Volumetric MRI assessment of brain regions in patients with refractory obsessive-compulsive disorder

From compulsivity to compulsion: the neural basis of compulsive disorders

Compulsive behaviour, an apparently irrational perseveration in often maladaptive acts, is a potential transdiagnostic symptom of several neuropsychiatric disorders, including obsessive-compulsive disorder and addiction, and may reflect the severe manifestation of a dimensional trait termed compulsivity. In this Review, we examine the psychological basis of compulsions and compulsivity and their underlying neural circuitry using evidence from human neuroimaging and animal models. Several main elements of this circuitry are identified, focused on fronto-striatal systems implicated in goal-directed behaviour and habits. These systems include the orbitofrontal, prefrontal, anterior cingulate and insular cortices and their connections with the basal ganglia as well as sensoriomotor and parietal cortices and cerebellum. We also consider the implications for future classification of impulsive-compulsive disorders and their treatment.

Assessing cortical features in early stage ASD children

Autism Spectrum Disorder (ASD) is defined as a neurodevelopmental disorder largely investigated in the neurologic field. Recently, neuroimaging studies have been conducted in order to investigate cerebral morphologic alterations in ASD patients, demonstrating an atypical brain development before the clinical manifestations of the disorder. Cortical Thickness (CT) and Local Gyrification Index (LGI) distribution for ASD children were investigated in this study, with the aim to evaluate possible relationship between brain measures and individual characteristics (i.e., IQ and verbal ability). 3D T1-w sequences from 129 ASD and 58 age-matched Healthy Controls (HC) were acquired and processed in order to assess CT and LGI for each subject. Intergroup differences between ASD and HC were investigated, including analyses of 2 ASD subgroups, split according to patient verbal ability and IQ. When compared to HC, ASD showed increased CT and LGI within several brain areas, both as an overall group and as verbal ability an IQ subgroups. Moreover, when comparing language characteristics of the ASD subjects, those patients with verbal ability exhibit significant CT and LGI increase was found within the occipital lobe of right hemisphere. No significant results occurred when comparing ASD patients according to their IQ value. These results support the hypothesis of abnormal brain maturation in ASD since early childhood with differences among clinical subgroups suggesting different anatomical substrates underlying an aberrant connectivity.

Tourette syndrome and obsessive-compulsive disorder: A comprehensive review of structural alterations and neurological mechanisms

Currently, it is possible to study the pathogenesis of Tourette's syndrome (TS) in more detail, due to more advanced methods of neuroimaging. However, medical and surgical treatment options are limited by a lack of understanding of the nature of the disorder and its relationship to some psychiatric disorders, the most common of which is obsessive-compulsive disorder (OCD). It is believed that the origin of chronic tic disorders is based on an imbalance of excitatory and inhibitory influences in the Cortico-Striato-Thalamo-Cortical circuits (CSTC). The main CSTCs involved in the pathological process have been identified by studying structural and neurotransmitter disturbances in the interaction between the cortex and the basal ganglia. A neurotransmitter deficiency in CSTC has been demonstrated by immunohistochemical and genetic methods, but it is still not known whether it arises as a consequence of genetically determined disturbances of neuronal migration during ontogenesis or as a consequence of altered production of proteins involved in neurotransmitter production. The aim of this review is to describe current ideas about the comorbidity of TS with OCD, the involvement of CSTC in the pathogenesis of both disorders and the background of structural and neurotransmitter changes in CSTC that may serve as targets for drug and neuromodulatory treatments.

Cortical Thickness of the Orbitofrontal Cortex in Patients with Alcohol Use Disorder

Aims: In the present study, it was hypothesised that compared to healthy control subjects, significant differences in the cortical thickness of the orbitofrontal cortex (OFC) region of the brain, which is relevant to both impulsivity and decision making, would be identified. Methods: The subject groups included in the study were composed of 15 individuals who met the criteria for alcohol use disorder, according to the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM 5) diagnostic criteria based on the Structured Clinical Interview for DSM 5 (SCID), and were admitted to the Firat University School of Medicine Department of Psychiatry or were hospitalised, and 17 healthy control comparisons were made. The volumes of and cortical thickness of the OFC were measured in the subjects. Results: It was found that patients with alcohol use disorder had reduced volumes of the OFC bilaterally and a thinner cortical thickness of the same region bilaterally compared to those of the healthy control comparisons. Conclusions: Consequently, it is suggested that the OFC region of the brain appears to be statistically significantly smaller in patients with alcohol use disorder, both in terms of cortical thickness and volume, compared to healthy controls. Future research should focus on the status of these relationships longitudinally and should assess the causality of the association with the treatment response.

Associations of medication with subcortical morphology across the lifespan in OCD: Results from the international ENIGMA Consortium

BACKGROUND

Widely used psychotropic medications for obsessive-compulsive disorder (OCD) may change the volumes of subcortical brain structures, and differently in children vs. adults. We measured subcortical volumes cross-sectionally in patients finely stratified for age taking various common classes of OCD drugs.

METHODS

The ENIGMA-OCD consortium sample (1081 medicated/1159 unmedicated OCD patients and 2057 healthy controls aged 6-65) was divided into six successive 6-10-year age-groups. Individual structural MRIs were parcellated automatically using FreeSurfer into 8 regions-of-interest (ROIs). ROI volumes were compared between unmedicated and medicated patients and controls, and between patients taking serotonin reuptake inhibitors (SRIs), tricyclics (TCs), antipsychotics (APs), or benzodiazepines (BZs) and unmedicated patients.

RESULTS

Compared to unmedicated patients, volumes of accumbens, caudate, and/or putamen were lower in children aged 6-13 and adults aged 50-65 with OCD taking SRIs (Cohen's d = -0.24 to -0.74). Volumes of putamen, pallidum (d = 0.18-0.40), and ventricles (d = 0.31-0.66) were greater in patients aged 20-29 receiving APs. Hippocampal volumes were smaller in patients aged 20 and older taking TCs and/or BZs (d = -0.27 to -1.31).

CONCLUSIONS

Results suggest that TCs and BZs could potentially aggravate hippocampal atrophy of normal aging in older adults with OCD, whereas SRIs may reduce striatal volumes in young children and older adults. Similar to patients with psychotic disorders, OCD patients aged 20-29 may experience subcortical nuclear and ventricular hypertrophy in relation to APs. Although cross-sectional, present results suggest that commonly prescribed agents exert macroscopic effects on subcortical nuclei of unknown relation to therapeutic response.

Smaller volume of posterior thalamic nuclei in patients with obsessive-compulsive disorder

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Thalamic subregional volumes were compared between medication-free OCD and HC groups.

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Left posterior thalamic nuclei volumes were smaller in OCD patients compared to HCs.

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The smaller thalamic subregional volumes were associated with later onset of OCD.

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Posterior thalamic nuclei volume may reflect OCD subtype related to the age of onset.

Aim

Although the thalamus is a key structure in the pathophysiology of obsessive–compulsive disorder (OCD), reports regarding thalamic volume alterations in OCD patients have been inconsistent. Because the thalamus has a complex structure with distinct functions, we investigated subregional volume changes in the thalamus and their relationship with clinical attributes in a large sample of medication-free OCD patients.

Methods

We collected T1-weighted magnetic resonance imaging data from 177 OCD patients and 152 healthy controls (HCs). Using FreeSurfer, we segmented the thalamus into 12 nuclei groups; subregional volumes were compared between groups using an analysis of covariance. The relationships between altered thalamic volumes and OC symptom severity and OCD onset age were investigated.

Results

Compared to HCs, OCD patients showed a smaller volume of the left posterior thalamic nuclei. Other thalamic subregions did not show significant group differences. There was a significant negative correlation between the volume of the left posterior thalamic nuclei and the age of OCD onset but no significant correlation with OC symptom severity.

Conclusions

This is the first study to report reduced volume of the posterior thalamic nuclei in a large sample of medication-free OCD patients. Our results suggest that the volume of posterior thalamic nuclei may reflect different pathophysiological mechanisms of OCD subtypes related to the age of onset. Additional studies with pediatric samples are required to clarify the relationship between thalamic alterations and the onset age of OCD.

Lower excitatory synaptic gene expression in orbitofrontal cortex and striatum in an initial study of subjects with obsessive compulsive disorder

Obsessive compulsive disorder (OCD) is a severe illness that affects 2-3% of people worldwide. OCD neuroimaging studies have consistently shown abnormal activity in brain regions involved in decision-making (orbitofrontal cortex [OFC]) and action selection (striatum). However, little is known regarding molecular changes that may contribute to abnormal function. We therefore examined expression of synaptic genes in post-mortem human brain samples of these regions from eight pairs of unaffected comparison and OCD subjects. Total grey matter tissue samples were obtained from medial OFC (BA11), lateral OFC (BA47), head of caudate, and nucleus accumbens (NAc). Quantitative polymerase chain reaction (qPCR) was then performed on a panel of transcripts encoding proteins related to excitatory synaptic structure, excitatory synaptic receptors/transporters, and GABA synapses. Relative to unaffected comparison subjects, OCD subjects had significantly lower levels of several transcripts related to excitatory signaling in both cortical and striatal regions. However, a majority of transcripts encoding excitatory synaptic proteins were lower in OFC but not significantly different in striatum of OCD subjects. Composite transcript level measures supported these findings by revealing that reductions in transcripts encoding excitatory synaptic structure proteins and excitatory synaptic receptors/transporters occurred primarily in OFC of OCD subjects. In contrast, transcripts associated with inhibitory synaptic neurotransmission showed minor differences between groups. The observed lower levels of multiple glutamatergic transcripts across both medial and lateral OFC may suggest an upstream causal event. Together, these data provide the first evidence of molecular abnormalities in brain regions consistently implicated in OCD human imaging studies.

An association of Myelin Oligodendrocyte Glycoprotein (MOG) gene variants with white matter volume in pediatric obsessive-compulsive disorder

An increasing number of neuroimaging studies have implicated alterations of white matter in obsessive-compulsive disorder (OCD). The myelin oligodendrocyte glycoprotein (MOG) gene plays a major role in myelination, and has previously demonstrated significant association with this disorder, thus variations in this gene may contribute to observed white matter alterations. The purpose of this study is to examine the relationship between white matter volume in OCD and genetic variations in the MOG gene. Two polymorphisms in the MOG gene, MOG(C1334T) and MOG(C10991T), were investigated for association with total white matter volume as measured using volumetric magnetic resonance imaging in 37 pediatric OCD patients. We compared white matter volumes between allele and genotype groups for each polymorphism using ANCOVA. A significant relationship was detected between genotype C/C of MOG(C10991T) and decreased total white matter volume (P = 0.016). Our results showed an association between a MOG genetic variant and white matter volume. This finding is intriguing in light of the posited role of white matter alteration in the etiology of at least some cases of childhood-onset OCD. Further investigation with larger samples and sub-regional white matter volume phenotypes is warranted.

Are candidate neurocognitive endophenotypes of OCD present in paediatric patients? A systematic review

To-date it has been difficult to ascertain the exact cognitive profile of childhood OCD as studies report variable results. Adult OCD research lately utilises the endophenotype approach; studying cognitive traits that are present in both patients and their unaffected first-degree relatives, and are thought to lie closer to the genotype than the full-blown disorder. By observing whether candidate endopenotypes of adult OCD are present in child patients, we can determine whether the two subtypes show cognitive overlap. We conducted a systematic review of the paediatric OCD literature focussing on proposed neurocognitive endophenotypes of OCD: cognitive flexibility, response inhibition, memory, planning, decision-making, action monitoring, and reversal learning. We found that paediatric patients present robust increases in brain error related negativity associated with abnormal action monitoring, impaired decision-making under uncertainty, planning, and visual working memory, but there is less evidence for deficits in other cognitive domains. This implies that children with OCD show some cognitive similarities with adult patients, but other dysfunctions may only manifest later in the disorder trajectory.

The Neuronal Glutamate Transporter EAAT3 in Obsessive-Compulsive Disorder

Obsessive compulsive disorder (OCD) is a heterogeneous psychiatric disorder affecting 1%–3% of the population worldwide. About half of OCD afflicted individuals do not respond to currently available pharmacotherapy, which is mainly based on serotonin reuptake inhibition. Therefore, there is a critical need to search novel and improved therapeutic targets to treat this devastating disorder. In recent years, accumulating evidence has supported the glutamatergic hypothesis of OCD, and particularly pointing a potential role for the neuronal glutamate transporter EAAT3. This mini-review summarizes recent findings regarding the neurobiological basis of OCD, with an emphasis on the glutamatergic neurotransmission and EAAT3 as a key player in OCD etiology.

Pineal gland volumes are changed in patients with obsessive-compulsive personality disorder

OBJECTIVE

In the present study, taking into consideration our previous studies showing an association on the neuroanatomy of OCD and obsessive-compulsive personality disorders (OCPD), we also decided to examine pineal gland volumes in patients with obsessive-compulsive personality disorder and hypothesized that gland volumes would be found as altered in comparison with those of healthy subjects.

METHODS

Sixteen patients with OCPD and eighteen healthy control subjects underwent magnetic resonance imaging (MRI). We compared the volumes of pineal gland by using MRI between groups.

RESULTS

As compared to healthy control subjects, patients with OCPD had statistically significant smaller pineal gland volumes by using independent sample t test (87.34 ± 19.72 mm³ for patients with OCPD vs. 108.62 ± 22.56 mm³, with a statistically significantly difference of p < 0.01.When controlling for gender distribution, age and whole brain volumes in the General Linear Model, we saw that patients with OCPD had still statistically significant smaller pineal volumes compared to those of healthy control subjects.

CONCLUSION

Finally, the findings of the present study revealed that patients with OCPD had reduced pineal gland volumes compared to those of healthy control subjects, supporting the fact that OCPD might be included in the OCD spectrum disorders, since we have previously found same result in patients with OCPD.

Volumetric MRI study of orbito-frontal cortex and thalamus in obsessive-compulsive personality disorder

OBJECTIVES

Obsessive compulsive personality disorder (OCPD) is currently thought to bear a close relationship with obsessive-compulsive disorder (OCD), and other compulsive disorders such as eating disorder and autistic spectrum disorder, as well as with the personality disorders, focusing on some important dimensions like phenomenology, heritability, environmental risk factors, comorbidity, course of illness, neurocognitive endophenotypes, and treatment response. In the present study, when we have taken into consideration the knowledge aforementioned, we aimed to examine OFC and thalamus volumes in patients with OCPD.

METHODS

We comparatively measured orbito-frontal cortex (OFC) and thalamus volumes of patients with OCPD and healthy control subjects.

RESULTS

Patients with OCPD had considerably smaller left and right OFC volumes compared to those of healthy control subjects. We also found that thalamus volumes of patients were statistically significantly greater than those of healthy comparisons for both sides of region of interest.

CONCLUSIONS

We consider that volumetric alterations determined in the present study may be involved in the pathophysiology of the OCPD, considering that OCPD might be related to OCD spectrum disorders neuroanatomically.

Orbito-frontal cortex and thalamus volumes in the patients with obsessive-compulsive disorder before and after cognitive behavioral therapy

Background The effect of a variety of treatment modalities including psychopharmacological and cognitive behavioral therapy on the brain volumes and neurochemicals have not been investigated enough in the patients with obsessive-compulsive disorder. Therefore, in the present study, we aimed to investigate the effect of cognitive behavioral therapy on the volumes of the orbito-frontal cortex and thalamus regions which seem to be abnormal in the patients with obsessive-compulsive disorder. We hypothesized that there would be change in the volumes of the orbito-frontal cortex and thalamus. Methods Twelve patients with obsessive-compulsive disorder and same number of healthy controls were included into the study. At the beginning of the study, the volumes of the orbito-frontal cortex and thalamus were compared by using magnetic resonance imaging. In addition, volumes of these regions were measured before and after the cognitive behavioral therapy treatment in the patient group. Results The patients with obsessive-compulsive disorder had greater left and right thalamus volumes and smaller left and right orbito-frontal cortex volumes compared to those of healthy control subjects at the beginning of the study. When we compared baseline volumes of the patients with posttreatment ones, we detected that thalamus volumes significantly decreased throughout the period for both sides and that the orbito-frontal cortex volumes significantly increased throughout the period for only left side. Conclusions In summary, we found that cognitive behavioral therapy might volumetrically affect the key brain regions involved in the neuroanatomy of obsessive-compulsive disorder. However, future studies with larger sample are required.

Cell-Type-Specific Contributions of Medial Prefrontal Neurons to Flexible Behaviors

Behavioral flexibility and impulse control are necessary for successful execution of adaptive behavior. They are impaired in patients with damage to the prefrontal cortex (PFC) and in some clinically important conditions, such as obsessive-compulsive disorder. Although the medial prefrontal cortex (mPFC) has been investigated as a critical structure for behavioral flexibility and impulse control, the contribution of the underlying pyramidal neuron cell types in the mPFC remained to be understood. Here we show that interneuron-mediated local inactivation of pyramidal neurons in the mPFC of male and female mice induces both premature responses and choice bias, and establish that these impulsive and compulsive responses are modulated independently. Cell-type-specific photoinhibition of pyramidal deep layer corticostriatal or corticothalamic neurons reduces behavioral flexibility without inducing premature responses. Together, our data confirm the role of corticostriatal neurons in behavioral flexibility and demonstrate that flexible behaviors are also modulated by direct projections from deep layer corticothalamic neurons in the mPFC to midline thalamic nuclei.SIGNIFICANCE STATEMENT Behavioral flexibility and impulse control are indispensable for animals to adapt to changes in the environment and often affected in patients with PFC damage and obsessive-compulsive disorder. We used a probabilistic reversal task to dissect the underlying neural circuitry in the mPFC. Through characterization of the three major pyramidal cell types in the mPFC with optogenetic silencing, we demonstrated that corticostriatal and corticothalamic but not corticocortical pyramidal neurons are temporally recruited for behavioral flexibility. Together, our findings confirm the role of corticostriatal projections in cognitive flexibility and identify corticothalamic neurons as equally important for behavioral flexibility.

Orbito-frontal cortex and thalamus volumes in obsessive-compulsive disorder before and after pharmacotherapy

In the present study, we focused on the key brain regions, OFC and thalamus, to investigate the roles of antiobsessional agents on volume changes of these brain regions after 12 weeks of anti-obsessional treatment in patients with obsessive-compulsive disorder (OCD). Fourteen patients with OCD and the same number of healthy controls were included in the study. At baseline, the volumes of the OFC and thalamus were compared by using magnetic resonance imaging (MRI) between groups. The volumes of OFC and thalamus were evaluated before and after the anti-obsessional drug treatment solely in the patient group. Our study revealed that thalamus volumes were reduced statistically significantly throughout the treatment period. However, we found that OFC volumes did not change statistically significantly throughout the treatment period. In summary, our study found that anti-obsessional drug treatment had an effect on thalamus volumes throughout the treatment period for both sides but not on OFC volumes. However, future studies with larger sample are required.

Resting-state functional connectivity between right anterior insula and right orbital frontal cortex correlate with insight level in obsessive-compulsive disorder

Few studies have explored the neurobiological basis of insight level in obsessive-compulsive disorder (OCD), though the salience network (SN) has been implicated in insight deficits in schizophrenia. This study was then designed to investigate whether resting-state (rs) functional connectivity (FC) of SN was associated with insight level in OCD patients. We analyzed rs-functional magnetic resonance imaging (fMRI) data from 21 OCD patients with good insight (OCD-GI), 19 OCD patients with poor insight (OCD-PI), and 24 healthy controls (HCs). Seed-based whole-brain FC and ROI (region of interest)-wise connectivity analyses were performed with seeds/ROIs in the bilateral anterior insula (AI) and dorsal anterior cingulate cortex (dACC). The right AI-right medial orbital frontal cortex (mOFC) connectivity was found to be uniquely decreased in the OCD-PI group, and the value of this aberrant connectivity correlated with insight level in OCD patients. In addition, we found that the OCD-GI group had significantly increased right AI-left dACC connectivity within the SN, relative to HCs (overall trend for groups: OCD-GI > OCD-PI > HC). Our findings suggest that abnormal right AI-right mOFC FC may mediate insight deficits in OCD, perhaps due to impaired encoding and integration of self-evaluative information about OCD-related beliefs and behaviors. Our findings indicate a SN connectivity dissociation between OCD-GI and OCD-PI patients and support the notion of considering OCD-GI and OCD-PI as two distinct disorder subtypes.

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We examined the functional connectivity of SN in OCD-GI and OCD-PI.

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OCD-PI patients had decreased right AI-right mOFC connectivity.

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Right AI- right mOFC connectivity correlated with insight level in OCD.

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OCD-GI patients had elevated right AI-left dACC connectivity within SN.

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These results are helpful toward elucidating insight presentation in OCD.

Distinct Subcortical Volume Alterations in Pediatric and Adult OCD: A Worldwide Meta- and Mega-Analysis

OBJECTIVE

Structural brain imaging studies in obsessive-compulsive disorder (OCD) have produced inconsistent findings. This may be partially due to limited statistical power from relatively small samples and clinical heterogeneity related to variation in illness profile and developmental stage. To address these limitations, the authors conducted meta- and mega-analyses of data from OCD sites worldwide.

METHOD

T1 images from 1,830 OCD patients and 1,759 control subjects were analyzed, using coordinated and standardized processing, to identify subcortical brain volumes that differ between OCD patients and healthy subjects. The authors performed a meta-analysis on the mean of the left and right hemisphere measures of each subcortical structure, and they performed a mega-analysis by pooling these volumetric measurements from each site. The authors additionally examined potential modulating effects of clinical characteristics on morphological differences in OCD patients.

RESULTS

The meta-analysis indicated that adult patients had significantly smaller hippocampal volumes (Cohen's d=-0.13; % difference=-2.80) and larger pallidum volumes (d=0.16; % difference=3.16) compared with adult controls. Both effects were stronger in medicated patients compared with controls (d=-0.29, % difference=-4.18, and d=0.29, % difference=4.38, respectively). Unmedicated pediatric patients had significantly larger thalamic volumes (d=0.38, % difference=3.08) compared with pediatric controls. None of these findings were mediated by sample characteristics, such as mean age or scanning field strength. The mega-analysis yielded similar results.

CONCLUSIONS

The results indicate different patterns of subcortical abnormalities in pediatric and adult OCD patients. The pallidum and hippocampus seem to be of importance in adult OCD, whereas the thalamus seems to be key in pediatric OCD. These findings highlight the potential importance of neurodevelopmental alterations in OCD and suggest that further research on neuroplasticity in OCD may be useful.

The Co-evolution of Neuroimaging and Psychiatric Neurosurgery

The role of neuroimaging in psychiatric neurosurgery has evolved significantly throughout the field's history. Psychiatric neurosurgery initially developed without the benefit of information provided by modern imaging modalities, and thus lesion targets were selected based on contemporary theories of frontal lobe dysfunction in psychiatric disease. However, by the end of the 20th century, the availability of structural and functional magnetic resonance imaging (fMRI) allowed for the development of mechanistic theories attempting to explain the anatamofunctional basis of these disorders, as well as the efficacy of stereotactic neuromodulatory treatments. Neuroimaging now plays a central and ever-expanding role in the neurosurgical management of psychiatric disorders, by influencing the determination of surgical candidates, allowing individualized surgical targeting and planning, and identifying network-level changes in the brain following surgery. In this review, we aim to describe the coevolution of psychiatric neurosurgery and neuroimaging, including ways in which neuroimaging has proved useful in elucidating the therapeutic mechanisms of neuromodulatory procedures. We focus on ablative over stimulation-based procedures given their historical precedence and the greater opportunity they afford for post-operative re-imaging, but also discuss important contributions from the deep brain stimulation (DBS) literature. We conclude with a discussion of how neuroimaging will transition the field of psychiatric neurosurgery into the era of precision medicine.

A Framework for Understanding the Emerging Role of Corticolimbic-Ventral Striatal Networks in OCD-Associated Repetitive Behaviors

Significant interest in the mechanistic underpinnings of obsessive-compulsive disorder (OCD) has fueled research on the neural origins of compulsive behaviors. Converging clinical and preclinical evidence suggests that abnormal repetitive behaviors are driven by dysfunction in cortico-striatal-thalamic-cortical (CSTC) circuits. These findings suggest that compulsive behaviors arise, in part, from aberrant communication between lateral orbitofrontal cortex (OFC) and dorsal striatum. An important body of work focused on the role of this network in OCD has been instrumental to progress in the field. Disease models focused primarily on these regions, however, fail to capture an important aspect of the disorder: affective dysregulation. High levels of anxiety are extremely prevalent in OCD, as is comorbidity with major depressive disorder. Furthermore, deficits in processing rewards and abnormalities in processing emotional stimuli are suggestive of aberrant encoding of affective information. Accordingly, OCD can be partially characterized as a disease in which behavioral selection is corrupted by exaggerated or dysregulated emotional states. This suggests that the networks producing OCD symptoms likely expand beyond traditional lateral OFC and dorsal striatum circuit models, and highlights the need to cast a wider net in our investigation of the circuits involved in generating and sustaining OCD symptoms. Here, we address the emerging role of medial OFC, amygdala, and ventral tegmental area projections to the ventral striatum (VS) in OCD pathophysiology. The VS receives strong innervation from these affect and reward processing regions, and is therefore poised to integrate information crucial to the generation of compulsive behaviors. Though it complements functions of dorsal striatum and lateral OFC, this corticolimbic-VS network is less commonly explored as a potential source of the pathology underlying OCD. In this review, we discuss this network's potential role as a locus of OCD pathology and effective treatment.

1HMRS results of hippocampus in the patients with obsessive-compulsive disorder before and after cognitive behavioral therapy

OBJECTIVE

In the present study, we examined the effects of cognitive behavioral therapy (CBT) on the hippocampal neurochemistry in patients with obsessive-compulsive disorder (OCD).

METHODS

Twelve patients with OCD and same number of healthy controls were included into the study. Neurochemical variables of the hippocampus were measured before and after the CBT treatment in the patient group.

RESULTS

At baseline, the patients with OCD had significantly lower ratio of N-acetyl-l-aspartate/choline (NAA/CHO) compared with that of healthy control subjects. When comparing pre-treatment results of the patient group with those of post-treatment ones using paired t-test, we found that NAA/CHO ratio increased from 2.47 ± 0.64 to 3.66 ± 0.88, with a statisical significance.

CONCLUSIONS

The findings may implicate that CBT increases the level of NAA which is a marker of neuronal integrity.

Decreased limbic and increased fronto-parietal connectivity in unmedicated patients with obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is characterized by recurrent intrusive thoughts and ritualized, repetitive behaviors, or mental acts. Convergent experimental evidence from neuroimaging and neuropsychological studies supports an orbitofronto-striato-thalamo-cortical dysfunction in OCD. Moreover, an over excitability of the amygdala and over monitoring of thoughts and actions involving the anterior cingulate, frontal and parietal cortex has been proposed as aspects of pathophysiology in OCD. We chose a data driven, graph theoretical approach to investigate brain network organization in 17 unmedicated OCD patients and 19 controls using resting-state fMRI. OCD patients showed a decreased connectivity of the limbic network to several other brain networks: the basal ganglia network, the default mode network, and the executive/attention network. The connectivity within the limbic network was also found to be decreased in OCD patients compared to healthy controls. Furthermore, we found a stronger connectivity of brain regions within the executive/attention network in OCD patients. This effect was positively correlated with disease severity. The decreased connectivity of limbic regions (amygdala, hippocampus) may be related to several neurocognitive deficits observed in OCD patients involving implicit learning, emotion processing and expectation, and processing of reward and punishment. Limbic disconnection from fronto-parietal regions relevant for (re)-appraisal may explain why intrusive thoughts become and/or remain threatening to patients but not to healthy subjects. Hyperconnectivity within the executive/attention network might be related to OCD symptoms such as excessive monitoring of thoughts and behavior as a dysfunctional strategy to cope with threat and uncertainty.

Orbitofrontal and striatal circuits dynamically encode the shift between goal-directed and habitual actions

Shifting between goal-directed and habitual actions allows for efficient and flexible decision making. Here we demonstrate a novel, within-subject instrumental lever-pressing paradigm, in which mice shift between goal-directed and habitual actions. We identify a role for orbitofrontal cortex (OFC) in actions following outcome revaluation, and confirm that dorsal medial (DMS) and lateral striatum (DLS) mediate different action strategies. Simultaneous in vivo recordings of OFC, DMS and DLS neuronal ensembles during shifting reveal that the same neurons display different activities depending on whether presses are goal-directed or habitual, with DMS and OFC becoming more and DLS less engaged during goal-directed actions. Importantly, the magnitude of neural activity changes in OFC following changes in outcome value positively correlates with the level of goal-directed behavior. Chemogenetic inhibition of OFC disrupts goal-directed actions, whereas optogenetic activation of OFC specifically increases goal-directed pressing. These results also reveal a role for OFC in action revaluation, which has implications for understanding compulsive behavior.

Brain structural abnormalities in behavior therapy-resistant obsessive-compulsive disorder revealed by voxel-based morphometry

BACKGROUND

Although several functional imaging studies have demonstrated that behavior therapy (BT) modifies the neural circuits involved in the pathogenesis of obsessive-compulsive disorder (OCD), the structural abnormalities underlying BT-resistant OCD remain unknown.

METHODS

In this study, we examined the existence of regional structural abnormalities in both the gray matter and the white matter of patients with OCD at baseline using voxel-based morphometry in responders (n=24) and nonresponders (n=15) to subsequent BT. Three-dimensional T1-weighted magnetic resonance imaging was performed before the completion of 12 weeks of BT.

RESULTS

Relative to the responders, the nonresponders exhibited significantly smaller gray matter volumes in the right ventromedial prefrontal cortex, the right orbitofrontal cortex, the right precentral gyrus, and the left anterior cingulate cortex. In addition, relative to the responders, the nonresponders exhibited significantly smaller white matter volumes in the left cingulate bundle and the left superior frontal white matter.

CONCLUSION

These results suggest that the brain structures in several areas, including the orbitofrontal cortex, anterior cingulate cortex, and cingulate bundles, are related to the lack of a response to BT in patients with OCD. The use of a voxel-based morphometry approach may be advantageous to understanding differences in brain abnormalities between responders and nonresponders to BT.

A phenotypic structure and neural correlates of compulsive behaviors in adolescents

BACKGROUND

A compulsivity spectrum has been hypothesized to exist across Obsessive-Compulsive disorder (OCD), Eating Disorders (ED), substance abuse (SA) and binge-drinking (BD). The objective was to examine the validity of this compulsivity spectrum, and differentiate it from an externalizing behaviors dimension, but also to look at hypothesized personality and neural correlates.

METHOD

A community-sample of adolescents (N=1938; mean age 14.5 years), and their parents were recruited via high-schools in 8 European study sites. Data on adolescents' psychiatric symptoms, DSM diagnoses (DAWBA) and substance use behaviors (AUDIT and ESPAD) were collected through adolescent- and parent-reported questionnaires and interviews. The phenotypic structure of compulsive behaviors was then tested using structural equation modeling. The model was validated using personality variables (NEO-FFI and TCI), and Voxel-Based Morphometry (VBM) analysis.

RESULTS

Compulsivity symptoms best fit a higher-order two factor model, with ED and OCD loading onto a compulsivity factor, and BD and SA loading onto an externalizing factor, composed also of ADHD and conduct disorder symptoms. The compulsivity construct correlated with neuroticism (r=0.638; p ≤ 0.001), conscientiousness (r=0.171; p ≤ 0.001), and brain gray matter volume in left and right orbitofrontal cortex, right ventral striatum and right dorsolateral prefrontal cortex. The externalizing factor correlated with extraversion (r=0.201; p ≤ 0.001), novelty-seeking (r=0.451; p ≤ 0.001), and negatively with gray matter volume in the left inferior and middle frontal gyri.

CONCLUSIONS

Results suggest that a compulsivity spectrum exists in an adolescent, preclinical sample and accounts for variance in both OCD and ED, but not substance-related behaviors, and can be differentiated from an externalizing spectrum.

Influence of polymorphisms in genes SLC1A1, GRIN2B, and GRIK2 on clozapine-induced obsessive-compulsive symptoms

RATIONALE

Clinical observations indicate that atypical antipsychotics, especially clozapine, induce obsessive-compulsive (OC) symptoms in schizophrenia patients. Recent data from neuroimaging and clinical trials suggest a role for altered glutamate neurotransmission in the etiology of OC disorder (OCD), and SLC1A1, GRIN2B, and GRIK2 have all been reported to regulate glutamate transmission and affect OCD pathophysiology.

OBJECTIVES

This study aimed to determine whether SLC1A1, GRIN2B, and GRIK2 are associated with clozapine-induced OC symptoms.

METHODS

A total of 250 clinically stable schizophrenia patients receiving clozapine treatment were recruited. The Yale-Brown Obsessive Compulsive Scale (Y-BOCS) was used to evaluate the severity of OC symptoms. Based on their Y-BOCS scores, 250 patients were divided into the OC and non-OC groups (patients with or without OC symptoms, respectively). Additionally, three reported OCD susceptibility polymorphisms, SLC1A1 (rs2228622), GRIN2B (rs890), and GRIK2 (rs1556995), were genotyped.

RESULTS

Trends of association with OC symptoms were observed in rs2228622A and rs890T alleles. SLC1A1 and GRIN2B interaction was found in the significant two-locus gene-gene interaction model (p = 0.0021), using the multifactor dimensionality reduction method. Further analysis showed a significant interaction between SLC1A1 and GRIN2B on the Y-BOCS score (F 6, 137 = 7.650, p < 0.001), and individuals with AA/TT genotypes had a significantly higher mean Y-BOCS score than those with other genotypes, except AG/TT.

CONCLUSIONS

These results suggest that SLC1A1, GRIN2B, and interactions between the two may potentially confer a susceptibility to OC symptoms in schizophrenia patients receiving clozapine.

Morphometric brain characterization of refractory obsessive-compulsive disorder: diffeomorphic anatomic registration using exponentiated Lie algebra

BACKGROUND

Few studies have used neuroimaging to characterize treatment-refractory obsessive-compulsive disorder (OCD). This study sought to explore gray matter structure in patients with treatment-refractory OCD and compare it with that of healthy controls.

METHODS

A total of 18 subjects with treatment-refractory OCD and 26 healthy volunteers were analyzed by MRI using a 3.0-T scanner and voxel-based morphometry (VBM). Diffeomorphic anatomical registration using exponentiated Lie algebra (DARTEL) was used to identify structural changes in gray matter associated with treatment-refractory OCD. A partial correlation model was used to analyze whether morphometric changes were associated with Yale-Brown Obsessive-Compulsive Scale scores and illness duration.

RESULTS

Gray matter volume did not differ significantly between the two groups. Treatment-refractory OCD patients showed significantly lower gray matter density than healthy subjects in the left posterior cingulate cortex (PCC) and mediodorsal thalamus (MD) and significantly higher gray matter density in the left dorsal striatum (putamen). These changes did not correlate with symptom severity or illness duration.

CONCLUSIONS

Our findings provide new evidence of deficits in gray matter density in treatment-refractory OCD patients. These patients may show characteristic density abnormalities in the left PCC, MD and dorsal striatum (putamen), which should be verified in longitudinal studies.

Anxiety and affective disorder comorbidity related to serotonin and other neurotransmitter systems: obsessive-compulsive disorder as an example of overlapping clinical and genetic heterogeneity

Individuals with obsessive-compulsive disorder (OCD) have also been shown to have comorbid lifetime diagnoses of major depressive disorder (MDD; rates greater than 70%), bipolar disorder (rates greater than 10%) and other anxiety disorders (e.g. panic disorder, post-traumatic stress disorder (PTSD)). In addition, overlap exists in some common genetic variants (e.g. the serotonin transporter gene (SLC6A4), the brain-derived neurotrophic factor (BDNF) gene), and rare variants in genes/chromosomal abnormalities (e.g. the 22q11 microdeletion syndrome) found across the affective/anxiety disorder spectrums. OCD has been proposed as a possible independent entity for DSM-5, but by others thought best retained as an anxiety disorder subtype (its current designation in DSM-IV), and yet by others considered best in the affective disorder spectrum. This review focuses on OCD, a well-studied but still puzzling heterogeneous disorder, regarding alterations in serotonergic, dopaminergic and glutamatergic neurotransmission in addition to other systems involved, and how related genes may be involved in the comorbidity of anxiety and affective disorders. OCD resembles disorders such as depression, in which gene × gene interactions, gene × environment interactions and stress elements coalesce to yield OC symptoms and, in some individuals, full-blown OCD with multiple comorbid disorders.

Orbito-frontal cortex volumes in panic disorder

OBJECTIVE

Given the association between the pathophysiology of panic disorder and prefrontal cortex function, we aimed to perform a volumetric MRI study in patients with panic disorder and healthy controls focusing on the in vivo neuroanatomy of the OFC.

METHODS

Twenty right-handed patients with panic disorder and 20 right-handed healthy control subjects were studied. The volumes of whole brain, total white and gray matters, and OFC were measured by using T1-weighted coronal MRI images, with 1.5-mm-thick slices, at 1.5T. In addition, for psychological valuation, Hamilton Depression Rating (HDRS) and Panic Agoraphobia Scales (PAS) were administered.

RESULTS

Unadjusted mean volumes of the whole brain volume, total white and gray matter were not different between the patients and healthy controls while the patient group had significantly smaller left (t=-6.70, p<0.0001) and right (t=-5.86, p<0.0001) OFC volumes compared with healthy controls.

CONCLUSION

Our findings indicate an alteration of OFC morphology in the panic disorder and suggest that OFC abnormalities may be involved in the pathophysiology of panic disorder.

Comprehensive evaluation of cortical structure abnormalities in drug-naïve, adult patients with obsessive-compulsive disorder: a surface-based morphometry study

The study objective was to comprehensively evaluate drug-naïve, adult patients with Obsessive Compulsive Disorder (OCD) for cortical structure abnormalities in comparison with healthy controls. In this cross-sectional study of case-control design, Magnetic Resonance Imaging (1-mm) was performed in drug-naïve OCD patients (N = 50) & age- sex-, education- and handedness-matched healthy controls (N = 40). We examined cortical volume, thickness, surface area & local Gyrification Index (LGI) through a completely automated surface-based morphometric analysis using FreeSurfer software. OCD symptoms and insight were assessed using Yale-Brown Obsessive Compulsive Symptom (Y-BOCS) check-list and severity scale. Illness severity was assessed using Clinical Global Impression Severity (CGI-S) Scale. OCD patients had significantly deficient volume, thickness and surface area of right anterior cingulate gyrus (ACG). Right lingual gyrus surface area was found to be significantly decreased in patients. Y-BOCS obsession score had significant negative correlation with left frontal pole volume. Y-BOCS compulsion score had significant negative correlations with right ACG volume and surface area and right lateral orbitofrontal cortex LGI. CGI-Severity score had significant negative correlations with right lingual gyrus volume, thickness and surface area as well as right lateral orbitofrontal area. Y-BOCS insight score showed a significant negative correlation with LGI of left medial OFC and left rostral ACG. Identification of novel deficits involving occipital brain regions and first-time observations of relevant correlations between various illness characteristics and cortical measures in OCD patients supports a network involving anterior cingulate, orbitofrontal and occipital brain regions in the pathogenesis of OCD.

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.

Review of structural neuroimaging in patients with refractory obsessive-compulsive disorder

The notion that some special brain regions may be involved in the pathogenesis of obsessive-compulsive disorder (OCD) dates back to the beginning of the twentieth century. Structural neuroimaging studies in the past 2 decades have revealed important findings that facilitate understanding of OCD pathogenesis. Current knowledge based on functional and structural neuroimaging investigations largely emphasizes abnormalities in fronto-striatal-thalamic-cortical and orbitofronto-striato-thalamic circuits in the pathophysiology of OCD. However, these neuroimaging studies did not focus on refractory OCD. The present review mainly focused on structural neuroimaging performed in OCD, which had been ignored previously, and highlighted current evidence supporting that orbito-frontal cortex and thalamus are key brain regions, and that the hippocampus-amygdala complex is associated with refractoriness to the available treatment strategies. However, to fully reveal the neuroanatomy of refractoriness, longitudinal studies with larger samples are required.

Differences between effects of psychological versus pharmacological treatments on functional and morphological brain alterations in anxiety disorders and major depressive disorder: a systematic review

The most prevalent mental disorders, anxiety and mood disorders, are associated with both functional and morphological brain changes that commonly involve the 'fear network' including the (medial) prefrontal cortex, hippocampus and amygdala. Patients suffering from anxiety disorders and major depressive disorder often show excessive amygdala and reduced prefrontal cortex functioning. It is, however, still unclear whether these brain abnormalities disappear or diminish following effective treatment. This review aims to compare the effects of psychotherapy and pharmacotherapy on functional and morphological brain measures in these disorders. Sixty-three studies were included, 30 investigating psychotherapy effects and 33 investigating pharmacotherapy effects. Despite methodological differences, results suggest a functional normalization of the 'fear network'. Pharmacotherapy particularly decreases over-activity of limbic structures (bottom-up effect) while psychotherapy tends to increase activity and recruitment of frontal areas (top-down effect), especially the anterior cingulate cortex. Additionally, pharmacotherapy, but not psychotherapy, has been associated with morphological changes, depending on the disorder. These findings suggest that both types of treatments normalize (functional) brain abnormalities each in specific ways.

Do defense styles of ego relate to volumes of orbito-frontal cortex in patients with obsessive-compulsive disorder?

OBJECTIVE

Although the importance of orbito-frontal cortex (OFC) is established in the pathogenesis of obsessive compulsive disorder (OCD), no study have evaluated its relation to the traditional psychodynamic perspective. In the present study, we aimed to evaluate the relationship between the defense styles consisting of mature, immature and neurotic defenses and OFC volumes of patients with OCD.

METHODS

Subjects were selected among those of our previous study, and so eighteen patients with OCD and same number of healthy controls were took into the study. The patients and controls had underwent magnetic resonance imaging (MRI). In addition, the Defense Style Questionnaire-40 was administered to obtain defense styles of patients and controls.

RESULTS

No significant relationship was found between the right OFC volumes of both the patient and control groups and their scores of mature, neurotic, or immature defense mechanisms. As for the left OFC volumes, the only significant relationship for the scores of immature defense mechanism was found in the patient group.

CONCLUSION

The results of the present study indicated that there was no significant relationship between OFC volumes of the patient group and their scores of mature, neurotic, or immature defense mechanisms, except a significant relation with the scores of immature defense mechanisms.

Serotonin transporter gene polymorphism implicates reduced orbito-frontal cortex in obsessive-compulsive disorder

Although a number of magnetic resonance imaging (MRI) and genetic studies have been performed on obsessive-compulsive disorder (OCD), only limited studies in which genetic and neuroanatomical variables are evaluated concurrently have been performed. Therefore, the aim of our present study is (to understand) better understanding how genetic variation in the promoter region of the 5-HTT gene (5-HTTLPR) is associated with key brain structures in OCD, orbito-frontal cortex (OFC), thalamus and anterior cingulate. 5-HTT genotypes (SS, SL, LL) were determined for 40 patients with OCD and the same number of healthy controls. MRI-derived volumes of the OFC, thalamus, and anterior cingulate were determined by reliable tracing techniques. Volumetric measurements were made with T1-weighted coronal MRI images, with 1.5-mm-thick slices, at 1.5T, and were done blindly. In comparison with controls, OCD patients demonstrated volumes reduction in OFC, increased volumes of thalamus and total white matter volumes, but no difference in total brain volume, total gray matter volumes and anterior cingulate volumes. No significant difference was observed in allelic frequencies between the patients and controls. The stronger effects of 5-HTT polymorphism on brain morphology in OCD than those in controls were determined in the both OFC and thalamus. On the other hand, for the OCD patients, ANCOVA revealed a significant main effect of genotype for both the OFC and thalamus and a significant genotype-by-side interaction for the OFC, demonstrating that the short variants had a smaller right OFC than the long variants. In conclusion, we found a significant genotype-diagnosis interaction effects on key brain structures, with a stronger effects of 5-HTT polymorphism in OFC and thalamus of OCD patients, whereas no morphological changes related to the polymorphism were found in normal individuals.

Is there evidence of brain white-matter abnormalities in obsessive-compulsive disorder?: a narrative review

OBJECTIVE

Although several studies have confirmed the occurrence of gray-matter abnormalities in obsessive-compulsive disorder (OCD), the literature on white matter in OCD is more limited. In this study, we reviewed the role of white-matter abnormalities in the pathophysiology of OCD.

METHOD

We reviewed the PubMed studies investigating white-matter integrity in patients with OCD between 1980 and 2010.

RESULTS

Case studies of patients who developed obsessive-compulsive symptoms secondary to multiple sclerosis, cerebrovascular diseases, and paraneoplastic leucoencephalopathy and controlled studies of patients with OCD examined with neuroimaging techniques (eg, structural, diffusion, and spectroscopic magnetic resonance imaging) were all consistent with the existence of abnormalities in specific white-matter tracts (eg, internal capsule, cingulate bundle, and corpus callosum) of individuals with OCD.

CONCLUSIONS

Our review emphasizes that the reported white-matter alterations in OCD complement the broader gray-matter abnormalities identified and may well suggest that OCD is associated with large-scale disruption in brain systems or networks, as opposed to being a consequence of disturbances in isolated brain regions.

Evidence for specific cognitive deficits in visual information processing in patients with OCD compared to patients with unipolar depression

OBJECTIVE

Neuropsychological studies comparing cognitive performance in patients suffering from Obsessive-Compulsive Disorder (OCD) or Major Depressive Disorder (MDD) revealed deficits in the domains of verbal fluency and viso-motor speed/set shifting in both groups. Spatial working memory deficits, however, have been identified as specific markers of OCD. As yet, it has not been substantiated whether deficits in visual organization and complex visual memory are also specific to OCD and are not shared by MDD.

METHOD

Test performance in seven cognitive domains was assessed in 40 OCD patients, 20 MDD patients, and 40 healthy controls. Patient groups were matched according to severity of depressive symptoms.

RESULTS

Deficits shared by both patient groups, as compared to controls, were found in delayed spatial recall and verbal fluency while verbal memory was normal in both patient groups. Only patients with OCD, but not MDD patients were impaired in the domains visual memory, viso-motor speed/set shifting, visual organization, and problem solving. In addition, OCD patients differed significantly from MDD subjects in visual organization and problem solving. Visual organization scores correlated significantly with severity of current compulsions in the OCD group (r=-.324).

CONCLUSIONS

OCD patients demonstrate difficulties in visual organization and mental manipulation of complex visual material, which are not accounted for by depressive symptoms and which constitute a specific cognitive deficit of the disorder.

The association of myelin oligodendrocyte glycoprotein gene and white matter volume in obsessive-compulsive disorder

BACKGROUND

Morphological changes of white matter have been described in patients with obsessive-compulsive disorder (OCD). The aim of our study was to determine whether a functional polymorphism of the myelin oligodendrocyte glycoprotein (MOG) G511C (Val142Leu) is associated with white matter volumes in patients with OCD.

METHODS

The MOG G511C (Val142Leu) genotypes (Val/Val, Val/Leu and Leu/Leu) were determined for 30 patients with OCD and the same number of healthy controls. Magnetic resonance imaging (MRI) scans were obtained and analyzed by the software program.

RESULTS

In comparison with controls, while no difference in total brain volume and total gray matter volumes was seen, total white matter volumes of the patients were larger than those of healthy controls. The genotypic pattern of distribution of MOG G511C was not different between the OCD patients and the controls. ANCOVA analysis in the OCD patients revealed a significantly larger total white matter volumes in patients carrying the MOG G511C (Val142Leu) Val/Val genotype compared with those carrying the Val/Leu and Leu/Leu genotypes. The analyses revealed no significant effects of genotype in the combined group but there was a statistically significant diagnosis effect, and an interaction between diagnosis and genotype effect.

CONCLUSIONS

Our study provides first evidence that the MOG G511C (Val142Leu) polymorphism might be associated with structural changes in the total white matter volumes of OCD patients, which might indicate an interaction between genetics and neuroimaging abnormalities in these patients.

Brain morphology of patients with body dysmorphic disorder

BACKGROUND

There has been dearth of investigations concerning morphometric magnetic resonance imaging (MRI) study of regional brain volumes in body dysmorphic disorder (BDD). So we performed a volumetric MRI study in patients with BDD focusing on the in vivo neuroanatomy of thalamus, caudate nucleus, anterior cingulate cortex, and orbito-frontal cortex (OFC) concurrently.

METHODS

The whole brain, total gray and white matter volume, thalamus, caudate nucleus, anterior cingulate cortex, and OFC volumes were blindly measured in 12 unmedicated male BDD patients not having any comorbidity and 12 male control subjects matched for age, and gender.

RESULTS

The mean OFC and anterior cingulate volumes were significantly smaller than those of healthy controls. The mean white matter volume was larger than that of controls. There was a trend toward increased thalamic volume in patients compared with that of control subjects. Length of illness was inversely correlated with OFC volumes in the patient group both on the left and right sides.

CONCLUSIONS

These findings may be interpreted as further evidence for the inclusion of BDD among a group of obsessive-compulsive spectrum disorders. Future research is necessary to confirm these preliminary findings, to extend them, and to clarify their significance with respect to the etiology and pathophysiology of BDD.

Duration of untreated illness as a predictor of treatment response and remission in obsessive-compulsive disorder

OBJECTIVES

The Duration of Untreated Illness (DUI), defined as the time elapsing between the onset of a disorder and the beginning of the first pharmacological treatment, has been increasingly investigated as a predictor of outcome and course across different psychiatric disorders. Purpose of this naturalistic study was to evaluate the influence of DUI on treatment response and remission in a sample of patients with obsessive-compulsive disorder (OCD).

METHODS

Sixty-six outpatients with a DSM-IV diagnosis of OCD were included in the study. Patients received, according to their clinical conditions, an open pharmacological treatment of 12 weeks and were evaluated by the administration of the Yale Brown Obsessive Compulsive Scale (Y-BOCS) at baseline and endpoint. Treatment response was defined as a decrease .25% on Y-BOCS score compared to baseline, while remission was defined as an endpoint Y-BOCS total score #10. A logistic regression was performed considering DUI as the independent continuous variable and treatment response and remission as the dependent variables. Moreover, the sample was divided into two groups according to a categorical cut-off for the DUI of 24 months and odds ratios (OR) were calculated on the basis of the same variables.

RESULTS

DUI, considered as a continuous variable, was not predictive of treatment response (OR51.00, P50.15) nor remission (OR51.00, P50.59). When considered as a categorical variable, however, a DUI # 24 months was predictive of treatment response (OR50.27, P50.03).

CONCLUSIONS

Results from the present naturalistic study suggest a complicated relationship between DUI and treatment outcome in OCD encouraging further investigation with larger samples in order to better define long versus short DUI in this condition.

The neurocircuitry of fear, stress, and anxiety disorders

Anxiety disorders are a significant problem in the community, and recent neuroimaging research has focused on determining the brain circuits that underlie them. Research on the neurocircuitry of anxiety disorders has its roots in the study of fear circuits in animal models and the study of brain responses to emotional stimuli in healthy humans. We review this research, as well as neuroimaging studies of anxiety disorders. In general, these studies have reported relatively heightened amygdala activation in response to disorder-relevant stimuli in post-traumatic stress disorder, social phobia, and specific phobia. Activation in the insular cortex appears to be heightened in many of the anxiety disorders. Unlike other anxiety disorders, post-traumatic stress disorder is associated with diminished responsivity in the rostral anterior cingulate cortex and adjacent ventral medial prefrontal cortex. Additional research will be needed to (1) clarify the exact role of each component of the fear circuitry in the anxiety disorders, (2) determine whether functional abnormalities identified in the anxiety disorders represent acquired signs of the disorders or vulnerability factors that increase the risk of developing them, (3) link the findings of functional neuroimaging studies with those of neurochemistry studies, and (4) use functional neuroimaging to predict treatment response and assess treatment-related changes in brain function.

Basal ganglia MR relaxometry in obsessive-compulsive disorder: T2 depends upon age of symptom onset

Dysfunction in circuits linking frontal cortex and basal ganglia (BG) is strongly implicated in obsessive-compulsive disorder (OCD). On MRI studies, neuropsychiatric disorders with known BG pathology have abnormally short T2 relaxation values (a putative biomarker of elevated iron) in this region. We asked if BG T2 values are abnormal in OCD. We measured volume and T2 and T1 relaxation rates in BG of 32 adults with OCD and 33 matched controls. There were no group differences in volume or T1 values in caudate, putamen, or globus pallidus (GP). The OCD group had lower T2 values (suggesting higher iron content) in the right GP, with a trend in the same direction for the left GP. This effect was driven by patients whose OCD symptoms began from around adolescence to early adulthood. The results suggest a possible relationship between age of OCD onset and iron deposition in the basal ganglia.

Endophenotypes of obsessive-compulsive disorder: rationale, evidence and future potential

Obsessive-compulsive disorder (OCD) is a heritable and debilitating neuropsychiatric condition. Attempts to delineate genetic contributions have met with limited success, and there is an ongoing search for intermediate trait or vulnerability markers rooted in the neurosciences. Such markers would be valuable for detecting people at risk of developing the condition, clarifying etiological factors and targeting novel treatments. This review begins with brief coverage of the epidemiology of OCD, and presents a hierarchical model of the condition. The advantages of neuropsychological assessment and neuroimaging as objective measures of brain integrity and function are discussed. We describe the concept of endophenotypes and examples of their successful use in medicine and psychiatry. Key areas of focus in the search for OCD endophenotypes are identified, such as measures of inhibitory control and probes of the integrity of orbitofrontal and posterior parietal cortices. Finally, we discuss exciting findings in unaffected first-degree relatives of patients with OCD that have led to the identification of several candidate endophenotypes of the disorder, with important implications for neurobiological understanding and treatment of this and related conditions.

Inverse relationship between thalamic and orbitofrontal volumes in obsessive-compulsive disorder

Volumetric magnetic resonance imaging (MRI) studies in obsessive-compulsive disorder (OCD) have reported a smaller volume of the orbitofrontal cortex (OFC) and a larger volume of the thalamus compared with healthy controls. Both of these brain regions are strongly connected; therefore, it may be hypothesized that cortical and thalamic alterations are related. Here, we investigated the relationship between thalamic and orbitofrontal volumes in OCD patients relative to healthy controls. MRI volumetric measurements of the thalamus and the OFC were obtained in 16 OCD patients without comorbidity and 16 comparison subjects matched for age, sex and educational level. Partial correlation analyses that controlled for intracranial volume (ICV) were performed to explore relationships between thalamic and OFC volumes in each group. In order to assess the specificity of this relationship, we conducted similar analyses of the anterior cingulate cortex (ACC) as a non-OFC cortical volume. Finally, by using data from previously published volumetric MRI studies, we conducted a meta-regression to explore the relationships between volume changes in these regions of interest. Results showed that thalamic volumes were significantly negatively correlated with OFC volumes in OCD patients (r=-0.83, p<0.001), but not in healthy subjects (r=-0.15, p=0.59). A significant relationship between thalamic and ACC volumes was found neither in the OCD patients (r=0.03, p=0.91) nor in the comparison subjects (r=-0.23, p=0.40). Furthermore, meta-regression analyses showed that previously reported volume changes in the thalamus were significantly correlated with OFC volume changes (r=-0.71, p<0.05), but not with ACC volume changes (r=0.07, p=0.86). Although our results do not allow for any causal relationship to be established, they suggest that structural alterations of both the thalamus and the OFC are inversely and specifically related in OCD.