self-report designed to identify potentially dysfunctional parent-child systems. The K-CBCL was obtained before and after occlusion therapy, and the ATI and PSI were taken from parents only after occlusion therapy. We evaluated the change on the K-CBCL and the correlation between the K-CBCL and ATI., Results: The attention problem assessed by the K-CBCL significantly decreased after occlusion therapy. On the ATI, the social stigma was relatively lower than compliance and adverse effect factors (Likert scale 2.64, 3.11, and 3.11, respectively). The somatic problem assessed by the K-CBCL and compliance on the ATI were significantly correlated (p = 0.014). There was no significant change in percentile scores of each subscale (parental dominant scale and child dominant scale) of the PSI. Total stress index before and after occlusion therapy was 97.16 ± 8.38 and 97.00 ± 8.16 respectively (p = 0.382)., Conclusions: Occlusion therapy may influence the psychosocial impact on intermittent exotropia patients. Part-time occlusion significantly decreased the attention problem in children with intermittent strabismus. Children with a high somatic problem score on the KCBCL showed poor compliance to the part-time occlusion.

Background: Dysregulation of noradrenergic system may play important roles in pathophysiology of attention-deficit/hyperactivity disorder (ADHD). We examined the relationship between polymorphisms in the norepinephrine transporter SLC6A2 gene and attentional performance before and after medication in children with ADHD., Methods: Fifty-three medication-naïve children with ADHD were genotyped and evaluated using the continuous performance test (CPT). After 8-weeks of methylphenidate treatment, these children were evaluated by CPT again. We compared the baseline CPT measures and the post-treatment changes in the CPT measures based on the G1287A and the A-3081T polymorphisms of SLC6A2., Results: There was no significant difference in the baseline CPT measures associated with the G1287A or A-3081T polymorphisms. After medication, however, ADHD subjects with the G/G genotype at the G1287A polymorphism showed a greater decrease in the mean omission error scores (p = 0.006) than subjects with the G/A or A/A genotypes, and subjects with the T allele at the A-3081T polymorphism (T/T or A/T) showed a greater decrease in the mean commission error scores (p = 0.003) than those with the A/A genotypes., Conclusions: Our results provide evidence for the possible role of the G1287A and A-3081T genotypes of SLC6A2 in methylphenidate-induced improvement in attentional performance and support the noradrenergic hypothesis for the pathophysiology of ADHD.

Background: Neurobiologic studies have suggested that dysregulation of central noradrenergic systems may be involved in the pathophysiology of attention deficit hyperactivity disorder (ADHD), and it has been hypothesized that genetic changes in the norepinephrine pathways might contribute to dysfunction of the prefrontal cortex circuits in ADHD. We previously reported decreased cerebral blood flow in the right lateral prefrontal cortex and both orbitofrontal cortices in children with ADHD. Genetic investigations have shown that the alpha-2A-adrenergic receptor gene (ADRA2A) is associated with ADHD. Our aim was to examine whether the presence of a risk allele of the ADRA2A MspI polymorphism is associated with differences in regional cerebral blood flow in boys with ADHD., Methods: We recruited 21 Korean boys with ADHD (mean age 9.9, standard deviation [SD] 2.7 yr) and 11 age- and sex-matched controls (mean age 10.6 [SD 2.1] yr). Each participant underwent technetium-99m-hexamethylpropylene amine oxime ((99m)Tc-HMPAO) single-photon emission computed tomography. We performed image analyses with voxe-wise t statistics using SPM2., Results: We found regional hypoperfusion in the prefrontal regions, including the right orbitofrontal and right medial gyri, and the bilateral putamen and cerebellum in boys with ADHD relative to controls (p < 0.0005, uncorrected for multiple comparisons). Boys with ADHD who carried the C allele (n = 13) at the ADRA2A MspI polymorphism had reduced perfusion in the bilateral orbitofrontal regions compared with those without the C allele (n = 8) (p < 0.0005, uncorrected for multiple comparisons)., Limitations: This study was limited by the small sample size, and we did not obtain genetic data from the controls., Conclusion: Our findings suggest that regional differences in cerebral perfusion in the orbitofrontal cortex represent an intermediate neuroimaging phenotype associated with the ADRA2A MspI polymorphism; these data support the validity of the noradrenergic hypothesis regarding the pathophysiology of ADHD.

Previous studies have demonstrated that the MspI and DraI polymorphisms at the alpha-2A-adrenergic receptor gene (ADRA2A) are associated with ADHD. However, few studies have been designed to ascertain the association between the ADRA2A genotypes and the performance on neurocognitive measures in ADHD. The aims of this study were to examine the association of the ADRA2A MspI and DraI polymorphisms with ADHD in Korean subjects, and to determine the relationship between the genotypes of these two polymorphisms and the candidate endophenotypes, as measured by the continuous performance test (CPT). In a case-control study, we assessed 186 ADHD probands and 150 normal controls. One hundred eight trios were studied in a family based association analysis. The transmission disequilibrium test (TDT) analysis showed preferential transmission of the C allele of the DraI polymorphism (chi(2) = 5.88, P = 0.015). In the haplotype analyses, a trend of over-transmission of haplotype C/C was observed (chi(2) = 3.80, P = 0.051). The homozygous subjects for the C allele (C/C genotype) at the DraI polymorphism showed a trend toward a higher mean T-score with respect to the response time variability profiles of the CPT than did those with the other genotypes (C/T + T/T genotypes; P = 0.042). The homozygous subjects for the G allele (G/G genotype) at the MspI polymorphism showed a tendency to have a lower mean T-score with respect to the response time variability profiles of the CPT (P = 0.068). The results of this study provide important evidence for the involvement of the ADRA2A MspI and DraI polymorphisms in the etiology of ADHD in Korean subjects. In addition, our results provide evidence for the possible role of these two polymorphisms in ADHD symptom expression, such as increased response time variability., (2008 Wiley-Liss, Inc.)

The objective of this study was to evaluate the relationship between attention deficit-hyperactivity/impulsivity symptoms and Internet addiction. In total, 535 elementary school students (264 boys, 271 girls; mean age, 11.0 +/- 1.0 years) were recruited. The presence or severity of Internet addiction was assessed by the Young's Internet Addiction test. Parents and teachers of the children completed the DuPaul's attention deficit hyperactivity disorder (ADHD) rating scale (ARS; Korean version, K-ARS) and Child Behavior Checklists. Children with the highest and lowest quartiles in K-ARS scores were defined to be in ADHD and non-ADHD groups, respectively. Five children (0.9%) met criteria for a definite Internet addiction and 75 children (14.0%) met criteria for a probable Internet addiction. K-ARS scores had significant positive correlations with Young's Internet Addiction test scores. The Internet addiction group had higher total scores of K-ARS and ADHD-related subcategories in the Child Behavior Checklists than the non-addiction group. The ADHD group had higher Internet addiction scores compared with the non-ADHD group. Therefore, significant associations have been found between the level of ADHD symptoms and the severity of Internet addiction in children. In addition, current findings suggest that the presence of ADHD symptoms, both in inattention and hyperactivity-impulsivity domains, may be one of the important risk factors for Internet addiction.