Paediatric obsessive-compulsive disorder, a neurodevelopmental disorder? Evidence from neuroimaging

White matter abnormalities in pediatric obsessive-compulsive disorder

Diffusion tensor imaging (DTI) has been useful in allowing us to examine the nature and extent of neuronal disruption associated with obsessive-compulsive disorder (OCD). However, little is known about the underlying brain structure in OCD. Diffusion-weighted magnetic resonance imaging was performed in 16 children with OCD and 22 typically developing children. Tract-based spatial statistics (TBSS) was used to compare the microstructure of white-matter tracts of OCD children with those of typically developing children. Correlation/regression analyses were also performed on each diffusion measure in order to detect any correlation of white-matter microstructure with scales of symptom severity. Analysis revealed significantly greater axial diffusivity in both the genu and the splenium of the corpus callosum in the control compared to the OCD group; these regions consecutively connect bilateral medial frontal regions and bilateral parietal regions. Secondly, correlation and voxel-based regression analysis revealed that lower axial diffusion correlated with greater severity of symptoms within the OCD group, as measured by the Child Behaviour Checklist-Obsessive Compulsive Scale (CBCL-OCS). The findings demonstrated a correlation of axial diffusivity with severity of symptoms in children with OCD. DTI may provide novel ways to help reveal the relationships between clinical symptoms and altered brain regions.

Widespread decreased grey and white matter in paediatric obsessive-compulsive disorder (OCD): a voxel-based morphometric MRI study

Obsessive-compulsive disorder (OCD) is a chronic, relapsing anxiety disorder. To date, neuroimaging investigations of OCD have been variable and few studies have examined paediatric populations. Eight children with OCD and 12 typically developing children matched for age, gender, handedness and performance IQ underwent a high resolution T1-weighted structural magnetic resonance imaging (MRI) scan. A voxel-based morphometry (VBM) protocol (using DARTEL) compared the brains of the paediatric OCD children with those of typically developing children. Overall, children with OCD demonstrated significantly lower intra-cranial volume (ICV) and grey- and white-matter volumes. ICV was significantly reduced (∼9%) in the OCD group compared with the typically developing group. The VBM analysis demonstrated lower volumes in widespread grey matter in bilateral frontal, cingulate, temporal-parietal, occipital-frontal and right precuneus regions for OCD. Lower white matter volume was found bilaterally in the cingulate and occipital cortex, right frontal and parietal and left temporal regions, and the corpus callosum. In summary, this study provides further evidence of brain dysmorphology in paediatric OCD patients. In addition to fronto-striatal-thalamic neural networks, abnormalities in other brain regions, such as the parietal lobe and corpus callosum, were demonstrated. These brain regions may play an additional role in the pathophysiology of OCD.

What is special about the adolescent (JME) brain?

Juvenile myoclonic epilepsy (JME) involves cortico-thalamo-cortical networks. Thalamic, frontal gray matter, connectivity, and neurotransmitter disturbances have been demonstrated by structural/functional imaging studies. Few patients with JME show mutations in genes coding ion channels or GABAA (gamma-aminobutyric acid) receptor subunits. Recent research points to EFHC1 gene mutations leading to microdysgenesis and possible aberrant circuitry. Imaging studies have shown massive structural/functional changes of normally developing adolescent brain structures maturing at strikingly different rates and times. Gray matter (GM) volume diminishes in cortical areas (frontal and parietal) and deep structures (anterior thalamus, putamen, and caudate). Diffusion tensor imaging (DTI) findings support continued microstructural change in WM (white matter) during late adolescence with robust developmental changes in thalamocortical connectivity. The GABAA receptor distribution and specific receptor subunits' expression patterns change with age from neonate to adolescent/adult, contributing to age-related changes in brain excitability. Hormonal influence on brain structure development during adolescence is presented. Possible implications of brain changes during adolescence on the course of JME are discussed.

Surface anatomical profile of the cerebral cortex in obsessive-compulsive disorder: a study of cortical thickness, folding and surface area

BACKGROUND

Studying the distribution of anatomical abnormalities over the entire cortical surface can help to identify key neural circuits implicated in generating symptoms of neuropsychiatric disorders. There is a significant inconsistency among studies investigating the neuroanatomy of obsessive-compulsive disorder (OCD) because of the confounding influence of co-morbid depression and medication use and the lack of unbiased estimation of whole-brain morphometric changes. It is also unknown whether the distinct surface anatomical properties of thickness, surface area and gyrification, which collectively contribute to grey matter volume (GMV), are independently affected in OCD. Method The cortical maps of thickness, gyrification and surface areal change were acquired from 23 unmedicated OCD patients and 20 healthy controls using an unbiased whole-brain surface-based morphometric (SBM) method to detect regional changes in OCD. Subcortical structures were not assessed in this study.

RESULTS

Patients showed a significant increase in the right inferior parietal cortical thickness. Significant increases in gyrification were also noted in the left insula, left middle frontal and left lateral occipital regions extending to the precuneus and right supramarginal gyrus in OCD. Areal contraction/expansion maps revealed no significant regional differences between the patients and controls. In patients, gyrification of the insula significantly predicted the symptom severity measured using Yale-Brown Obsessive-Compulsive Scale (YBOCS).

CONCLUSIONS

An alteration in the cortical surface anatomy is an important feature of OCD seen in unmedicated samples that relates to the severity of the illness. The results underscore the presence of a neurodevelopmental aberration underlying the pathophysiology of OCD.

Increased orbital frontal gray matter volume after cognitive behavioural therapy in paediatric obsessive compulsive disorder

OBJECTIVES

Identify differences in regional brain volume between medication-free pediatric OCD patients and controls and examine changes after cognitive behavioural therapy.

METHODS

We assessed 29 medication-free paediatric OCD patients (Age: M = 13.78 years; SD = 2.58; range 8.2-19.0) and 29 controls, matched on age and gender, with T1-weighted MR scans in a repeated measures, pre-post treatment design. Voxel based morphometry (VBM) following diffeomorphic anatomical registration through exponential lie algebra (DARTEL) was used to test voxel-wise for the effects of diagnosis and treatment on regional gray matter (GM) and white matter (WM) volumes.

RESULTS

After cognitive behavioural therapy, orbitofrontal GM and capsula externa WM increased in paediatric OCD relative to controls. In patients, changes in symptom severity (delta CY-BOCS) correlated positively with GM volume in the orbitofrontal cortex after treatment. Furthermore, before treatment, paediatric OCD patients, compared to the controls, showed larger GM volume in left frontal pole and left parietal cortex and larger WM volume in cingulum and corpus callosum.

CONCLUSIONS

Our findings underscore the involvement of the ventral frontal-striatal circuit in paediatric OCD and the plasticity of this circuit in response to the modulatory effects of CBT. The possible relation to brain development is discussed.

Obsessive-compulsive symptom dimensions correlate to specific gray matter volumes in treatment-naïve patients

BACKGROUND

Clinical and sociodemographic findings have supported that OCD is heterogeneous and composed of multiple potentially overlapping and stable symptom dimensions. Previous neuroimaging investigations have correlated different patterns of OCD dimension scores and gray matter (GM) volumes. Despite their relevant contribution, some methodological limitations, such as patient's previous medication intake, may have contributed to inconsistent findings.

METHOD

Voxel-based morphometry was used to investigate correlations between regional GM volumes and symptom dimensions severity scores in a sample of 38 treatment-naïve OCD patients. Several standardized instruments were applied, including an interview exclusively developed for assessing symptom dimensions severity (DY-BOCS).

RESULTS

Scores on the "aggression" dimension were positively correlated with GM volumes in lateral parietal cortex in both hemispheres and negatively correlated with bilateral insula, left putamen and left inferior OFC. Scores on the "sexual/religious" dimension were positively correlated with GM volumes within the right middle lateral OFC and right DLPFC and negatively correlated with bilateral ACC. Scores on the "hoarding" dimension were positively correlated with GM volumes in the left superior lateral OFC and negatively correlated in the right parahippocampal gyrus. No significant correlations between GM volumes and the "contamination" or "symmetry" dimensions were found.

CONCLUSIONS

Building upon preexisting findings, our data with treatment-naïve OCD patients have demonstrated distinct GM substrates implicated in both cognitive and emotion processing across different OCS dimensions.

Investigation of cortical glutamate-glutamine and γ-aminobutyric acid in obsessive-compulsive disorder by proton magnetic resonance spectroscopy

Glutamatergic abnormalities in corticostriatal brain circuits are thought to underlie obsessive-compulsive disorder (OCD). Whether these abnormalities exist in adults with OCD is not clear. We used proton magnetic resonance spectroscopy (¹H MRS) to test our hypothesis that unmedicated adults with OCD have reduced glutamate plus glutamine (Glx) levels in the medial prefrontal cortex (MPFC) compared with healthy controls. Levels of γ-aminobutyric acid (GABA) were also explored. Twenty-four unmedicated adults with OCD and 22 matched healthy control subjects underwent ¹H MRS scans at 3.0 T. Resonances of both Glx and GABA were obtained using the standard J-editing technique and assessed as ratios relative to voxel tissue water (W) in the MPFC (the region of interest) and the dorsolateral prefrontal cortex (DLPFC) to explore the regional specificity of any finding. In the MPFC, Glx/W did not differ by diagnostic group (p=0.98) or sex (p=0.57). However, GABA/W was decreased in OCD (2.16±0.46 × 10⁻³) compared with healthy controls (2.43±0.45 × 10⁻³, p=0.045); moreover, age of OCD onset was inversely correlated with MPFC GABA/W (r=-0.50, p=0.015). MPFC GABA/W was higher in females than in males. In the DLPFC, there were no main effects of diagnosis or gender on Glx/W or GABA/W. These data indicate that unmedicated adults with OCD do not have Glx abnormalities in a MPFC voxel that includes the pregenual anterior cingulate cortex. However, they may have decreased MPFC GABA levels. How GABA abnormalities might contribute to corticostriatal dysfunction in OCD deserves further study.

White matter abnormalities in pediatric obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a prevalent and often severely disabling illness with onset generally in childhood or adolescence. Although white matter deficits have been implicated in the neurobiology of OCD, few studies have been conducted in pediatric patients when the brain is still developing and have examined their functional correlates. In this study, 23 pediatric OCD patients and 23 healthy volunteers, between the ages of 9 and 17 years, matched for sex, age, handedness, and IQ, received a diffusion tensor imaging exam on a 3T GE system and a brief neuropsychological battery tapping executive functions. Patient symptom severity was assessed using the Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS). Patients with OCD exhibited significantly greater fractional anisotropy compared to matched controls in the left dorsal cingulum bundle, splenium of the corpus callosum, right corticospinal tract, and left inferior fronto-occipital fasciculus. There were no regions of significantly lower fractional anisotropy in patients compared to controls. Higher fractional anisotropy in the splenium was significantly correlated with greater obsession severity on the CY-BOCS in the subgroup of psychotropic drug-naïve patients. Among patients, there was a significant association between greater fractional anisotropy in the dorsal cingulum bundle and better performance on measures of response inhibition and cognitive control. The overall findings suggest a pattern of greater directional coherence of white matter tracts in OCD very early in the course of illness, which may serve a compensatory mechanism, at least for response inhibition functions typically subserved by the cingulum bundle.

Hair pulling disorder (trichotillomania): genes, neurobiology, and a model for understanding impulsivity and compulsivity

Hair pulling disorder (trichotillomania) affects at least 3.7 million people in the United States and results in marked functional impairment. This article reviews empirical research investigating the genetics and neurobiology of hair pulling disorder (HPD). We also discuss recent advances in the characterization of this phenotype which have led to evidence supporting the existence of at least two disparate pulling styles-automatic and focused pulling. These pulling styles exhibit facets of behavioral processes, impulsivity and compulsivity, characteristic of several classes of disorders (e.g., obsessive-compulsive spectrum disorders, impulse control disorders). Available genetic, neurobiological, and clinical data support the importance of impulsivity for conceptualizing HPD. Impulsivity alone is insufficient to fully understand this complex phenotype. Characterizations of both automatic and focused pulling as well as preliminary findings from affective neuroscience across species highlight the importance of compulsivity for understanding HPD. Opposing and complementary aspects to impulsivity-compulsivity provide a more comprehensive conceptualization of HPD and supports HPD's potential importance for advancing scientific inquiry in relation to the pathogenesis and treatment of related phenotypes. This review concludes with a description of areas-phenotype, neurobiology, and genes-in need of further study.

White matter abnormalities in children and adolescents with obsessive-compulsive disorder: a diffusion tensor imaging study

BACKGROUND

There is paucity of data on white matter (WM) abnormalities in juvenile obsessive-compulsive disorder (OCD). This study aimed to identify WM microstructure changes in juvenile OCD.

METHODS

Fifteen children and adolescents with OCD and 15 matched healthy controls underwent diffusion tensor imaging using a 3 Tesla (Achieva, Best, The Netherlands) magnetic resonance imaging scanner. Voxelwise analyses were conducted on data processed through tract-based spatial statistics (TBSS).

RESULTS

Patients significantly differed from controls in axial as well as radial diffusivities, but not in fractional anisotropy. Patients demonstrated significantly increased axial diffusivity in corpus callosum (genu, body, and splenium), right and left superior longitudinal fasciculi, left inferior longitudinal fasciculus, right and left cingulum, bilateral anterior thalamic radiations, bilateral anterior limb of internal capsule, left posterior limb of the internal capsule, and middle cerebellar peduncle. In addition, significantly increased radial diffusivity was seen in patients in genu of the corpus, right and left superior longitudinal fasciculi, left inferior longitudinal fasciculus, right and left uncinate fasciculi, bilateral anterior thalamic radiation, bilateral inferior fronto-occipital fasciculus, left posterior limb of internal capsule, right superior cerebellar peduncle, middle cerebellar peduncle, and right inferior cerebellar peduncle.

CONCLUSIONS

Our findings suggest involvement of multiple WM tracts in juvenile OCD. In addition to the widely proposed hypothesis of orbitofrontal-striato-thalamo-cortical circuitry deficits in the development of OCD, our findings suggest involvement of additional brain regions, possibly parietal cortex, lateral prefrontal cortex, and limbic system. The widespread differences in WM among cases and controls also points to the possibility of underlying myelination changes.

Behavioral, pharmacological, and immunological abnormalities after streptococcal exposure: a novel rat model of Sydenham chorea and related neuropsychiatric disorders

Group A streptococcal (GAS) infections and autoimmunity are associated with the onset of a spectrum of neuropsychiatric disorders in children, with the prototypical disorder being Sydenham chorea (SC). Our aim was to develop an animal model that resembled the behavioral, pharmacological, and immunological abnormalities of SC and other streptococcal-related neuropsychiatric disorders. Male Lewis rats exposed to GAS antigen exhibited motor symptoms (impaired food manipulation and beam walking) and compulsive behavior (increased induced-grooming). These symptoms were alleviated by the D2 blocker haloperidol and the selective serotonin reuptake inhibitor paroxetine, respectively, drugs that are used to treat motor symptoms and compulsions in streptococcal-related neuropsychiatric disorders. Streptococcal exposure resulted in antibody deposition in the striatum, thalamus, and frontal cortex, and concomitant alterations in dopamine and glutamate levels in cortex and basal ganglia, consistent with the known pathophysiology of SC and related neuropsychiatric disorders. Autoantibodies (IgG) of GAS rats reacted with tubulin and caused elevated calcium/calmodulin-dependent protein kinase II signaling in SK-N-SH neuronal cells, as previously found with sera from SC and related neuropsychiatric disorders. Our new animal model translates directly to human disease and led us to discover autoantibodies targeted against dopamine D1 and D2 receptors in the rat model as well as in SC and other streptococcal-related neuropsychiatric disorders.

Neural substrates of childhood anxiety disorders: a review of neuroimaging findings

The development of fear is a normative process, and significant progress has been made in identifying fear neurocircuitry. The normal development of fear goes awry in children who develop anxiety disorders, and dysfunction in fear circuitry is likely. In this article, the authors present current knowledge about the neural basis of normal fear development and reviews findings from structural and functional neuroimaging studies of childhood anxiety disorders.

The centre of the brain: topographical model of motor, cognitive, affective, and somatosensory functions of the basal ganglia

The basal ganglia have traditionally been viewed as motor processing nuclei; however, functional neuroimaging evidence has implicated these structures in more complex cognitive and affective processes that are fundamental for a range of human activities. Using quantitative meta-analysis methods we assessed the functional subdivisions of basal ganglia nuclei in relation to motor (body and eye movements), cognitive (working-memory and executive), affective (emotion and reward) and somatosensory functions in healthy participants. We document affective processes in the anterior parts of the caudate head with the most overlap within the left hemisphere. Cognitive processes showed the most widespread response, whereas motor processes occupied more central structures. On the basis of these demonstrated functional roles of the basal ganglia, we provide a new comprehensive topographical model of these nuclei and insight into how they are linked to a wide range of behaviors.

Neuroimaging of cognitive brain function in paediatric obsessive compulsive disorder: a review of literature and preliminary meta-analysis

Obsessive compulsive disorder (OCD) is a frequent psychiatric disorder with a prevalence of 1-3 %, and it places an enormous burden on patients and their relatives. Up to 50 % of all cases suffer from onset in childhood or adolescence, and the disorder often takes a chronic course with a poor long-term prognosis. Paediatric OCD, with its high familiality, is often referred to as a distinct OCD subtype that coincides with a developmental period in which the prefrontal cortex exhibits extensive structural and functional maturation. In the present review, we included all studies examining cognitive brain activation in children and/or adolescents with OCD. We conducted extensive literature searches for relevant articles (Pubmed, ScienceDirect) and summarize, tabulate, and discuss their results. For the eight activation studies using functional magnetic resonance imaging, we also performed preliminary meta-analyses to assess the most consistent hypo- and hyperactivation in paediatric OCD patients during cognitive task performance. The review of literature as well as our preliminary meta-analyses of paediatric studies indicated altered functional activation in the same brain regions of affective and cognitive cortico-striatal-thalamic (CST) circuits as for adult OCD patients despite some variations in the direction of activation difference. The still small number of studies that examined brain activation in paediatric OCD patients thereby largely converged with previous findings in adult patients and with the established neurobiological models of CST circuit dysfunction in OCD.

Impaired sensorimotor gating in unmedicated adults with obsessive-compulsive disorder

Functional and structural imaging studies suggest that obsessive-compulsive disorder (OCD) symptoms arise from dysfunction in cortico-striato-thalamo-cortical circuits. It has therefore been hypothesized that neurophysiological tasks subserved by these circuits should be abnormal in OCD patients. One neurocognitive probe associated with this circuitry is prepulse inhibition (PPI) of the acoustic startle response. PPI deficits are thought to reflect abnormalities in processing and integration of sensory and motor information. Two prior studies found that OCD patients had PPI deficits at single prepulse (PP) intensities. However, most patients in these studies were taking psychotropic medications at the time of PPI testing, and preclinical studies have demonstrated effects of psychotropic medications on PPI. We examined PPI in 22 unmedicated OCD patients and 22 matched healthy controls at three different PP intensities (74, 78, and 86 dB). OCD patients had significantly less PPI across all three PP intensities compared with controls. Exploratory analyses indicated that OCD patients with a history of tics had lower levels of PPI. Our results demonstrate that unmedicated OCD patients have impaired sensorimotor gating as measured by PPI. This indicates that PPI deficits are present in OCD patients and are not the result of medication effects. Our findings also suggest that OCD patients with a history of tics may have greater impairment in sensorimotor gating than the general OCD population. Future studies should be designed to examine whether PPI deficits characterize tic-related OCD.

Neurobiological circuits regulating attention, cognitive control, motivation, and emotion: disruptions in neurodevelopmental psychiatric disorders

OBJECTIVE

This article aims to review basic and clinical studies outlining the roles of prefrontal cortical (PFC) networks in the behavior and cognitive functions that are compromised in childhood neurodevelopmental disorders and how these map into the neuroimaging evidence of circuit abnormalities in these disorders.

METHOD

Studies of animals, normally developing children, and patients with neurodevelopmental disorders were reviewed, with focus on neuroimaging studies.

RESULTS

The PFC provides "top-down" regulation of attention, inhibition/cognitive control, motivation, and emotion through connections with posterior cortical and subcortical structures. Dorsolateral and inferior PFC regulate attention and cognitive/inhibitory control, whereas orbital and ventromedial structures regulate motivation and affect. PFC circuitries are very sensitive to their neurochemical environment, and small changes in the underlying neurotransmitter systems, e.g. by medications, can produce large effects on mediated function. Neuroimaging studies of children with neurodevelopmental disorders show altered brain structure and function in distinctive circuits respecting this organization. Children with attention-deficit/hyperactivity disorder show prominent abnormalities in the inferior PFC and its connections to striatal, cerebellar, and parietal regions, whereas children with conduct disorder show alterations in the paralimbic system, comprising ventromedial, lateral orbitofrontal, and superior temporal cortices together with specific underlying limbic regions, regulating motivation and emotion control. Children with major depressive disorder show alterations in ventral orbital and limbic activity, particularly in the left hemisphere, mediating emotions. Finally, children with obsessive-compulsive disorder appear to have a dysregulation in orbito-fronto-striatal inhibitory control pathways, but also deficits in dorsolateral fronto-parietal systems of attention.

CONCLUSIONS

Altogether, there is a good correspondence between anatomical circuitry mediating compromised functions and patterns of brain structure and function changes in children with neuropsychiatric disorders. Medications may optimize the neurochemical environment in PFC and associated circuitries, and improve structure and function.

Changes in gray matter volume and white matter microstructure in adolescents with obsessive-compulsive disorder

BACKGROUND

There is a paucity of neuroimaging data in pediatric-onset obsessive-compulsive disorder (OCD). This multimodal neuroimaging study aimed to identify structural gray (GM) and white matter (WM) microstructure changes in pediatric OCD.

METHODS

We obtained structural and diffusion tensor magnetic resonance images from 26 OCD patients and 26 matched healthy adolescents. We carried out a series of image analyses including, volumetric and shape analysis of subcortical gray structures, as well as voxel-based morphometry on GM volume and fractional anisotropy of the WM.

RESULTS

Patients had increased GM volume in the caudate bilaterally and right putamen. Shape analyses revealed specific hypertrophy of the dorsal caudate in pediatric OCD. The striatum was larger in healthy boys compared with healthy girls, whereas such a gender effect was not seen in the OCD group. OCD subjects showed higher fractional anisotropy values in left inferior longitudinal fasciculus, bilateral superior longitudinal fasciculus, right inferior fronto-occipital fasciculus, bilateral corticospinal tract, corpus callosum splenium and genu, bilateral forceps major, bilateral forceps minor, left cingulum, and right uncinate fasciculus. OCD symptom severity was positively correlated with GM volume in right insula, posterior orbitofrontal cortex, brainstem, and cerebellum and inversely correlated with widespread reduction in cortical GM volume. Furthermore, symptom severity positively correlated with increased WM fractional anisotropy in various WM tracts, including the anterior limb of the internal capsule.

CONCLUSIONS

Adolescents with OCD had a wide range of GM and WM changes compared to healthy control subjects that are broadly consistent with those identified in the adult OCD literature but are more extensive.

Serotonin 2A receptors in obsessive-compulsive disorder: a positron emission tomography study with [11C]MDL 100907

BACKGROUND

Serotonergic abnormalities are hypothesized to contribute to obsessive-compulsive disorder (OCD). This study used positron emission tomography with the radioligand [11C]MDL 100907 to examine whether the distribution of serotonin 2A (5-HT(2A)) receptors is altered in OCD.

METHODS

Nineteen OCD subjects, free of psychiatric medications and depression, and 19 matched healthy subjects underwent positron emission tomography scans following injection of [11C]MDL 100907. Total distribution volumes were derived by kinetic analysis using the arterial input function. Two measures of 5-HT(2A) availability were computed: the ratio at equilibrium of specifically bound radiotracer either to nondisplaceable radiotracer in tissue (BP(ND)) or to unmetabolized tracer in arterial plasma (BP(p)). Groups were compared using a region of interest (ROI) analysis and voxelwise analysis of spatially normalized parametric maps. ROIs included cortical (orbitofrontal, dorsolateral prefrontal, medial prefrontal, anterior cingulate, temporal, parietal, occipital, and insular cortex) and limbic (entorhinal cortex, parahippocampal gyrus, and medial temporal lobe) regions.

RESULTS

No significant group differences were observed in [11C]MDL 100907 BP(ND) or BP(p) in the ROIs or in the voxelwise analysis of BP(ND) maps. There was a significant correlation in the orbitofrontal cortex between [11C]MDL 100907 binding and age of onset, with earlier age of onset associated with higher binding.

CONCLUSIONS

Adults with OCD are not characterized as a group by major changes in 5-HT(2A) availability in cortical or limbic brain regions. Further research is warranted to examine potential differences in 5-HT(2A) availability between early- and late-onset OCD and to assess 5-HT(2A) function in relation to other neurotransmitter systems implicated in OCD.

Neonatal head ultrasound abnormalities in preterm infants and adolescent psychiatric disorders

CONTEXT

Infants born prematurely are at risk for a perinatal encephalopathy characterized by white and gray matter injuries that affect subsequent cortical development and neural connectivity and potentially increase risk for later psychiatric disorder.

OBJECTIVE

To determine the relation of perinatal brain injury, as detected by neonatal head ultrasound, to psychiatric disorders in adolescents who were born prematurely.

DESIGN

Prospective cohort.

SETTING

Community.

PARTICIPANTS

Adolescent survivors of a population-based low-birth-weight (<2000 g; 96% preterm; born 1984-1987) cohort (n = 1105) screened as neonates with serial head ultrasounds. Neonatal head ultrasound abnormalities were categorized as either (1) germinal matrix and/or intraventricular hemorrhage or (2) parenchymal lesions and/or ventricular enlargement. Of 862 eligible survivors, 628 (72.9%) were assessed at age 16 years. The sample consisted of 458 nondisabled survivors assessed in person. Main Outcome Measure  Adolescent current and lifetime psychiatric disorders assessed with parent report on the Diagnostic Interview Schedule for Children-IV.

RESULTS

Compared with no abnormality, germinal matrix/intraventricular hemorrhage increased risk for current major depressive disorder (odds ratio, 2.7; 95% confidence interval, 1.0-6.8) and obsessive-compulsive disorder (9.5; 3.0-30.1). Parenchymal lesions/ventricular enlargement increased risk for current attention-deficit/hyperactivity disorder-inattentive type (odds ratio, 7.6; 95% confidence interval, 2.0-26.5), tic disorders (8.4; 2.4-29.6), and obsessive-compulsive disorder (7.6; 1.39-42.0). Parenchymal lesions/ventricular enlargement were not related to lifetime attention-deficit/hyperactivity disorder-inattentive type, but all other relations were similar for lifetime disorders. Control for other early risk factors did not alter these relations. Most of these relations persisted with control for concurrent cognitive or motor problems.

CONCLUSION

In preterm infants, 2 distinct types of perinatal brain injury detectable with neonatal head ultrasound selectively increase risk in adolescence for psychiatric disorders in which dysfunction of subcortical-cortical circuits has been implicated.

Developmental alterations of frontal-striatal-thalamic connectivity in obsessive-compulsive disorder

OBJECTIVE

Pediatric obsessive-compulsive disorder is characterized by abnormalities of frontal-striatal-thalamic circuitry that appear near illness onset and persist over its course. Distinct frontal-striatal-thalamic loops through cortical centers for cognitive control (anterior cingulate cortex) and emotion processing (ventral medial frontal cortex) follow unique maturational trajectories, and altered connectivity within distinct loops may be differentially associated with OCD at specific stages of development.

METHOD

Altered development of striatal and thalamic connectivity to medial frontal cortex was tested in 60 OCD patients compared with 61 healthy control subjects at child, adolescent, and adult stages of development, using resting-state functional connectivity MRI.

RESULTS

OCD in the youngest patients was associated with reduced connectivity of dorsal striatum and medial dorsal thalamus to rostral and dorsal anterior cingulate cortex, respectively. Increased connectivity of dorsal striatum to ventral medial frontal cortex was observed in patients at all developmental stages. In child patients, reduced connectivity between dorsal striatum and rostral anterior cingulate cortex correlated with OCD severity.

CONCLUSIONS

Frontal-striatal-thalamic loops involved in cognitive control are hypoconnected in young patients near illness onset, whereas loops implicated in emotion processing are hyperconnected throughout the illness.

Inefficiently increased anterior cingulate modulation of cortical systems during working memory in young offspring of schizophrenia patients

BACKGROUND

Children and adolescent offspring of schizophrenia patients are at increased risk for schizophrenia and are also characterized by impairments in brain structure and function. To date, few studies have investigated whether functional interactions between brain regions are intact or altered. Using an established verbal working memory paradigm with variable levels of memory load, we investigated the modulatory effect of activity in cognitive control regions of the brain (specifically the dorsal anterior cingulate cortex) on activity in core working memory regions, in particular the dorsal prefrontal cortex and the parietal lobe.

METHODS

Forty four subjects participated. An n-back task with two levels of working memory load (1- and 2-back) was employed during fMRI (4 T Bruker MedSpec system). Data were processed with SPM5 and the modulatory effects of the anterior cingulate were investigated using psycho-physiological interaction (PPI).

RESULTS

In spite of only subtle activation differences, and no significant differences in performance accuracy, a significant group x memory load interaction in the parietal lobe, indicated aberrantly increased modulatory inputs to this region under conditions of high working memory load in schizophrenia offspring.

DISCUSSION

Increased modulatory inputs from a central control region like the anterior cingulate presumably reflect relative inefficiency in intra-cortical interactions in the vulnerable brain. This inefficiency may reflect a developmentally mediated impairment in functional brain interactions in this important vulnerable population. It is highly plausible that the resultant effect of these altered interactions is an increased vulnerability to impaired brain development, and therefore to psychiatric disorders including schizophrenia.

Objective sleep patterns and severity of symptoms in pediatric obsessive compulsive disorder: a pilot investigation

Sleep disturbances are common among youth with anxiety disorders, yet objective assessments of sleep in children with obsessive compulsive disorder (OCD) have been the focus of scant research. We therefore compared a small group of non-medicated, non-depressed children with primary OCD (ages 7-11 years) to matched healthy controls using home-based actigraphy during a 7-day prospective assessment. Validated parent and child sleep measures also were collected, and associations among objective sleep variables and severity of obsessions and compulsions were examined. We found significantly fragmented sleep patterns in the OCD group compared to controls including reduced total sleep time (TST) and longer wake periods after sleep onset. Severity of compulsions showed a significant negative correlation with TST. These preliminary findings indicate the presence of sleep abnormalities in pre-pubescent OCD patients with potential implications for future examinations of early developmental processes and features of the disorder.

Thalamocortical connectivity in healthy children: asymmetries and robust developmental changes between ages 8 and 17 years

BACKGROUND AND PURPOSE

Thalamocortical connections play a crucial role in complex cognitive functioning, and several neuropsychiatric disorders may involve aberrant thalamocortical circuitry. Here, we quantified the cortical pattern and age-related changes of thalamocortical connections by using probabilistic tractography in children and adolescents. We hypothesized that detectable asymmetry (left>right) exists in thalamocortical fiber connections and the connectivity increases with age during maturation.

MATERIALS AND METHODS

Diffusion tensor imaging was acquired in 15 normally developing children (age range, 8.3-17.3 years; 11 males), and fiber tracking was initiated from the thalami. The cortical distribution of ipsilateral thalamocortical fibers was quantified by using a landmark-constrained conformal mapping technique. Furthermore, hemispheric asymmetries and potential age-related changes in regional thalamocortical connections were assessed.

RESULTS

The left thalamus had significantly higher overall cortical connectivity than the right thalamus (P < .001). Left prefrontal cortical areas showed significantly higher thalamic connectivity compared with homotopic regions of the right hemisphere (P < .001), regardless of the applied parameters. There was an increase of overall thalamocortical connectivity with age, with the most pronounced age-related increases in bilateral prefrontal areas (P < .002). However, thalamic connectivity of some other cortical regions (right sensorimotor, left inferior temporal) showed a decrease with age.

CONCLUSIONS

Our results indicate a region-specific left>right asymmetry and robust developmental changes in thalamocortical (particularly thalamo-prefrontal) connectivity during late childhood and adolescence. These data further add to our knowledge about structural lateralizations and their development in the maturing brain.

Disorder-specific dysfunctions in patients with attention-deficit/hyperactivity disorder compared to patients with obsessive-compulsive disorder during interference inhibition and attention allocation

BACKGROUND

Abnormalities in inhibitory control and underlying fronto-striatal networks is common to both attention deficit hyperactivity disorder (ADHD) and obsessive-compulsive-disorder (OCD). The aim of this study was to investigate disorder-specific abnormalities in neural networks mediating interference inhibition and selective attention.

METHOD

Event-related functional magnetic resonance imaging (fMRI) was used to compare brain activation of boys with ADHD (18), with OCD (10), and healthy boys during (20) during a Simon task that measures interference inhibition and controls for and therefore comeasures attention allocation.

RESULTS

During interference inhibition, both patient groups shared mesial frontal dysfunction compared to controls. Disorder-specific dysfunctions were observed in OCD patients in dorsolateral prefrontal cortex during the oddball condition and in ADHD patients in inferior parietal lobe during interference inhibition and in caudate and posterior cingulate during the simpler oddball condition. The decreased activation in caudate and cingulate in ADHD was furthermore negatively correlated with ADHD symptoms and positively with OCD behavioral traits.

CONCLUSIONS

The study shows that ADHD and OCD patients have shared but also disorder-specific brain dysfunctions during interference inhibition and attention allocation. Both disorders shared dysfunction in mesial frontal cortex. Disorder-specific dysfunctions, however, were observed in dorsolateral prefrontal cortex in OCD patients and in caudate, cingulate, and parietal brain regions in ADHD patients. The disorder-specific dissociation of striato-cingulate activation that was increased in OCD compared to ADHD patients, was furthermore inversely related to the symptomatology of the two disorders, and may potentially reflect differential dopamine modulation of striatal brain regions.

Neurocognitive performance in children with ADHD and OCD

Attention-deficit/hyperactivity Disorder (ADHD) and obsessive-compulsive disorder (OCD) have both been linked to dysfunction in the cortico-striato-thalamo-cortical circuitry (CSTCC). However, the exact nature of neurocognitive deficits remains to be investigated in both disorders. We applied two neuropsychological tasks that tap into different functions associated with the CSTCC, namely a serial reaction time (SRT) task, developed to assess implicit sequence learning, and a delay aversion (DA) task in order to assess abnormal motivational processes. The performance data of boys with ADHD (n=20), OCD (n=20) and healthy controls (n=25), all aged 10-18 years, were compared. Subjects with ADHD less frequently chose the larger, more delayed reward compared to those with OCD and controls, while subjects with OCD showed impaired implicit learning. In contrast, the ADHD group was unimpaired in their implicit learning behavior and the OCD group was not characterized by a DA style. Within the OCD-group, severity of obsessions was associated with implicit learning deficits and impulsive symptoms with DA in the ADHD-group. This double dissociation highlights the distinct cognitive dysfunctions associated with ADHD and OCD and might possibly point to different neural abnormalities in both disorders.

Functional magnetic resonance imaging during planning before and after cognitive-behavioral therapy in pediatric obsessive-compulsive disorder

OBJECTIVE

Pediatric obsessive compulsive disorder (OCD) has been associated with cognitive abnormalities, in particular executive impairments, and dysfunction of frontal-striatal-thalamic circuitry. The aim of this study was to investigate if planning as an executive function is compromised in pediatric OCD and is associated with frontal-striatal-thalamic dysfunction, and if this dysfunction would normalize after successful treatment.

METHOD

Twenty-five medication-free pediatric patients (mean ± SD 13.95 ± 2.52 years old, range 9 to 19 years) with OCD and 25 healthy controls, matched by age and gender, were scanned twice using a self-paced pseudo-randomized event-related functional magnetic resonance imaging version of the Tower of London. Patients were rescanned after 16 sessions of protocol-based cognitive behavioral therapy; healthy controls were rescanned after a similar interval.

RESULTS

Patients performed the task significantly slower but with similar accuracy compared with controls. Neuroimaging results showed less recruitment of frontal and parietal regions in patients with OCD compared with controls during the planning versus control task. With increasing task load patients compared with controls showed more recruitment of ventrolateral and medial prefrontal cortex and insula and anterior cingulate cortex. After treatment, these differences ceased to be significant, with time by group by task load interaction analyses showing a significant decrease in right posterior prefrontal activity in patients with OCD compared with healthy controls.

CONCLUSION

Pediatric patients with OCD showed subtle planning impairments and decreased dorsolateral prefrontal and parietal recruitment that normalized after cognitive behavioral treatment. Planning dysfunction is likely to be a state rather than a trait feature of pediatric OCD.

High but not low frequency stimulation of both the globus pallidus and the entopeduncular nucleus reduces 'compulsive' lever-pressing in rats

The anti-compulsive effects of high and low frequency stimulation (LFS, HFS) of the entopeduncular nucleus and globus pallidus (the rat's equivalent, respectively, of the primate's internal and external segments of the globus pallidus) were assessed in the signal attenuation rat model of obsessive-compulsive disorder (OCD). HFS, but not LFS, of the two nuclei exerted an anti-compulsive effect, suggesting that HFS of either segment of the globus pallidus may provide an additional therapeutic strategy for OCD.

Disorder-specific dysfunction in right inferior prefrontal cortex during two inhibition tasks in boys with attention-deficit hyperactivity disorder compared to boys with obsessive-compulsive disorder

BACKGROUND

Inhibitory dysfunction is a key behavioral and cognitive phenotype of attention-deficit hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD). Both disorders show neuropsychological deficits and fronto-striatal dysfunction during tasks of motor response inhibition and cognitive flexibility. This study investigates differences and commonalities in functional neural networks mediating inhibitory control between adolescents with ADHD and those with OCD to identify disorder-specific neurofunctional markers that distinguish these two inhibitory disorders.

METHODS

Event-related fMRI was used to compare brain activation between 20 healthy boys, 18 (Stop task) or 12 boys (Switch task) with ADHD, and 10 boys with OCD during a tracking Stop task that measures inhibition and stopping failure and during a visual-spatial switching task measuring cognitive flexibility.

RESULTS

Both patient groups shared brain dysfunction compared to healthy controls in right orbitofrontal (successful inhibition) and left dorsolateral prefrontal cortices (failed inhibition). Right inferior prefrontal dysfunction, however, was disorder-specific to ADHD during both tasks. Left inferior prefrontal dysfunction during the Switch task was significant in children with ADHD relative to controls, but only reached a trend in patients with OCD. Patients with ADHD furthermore showed disorder-specific dysfunction in left basal ganglia and cingulate gyrus during the Switch task.

CONCLUSIONS

Patients with ADHD compared to those with OCD have both common and distinct dysfunctions during inhibitory control. The most consistently reported functional abnormality in children with ADHD in right inferior prefrontal cortex during inhibitory control appears to be disorder-specific when compared to patients with OCD and may be a specific neurofunctional biomarker of ADHD.