Seog Ju Kim

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.

Putaminal gray matter volume decrease in panic disorder: An optimized voxel-based morphometry study

Our study aimed to identify gray matter volume differences between panic disorder patients and healthy volunteers using optimized voxel‐based morphometry. Gray matter volume was compared between 18 panic subjects and 18 healthy volunteers. Panic disorder severity scale (PDSS) and Zung self‐rating anxiety scale (Z‐SAS) were administered. Gray matter volumes of bilateral putamen were decreased in panic subjects relative to healthy comparison subjects (corrected P < 0.05). Decreased gray matter volume was also observed in the right precuneus, right inferior temporal gyrus, right inferior frontal gyrus, left superior temporal gyrus, and left superior frontal gyrus at a less conservative level of significance. PDSS score negatively correlated with gray matter volume in the left putamen, right putamen, right inferior frontal gyrus, and left superior frontal gyrus in panic subjects. The duration of illness negatively correlated with left putaminal gray matter volume. There was also a negative correlation between gray matter volume in right putamen and Z‐SAS score in panic subjects. The current study reports a putaminal gray matter volume decrease in panic subjects, which may be related to the clinical severity of panic disorder.

Insufficient sleep and suicidality in adolescents.

STUDY OBJECTIVES To investigate the association between the behaviorally induced insufficient sleep and suicidality among adolescents. DESIGN A population-based, cross-sectional survey. SETTING General community. PARTICIPANTS A sample of 8,530 students (grades 7-11) was recruited in the Republic of Korea. The participants were 8,010 students who completed all questionnaires. INTERVENTION N/A. MEASUREMENTS The survey included the Beck Scale for Suicidal Ideation (SSI), the Beck Depression Inventory (BDI), a modified Epworth Sleepiness Scale (ESS), and questionnaires about sleep (weekday/weekend sleep schedule/duration, insomnia and snoring). RESULTS Adolescents with behaviorally induced insufficient sleep syndrome (BISS) had higher SSI scores than those who slept ≥ 7 hours on weekdays, even after controlling for age, sex, and BDI score (F = 11.71, P < 0.001). After controlling for age and sex, longer weekend oversleep and shorter weekday sleep duration predicted a higher SSI score (β = 0.19, P < 0.001; β = 0.37, P < 0.001). The association between weekend oversleep and SSI score remained significant even after additionally controlling for BDI and ESS scores and presence of insomnia and snoring (β = 0.07, P < 0.01). CONCLUSION BISS was found to be associated with increased suicidality. Weekend oversleep was associated with suicidality independently of depression, daytime sleepiness, snoring, and insomnia. The study findings suggest that chronic sleep restriction among adolescents may increase suicidal risk.

Asymmetrically altered integrity of cingulum bundle in posttraumatic stress disorder

Previously, our group reported the altered white matter tract integrity of the left anterior cingulate in posttraumatic stress disorder (PTSD) in whole-brain exploration. Current study intended to explore whether the alteration was more prominent in any specific regions of the cingulum bundle. Diffusion tensor images of 21 PTSD subjects and 21 healthy comparison subjects were acquired. Eight isocubic regions of interest (ROIs), i.e. bilateral rostral, subgenual, dorsal, and upper cingulum bundle, were selected. Fractional anisotropy values in each ROI, which indicate the white matter tract integrity, were measured and compared between groups. Relative to comparison subjects, PTSD subjects had significantly smaller fractional anisotropy values in the left side of rostral, subgenual and dorsal cingulum bundle (26.7, 25.0, 22.2% decrease, respectively), but not in the right side ROIs. We report an asymmetrical alteration of the cingulum bundle in PTSD.

Disrupted white matter tract integrity of anterior cingulate in trauma survivors

The objective of this study was to examine the integrity of whole-brain white matter in posttraumatic stress disorder patients. Twenty posttraumatic stress disorder patients who survived the Taegu subway fire incident and 20 healthy volunteers participated in this study. Statistical parametric mapping was used to evaluate the global differences in fractional anisotropy values between the two groups. The results show that posttraumatic stress disorder patients had significantly lower fractional anisotropy values in the left anterior cingulate regions. Posttraumatic stress disorder symptom severity negatively correlated to the level of decrease in anterior cingulate fractional anisotropy values. The outcome of the current study suggests that the disruption of the left anterior cingulate white matter tract integrity may play an important role in the pathophysiology of posttraumatic stress disorder.

Quantitative analysis of the hippocampus using images obtained from 7.0 T MRI

In-vivo volumetric measurements of hippocampus have proven to be highly informative for studying various neurological diseases such as Alzheimers disease. The usefulness of volumetric imaging, however, has been limited due to the poor image resolutions obtained by currently available MRI images. In this study, a new result of volumetric image measurement of the hippocampus using 7.0 T MRI images of high contrast and resolution is described. To verify the usefulness of the proposed method, its reliability and sensitivity were examined and compared with existing imaging techniques such as 1.5 T or 3.0 T MRI imaging. The results of our study with 7.0 T MRI clearly demonstrated superior boundary detection for the hippocampal head, body, and tail compared with low field MRIs. In conclusion, robust and reproducible volumetric measurements as well as 3D images of clear contrast obtained with 7.0 T suggest the usefulness of high field MR imaging and its eventual use for the accurate diagnosis of hippocampal diseases and related research.