Jaeuk Hwang

Attention deficit hyperactivity symptoms and Internet addiction

Abstract  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 Youngs Internet Addiction test. Parents and teachers of the children completed the DuPauls 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 Youngs 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.

Prefrontal and temporal gray matter density decreases in opiate dependence

RationaleThere have been only a few structural brain-imaging studies, with varied findings, of opiate-dependent subjects. Voxel-based morphometry (VBM) is suitable for studying whole brain-wise structural brain changes in opiate-dependent subjects.ObjectivesThe objective of the current study is to explore gray matter density in opiate-dependent subjects.MethodsGray matter density in 63 opiate-dependent subjects and 46 age- and sex-matched healthy comparison subjects was compared using VBM.ResultsRelative to healthy comparison subjects, opiate-dependent subjects exhibited decreased gray matter density in bilateral prefrontal cortex [Brodmann areas (BA) 8, 9, 10, 11, and 47], bilateral insula (BA 13), bilateral superior temporal cortex (BA 21 and 38), left fusiform cortex (BA 37), and right uncus (BA 28).ConclusionsThis study reports that opiate-dependent subjects have gray matter density decreases in prefrontal and temporal cortex, which may be associated with behavioral and neuropsychological dysfunction in opiate-dependent subjects.

Trait and state aspects of harm avoidance and its implication for treatment in major depressive disorder, dysthymic disorder, and depressive personality disorder

Abstract  The authors evaluated the trait/state issues of harm avoidance in depressive‐spectrum disorders and its predictive potential for antidepressant response. Subjects with Diagnostic and Statistical Manual of Mental Disorders (4th edn; DSM‐IV) major depressive disorder (n = 39), dysthymic disorder (n = 37), depressive personality disorder (n = 39), and healthy control subjects (n = 40) were evaluated with the Temperament and Character Inventory and the 17‐item Hamilton Depression Rating Scale (HDRS‐17) at baseline and after a 12 week antidepressant treatment period. Higher harm avoidance scores predicted lesser improvement in subjects with dysthymic disorder and major depressive disorder, as determined by lesser decrease in HDRS‐17 scores. Mean harm avoidance scores in depressed subjects were consistently greater than those in healthy controls, controlling for age, gender and diagnosis. Mean harm avoidance scores decreased significantly in all depressive‐spectrum disorders after treatment, but still remained higher than harm avoidance scores in control subjects. The present study reports that harm avoidance is a reliable predictor of antidepressant treatment in subjects with major depressive disorder and dysthymic disorder and that harm avoidance is both trait‐ and state‐dependent in depressive‐spectrum disorders.

Decreased frontal white-matter integrity in abstinent methamphetamine abusers.

This study explored differences in frontal white-matter (WM) integrity between methamphetamine (MA) abusers and healthy comparison subjects using diffusion tensor imaging (DTI). Fractional anisotropy (FA) values, which indicate WM integrity, were calculated for regions-of-interest in frontal WM on diffusion tensor images of 32 MA abusers and 30 healthy comparison subjects. Frontal executive functions were also assessed by the Wisconsin Card Sorting test (WCST). MA abusers had significantly lower FA values in bilateral frontal WM at the anterior commissure-posterior commissure (AC-PC) plane and the right frontal WM 5 mm above the AC-PC plane relative to healthy comparison subjects. MA abusers had more total, perseveration and non-perseveration errors in the WCST relative to healthy comparison subjects. FA values of the right frontal WM 5 mm above the AC-PC plane negatively correlated with the number of total and non-perseveration errors in the WCST in MA abusers. In the sub-analysis for gender differences, lower FA values in frontal WM and more errors in the WCST were found only in male MA abusers, not in female MA abusers, relative to comparison subjects of the respective gender. We report that frontal WM integrity of MA abusers is compromised. This finding may also be related to impairment in frontal executive function. In addition, the neurotoxic effect of MA on frontal WM may be less prominent in women than in men, possibly due to oestrogens neuroprotective effect.

Frontal Glucose Hypometabolism in Abstinent Methamphetamine Users

Changes in relative regional cerebral glucose metabolism (rCMRglc) and their potential gender differences in abstinent methamphetamine (MA) users were explored. Relative rCMRglc, as measured by 18F-fluorodeoxyglucose positron emission tomography, and frontal executive functions, as assessed by Wisconsin card sorting test (WCST), were compared between 35 abstinent MA users and 21 healthy comparison subjects. In addition, male and female MA users and their gender-matched comparison subjects were compared to investigate potential gender differences. MA users had lower rCMRglc levels in the right superior frontal white matter and more perseveration and nonperseveration errors in the WCST, relative to healthy comparison subjects. Relative rCMRglc in the frontal white matter correlated with number of errors in the WCST in MA users. In the subanalysis for gender differences, lower rCMRglc in the frontal white matter and more errors in the WCST were found only in male MA users, not in female MA users, relative to their gender-matched comparison subjects. The current findings suggest that MA use causes persistent hypometabolism in the frontal white matter and impairment in frontal executive function. Our findings also suggest that the neurotoxic effect of MA on frontal lobes of the brain might be more prominent in men than in women.

White matter hyperintensities in subjects with bipolar disorder

Abstract  There have been divergent reports on the prevalence and severity of white matter hyperintensities (WMH) on brain magnetic resonance (MR) images in subjects with bipolar disorder. In the present study, evaluations were made on the prevalence and severity of WMH in subjects with bipolar disorder using contiguous 3‐mm thick MR slices as well as fluid attenuated inversion recovery (FLAIR) images. A detailed WMH rating system was employed to assess these WMH. A total of 43 bipolar patients, as diagnosed by the Structured Clinical Interview from the Diagnostic and Statistical Manual‐IV (SCID‐IV), and 39 healthy comparison subjects were scanned using a 1.5‐T whole body GE magnetic resonance scanner. WMH were assessed with a modified composite version of the Fazekas’ and Coffeys rating scales to detect less severe WMH. Periventricular and subcortical WMH were coded separately. Subjects with bipolar disorder had greater prevalence of WMH abnormalities than comparison subjects (Bipolar, grade 1 = 11.6%, grade 2 = 9.3%, grade 3 = 7.0%; Comparison, grade 1 = 5.1%, grade 2 = 2.6%, grade 3 = 0%). This difference is mainly due to the differences in deep WMH (Bipolar, grade 1 = 14.0%, grade 2 = 14.0%; Comparison, grade 1 = 7.7%, grade 2 = 0%). The current study confirms the higher prevalence of WMH in subjects with bipolar disorder. Differences of small‐sized WMH abnormalities between groups were successfully detected using a large number of bipolar subjects and thinner sliced MR images with FLAIR.

Laterobasal Amygdalar Enlargement in 6- to 7-Year-Old Children With Autism Spectrum Disorder

CONTEXT There is substantial imaging evidence for volumetric abnormalities of the amygdala in younger children with autism spectrum disorder (ASD). The amygdala can be divided into functionally distinct laterobasal, superficial, and centromedial subregions. To date, we are not aware of any in vivo reports specifically assessing subregional amygdalar abnormalities in individuals with ASD. OBJECTIVES To evaluate alterations in subregional amygdalar morphology in children with ASD compared with typically developing (TD) children and to examine the relationships with ASD symptom severity. DESIGN A cross-sectional study encompassing a narrow age range of children with ASD and age-matched TD children that evaluated magnetic resonance imaging-defined subregional morphology of the amygdala using a novel subregional analytic method. SETTING Participants were recruited and clinically evaluated through the University of Washington Autism Center and imaged at the Diagnostic Imaging Sciences Center at the University of Washington. Imaging data were analyzed through the Brain Imaging Laboratory at the Seoul National University. PARTICIPANTS Fifty-one children 6 to 7 years of age (ASD, n = 31 and TD, n = 20) were assessed using magnetic resonance imaging and behavioral measures. MAIN OUTCOME MEASURES Volume and subregional measures of the amygdala and measures of social and communication functioning. RESULTS The ASD group exhibited larger right and left amygdalae, by 12.7% and 11.0%, respectively, relative to the TD group. Subregional analysis revealed that the ASD group had enlarged laterobasal amygdalar subregions, relative to the TD group, after adjusting for age, sex, and hemispheric cerebral volume (P < .05, false discovery rate corrected and with clustered surface points >15). Exploratory analyses revealed that there were linear trends comparing a strictly defined subgroup of children with autistic disorder, who exhibited the greatest extent of laterobasal enlargement, followed by a subgroup of children with pervasive developmental disorder not otherwise specified and then the group of TD children (P for linear trend <.001). There were linear trends between enlargement of laterobasal subregions and lower levels of social and communication functioning (P < .001, P < .001, and P = .001 for 3 areas in the right laterobasal subregion; P < .001 for 1 area in the left laterobasal subregion). CONCLUSION The current study demonstrates bilateral enlargement of laterobasal subregions of the amygdala in 6- to 7-year-old children with ASD and that subregional alterations are associated with deficits in social and communicative behavior.

Shape changes of the corpus callosum in abstinent methamphetamine users

The objective of the current study was to evaluate structural changes of the corpus callosum (CC) in abstinence methamphetamine (MA) users. Shape and size of the CC in 27 MA users were compared to those of 18 healthy comparison subjects. To define the local curvature and width of the CC, medial model-based shape analysis was performed using CC skeletons extracted from a distance map. To define the local displacement of the CC, a boundary model-based shape analysis was performed. In addition, the size of regional areas of the CC was measured according to the Witelsons definition for comparison. In the medial model-based shape analysis, increased curvature in the genu (curvature angle difference = 4.1 degrees) and decreased width in posterior midbody (width difference = 0.77 mm) and isthmus area (width difference = 0.86 mm) of the CC were observed in MA users relative to healthy comparison subjects. In the boundary model-based shape analysis, significant displacement was observed in MA users where there were differences in shape/width patterns by the medial model-based shape analysis. There were no differences in the size of regional areas of the CC between groups. Findings suggest that MA use is associated with regional changes in interhemispheric white matter tracts, which connect frontal and parietal cortices and that these frontal and parietal abnormalities may underlie clinical manifestations of the MA abuse.

Network-level structural abnormalities of cerebral cortex in type 1 diabetes mellitus.

Type 1 diabetes mellitus (T1DM) usually begins in childhood and adolescence and causes lifelong damage to several major organs including the brain. Despite increasing evidence of T1DM-induced structural deficits in cortical regions implicated in higher cognitive and emotional functions, little is known whether and how the structural connectivity between these regions is altered in the T1DM brain. Using inter-regional covariance of cortical thickness measurements from high-resolution T1-weighted magnetic resonance data, we examined the topological organizations of cortical structural networks in 81 T1DM patients and 38 healthy subjects. We found a relative absence of hierarchically high-level hubs in the prefrontal lobe of T1DM patients, which suggests ineffective top-down control of the prefrontal cortex in T1DM. Furthermore, inter-network connections between the strategic/executive control system and systems subserving other cortical functions including language and mnemonic/emotional processing were also less integrated in T1DM patients than in healthy individuals. The current results provide structural evidence for T1DM-related dysfunctional cortical organization, which specifically underlie the top-down cognitive control of language, memory, and emotion.

Association of RANBP1 haplotype with smooth pursuit eye movement abnormality.

Schizophrenia is a multifactorial disorder and smooth pursuit eye movement (SPEM) disturbance is proposed as one of the most consistent neurophysiological endophenotype in schizophrenia. The aim of this study was to examine the genetic association of RANBP1 polymorphisms with the risk of schizophrenia and with the risk of SPEM abnormality in schizophrenia patients in a Korean population. Two SNPs of RANBP1 were genotyped by TaqMan assay. Their genetic effect of single/haplotype polymorphisms on the risk of schizophrenia and SPEM abnormality from 354 patients and 396 controls were performed using χ2 and multiple regression analyses. Although no RANBP1 polymorphisms were associated with the risk of schizophrenia, a common haplotype, RANBP1‐ht2 (rs2238798G–rs175162T), showed significant association with the risk of SPEM abnormality among schizophrenia patients after multiple correction (Pcorr = 0.002–0.0003). The results of present study provide the evidence that RANBP1 on 22q11.21 locus might be causally related to the SPEM abnormality rather than the development of schizophrenia.