Neuroanatomical correlates of attention-deficit-hyperactivity disorder accounting for comorbid oppositional defiant disorder and conduct disorder

Aim: An increasing number of neuroimaging studies have been conducted to uncover the pathophysiology of attention-deficit-hyperactivity disorder (ADHD). The findings are inconsistent, however, at least partially due to methodological differences. In the present study voxel-based morphometry (VBM) was used to evaluate brain morphology in ADHD subjects after taking into account the confounding effect of oppositional defiant disorder (ODD) and conduct disorder (CD) comorbidity. Methods: Eighteen children with ADHD and 17 age-and gender-matched typically developing subjects underwent high-spatial resolution magnetic resonance imaging. The regional gray matter volume differences between the children with ADHD and controls were examined with and without accounting for comorbid ODD and CD in a voxel-by-voxel manner throughout the entire brain. Results: The VBM indicated significantly smaller regional gray matter volume in regions including the bilateral temporal polar and occipital cortices and the left amygdala in subjects with ADHD compared with controls. Significantly smaller regional gray matter volumes were demonstrated in more extensive regions including the bilateral temporal polar cortices, bilateral amygdala, right occipital cortex, right superior temporal sulcus, and left middle frontal gyrus after controlling for the confounding effect of comorbid ODD and CD. Conclusion: Morphological abnormalities in ADHD were seen not only in the regions associated with executive functioning but also in the regions associated with social cognition. When the effect of comorbid CD and ODD was taken into account, there were more extensive regions with significantly smaller volume in ADHD compared to controls.ArticlePSYCHIATRY AND CLINICAL NEUROSCIENCES. 64(4):394-402 (2010)journal articl

Impact of behavioral/developmental disorders comorbid with conduct disorder

Aims: The aim of the present study was to verify the comorbidity of conduct disorder (CD) and behavioral/developmental disorders in children and adolescents, and to examine the traits of CD comorbid with them. Methods: Subjects were 64 children (60 boys, four girls) who were resident at three institutions for delinquent children or who were conduct-disordered outpatients of a university hospital aged under 18 years. A diagnostic interview was carried out by experienced child psychiatrists and the intelligence score and the Adverse Childhood Experiences score were measured by a licensed psychologist. Results: A total of 57 children were diagnosed as having CD, of whom 26 (45.6%) were diagnosed with comorbid attention-deficit-hyperactivity disorder (ADHD), 12 were diagnosed with comorbid pervasive developmental disorder (PDD, 21,1%), and 19 (33.3%) had no comorbidity of either disorder. Six children (18.8% of CD comorbid with ADHD) met the criteria for both ADHD and PDD. The group with comorbid PDD was significantly younger at onset (F = 6.51, P = 0.003) and included unsocialized type more frequently (KH2 = 6.66, P = 0.036) compared with the other two groups. Conclusions: Clinicians should be aware that not only ADHD but also PDD may be comorbid with CD. Establishment of the correct diagnosis is important because recognizing the presence of PDD will enable us to provide appropriate treatment and guidance, which may improve prognosis.ArticlePSYCHIATRY AND CLINICAL NEUROSCIENCES. 63(6):762-768 (2009)journal articl

Negative Correlation between Serum Cytokine Levels and Cognitive Abilities in Children with Autism Spectrum Disorder

Evidence suggests that cytokines may be one of the major factors influencing cognitive development in those with autism spectrum disorder (ASD). To shed light on the neural and cognitive mechanisms of ASD, we investigated the association between peripheral cytokine levels and cognitive profiles in children with ASD. The serum levels of 10 cytokines (granulocyte macrophage colony-stimulating factor, interferon (IFN)-γ, interleukin (IL)-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, and tumor necrosis factor-α) were examined in 14 children with ASD using the Human Ultrasensitive Cytokine Magnetic 10-Plex Panel for the Luminex platform. The Wechsler Intelligence Scale for Children (WISC) was administered to each subject, and the relationships between WISC scores and serum levels of the cytokines were examined. The full-scale intelligence quotient (IQ) was significantly negatively correlated with the levels of IL-6 (Spearman’s rank, p < 0.0001, false discovery rate q < 0.01). The levels of IL-6 and IFN-γ showed significant negative correlations with the verbal comprehension index (p < 0.001, q < 0.01) and working memory index (p < 0.01, q < 0.05), respectively. No other cytokines were significantly correlated with full-scale IQ or with any of the subscale scores of the WISC. The present results suggest negative correlations of IL-6 and IFN-γ levels with cognitive development of children with ASD. Our preliminary findings add to the evidence that cytokines may play a role in the neural development in ASD.ArticleJOURNAL OF INTELLIGENCE. 5(2):19 (2017)journal articl

White matter microstructural alterations across four major psychiatric disorders : mega-analysis study in 2937 individuals

Identifying both the commonalities and differences in brain structures among psychiatric disorders is important for understanding the pathophysiology. Recently, the ENIGMA-Schizophrenia DTI Working Group performed a large-scale meta-analysis and reported widespread white matter microstructural alterations in schizophrenia; however, no similar cross-disorder study has been carried out to date. Here, we conducted mega-analyses comparing white matter microstructural differences between healthy comparison subjects (HCS; N = 1506) and patients with schizophrenia (N = 696), bipolar disorder (N = 211), autism spectrum disorder (N = 126), or major depressive disorder (N = 398; total N = 2937 from 12 sites). In comparison with HCS, we found that schizophrenia, bipolar disorder, and autism spectrum disorder share similar white matter microstructural differences in the body of the corpus callosum; schizophrenia and bipolar disorder featured comparable changes in the limbic system, such as the fornix and cingulum. By comparison, alterations in tracts connecting neocortical areas, such as the uncinate fasciculus, were observed only in schizophrenia. No significant difference was found in major depressive disorder. In a direct comparison between schizophrenia and bipolar disorder, there were no significant differences. Significant differences between schizophrenia/bipolar disorder and major depressive disorder were found in the limbic system, which were similar to the differences in schizophrenia and bipolar disorder relative to HCS. While schizophrenia and bipolar disorder may have similar pathological characteristics, the biological characteristics of major depressive disorder may be close to those of HCS. Our findings provide insights into nosology and encourage further investigations of shared and unique pathophysiology of psychiatric disorders

Molecular Mechanism of the Reaction Specificity in Threonine Synthase: Importance of the Substrate Conformations

Threonine synthase (ThrS) catalyzes the final chemical reaction of l-threonine biosynthesis from its precursor, <i>O</i>-phospho-l-homoserine. As the phosphate ion generated in its former half reaction assists its latter reaction, ThrS is recognized as one of the best examples of product-assisted catalysis. In our previous QM/MM study, the chemical reactions for the latter half reactions, which are critical for the product-assisted catalysis, were revealed. However, accurate free energy changes caused by the conformational ensembles and entrance of water molecules into the active site are unknown. In the present study, by performing long-time scale MD simulations, the free energy changes by the divalent anions (phosphate or sulfate ions) and conformational states of the intermediate states were theoretically investigated. We found that the calculated free energy double differences are in good agreement with the experimental results. We also revealed that the phosphate ion contributes to forming hydrogen bonds that are suitable for the main reaction progress. This means that the conformation of the active site amino acid residues and the substrate, and hence, the tunable catalysis, are controlled by the product phosphate ion, and this clearly demonstrates a molecular mechanism of the product-assisted catalysis in ThrS