Reduced cortical thickness in non-medicated patients with obsessive-compulsive disorder

Increasing evidence suggests the presence of grey matter volume abnormalities in patients with obsessive-compulsive disorder (OCD) and the mediation of the expression of different OCD symptoms by discrete neural systems of the brain. However, limited studies have investigated the abnormalities of cortical thickness, and their results are comparatively inconsistent, possibly owing to the inclusion of medicated patients. Therefore, this study investigated cortical thickness abnormalities using surface-based analysis to identify distinct neural correlates of each symptom dimension in non-medicated patients with OCD. Thirty non-medicated patients with OCD and 30 age- and gender-matched healthy controls underwent magnetic resonance imaging. Group comparison of cortical thickness was performed using surface-based analysis. We also conducted correlation analysis between cortical thickness and each symptom dimension score. Compared to the healthy controls, the OCD patients had statistically significant reduction in cortical thickness in the cluster that contained the left superior temporal gyrus and posterior insular cortex (p<.05, corrected); no areas of the brain had significantly greater cortical thickness. Negative correlation was also found between cortical thickness and "cleaning" dimension scores in the left postcentral and right superior parietal gyri. The present results suggest that cortical thinning in the region that contains the left superior temporal gyrus and posterior insula may underlie pathophysiology of OCD and that discrete neural systems may mediate the "cleaning" symptom dimension.     

Autism and ADHD Symptoms in Patients with OCD: Are They Associated with Specific OC Symptom Dimensions or OC Symptom Severity?

In obsessive-compulsive disorder (OCD), the relationship between autism spectrum disorders (ASD), attention-deficit/hyperactivity disorder (ADHD) symptom, and obsessive-compulsive (OC) symptom dimensions and severity has scarcely been studied. Therefore, 109 adult outpatients with primary OCD were compared to 87 healthy controls on OC, ADHD and ASD symptoms. OCD patients showed increased ADHD and autism symptom frequencies, OCD + ADHD patients reporting more autism symptoms (particularly attention switching and social skills problems) than OCD − ADHD patients. Attention switching problems were most significant predictors of OC symptom dimensions (except hoarding) and of symptom severity. Hoarding was not associated with elevated autism scale scores, but with inattention. In conclusion, attention switching problems may reflect both symptom overlap and a common etiological factor underlying ASD, ADHD and OCD.     

Brain structural abnormalities in psychotropic drug-naive pediatric patients with obsessive-compulsive disorder

OBJECTIVE: The authors investigated structural abnormalities in brain regions comprising cortical-striatal-thalamic-cortical loops in pediatric patients with obsessive-compulsive disorder (OCD). METHOD: Volumes of the caudate nucleus, putamen, and globus pallidus and gray and white matter volumes of the anterior cingulate gyrus and superior frontal gyrus were computed from contiguous 1.5-mm magnetic resonance images from 23 psychotropic drug-naive pediatric patients with OCD (seven male patients and 16 female patients) and 27 healthy volunteers (12 male subjects and 15 female subjects). RESULTS: Patients had smaller globus pallidus volumes than healthy volunteers, but the two groups did not differ in volumes of the caudate nucleus, putamen, or frontal white matter regions. Compared to healthy volunteers, patients had more total gray matter in the anterior cingulate gyrus but not the superior frontal gyrus. Total anterior cingulate gyrus volume correlated significantly and positively with globus pallidus volume in the healthy volunteers but not in patients. CONCLUSIONS: These findings provide evidence of smaller globus pallidus volume in patients with OCD without the potentially confounding effects of prior psychotropic drug exposure. Volumetric abnormalities in the anterior cingulate gyrus appear specific to the gray matter in OCD, at least at the gross anatomic level, and are consistent with findings of functional neuroimaging studies that have reported anterior cingulate hypermetabolism in the disorder.     

The neural basis of dysfunctional beliefs in non-medicated patients with obsessive-compulsive disorder

Dysfunctional beliefs may contribute to the development and maintenance of obsessive-compulsive disorder (OCD) according to some cognitive theories. As little has been investigated about the pathophysiology of dysfunctional beliefs in OCD, this study aimed to determine the anatomical regions that are related to OCD-related dysfunctional beliefs. We first examined 23 non-medicated patients with OCD by magnetic resonance imaging (MRI) and assessed their dysfunctional beliefs using the Obsessive Beliefs Questionnaire-44 (OBQ-44). OBQ-44 has three factors: (1) inflated personal responsibility and the tendency to overestimate threat (OBQ-RT), (2) perfectionism and intolerance of uncertainty (OBQ-PI), and (3) over-importance and over-control of thoughts (OBQ-IC). Voxelwise analysis was used to investigate the correlation between whole brain gray matter volume and each score of OBQ-44 covarying for age, gender, education, severity, and intracranial volume. We found a significant negative correlation between gray matter volume and OBQ-IC scores in the left amygdala; there was no significant correlation with other scores. Comparison of the amygdala volume between patients with OCD and 23 matched healthy controls indicated no volume difference between groups. Taken together, the left amygdala volume may play a role in the presence of certain dysfunctional beliefs in OCD patients.     

Regional gray matter abnormalities in obsessive-compulsive disorder: a voxel-based morphometry study.

BACKGROUND: Several structural magnetic resonance imaging (MRI) studies have investigated the presence of brain abnormalities in obsessive-compulsive disorder (OCD) but have not produced consistent findings. This might be partly related to their use of a regions-of-interest approach. We assessed gray matter volumes in 19 OCD subjects and 15 healthy volunteers, using voxel-based morphometry (VBM). METHODS: Images were acquired with a 1.5-T MRI scanner, spatially normalized, and segmented with optimized VBM. Statistical comparisons were performed with the general linear model. RESULTS: Significant findings were detected in regions predicted a priori to be implicated in OCD, including increased gray matter in OCD subjects relative to control subjects in posterior orbitofrontal and parahippocampal regions; decreased gray matter in OCD patients in the left anterior cingulate cortex; and inverse correlations between obsessive-compulsive symptom severity and gray matter in the medial thalamus (p < .001, uncorrected for multiple comparisons). Also, an unpredicted site of gray matter reduction in OCD patients in the right parietal associative cortex approached significance (p = .052, corrected for multiple comparisons). CONCLUSIONS: Our findings are consistent with previous studies implicating dysfunction of orbitofrontal, cingulate, thalamic, and temporolimbic regions in OCD and suggest that the involvement of the parietal cortex in the pathophysiology of OCD warrants further investigation.     

Reduced gray matter volume of dorsal cingulate cortex in patients with obsessive-compulsive disorder: a voxel-based morphometric study

Aims: Previous morphometric studies using magnetic resonance imaging (MRI) have revealed structural brain abnormalities in obsessive–compulsive disorder (OCD). The aim of the present study was to investigate the alterations in brain structure of patients with OCD using a voxel‐based morphometry (VBM) method. Methods: Sixteen patients with OCD free of comorbid major depression, and 32 sex‐ and age‐matched healthy subjects underwent MRI using a 1.5‐T MR scanner. OCD severity was assessed with the Yale–Brown Obsessive–Compulsive Scale (mean ± SD: 22 ± 7.6; range: 7–32). MR images were spatially normalized and segmented using the VBM5 package ( http://dbm.neuro.uni‐jena.de/vbm/ ). Statistical analysis was performed using statistical parametric mapping software. Results: Significant reductions in regional gray matter volume were detected in the left caudal anterior cingulate cortex and right dorsal posterior cingulate cortex in the patients with OCD as compared to healthy controls (uncorrected, P < 0.001). No significant differences in white matter volumes were observed in any brain regions of the patients. No significant correlation between Yale–Brown Obsessive–Compulsive Scale score and regional gray matter or white matter volume was observed. Conclusions: Regional gray matter alteration in the dorsal cingulate cortex, which is suggested to play a role in non‐emotional cognitive processes, may be related to the pathophysiology in OCD.     

Morphometric alterations of anterior superior temporal cortex in obsessive-compulsive disorder

The superior temporal gyrus (STG) may be involved in the pathophysiology of obsessive-compulsive disorder (OCD). Moreover, the anterior STG has rich interconnections with the orbitofrontal cortex and the amygdala, and plays a role in visuospatial processing, which is impaired in patients with OCD. This study was designed to examine the morphological abnormalities of the anterior STG and their relationships with visuospatial function and clinical symptom in patients with OCD. We measured gray matter volumes of the anterior STG [rostral STG and planum polare (PP)] by three-dimensional (3D) magnetic resonance imaging in age- and sex-matched groups, which consisted of 22 patients with OCD and 22 normal volunteers. Visuospatial function and clinical symptom were assessed using the Rey-Osterrieth Complex Figure (ROCF) test, the Yale-Brown Obsessive Compulsive Scale, and the Maudsley Obsessive Compulsive Inventory. We found significant volume reductions in bilateral PPs, but there were no significant correlations between brain volumes and the ROCF copy score, immediate or delayed recall score, and clinical symptom in patients with OCD. These results suggest that volume reduction of the anterior STG, especially the PP, may be related to the pathophysiology of OCD, but further research may be needed to explore a relationship of the PP volume change with cognitive impairment observed in patients with OCD.     

不同症状群强迫症患者的生活质量比较

目的探讨强迫症患者的症状群对其生活质量的影响。方法收集78例门诊强迫症患者（病例组）及60名正常对照,采用世界卫生组织生存质量测定量表简表（WHOQOL-BREF）中文版调查生活质量。对强迫症患者的耶鲁-布朗强迫症状检查提纲评分进行分析。结果病例组WHOQOL-BREF量表的生理领域、心理领域、社会关系领域、环境领域得分[分别为（64.7±10.3）分、（47.6±11.5）分、（53.1±12.2）分、（63.7±10.6）分]均低于正常对照组[分别为（79.2±9.6）分、（71.2±10.4）分、（74.1±9.8）、（75.1±10.3）分],差异有统计学意义（t值分别为-8.3、-12.5、-10.9、-6.3,P值均〈0.001）。根据患者的主要症状分为洗涤组、检查组、贮物组、对称组。方差分析显示4组患者WHOQOL-BREF各领域得分均存在差异（P〈0.05）。结论强迫症患者生活质量低于正常人群。不同症状群强迫症患者的生活质量受损害的领域存在差异。     

White matter structure and symptom dimensions in obsessive-compulsive disorder

There is evidence that the different symptom dimensions in obsessive-compulsive disorder (OCD) may be mediated by partially distinct neural systems. This DTI study investigated the relationship between symptom dimensions and white matter microstructure. Fractional anisotropy (FA), axial and radial diffusivity was analyzed in relation to the main OCD symptom dimensions. Symptom severity on the obsessing dimension was negatively correlated with FA in the corpus callosum and the cingulate bundle. Severity on the ordering dimension was negatively correlated with FA in, amongst others, the right inferior fronto-occipital fasciculus and the right optic radiation. All correlations were ascribable to alterations in radial diffusivity while there was no association between symptoms and axial diffusivity. Present results illustrate an association between alterations in visual processing tracts and ordering symptoms which are characterized by altered visual processing and increased attention towards irrelevant detail. They also indicate an association between obsessive thoughts and alterations in structures known to be relevant for cognitive control and inhibition. Hence, different symptom dimensions must be taken into account in order to disentangle the neurobiological underpinnings of OCD.     

White matter abnormalities in obsessive-compulsive disorder: a diffusion tensor imaging study

CONTEXT: Several neurobiological models of obsessive-compulsive disorder (OCD) posit a primary role for dysfunction of the anterior cingulate gyrus. Both functional and structural neuroimaging studies have implicated anterior cingulate gray matter abnormalities in the pathophysiology of OCD, but there has been little investigation of the anterior cingulate white matter in this disorder. OBJECTIVE: To test the hypothesis that patients with OCD have abnormal white matter microstructure in the anterior cingulate gyrus compared with healthy volunteers as inferred from diffusion tensor imaging. Additional analyses examined group differences in white matter integrity across the entire brain. DESIGN, SETTING, AND PARTICIPANTS: Fifteen patients with a DSM-IV diagnosis of OCD and 15 healthy volunteers matched for age, sex, and handedness underwent diffusion tensor imaging and structural magnetic resonance imaging examinations. Fractional anisotropy (FA), a robust intravoxel measure of water self-diffusion, was compared between groups on a voxel-by-voxel basis in the anterior cingulate white matter after standardization in Talairach space. MAIN OUTCOME MEASURES: Clinical ratings of symptom severity (ie, Yale-Brown Obsessive-Compulsive Scale) and FA. RESULTS: Compared with healthy volunteers, patients demonstrated significantly lower FA bilaterally in 3 areas of the anterior cingulate gyrus white matter. Additional analyses conducted across the rest of the brain white matter revealed lower FA bilaterally in the parietal region (supramarginal gyri), right posterior cingulate gyrus, and left occipital lobe (lingual gyrus). No areas of significantly higher FA were observed in patients compared with healthy volunteers. Lower FA in the parietal region correlated significantly with higher Yale-Brown Obsessive-Compulsive Scale scores. CONCLUSIONS: These preliminary findings provide evidence of an abnormality that involves the anterior cingulate white matter in the pathogenesis of OCD and are consistent with neurobiological models that posit a defect in connectivity in the anterior cingulate basal ganglia-thalamocortical circuit. White matter abnormalities in other brain regions may also be implicated in the neurobiology of OCD.     

不接受/禁忌思维亚型强迫障碍患者的脑白质磁共振弥散张量成像研究

目的:运用磁共振扩散张量成像技术探讨未经治疗的不接受/禁忌思维亚型强迫障碍(OCD)患者脑白质的变化及与临床症状之间的相关性。方法:对26例不接受/禁忌思维亚型OCD患者和28名性别、年龄、受教育程度相匹配的健康对照者进行弥散张量成像(DTI)扫描,采用耶鲁-布朗强迫量表(Y-BOCS)、17项汉密尔顿抑郁量表(HAMD-17)、汉密尔顿焦虑量表(HAMA)等评估临床症状,采用基于纤维束空间统计分析(TBSS)等方法比较两组全脑DTI的各向异性分数(FA),得出有差异脑区,并分析患者组脑白质改变与临床症状严重程度之间的关系。结果:和正常对照组相比,患者组的大脑胼胝体、右侧上纵束、右侧下额-枕束、右侧丘脑后辐射(视辐射部)等部位的FA值显著降低;未发现任何脑区的FA值与临床行为学量表之间的相关性。结论:多个脑白质区的结构异常可能构成不接受/禁忌思维亚型OCD患者的病理生理基础,这些脑白质区的变化可能是此亚型OCD的特征标志。     

Mapping structural brain alterations in obsessive-compulsive disorder

BACKGROUND: Recent technical developments have made it feasible to comprehensively assess brain anatomy in psychiatric populations. OBJECTIVE: To describe the structural brain alterations detected in the magnetic resonance images of a large series of patients with obsessive-compulsive disorder (OCD) using imaging procedures that allow the evaluation of volume changes throughout the brain. DESIGN: Case-control study. SETTING: Referral OCD unit in a tertiary hospital. PARTICIPANTS: A consecutive sample of 72 outpatients with OCD and 72 age- and sex-matched control subjects. INTERVENTIONS: Three-dimensional sequences were obtained in all participants. A statistical parametric mapping approach was used to delineate possible anatomical alterations in the entire brain. To preserve volumetric information, voxel values were modulated by the Jacobian determinants (volume change measurement) derived from spatial normalization. MAIN OUTCOME MEASURES: Voxelwise brain volumes. RESULTS: The brains of patients with OCD showed reduced gray matter volume in the medial frontal gyrus, the medial orbitofrontal cortex, and the left insulo-opercular region. A relative increase in gray matter volume was observed bilaterally in the ventral part of the putamen and in the anterior cerebellum. All these brain alterations were abnormally correlated in patients with OCD, and age statistically significantly contributed to the relative enlargement observed in the striatal areas. Disease severity, the nature of symptoms, and comorbidities were not related to the changes described. Nevertheless, patients with prominent aggressive obsessions and checking compulsions showed reduced amygdala volume in the right hemisphere. CONCLUSIONS: The pattern of anatomical features depicted by this voxelwise approach is consistent with data from functional studies. The reported anatomical maps identified the specific parts of the frontostriatal system that were altered in patients with OCD and detected changes in anatomically connected distant regions. These data further define the structural brain alterations in OCD and may contribute to constraining the prevailing biological models of this psychiatric process.     

Brain structural imaging correlates of olfactory dysfunction in obsessive–compulsive disorder

Olfactory dysfunction has been described in obsessive–compulsive disorder (OCD). Brain regions involved in smell processing partially overlap with structures included in the neurobiological models of OCD, although no previous studies have analyzed the neuroanatomical correlates of olfactory dysfunction in this disorder. The aim of our study was to examine the association between regional gray matter volume, as assessed by a voxel-based morphometry analysis of magnetic resonance images (MRI), and olfactory function, as assessed by the Sniffin’ Sticks test (SST). Olfactory function was assessed in 19 OCD patients and 19 healthy volunteers. All participants were also scanned in a 1.5-T magnet to obtain T1-weighted anatomical MRIs, which were pre-processed and analyzed with SPM8. Three different correlation models were used to study the association between regional gray matter volumes and olfactory function in the domains assessed by the SST: detection threshold, discrimination, and identification. OCD patients showed a significant impairment in all the domains assessed by the SST. Voxel-based mapping revealed a positive association in healthy controls between detection threshold and the gray matter content of a left anterior cingulate cortex cluster. In OCD patients, a positive correlation was observed between identification errors and the gray matter volume of the left medial orbital gyrus. In a post hoc analysis, these two gray matter regions were shown to be enlarged in OCD patients. Our findings support the idea that olfactory dysfunction in OCD is associated with volumetric changes in brain areas typically implicated in the neurobiology of the disorder.     

Gray matter volume reduction in obsessive-compulsive disorder with schizotypal personality trait

OBJECTIVES: Obsessive-compulsive disorder (OCD) with schizotypal personality trait (SPT) and OCD without SPT demonstrated differences in cognitive dysfunction and treatment response. This study aimed to investigate whether brain volume differs between OCD with SPT and OCD without SPT. METHODS: OCD with SPT (n=20), OCD without SPT (n=47), healthy comparison subjects (n=83) and schizophrenic patients (n=59) participated in this study. We assessed brain volume such as gray matter (GM), white matter (WM) and cerebrospinal fluid (CSF) using magnetic resonance imaging. The imaging data sets were filtered using anisotropic diffusion methods to improve the signal to noise ratio. The semi-automated region-growing method was used to remove images of tissues exterior to the brain. The fuzzy C-means algorithm was used to segment the extracted brain images into gray matter, white matter and cerebrospinal fluid. RESULTS: OCD with SPT (p=0.048) and Schizophrenic patients (p<0.001) demonstrated a significant GM volume reduction compared to healthy controls. OCD without SPT revealed no significant GM volume reduction compared to healthy controls (p=0.504). CONCLUSION: This study suggests that OCD with SPT could be distinguished as a distinct subtype of OCD, based on observations of gray matter volume.     

Left anterior subregion of orbitofrontal cortex volume reduction and impaired organizational strategies in obsessive-compulsive disorder

The orbitofrontal cortex (OFC) may be involved in the clinical and cognitive expressions of obsessive-compulsive disorder (OCD) and is a heterogenous region with respect to its cytoarchitecture, function and connectivity. This study was designed to examine the morphological abnormality of the anterior subregion of OFC and its relationship to clinical symptoms and cognitive performance in patients with OCD. We divided the OFC into anterior and posterior subregions using an external landmark and measured the gray matter volumes of each by three-dimensional magnetic resonance imaging in age- and sex-matched groups, which consisted of 34 OCD and 34 normal volunteers. Clinical and cognitive evaluations were completed using Yale-Brown Obsessive Compulsive Scale (YBOCS) and four sets of neuropsychological tests that assessed executive functions and visual memory. Volume reduction of the left anterior OFC was observed in patients with OCD versus normal controls. Also, a significant positive correlation was found between left anterior OFC gray matter volume and the copy score of the Rey-Osterrieth Complex Figure Test in patients with OCD. These results suggest that left anterior subregion volume reduction of the OFC may be related to impaired organizational strategies in patients with OCD.     

Temperament and character in subjects with obsessive-compulsive disorder

Background

The aims of this study were to evaluate the differences between personality traits of patients with obsessive-compulsive disorder (OCD) and normal controls using the Temperament and Character Inventory (TCI) and to examine the relationship of personality traits and the severity of obsessive-compulsive (OC) symptoms. We also aimed to examine the influence a particular personality trait might have on the 5 factor-analyzed symptom dimension scores of OCD.

Method

We recruited 130 patients with OCD and 185 age- and sex-matched normal controls. All subjects completed the TCI. Patients with OCD were assessed with the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), the Hamilton Depression Rating Scale, and the factor-analyzed symptom dimension scores from the Y-BOCS checklist.

Results

Patients with OCD had higher harm avoidance scores and lower self-directedness (SD), reward dependence (RD), and cooperativeness (C) scores than the controls. Lower SD scores and lower C scores were associated with OC symptom severity measured by the Y-BOCS after adjusting for age and depression severity. Hoarding dimension of OC symptoms was associated with lower SD scores and higher persistence (P) scores after adjusting for age, OC symptom severity, and depression severity.

Conclusions

There were significant differences in TCI subscales between patients with OCD and controls. Particular personality traits may have an influence on the severity and the dimensions of OC symptoms.     

Alexithymia in obsessive-compulsive disorder: clinical correlates and symptom dimensions

Previous studies have indicated that obsessive-compulsive disorder (OCD) is associated with alexithymic traits. The purpose of the current study was to evaluate the difference of alexithymia in OCD patients and healthy controls. This study was also designed to elucidate a specific link between certain OCD symptom dimensions and alexithymia. Forty-five patients with OCD and 45 healthy controls completed measures of the OCD symptom severity, alexithymia, anxiety, and depression. Patients with OCD had significantly higher scores of alexithymia than did the healthy controls. Multiple regression analysis revealed that age at onset and the level of anxiety were significantly associated with alexithymia. "Sexual/religious obsessions" was the only symptom dimension that showed a positive association with alexithymia in OCD patients. These findings suggest that OCD patients with a high level of anxiety and an early age of onset may have greater alexithymic tendency. We also found the first evidence for a specific link between sexual/religious obsessions and alexithymia in patients with OCD.     

The impacts of elevated autism spectrum disorder traits on clinical and psychosocial features and long-term treatment outcome in adult patients with obsessive-compulsive disorder

Background

While a close relation between obsessive-compulsive disorder (OCD) and autism spectrum disorder (ASD) has been pointed out, there are few studies that have investigated whether highly elevated ASD traits may have significant impacts on clinical and psychosocial features as well as long-term treatment outcome in adult OCD patients.

Methods

We assessed ASD traits using the Autism Spectrum Quotient (AQ) in 81 Japanese patients with OCD. The relation between degree of ASD traits and clinical and psychosocial variables and the 48-week treatment outcomes was analyzed in the subjects.

Results

A substantial proportion of the subjects showed higher ASD traits (35%) with more severe depressive or pervasive anxiety status, and social impairments and lower QOL compared to other OCD individuals. However, elevated ASD traits may exert rather smaller impact on the OCD phenomenology along with on the long-term treatment outcome than expected.

Conclusions

Elevated ASD traits may further emphasize the general psychopathological and socio-dysfunctional features rather than clinical aspects associated with OCD. Co-existing depressive or anxious symptom severity may further exacerbate the core-deficits related to ASD pathology. Thus the assessment of ASD traits should be important for understanding the clinical and psychosocial features and treatment responses in OCD patients.     

Neural correlates of anxiety associated with obsessive-compulsive symptom dimensions in normal volunteers.

BACKGROUND: The neural correlates of anxiety associated with obsessive-compulsive symptomlike provocation in normal volunteers are unknown. METHODS: Ten healthy volunteers participated in four functional magnetic resonance experiments. Subjects were scanned while viewing alternating blocks of emotional (normally aversive, washing-relevant, checking-relevant, or hoarding-relevant pictures) and neutral pictures, and imagining scenarios related to the content of each picture type. Nonparametric brain mapping analyses were used. RESULTS: In response to the provocative pictures in all experiments, increases in subjective anxiety and activation in bilateral ventral prefrontal, limbic, dorsal prefrontal, and visual regions were demonstrated. Anxiety related to different symptom dimensions was associated with different patterns of activation: provocation of washing-relevant anxiety predominantly activated dorsal and ventral prefrontal regions; checking-relevant anxiety predominantly activated dorsal prefrontal regions; and hoarding-relevant anxiety predominantly activated ventral prefrontal regions and the left amygdala. CONCLUSIONS: Our findings support a dimensional model of obsessive-compulsive disorder (OCD) whereby 1) the brain systems implicated in the mediation of anxiety in response to symptom-related material in normal subjects are similar to those identified in OCD patients during symptom provocation, and 2) anxiety associated with different symptom dimensions is associated with differential patterns of activation of these neural systems. Further investigation of the neural basis of OCD symptom dimensions is required.     

Differential effects of age on brain gray matter in bipolar patients and healthy individuals

This study examined possible differences in total gray and white matter brain content in bipolar patients and healthy individuals, and their relationship with age. 22 DSM-IV bipolar patients and 22 healthy controls underwent a 1.5-tesla Spoiled Gradient Recalled Acquisition (SPGR) MRI. Evaluators blind to patients' identities measured total brain, gray and white matter volumes using a semi-automated software. No differences were found for total brain volume, gray matter or white matter volumes between bipolar patients and healthy controls (MANCOVA, age as covariate, p > 0.05). Age was inversely correlated with total gray matter volume in patients (r = -0.576, p = 0.005), but not in controls (r = -0.193, p = 0.388). Our findings suggest that any existing gray matter deficits in bipolar disorder are likely to be localized to specific brain regions, rather than generalized. The inverse correlation between age and brain gray matter volumes in bipolar patients, not present in healthy controls, in this sample of mostly middle-aged adults, could possibly indicate more pronounced age-related gray matter decline in bipolar patients, and may be of potential relevance for the pathophysiology of the disorder.