The involvement of distinct neural systems in patients with obsessive-compulsive disorder with autogenous and reactive obsessions

Comparison of autogenous and reactive type obsessive-compulsive disorders in terms of clinical characteristics: A meta-analysis study

Obsessive-compulsive disorder (OCD) has been divided into two subgroups autogenous and reactive types, based on obsessive symptoms. To our knowledge, no meta-analysis study compares sociodemographic and clinical characteristics. Investigation of the differences between the two groups in terms of these basic characteristics may provide information about the accuracy of this classification. This is the first meta-analysis to examine gender, age at onset and some clinical differences between patients with autogenous and reactive OCD. Electronic bibliographic databases of Scopus and PubMed were searched up to March 2024. Random effect models were conducted for this meta-analysis. The analysis was carried out using the standardized mean difference as the outcome measure. Publication bias was evaluated using the Begg and Eggers funnel plot, and fail-safe N calculation using the Rosenthal approach. The current meta-analysis summarizes the data from primary studies comparing the gender rates, age at onset of OCD, severity of obsessive-compulsive symptoms, and severity of depression and anxiety symptoms between autogenous and reactive types of OCD. The results of this study showed that the rate of male gender was higher in the autogenous type OCD. In addition, increased severity of anxiety, and depression were associated with autogenous type OCD. There was no significant difference between groups regarding the severity of obsessive-compulsive symptoms. Age of OCD onset findings were insignificant, but excluding an outlier study suggested earlier onset in autogenous type OCD. These results support the distinction between autogenous and reactive type OCD.

Guilt and Shame in Patients with Obsessive-Compulsive Disorders

INTRODUCTION

Obsessive-compulsive disorder (OCD) is a tremendous psychiatric illness with a variety of severe symptoms. Feelings of shame and guilt are universal social emotions that fundamentally shape the way people interact with each other. Mental illness is therefore often related to pronounced feelings of shame and guilt in a maladaptive form.

METHODS

A total of 62 participants (38 women and 24 men) were clinically and psychometrically investigated.

RESULTS

The OCD patients (n = 31) showed a maladaptive guilt and shame profile, characterized by increased interpersonal feelings of guilt accompanied by a stronger tendency to self-criticism and increased punitive sense of guilt with a simultaneous prevailing tendency to perfectionism, as well as an increased concern for the suffering of others. The proneness to profuse shame in OCD patients seems to be in the context of the violation of inner values and a negative self-image with persistent self-criticism.

CONCLUSION

Although there are limitations with a small sample size in this monocentric approach, our study underlines the importance of an individual consideration of the leading obsessive-compulsive symptomatology, especially in the context of very personal feelings of guilt and shame. Further multidimensional studies on guilt and shame could contribute to their implementation more strongly in individualized psychotherapy.

Neural substrates for dissociation of cognition inhibition in autogenous- and reactive-type obsessive-compulsive disorder

BACKGROUND

The taxonomy of autogenous- and reactive-type obsessive-compulsive disorder (OCD) (AO vs. RO) is one of the most valid subtyping approaches to the heterogeneity of OCD. The present study aimed to seek evidence of neural substrates supporting the dissociation of cognition inhibition in AO and RO which was revealed by our previous behavioral and electrophysiological work.

METHODS

A total of 165 patients with OCD (86 AO versus 79 RO), and 79 healthy controls (HC) underwent resting-state functional magnetic resonance imaging scans. Within-network connectivity, node strength, and edge-wise functional connectivity (FC) in cognition and response inhibition networks were calculated. Results from 3 cognition and 2 response inhibition network atlases were compared to confirm the robustness of the findings.

RESULTS

Both AO and RO showed lower within-network connectivity in response inhibition networks, while lower within cognition inhibition network connectivity was only detected in AO. Besides shared weaker node strength in the anterior insula (AI), anterior cingulate cortex (ACC), and supplementary motor area (SMA), AO had a broader range of nodes within cognition inhibition networks exhibiting weaker strength, including nodes in right inferior frontal gyrus (IFG), left parietal and occipital regions. Decreased FC of left AI-CC, left IFG-ACC, and frontal-parietal regions in cognition inhibition networks were found in AO.

CONCLUSIONS

Findings indicate that unlike deficits in connectivity within response inhibition networks which may reflect a common pathology in AO and RO, deficits in connectivity within cognition inhibition networks were more pronounced in AO. These findings strengthen our insight into the heterogeneity in OCD.

Two distinct subtypes of obsessive compulsive disorder revealed by a framework integrating multimodal neuroimaging information

Patients with obsessive compulsive disorder (OCD) exhibit tremendous heterogeneity in structural and functional neuroimaging aberrance. However, most previous studies just focus on group‐level aberrance of a single modality ignoring heterogeneity and multimodal features. On that account, we aimed to uncover OCD subtypes integrating structural and functional neuroimaging features with the help of a multiview learning method and examined multimodal aberrance for each subtype. Ninety‐nine first‐episode untreated patients with OCD and 104 matched healthy controls (HCs) undergoing structural and functional MRI were included in this study. Voxel‐based morphometric and amplitude of low‐frequency fluctuation (ALFF) were adopted to assess gray matter volumes (GMVs) and the spontaneous neuronal fluctuations respectively. Structural/functional distance network was obtained by calculating Euclidean distance between pairs of regional GMVs/ALFF values across patients. Similarity network fusion, one of multiview learning methods capturing shared and complementary information from multimodal data sources, was used to fuse multimodal distance networks into one fused network. Then spectral clustering was adopted to categorize patients into subtypes. As a result, two robust subtypes were identified. These two subtypes presented opposite GMV aberrance and distinct ALFF aberrance compared with HCs while shared indistinguishable clinical and demographic features. In addition, these two subtypes exhibited opposite structure–function difference correlation reflecting distinct adaptive modifications between multimodal aberrance. Altogether, these results uncover two objective subtypes with distinct multimodal aberrance and provide a new insight into taxonomy of OCD.

Two distinct subtypes of obsessive compulsive disorder revealed by heterogeneity through discriminative analysis

Neurobiological heterogeneity in obsessive compulsive disorder (OCD) is understudied leading to conflicting neuroimaging findings. Therefore, we investigated objective neuroanatomical subtypes of OCD by adopting a newly proposed method based on gray matter volumes (GMVs). GMVs were derived from T1‐weighted anatomical images of patients with OCD (n = 100) and matched healthy controls (HCs; n = 106). We first inquired whether patients with OCD presented higher interindividual variability HCs in terms of GMVs. Then, we identified distinct subtypes of OCD by adopting heterogeneity through discriminative analysis (HYDRA), where regional GMVs were treated as features. Patients with OCD presented higher interindividual variability than HCs, suggesting a high structural heterogeneity of OCD. HYDRA identified two distinct robust subtypes of OCD presenting opposite neuroanatomical aberrances compared with HCs, while sharing indistinguishable clinical and demographic features. Specifically, Subtype 1 exhibited widespread increased GMVs in cortical and subcortical regions, including the orbitofrontal gyrus, right anterior insula, bilateral hippocampus, and bilateral parahippocampus and cerebellum. Subtype 2 demonstrated overall decreased GMVs in regions such as the orbitofrontal gyrus, right anterior insula, and precuneus. When mixed together, none of patients presented significant differences compared with HCs. In addition, the total intracranial volume of Subtype 2 was significantly correlated with the total score of the Yale–Brown Obsessive Compulsive Scale while that of Subtype 1 was not. These results identified two distinct neuroanatomical subtypes, providing a possible explanation for conflicting neuroimaging findings, and proposed a potential objective taxonomy contributing to precise clinical diagnosis and treatment in OCD.

Functional connectivity within the salience network differentiates autogenous- from reactive-type obsessive-compulsive disorder

BACKGROUND

Obsessive-compulsive disorder (OCD) is a clinically heterogeneous condition. To better understand and treat patients, symptomatology of OCD has been categorized into more homogenous symptom dimensions. The autogenous-reactive classification model has proven helpful in the elucidation of the neurobiological substrates for clinical heterogeneity in OCD. The purpose of the current study was to systematically compare regional and network functional alterations between OCD subtypes based on the autogenous-reactive model.

METHODS

Autogenous-type OCD patients (OCD-AO, n = 40), reactive-type patients (OCD-RO, n = 42), and healthy controls (HC, n = 70) underwent functional magnetic resonance imaging (fMRI) scans. The amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) were compared among subjects. Areas of abnormal local spontaneous brain activity that differentiated OCD-AO and OCD-RO patients were identified and entered as seeds in functional connectivity (FC) analysis.

RESULTS

Compared to OCD-RO patients and HC participants, OCD-AO patients showed increased ALFF in the left anterior insula (AI), increased ReHo in the right AI, and hyperconnectivity between bilateral AI and anterior cingulate cortex (ACC). Both OCD-AO and OCD-RO patients shared regional function deficits in several areas within the prefrontal cortex, and stronger FC between bilateral AI and major nodes of the default mode network (DMN) compared to healthy controls.

CONCLUSION

The current results suggest that aberrant functional interaction between the salience network (SN) and the DMN may represent a common substrate in the pathophysiology of OCD, while impaired functional coupling within the SN is distinct to autogenous-type OCD patients. These findings provide further neurobiological evidence to support the autogenous-reactive classification model and contribute to the understanding of the neurobiological basis for clinical heterogeneity in OCD.

Psychopharmacological Treatment of Obsessive-Compulsive Disorder (OCD)

Background:

Obsessive-compulsive disorder (OCD) is associated with affective and cognitive symptoms causing personal distress and reduced global functioning. These have considerable societal costs due to healthcare service utilization.

Objective:

Our aim was to assess the efficacy of pharmacological interventions in OCD and clinical guidelines, providing a comprehensive overview of this field.

Methods:

We searched the PubMed database for papers dealing with drug treatment of OCD, with a specific focus on clinical guidelines, treatments with antidepressants, antipsychotics, mood stabilizers, off-label medications, and pharmacogenomics.

Results:

Prolonged administration of selective serotonin reuptake inhibitors (SSRIs) is most effective. Better results can be obtained with a SSRI combined with cognitive behavioral therapy (CBT) or the similarly oriented exposure and response prevention (ERP). Refractory OCD could be treated with different strategies, including a switch to another SSRI or clomipramine, or augmentation with an atypical antipsychotic. The addition of medications other than antipsychotics or intravenous antidepressant administration needs further investigation, as the evidence is inconsistent. Pharmacogenomics and personalization of therapy could reduce treatment resistance.

Conclusions:

SSRI/clomipramine in combination with CBT/ERP is associated with the optimal response compared to each treatment alone or to other treatments. New strategies for refractory OCD are needed. The role of pharmacogenomics could become preponderant in the coming years.

Differences between autogenous and reactive obsessions in terms of metacognitions and automatic thoughts

BACKGROUND

Obsessive compulsive disorder (OCD) is characterized by obsessions and compulsions. Obsessions have been classified as autogenous obsessions and reactive obsessions on the basis of the cognitive theory of Lee and Kwon. The aim of this study was to investigate the differences between autogenous groups (AG) and reactive groups (RG) in terms of metacognition and automatic thoughts, for the purpose of investigating the differences of cognitive appraisals.

METHODS

One hundred and thirty-three patients diagnosed with OCD were included in the study as the patient group. A control group was formed of 133 age, gender and education-matched healthy individuals. The OCD group patients were separated into subgroups according to the primary obsessions. The sociodemographic data, and the Yale-Brown Obsessive Compulsive Scale, Metacognition Questionnaire-30 (MCQ-30), Automatic Thoughts Questionnaire (ATQ), Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI) scores of the AG, RG, and control groups were compared.

RESULTS

The MCQ-30 (total) and the subscales of MCQ-30 and ATQ scale points were seen to be significantly higher in the AG than in the RG and significantly higher in the RG than in the control group. In the reactive obsession group, the predictive variables of the ATQ points were determined to be MCQ-30 (total), BDI and BAI. In the autogenous obsession group, the predictive variables of the ATQ points were determined to be BDI and BAI.

CONCLUSION

In the current study, differences were determined between the AG and the RG in respect of metacognitions and automatic thoughts. In light of these results, the recommended grouping can be considered useful in the identification of OCD sub-types. There is a need for further studies to identify more homogenous sub-types of OCD. Future multi-centered studies of sub-typing with larger samples using more specific instruments to sub-type and dimensional evaluation will be useful for detailed evaluation and better understanding of the subject.

A mathematical model of reward and executive circuitry in obsessive compulsive disorder

The neuronal circuit that controls obsessive and compulsive behaviors involves a complex network of brain regions (some with known involvement in reward processing). Among these are cortical regions, the striatum and the thalamus (which compose the CSTC pathway), limbic areas such as the amygdala and the hippocampus, as well as dopamine pathways. Abnormal dynamic behavior in this brain network is a hallmark feature of patients with increased anxiety and motor activity, like the ones affected by OCD. There is currently no clear understanding of precisely what mechanisms generate these behaviors. We attempt to investigate a collection of connectivity hypotheses of OCD by means of a computational model of the brain circuitry that governs reward and motion execution. Mathematically, we use methods from ordinary differential equations and continuous time dynamical systems. We use classical analytical methods as well as computational approaches to study phenomena in the phase plane (e.g., behavior of the system's solutions when given certain initial conditions) and in the parameter space (e.g., sensitive dependence of initial conditions). We find that different obsessive-compulsive subtypes may correspond to different abnormalities in the network connectivity profiles. We suggest that it is a combination of parameters (connectivity strengths between regions), rather than the value of any one parameter taken independently, that provide the best basis for predicting behavior, and for understanding the heterogeneity of the illness.

Cingulate and thalamic metabolites in obsessive-compulsive disorder

Focal brain metabolic effects detected by proton magnetic resonance spectroscopy (MRS) in obsessive-compulsive disorder (OCD) represent prospective indices of clinical status and guides to treatment design. Sampling bilateral pregenual anterior cingulate cortex (pACC), anterior middle cingulate cortex (aMCC), and thalamus in 40 adult patients and 16 healthy controls, we examined relationships of the neurometabolites glutamate+glutamine (Glx), creatine+phosphocreatine (Cr), and choline-compounds (Cho) with OCD diagnosis and multiple symptom types. The latter included OC core symptoms (Yale-Brown Obsessive-Compulsive Scale - YBOCS), depressive symptoms (Montgomery-Åsberg Depression Rating Scale - MADRS), and general functioning (Global Assessment Scale - GAS). pACC Glx was 9.7% higher in patients than controls. Within patients, Cr and Cho correlated negatively with YBOCS and MADRS, while Cr correlated positively with the GAS. In aMCC, Cr and Cho correlated negatively with MADRS, while Cr in thalamus correlated positively with GAS. These findings present moderate support for glutamatergic and cingulocentric perspectives on OCD. Based on our prior metabolic model of OCD, we offer one possible interpretation of these group and correlational effects as consequences of a corticothalamic state of elevated glutamatergic receptor activity alongside below-normal glutamatergic transporter activity.

Psychopharmacological treatment differences in autogenous and reactive obsessions: A retrospective chart review

BACKGROUND

Identification of homogeneous subgroups of obsessive compulsive disorder (OCD) patients may have important implications for improving effective treatment options. It has been proposed that obsessive thoughts can be classified into two subtypes, i.e. autogenous and reactive obsessions. Although it has been shown that patients with autogenous obsessions may display a worse response to treatment, no studies have yet addressed whether there is a different need for the psychopharmacological treatment options in the subtypes of OCD patients.

AIM

To investigate the clinical characteristics and treatment differences between autogenous (A-OCD) and reactive (R-OCD) subtypes of OCD patients.

METHODS

Both OCD subgroups (n = 50 for A-OCD, n = 130 for R-OCD) were compared with each other in terms of their demographic and clinical parameters. Odds ratio values for gender, treatment options, co-morbidity, severity of OCD, and response to treatment were computed. Multivariate hierarchical regression analyses were performed to identify any predictors for treatment options, severity of OCD, and response to treatment.

RESULTS

Our results indicated that the A-OCD and R-OCD groups differed from each other on some demographic and clinical variables in addition to their psychopharmacological treatment needs. Patients in the A-OCD group were found to be prescribed an atypical antipsychotic 2.3 times more likely than the R-OCD group. The odds for a combination treatment, or the improvement of OCD symptoms from baseline levels did not differ between the two subtypes of obsession groups.

CONCLUSIONS

Autogenous and reactive subtypes of obsessions may need to be offered different psychopharmacological treatment options.

Psychometric Properties of a Short Korean Version of the Revised Obsessive Intrusion Inventory

OBJECTIVE

The Revised Obsessive Intrusion Inventory (ROII) is a 52-item scale that evaluates obsessional intrusive thoughts. The aim of the present study was to validate a short, 20-item Korean version of the ROII (ROII-20).

METHODS

Of the 1125 participants who completed the ROII-20, 895 participants completed the scale to examine the factor structure of the scale. A subgroup of these participants (n=53) completed the scale twice to determine test-retest reliability. To establish external validity, 230 participants completed the scale and other questionnaires.

RESULTS

Exploratory factor analyses suggested a hierarchical model comprising two higher order factors of autogenous obsessions (resulting from aggressive thoughts and sexual thoughts) and reactive obsessions (resulting from thoughts about contamination, thoughts about accidents, and thoughts about dirt). Confirmatory factor analyses supported this model. The results indicated good internal consistency and test-retest reliability. External validity was supported by relationships with obsessive-compulsive symptoms and general distress.

CONCLUSION

The ROII-20 presents good psychometric properties and may be considered as a promising instrument for measuring obsessional intrusions.

Decreased thalamic glutamate level in unmedicated adult obsessive-compulsive disorder patients detected by proton magnetic resonance spectroscopy

BACKGROUND

Previous neuroimaging studies implied that the dysfunction of cortico-striato-thalamo-cortical (CSTC) circuit served as the neural basis for the pathophysiology of obsessive-compulsive disorder (OCD). The imbalances in neuronal metabolite and neurotransmitter within CSTC circuit have been shown as the leading reasons of the OCD onset. The aim of this study is to investigate the metabolic alterations, especially the glutamatergic signal dysfunction within CSTC circuit, and the relationships between neural metabolites and the symptom severity of OCD patients.

METHODS

Single voxel magnetic resonance spectroscopy (MRS) was conducted in medial prefrontal cortex (mPFC) and bilateral thalamus areas for thirteen unmedicated adult OCD patients with age-, gender-, and education-matched healthy controls. Quantification and multivariate analysis were performed to identify vital metabolic biomarkers for patients and healthy controls group differentiation. Moreover, we performed Spearman׳s rank correlation analysis for OCD patients to examine the relationship between the metabolite concentration level and OCD symptomatology.

RESULTS

Patients with OCD showed significantly decreased glutamate level in mPFC (p=0.021) and right thalamus (p=0.039), and significantly increased choline compounds in left thalamus (p=0.044).The glutamate in right thalamus was shown as the most important metabolite for group separation from multivariate analysis (Q(2)=0.134) and was significantly correlated with the patients׳ compulsion scores (Spearman r=-0.674, p=0.016).

LIMITATIONS

Limited sample size, the use of creatine and phosphocreatine (Cr) ratios rather than absolute concentrations and unresolved glutamine (Gln) are limitations of the present study.

CONCLUSION

Our study results consolidated the hypothesis about glutamatergic signaling dysfunction in OCD. To our knowledge, it is the first finding about a reduced thalamic glutamate level in adult unmedicated OCD patients. The dysregulation of glutamate serves as a potential target for the OCD pharmacotherapy and the detailed mechanisms underlying the glutamate alterations within CSTC circuits merit further investigations.

Latent class analysis of obsessive-compulsive symptoms in a clinical sample

OBJECTIVE

Obsessive-compulsive disorder (OCD) is probably a heterogeneous condition. To date, research investigating the symptom structure of OCD has generally focused on variable-classification approaches, primarily factor analysis. Our aim was to use the latent class analysis, an advanced individual-classification method, in order to define homogeneous sub-groups based on the Yale-Brown Obsessive-Compulsive Scale Check List (Y-BOCS CL) assessments within 193 outpatients with OCD.

METHOD

Latent class analysis of 13 obsessive-compulsive symptom-clusters measured by the Yale-Brown Obsessive-Compulsive Scale Check List was performed. Associations of demographic and clinical features with latent class membership were tested by using logistic regression models. Differences in severity of obsessive-compulsive symptoms, obsessive beliefs, and depressive symptomotology between latent classes were evaluated with the chi-square likelihood test.

RESULTS

Latent class analysis models of best fit yielded 3 latent classes: "autogenous obsessions", "reactive obsessive-compulsive", and "reactive obsessions". Outpatients in reactive obsessive-compulsive group reported significantly higher scores on the Y-BOCS global, obsessions, and compulsions scales than outpatients in other two sub-groups. Participants in reactive obsessive-compulsive group were predominantly female, single, and had a history of family psychopathology; whereas autogenous and reactive obsessions groups were predominantly male. There were no differences in severity of depression and obsessive belief domains.

CONCLUSIONS

The results provide support for the validity of autogenous/reactive distinction for OCD. These three classes may have important implications for research and clinical purposes.

Deep brain stimulation: a mechanistic and clinical update

Deep brain stimulation (DBS), the practice of placing electrodes deep into the brain to stimulate subcortical structures with electrical current, has been increasing as a neurosurgical procedure over the past 15 years. Originally a treatment for essential tremor, DBS is now used and under investigation across a wide spectrum of neurological and psychiatric disorders. In addition to applying electrical stimulation for clinical symptomatic relief, the electrodes implanted can also be used to record local electrical activity in the brain, making DBS a useful research tool. Human single-neuron recordings and local field potentials are now often recorded intraoperatively as electrodes are implanted. Thus, the increasing scope of DBS clinical applications is being matched by an increase in investigational use, leading to a rapidly evolving understanding of cortical and subcortical neurocircuitry. In this review, the authors discuss recent innovations in the clinical use of DBS, both in approved indications as well as in indications under investigation. Deep brain stimulation as an investigational tool is also reviewed, paying special attention to evolving models of basal ganglia and cortical function in health and disease. Finally, the authors look to the future across several indications, highlighting gaps in knowledge and possible future directions of DBS treatment.

Clinical features of pure obsessive-compulsive disorder

OBJECTIVE

Psychiatric comorbidity is the rule in obsessive-compulsive disorder (OCD); however, very few studies have evaluated the clinical characteristics of patients with no co-occurring disorders (non-comorbid or "pure" OCD). The aim of this study was to estimate the prevalence of pure cases in a large multicenter sample of OCD patients and compare the sociodemographic and clinical characteristics of individuals with and without any lifetime axis I comorbidity.

METHOD

A cross-sectional study with 955 adult patients of the Brazilian Research Consortium on Obsessive-Compulsive Spectrum Disorders (C-TOC). Assessment instruments included the Yale-Brown Obsessive-Compulsive Scale, the Dimensional Yale-Brown Obsessive-Compulsive Scale, The USP-Sensory Phenomena Scale and the Brown Assessment of Beliefs Scale. Comorbidities were evaluated using the Structured Clinical Interview for DSM-IV Axis I Disorders. Bivariate analyses were followed by logistic regression.

RESULTS

Only 74 patients (7.7%) presented pure OCD. Compared with those presenting at least one lifetime comorbidity (881, 92.3%), non-comorbid patients were more likely to be female and to be working, reported less traumatic experiences and presented lower scores in the Y-BOCS obsession subscale and in total DY-BOCS scores. All symptom dimensions except contamination-cleaning and hoarding were less severe in non-comorbid patients. They also presented less severe depression and anxiety, lower suicidality and less previous treatments. In the logistic regression, the following variables predicted pure OCD: sex, severity of depressive and anxious symptoms, previous suicidal thoughts and psychotherapy.

CONCLUSIONS

Pure OCD patients were the minority in this large sample and were characterized by female sex, less severe depressive and anxious symptoms, less suicidal thoughts and less use of psychotherapy as a treatment modality. The implications of these findings for clinical practice are discussed.

Brain structural alterations in obsessive-compulsive disorder patients with autogenous and reactive obsessions

Obsessive-compulsive disorder (OCD) is a clinically heterogeneous condition. Although structural brain alterations have been consistently reported in OCD, their interaction with particular clinical subtypes deserves further examination. Among other approaches, a two-group classification in patients with autogenous and reactive obsessions has been proposed. The purpose of the present study was to assess, by means of a voxel-based morphometry analysis, the putative brain structural correlates of this classification scheme in OCD patients. Ninety-five OCD patients and 95 healthy controls were recruited. Patients were divided into autogenous (n = 30) and reactive (n = 65) sub-groups. A structural magnetic resonance image was acquired for each participant and pre-processed with SPM8 software to obtain a volume-modulated gray matter map. Whole-brain and voxel-wise comparisons between the study groups were then performed. In comparison to the autogenous group, reactive patients showed larger gray matter volumes in the right Rolandic operculum. When compared to healthy controls, reactive patients showed larger volumes in the putamen (bilaterally), while autogenous patients showed a smaller left anterior temporal lobe. Also in comparison to healthy controls, the right middle temporal gyrus was smaller in both patient subgroups. Our results suggest that autogenous and reactive obsessions depend on partially dissimilar neural substrates. Our findings provide some neurobiological support for this classification scheme and contribute to unraveling the neurobiological basis of clinical heterogeneity in OCD.

A critical review of magnetic resonance spectroscopy studies of obsessive-compulsive disorder

Functional neuroimaging studies have converged to suggest that cortico-striatal-thalamo-cortical (CSTC) circuit dysfunction is a core pathophysiologic feature of obsessive-compulsive disorder (OCD). Now, complementary approaches examining regional neurochemistry are beginning to yield additional insights with regard to the neurobiology of aberrant CSTC circuitry in OCD. In particular, proton magnetic resonance spectroscopy, which allows for the in vivo quantification of various neurochemicals in the CSTC circuit and other brain regions, has recently been used extensively in studies of OCD patients. In this review, we summarize the diverse and often seemingly inconsistent findings of these studies, consider methodological factors that might help to explain these inconsistencies, and discuss several convergent findings that tentatively seem to be emerging. We conclude with suggestions for possible future proton magnetic resonance spectroscopy studies in OCD.

Reduction of N-acetylaspartate in the medial prefrontal cortex correlated with symptom severity in obsessive-compulsive disorder: meta-analyses of (1)H-MRS studies

Structural and functional neuroimaging findings suggest that disturbance of the cortico-striato-thalamo-cortical (CSTC) circuits may underlie obsessive-compulsive disorder (OCD). However, some studies with (1)H-magnetic resonance spectroscopy ((1)H-MRS) reported altered level of N-acetylaspartate (NAA), they yielded inconsistency in direction and location of abnormality within CSTC circuits. We conducted a comprehensive literature search and a meta-analysis of (1)H-MRS studies in OCD. Seventeen met the inclusion criteria for a meta-analysis. Data were separated by frontal cortex region: medial prefrontal cortex (mPFC), dorsolateral prefrontal cortex, orbitofrontal cortex, basal ganglia and thalamus. The mean and s.d. of the NAA measure were calculated for each region. A random effects model integrating 16 separate datasets with 225 OCD patients and 233 healthy comparison subjects demonstrated that OCD patients exhibit decreased NAA levels in the frontal cortex (P=0.025), but no significant changes in the basal ganglia (P=0.770) or thalamus (P=0.466). Sensitivity analysis in an anatomically specified subgroup consisting of datasets examining the mPFC demonstrated marginally significant reduction of NAA (P=0.061). Meta-regression revealed that NAA reduction in the mPFC was positively correlated with symptom severity measured by Yale-Brown Obsessive Compulsive Scale (P=0.011). The specific reduction of NAA in the mPFC and significant relationship between neurochemical alteration in the mPFC and symptom severity indicate that the mPFC is one of the brain regions that directly related to abnormal behavior in the pathophysiology of OCD. The current meta-analysis indicates that cortices and sub-cortices contribute in different ways to the etiology of OCD.

Mechanisms of deep brain stimulation for obsessive compulsive disorder: effects upon cells and circuits

Deep brain stimulation (DBS) has emerged as a safe, effective, and reversible treatment for a number of movement disorders. This has prompted investigation of its use for other applications including psychiatric disorders. In recent years, DBS has been introduced for the treatment of obsessive compulsive disorder (OCD), which is characterized by recurrent unwanted thoughts or ideas (obsessions) and repetitive behaviors or mental acts performed in order to relieve these obsessions (compulsions). Abnormal activity in cortico-striato-thalamo-cortical (CSTC) circuits including the orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), ventral striatum, and mediodorsal (MD) thalamus has been implicated in OCD. To this end a number of DBS targets including the anterior limb of the internal capsule (ALIC), ventral capsule/ventral striatum (VC/VS), ventral caudate nucleus, subthalamic nucleus (STN), and nucleus accumbens (NAc) have been investigated for the treatment of OCD. Despite its efficacy and widespread use in movement disorders, the mechanism of DBS is not fully understood, especially as it relates to psychiatric disorders. While initially thought to create a functional lesion akin to ablative procedures, it is increasingly clear that DBS may induce clinical benefit through activation of axonal fibers spanning the CSTC circuits, alteration of oscillatory activity within this network, and/or release of critical neurotransmitters. In this article we review how the use of DBS for OCD informs our understanding of both the mechanisms of DBS and the circuitry of OCD. We review the literature on DBS for OCD and discuss potential mechanisms of action at the neuronal level as well as the broader circuit level.