Cognitive and clinical predictors of a long-term course in obsessive compulsive disorder: A machine learning approach in a prospective cohort study

BACKGROUND

Obsessive compulsive disorder (OCD) is a disabling illness with a chronic course, yet data on long-term outcomes are scarce. This study aimed to examine the long-term course of OCD in patients treated with different approaches (drugs, psychotherapy, and psychosurgery) and to identify predictors of clinical outcome by machine learning.

METHOD

We included outpatients with OCD treated at our referral unit. Demographic and neuropsychological data were collected at baseline using standardized instruments. Clinical data were collected at baseline, 12 weeks after starting pharmacological treatment prescribed at study inclusion, and after follow-up.

RESULTS

Of the 60 outpatients included, with follow-up data available for 5-17 years (mean = 10.6 years), 40 (67.7 %) were considered non-responders to adequate treatment at the end of the study. The best machine learning model achieved a correlation of 0.63 for predicting the long-term Yale-Brown Obsessive Compulsive Scale (Y-BOCS) score by adding clinical response (to the first pharmacological treatment) to the baseline clinical and neuropsychological characteristics.

LIMITATIONS

Our main limitations were the sample size, modest in the context of traditional ML studies, and the sample composition, more representative of rather severe OCD cases than of patients from the general community.

CONCLUSIONS

Many patients with OCD showed persistent and disabling symptoms at the end of follow-up despite comprehensive treatment that could include medication, psychotherapy, and psychosurgery. Machine learning algorithms can predict the long-term course of OCD using clinical and cognitive information to optimize treatment options.

Sex differences in clinical response to deep brain stimulation in resistant obsessive-compulsive disorder

INTRODUCTION

Deep brain stimulation (DBS) is an effective alternative to treat severe refractory obsessive-compulsive disorder (OCD), although little is known on factors predicting response. The objective of this study was to explore potential sex differences in the pattern of response to DBS in OCD patients.

METHODS

We conducted a prospective observational study in 25 patients with severe resistant OCD. Response to treatment was defined as a ≥35% reduction in Yale-Brown Obsessive Compulsive Scale (Y-BOCS) score. Logistic regression models were calculated to measure the likelihood of response at short and long-term follow-up by sex as measured by Y-BOCS score. Similar analyses were carried out to study changes in depressive symptomatology assessed with the Hamilton Depression Rating Scale (HDRS). Additionally, effect sizes were calculated to assess clinical significance.

RESULTS

We did not observe significant clinical differences between men and women prior to DBS implantation, nor in the response after one year of stimulation. At long-term follow-up, 76.9% of men could be considered responders to DBS versus only 33.3% of women. The final response odds ratio in men was 10.05 with significant confidence intervals (88.90-1.14). No other predictors of response were identified. The sex difference in Y-BOCS reduction was clinically significant, with an effect size of 3.2. The main limitation was the small sample size.

CONCLUSIONS

Our results suggest that gender could influence the long-term response to DBS in OCD, a finding that needs to be confirmed in new studies given the paucity of results on predictors of response to DBS.

The genomics of visuospatial neurocognition in obsessive-compulsive disorder: A preliminary GWAS

BACKGROUND

The study of Obsessive-Compulsive Disorder (OCD) genomics has primarily been tackled by Genome-wide association studies (GWAS), which have encountered troubles in identifying replicable single nucleotide polymorphisms (SNPs). Endophenotypes have emerged as a promising avenue of study in trying to elucidate the genomic bases of complex traits such as OCD.

METHODS

We analyzed the association of SNPs across the whole genome with the construction of visuospatial information and executive performance through four neurocognitive variables assessed by the Rey-Osterrieth Complex Figure Test (ROCFT) in a sample of 133 OCD probands. Analyses were performed at SNP- and gene-level.

RESULTS

No SNP reached genome-wide significance, although there was one SNP almost reaching significant association with copy organization (rs60360940; P = 9.98E-08). Suggestive signals were found for the four variables at both SNP- (P < 1E-05) and gene-levels (P < 1E-04). Most of the suggestive signals pointed to genes and genomic regions previously associated with neurological function and neuropsychological traits.

LIMITATIONS

Our main limitations were the sample size, which was limited to identify associated signals at a genome-wide level, and the composition of the sample, more representative of rather severe OCD cases than a population-based OCD sample with a broad severity spectrum.

CONCLUSIONS

Our results suggest that studying neurocognitive variables in GWAS would be more informative on the genetic basis of OCD than the classical case/control GWAS, facilitating the genetic characterization of OCD and its different clinical profiles, the development of individualized treatment approaches, and the improvement of prognosis and treatment response.

Neuropsychological performance and predictors of pharmacological treatment response in obsessive compulsive disorder

BACKGROUND

Obsessive Compulsive Disorder (OCD) is characterized by the presence of executive dysfunctions. As organizational strategies may play an important role as a possible endophenotype of the disorder, we decided to investigate non-verbal memory and organizational abilities in OCD. We also investigated how organization and non-verbal memory differ between responder and non-responder patients to pharmacological treatment, to test whether cognitive functions can predict the response to pharmacological treatment.

METHODS

In Study 1, executive and clinical functioning measures were applied to 162 OCD and 95 controls. In Study 2, clinical, intelligence and executive functioning measures were applied to 72 OCD responders and 63 OCD non-responder patients.

RESULTS

OCD patients and controls from Study 1 differed in copy organization (p < 0.01) and delayed recall (p = 0.048). In Study 2, the OCD responders displayed better copy organization (p = 0.013) and lower depressive, anxious and OCD symptoms (p < 0.01 in the three cases). Scores in the following instruments were found to predict the response to pharmacological treatment: HDRS, Y-BOCS, Raven progressive matrices, and Direct digit subtest from the Wechsler's scale (p < 0.01 in all four cases).

LIMITATIONS

In Study 1, the imbalance of the sample can be considered a limitation, whilst in Study 2, some of the levels of pharmacological resistance were not represented.

CONCLUSIONS

In this study, non-verbal memory and organization was affected in OCD. Responder patients also displayed better executive functioning and fluid intelligence. Organizational ability is a predictor of pharmacological response to SSRI monotherapy in a predictive model controlling for anxious symptoms.

Neural correlates of fear conditioning and fear extinction and its association with cognitive-behavioral therapy outcome in adults with obsessive-compulsive disorder

Recent neurobiological models of obsessive-compulsive disorder (OCD) have highlighted the potential role of abnormalities in fear learning processes. We compared brain activation -as assessed with whole-brain functional magnetic resonance imaging- during fear conditioning, fear extinction learning, and fear extinction recall in patients with OCD (n = 18) and healthy controls (n = 18). We also investigated whether brain activation during any of these processes was associated with exposure-based cognitive-behavioral therapy (CBT) outcome in patients. Patients with OCD showed significantly lower brain activation in the right insulo-opercular region and the dorsal anterior cingulate cortex during fear conditioning in comparison to healthy controls. Moreover, brain activation in the right insula predicted CBT outcome, with lower activation predicting a better outcome. Brain activation during extinction learning or recall did not differ between patients and controls or predicted CBT outcome in patients. Our results suggest that neural activations during fear conditioning in patients with OCD are abnormal and predict CBT outcome.

First manic/hypomanic episode in obsessive-compulsive disorder patients treated with antidepressants: A systematic review

High doses of antidepressants, particularly clomipramine and selective serotonin reuptake inhibitors (SSRIs), are the well-established treatment for obsessive-compulsive disorder (OCD), but manic/hypomanic episodes are potential adverse events associated with this treatment. A systematic literature review was performed on manic/hypomanic episodes in non-bipolar OCD patients. Clinical, sociodemographic and antidepressant characteristics during the manic/hypomanic switch were extracted using descriptive statistics. Data were obtained from 20 case reports and case series. Switching episodes mostly appeared in the first 12 weeks after antidepressant initiation and took place more frequently during SSRI use (mostly fluoxetine) in 64.3% of cases. Clomipramine and SSRI use differed non-significantly between the switching episodes that appeared during the first 12 weeks of antidepressant treatment and the episodes that appeared beyond 12 weeks. Switching episodes emerging before 12 weeks were associated with a lower defined daily dose of antidepressants than episodes emerging after 12 weeks. These findings suggest that there are two independent characteristics involved in manic/hypomanic switch in OCD: a) they appeared most frequently with SSRI use (fluoxetine) regardless of the time of it use, and b) episodes appeared in the first 12 weeks after SSRI or clomipramine initiation had a lower dose of antidepressant than episodes appeared after 12 weeks.

Childhood maltreatment interacts with hypothalamic-pituitary-adrenal axis negative feedback and major depression: effects on cognitive performance

Background: Childhood maltreatment (CM) is associated with impaired hypothalamic-pituitary-adrenal (HPA) axis negative feedback and cognitive dysfunction, resembling those abnormalities linked to major depressive disorder (MDD). Objectives: We aimed to assess the potential modulating effects of MDD diagnosis or HPA axis function in the association between different types of CM and cognitive performance in adulthood. Methods: Sixty-eight MDD patients and 87 healthy controls were recruited. CM was assessed with the Childhood Trauma Questionnaire. We obtained three latent variables for neuropsychological performance (verbal memory, visual memory and executive function/processing speed) after running a confirmatory factor analysis with cognitive tests applied. Dexamethasone suppression test ratio (DSTR) was performed using dexamethasone 0.25 mg. Results: Different types of CM had different effects on cognition, modulated by MDD diagnosis and HPA axis function. Individuals with physical maltreatment and MDD presented with enhanced cognition in certain domains. The DSTR differentially modulated the association between visual memory and physical neglect or sexual abuse. Conclusions: HPA axis-related neurobiological mechanisms leading to cognitive impairment might differ depending upon the type of CM. Our results suggest a need for early assessment and intervention on cognition and resilience mechanisms in individuals exposed to CM to minimize its deleterious and lasting effects.

Sleep disturbances in obsessive-compulsive disorder: influence of depression symptoms and trait anxiety

BACKGROUND

Sleep disturbances have been reported in obsessive-compulsive disorder (OCD) patients, with heterogeneous results. The aim of our study was to assess sleep function in OCD and to investigate the relationship between sleep and the severity of obsessive-compulsive (OC) symptoms, depressive symptoms and trait anxiety.

METHODS

Sleep quality was measured in 61 OCD patients and 100 healthy controls (HCs) using the Pittsburgh Sleep Quality Index (PSQI). Multiple linear regression was conducted to explore the association between sleep and psychopathological measures; a mediation analysis was also performed.

RESULTS

OCD patients showed poor sleep quality and more sleep disturbances compared to HCs. The severity of depression, trait anxiety and OC symptomatology were correlated with poor sleep quality. Multiple linear regression analyses controlling for potential confounders revealed that the severity of depression and trait anxiety were independently related to poor sleep quality in OCD. A mediation analysis showed that both the severity of trait anxiety and depression mediate the relationship between the severity of OC symptoms and poor sleep quality among patients with OCD.

CONCLUSIONS

Our findings support the existence of sleep disturbances in OCD. Trait anxiety and depression play a key role in sleep quality among OCD patients.

Sex differences in the association between obsessive-compulsive symptom dimensions and diurnal cortisol patterns

Previous studies in non-clinical populations suggest that obsessive-compulsive symptoms are associated with hypothalamic-pituitary-adrenal (HPA) axis measures and that there are sex differences in these associations. We aimed to replicate these findings in a sample of 57 patients with obsessive-compulsive disorder (OCD) and 98 healthy subjects. Current and lifetime OCD symptom dimensions were assessed with the Dimensional Yale-Brown Obsessive Compulsive Scale (DY-BOCS). Depressive symptoms and state and trait anxiety were also assessed. The following HPA axis measures were analysed in saliva: the diurnal cortisol slope (calculated using two formulas: [1] awakening to 11 p.m. [AWE diurnal slope] and [2] considering fixed time points [FTP diurnal slope] from 10 a.m. to 11 p.m.) and the dexamethasone suppression test ratio (DSTR) after 0.25 mg of dexamethasone. Multiple linear regression analyses were conducted to explore the contribution of OCD symptom dimensions to each HPA axis measure while adjusting for age, sex, BMI, smoking, trait anxiety and depressive symptoms. A sex-specific association between current ordering/symmetry symptoms and AWE diurnal cortisol slope (positive association [flattened slope] in men, inverse association [stepper slope] in women) was found. Two similar sex by OCD dimensions interactions were found for lifetime aggressive and ordering/symmetry symptoms and both (FTP, AWE) diurnal cortisol slopes. Current and lifetime hoarding symptoms were associated to a more flattened FTP diurnal cortisol slope in women. The DSTR was not associated with OCD symptoms. The lifetime interference in functionality was associated with a more flattened AWE diurnal cortisol slope. In conclusion, our study suggests that there are sex differences in the association between OCD subtypes and specific HPA axis measures.

Is glutamate associated with fear extinction and cognitive behavior therapy outcome in OCD? A pilot study

Cognitive behavioral therapy (CBT) including exposure and response prevention is a well-established treatment for obsessive-compulsive disorder (OCD) and is based on the principles of fear extinction. Fear extinction is linked to structural and functional variability in the ventromedial prefrontal cortex (vmPFC) and has been consistently associated with glutamate neurotransmission. The relationship between vmPFC glutamate and fear extinction and its effects on CBT outcome have not yet been explored in adults with OCD. We assessed glutamate levels in the vmPFC using 3T magnetic resonance spectroscopy, and fear extinction (learning and recall) using skin conductance responses during a 2-day experimental paradigm in OCD patients (n = 17) and in healthy controls (HC; n = 13). Obsessive-compulsive patients (n = 12) then received manualized CBT. Glutamate in the vmPFC was negatively associated with fear extinction recall and positively associated with CBT outcome (with higher glutamate levels predicting a better outcome) in OCD patients. Glutamate levels in the vmPFC in OCD patients were not significantly different from those in HC, and were not associated with OCD severity. Our results suggest that glutamate in the vmPFC is associated with fear extinction recall and CBT outcome in adult OCD patients.

Looking into the genetic bases of OCD dimensions: a pilot genome-wide association study

The multidimensional nature of obsessive-compulsive disorder (OCD) has been consistently reported. Clinical and biological characteristics have been associated with OCD dimensions in different ways. Studies suggest the existence of specific genetic bases for the different OCD dimensions. In this study, we analyze the genomic markers, genes, gene ontology and biological pathways associated with the presence of aggressive/checking, symmetry/order, contamination/cleaning, hoarding, and sexual/religious symptoms, as assessed via the Dimensional Yale-Brown Obsessive Compulsive Scale (DY-BOCS) in 399 probands. Logistic regression analyses were performed at the single-nucleotide polymorphism (SNP) level. Gene-based and enrichment analyses were carried out for common (SNPs) and rare variants. No SNP was associated with any dimension at a genome-wide level (p < 5 × 10^-8). Gene-based analyses showed one gene to be associated with hoarding (SETD3, p = 1.89 × 10^-08); a gene highly expressed in the brain and which plays a role in apoptotic processes and transcriptomic changes, and another gene associated with aggressive symptoms (CPE; p = 4.42 × 10^-6), which is involved in neurotrophic functions and the synthesis of peptide hormones and neurotransmitters. Different pathways or biological processes were represented by genes associated with aggressive (zinc ion response and lipid metabolism), order (lipid metabolism), sexual/religious (G protein-mediated processes) and hoarding (metabolic processes and anion transport) symptoms after FDR correction; while no pathway was associated with contamination. Specific genomic bases were found for each dimension assessed, especially in the enrichment analyses. Further research with larger samples and different techniques, such as next-generation sequencing, are needed to better understand the differential genetics of OCD dimensions.

Exploring genetic variants in obsessive compulsive disorder severity: A GWAS approach

BACKGROUND

The severity of Obsessive-Compulsive Disorder (OCD) varies significantly among probands. No study has specifically investigated the genetic base of OCD severity. A previous study from our group found an OCD polygenic risk score to predict pre- and post-treatment severity. This study explores the genomic bases of OCD severity.

METHODS

We administered the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) to 401 patients at their first visit to our clinic to measure their OCD severity. Genotyping data was collected by using the Infinium PsychArray-24 BeadChip kit (Illumina). We analyzed genetic association with OCD severity in a linear regression analysis at single-nucleotide polymorphism (SNP)- and gene-levels, this last also considering rare variants. Enrichment analyses were performed from gene-based analyses' results.

RESULTS

No SNP reached significant association (p < 10^-8) with the YBOCS. Six markers showed suggestive association (p < 10^-5). The top SNP was an intergenic variant in chromosome 2: rs7578149 (p < 1.89 × 10^-6), located in a region suggestively associated with MDD. Linkage disequilibrium was found for two clusters of SNPs located between SLC16A14 and SP110 in chromosome 2, all of them forming one peak of association. Enrichment analyses revealed OCD genes to be associated with porin activity (FDR = 0.01) and transmembrane structure (FDR = 0.04).

LIMITATIONS

The size of the sample and the transversal nature of the severity measure are limitations of this study.

CONCLUSION

This study contributes to better characterize OCD at an individual level, helping to know more about the prognosis of the disorder and develop more individualized treatments.

Do polygenic risk and stressful life events predict pharmacological treatment response in obsessive compulsive disorder? A gene-environment interaction approach

The rate of response to pharmacological treatment in Obsessive-compulsive disorder (OCD) oscillates between 40 and 70%. Genetic and environmental factors have been associated with treatment response in OCD. This study analyzes the predictive ability of a polygenic risk score (PRS) built from OCD-risk variants, for treatment response in OCD, and the modulation role of stressful life events (SLEs) at the onset of the disorder. PRSs were calculated for a sample of 103 patients. Yale-Brown Obsessive Compulsive Scale (YBOCS) scores were obtained before and after a 12-week treatment. Regression analyses were performed to analyze the influence of the PRS and SLEs at onset on treatment response. PRS did not predict treatment response. The best predictive model for post-treatment YBOCS (post YBOCS) included basal YBOCS and age. PRS appeared as a predictor for basal and post YBOCS. SLEs at onset were not a predictor for treatment response when included in the regression model. No evidence for PRS predictive ability for treatment response was found. The best predictor for treatment response was age, agreeing with previous literature specific for SRI treatment. Suggestions are made on the possible role of neuroplasticity as a mediator on this association. PRS significantly predicted OCD severity independent on pharmacological treatment. SLE at onset modulation role was not evidenced. Further research is needed to elucidate the genetic and environmental bases of treatment response in OCD.

Intrinsic functional and structural connectivity of emotion regulation networks in obsessive-compulsive disorder

Despite emotion regulation being altered in patients with obsessive-compulsive disorder (OCD), no studies have investigated its relation to multimodal amygdala connectivity. We compared corticolimbic functional and structural connectivity between OCD patients and healthy controls (HCs), and correlated this with the dispositional use of emotion regulation strategies and with OCD severity. OCD patients (n = 73) and HCs (n = 42) were assessed for suppression and reappraisal strategies using the Emotion Regulation Questionnaire (ERQ) and for OCD severity using the Yale-Brown Obsessive-Compulsive Scale. Resting-state functional magnetic resonance imaging (rs-fMRI) connectivity maps were generated using subject-specific left amygdala (LA) and right amygdala (RA) masks. We identified between-group differences in amygdala whole-brain connectivity, and evaluated the moderating effect of ERQ strategies. Significant regions and amygdala seeds were used as targets in probabilistic tractography analysis. Patients scored higher in suppression and lower in reappraisal. We observed higher rs-fMRI RA-right postcentral gyrus (PCG) connectivity in HC, and in patients this was correlated with symptom severity. Reappraisal scores were associated with higher negative LA-left insula connectivity in HC, and suppression scores were negatively associated with LA-precuneus and angular gyri connectivity in OCD. Structurally, patients showed higher mean diffusivity in tracts connecting the amygdala with the other targets. RA-PCG connectivity is diminished in patients, while disrupted emotion regulation is related to altered amygdala connectivity with the insula and posterior brain regions. Our results are the first showing, from a multimodal perspective, the association between amygdala connectivity and specific emotional processing domains, emphasizing the importance of amygdala connectivity in OCD pathophysiology.

FKBP5 polymorphisms and hypothalamic-pituitary-adrenal axis negative feedback in major depression and obsessive-compulsive disorder

Major depressive disorder (MDD) and obsessive-compulsive disorder (OCD) have both been linked to abnormalities in the hypothalamic-pituitary-adrenal (HPA) axis. Polymorphisms in the genes involved in HPA axis activity, such as FKBP5, and their interactions with childhood trauma have been associated with stress-related mental disorders. Our goal was to study the role of FKBP5 genetic variants in HPA axis negative feedback regulation as a possible risk factor for different mental disorders such as MDD and OCD, while controlling for childhood trauma, anxiety and depressive symptoms. The sample included 266 participants divided into three groups: 1) MDD (n = 89 [n = 73 melancholic; n = 3 atypical]), 2) OCD (n = 51; 39% with comorbid MDD [n = 13 melancholic; n = 7 atypical]) and 3) healthy controls (n = 126). Childhood trauma, trait anxiety and depressive symptoms were assessed. HPA negative feedback was analyzed using the dexamethasone suppression test ratio (DSTR) after administration of 0.25 mg of dexamethasone. Twelve SNPs in the FKBP5 gene were selected for genotyping. Multiple linear regressions, after adjusting for the covariates considered, showed a reduced DSTR in individuals with the rs9470079-A variant that was significant after correction for multiple testing. Childhood trauma did not moderate the association between the rs9470079 and DSTR. Our results support the evidence that FKBP5 genetic variation could lead to abnormal HPA axis negative feedback independent of diagnosis. Therefore, this association can be identified as a transdiagnostic feature, offering an interesting opportunity to identify patients with higher stress vulnerability. Further studies focusing on the influence of FKBP5 on measurable biological endophenotypes are needed.

Brain alterations in low-frequency fluctuations across multiple bands in obsessive compulsive disorder

The extent of functional abnormalities in frontal-subcortical circuits in obsessive-compulsive disorder (OCD) is still unclear. Although neuroimaging studies, in general, and resting-state functional Magnetic Resonance Imaging (rs-fMRI), in particular, have provided relevant information regarding such alterations, rs-fMRI studies have been typically limited to the analysis of between-region functional connectivity alterations at low-frequency signal fluctuations (i.e., <0.08 Hz). Conversely, the local attributes of Blood Oxygen Level Dependent (BOLD) signal across different frequency bands have been seldom studied, although they may provide valuable information. Here, we evaluated local alterations in low-frequency fluctuations across different oscillation bands in OCD. Sixty-five OCD patients and 50 healthy controls underwent an rs-fMRI assessment. Alterations in the fractional amplitude of low-frequency fluctuations (fALFF) were evaluated, voxel-wise, across four different bands (from 0.01 Hz to 0.25 Hz). OCD patients showed decreased fALFF values in medial orbitofrontal regions and increased fALFF values in the dorsal-medial prefrontal cortex (DMPFC) at frequency bands <0.08 Hz. This pattern was reversed at higher frequencies, where increased fALFF values also appeared in medial temporal lobe structures and medial thalamus. Clinical variables (i.e., symptom-specific severities) were associated with fALFF values across the different frequency bands. Our findings provide novel evidence about the nature and regional distribution of functional alterations in OCD, which should contribute to refine neurobiological models of the disorder. We suggest that the evaluation of the local attributes of BOLD signal across different frequency bands may be a sensitive approach to further characterize brain functional alterations in psychiatric disorders.

Hypothalamic-pituitary-adrenal axis activity in the comorbidity between obsessive-compulsive disorder and major depression

Major depressive disorder (MDD) is the most common psychiatric comorbidity in patients with obsessive-compulsive disorder (OCD). Hypothalamic-pituitary-adrenal (HPA) axis abnormalities have been described in both disorders and might play a role in the association between them. We aimed to study the role of HPA axis activity in the comorbidity between OCD and MDD, while controlling for psychopathological dimensions such as anxiety and depressive symptoms. We studied 324 participants belonging to four diagnostic groups: 1) MDD (n = 101), 2) OCD with comorbid MDD (n = 33), 3) OCD without MDD (n = 52), and 4) healthy subjects (n = 138). State anxiety, trait anxiety and depressive symptoms were assessed. Three HPA axis measures were analyzed in saliva: cortisol awakening response (CAR), diurnal cortisol slope (calculated using two formulas: [1] awakening to 11 p.m. [AWE diurnal slope]; [2] considering fixed time points [FTP diurnal slope] from 10 a.m. to 11 p.m.), and dexamethasone suppression test ratio after 0.25 mg of dexamethasone (DSTR). Multiple linear regression analyses were conducted to explore the contribution of clinical diagnosis and symptom dimensions to each HPA axis measure. A more flattened FTP diurnal cortisol slope was observed for OCD patients with comorbid MDD. Regarding the CAR and DSTR, a significant interaction was found between trait anxiety and OCD, as OCD patients with greater trait anxiety showed an increased CAR and reduced cortisol suppression after dexamethasone administration. Our results suggest that trait anxiety plays an important role in the relationship between HPA axis measures and OCD/MDD comorbidity.

Altered functional connectivity of the subthalamus and the bed nucleus of the stria terminalis in obsessive-compulsive disorder

BACKGROUND

The assessment of inter-regional functional connectivity (FC) has allowed for the description of the putative mechanism of action of treatments such as deep brain stimulation (DBS) of the nucleus accumbens in patients with obsessive-compulsive disorder (OCD). Nevertheless, the possible FC alterations of other clinically-effective DBS targets have not been explored. Here we evaluated the FC patterns of the subthalamic nucleus (STN) and the bed nucleus of the stria terminalis (BNST) in patients with OCD, as well as their association with symptom severity.

METHODS

Eighty-six patients with OCD and 104 healthy participants were recruited. A resting-state image was acquired for each participant and a seed-based analysis focused on our two regions of interest was performed using statistical parametric mapping software (SPM8). Between-group differences in FC patterns were assessed with two-sample t test models, while the association between symptom severity and FC patterns was assessed with multiple regression analyses.

RESULTS

In comparison with controls, patients with OCD showed: (1) increased FC between the left STN and the right pre-motor cortex, (2) decreased FC between the right STN and the lenticular nuclei, and (3) increased FC between the left BNST and the right frontopolar cortex. Multiple regression analyses revealed a negative association between clinical severity and FC between the right STN and lenticular nucleus.

CONCLUSIONS

This study provides a neurobiological framework to understand the mechanism of action of DBS on the STN and the BNST, which seems to involve brain circuits related with motor response inhibition and anxiety control, respectively.

Basolateral amygdala-ventromedial prefrontal cortex connectivity predicts cognitive behavioural therapy outcome in adults with obsessive-compulsive disorder

BACKGROUND

Cognitive behavioural therapy (CBT), including exposure and ritual prevention, is a first-line treatment for obsessive-compulsive disorder (OCD), but few reliable predictors of CBT outcome have been identified. Based on research in animal models, we hypothesized that individual differences in basolateral amygdala-ventromedial prefrontal cortex (BLA-vmPFC) communication would predict CBT outcome in patients with OCD.

METHODS

We investigated whether BLA-vmPFC resting-state functional connectivity (rs-fc) predicts CBT outcome in patients with OCD. We assessed BLA-vmPFC rs-fc in patients with OCD on a stable dose of a selective serotonin reuptake inhibitor who then received CBT and in healthy control participants.

RESULTS

We included 73 patients with OCD and 84 healthy controls in our study. Decreased BLA-vmPFC rs-fc predicted a better CBT outcome in patients with OCD and was also detected in those with OCD compared with healthy participants. Additional analyses revealed that decreased BLA-vmPFC rs-fc uniquely characterized the patients with OCD who responded to CBT.

LIMITATIONS

We used a sample of convenience, and all patients were receiving pharmacological treatment for OCD.

CONCLUSION

In this large sample of patients with OCD, BLA-vmPFC functional connectivity predicted CBT outcome. These results suggest that future research should investigate the potential of BLA-vmPFC pathways to inform treatment selection for CBT across patients with OCD and anxiety disorders.

Hypothalamic-pituitary-adrenal axis activity and cognition in major depression: The role of remission status

OBJECTIVES

Neuropsychological deficits and hypothalamic-pituitary-adrenal (HPA) axis dysfunction have been described in major depressive disorder (MDD). We conducted an exploratory study to investigate the role of remission status in the relationship between HPA axis and cognition in MDD.

METHODS

Ninety-seven MDD patients (44 remitted, 53 non-remitted) and 97 healthy controls (HC) were evaluated. We measured verbal and visual memory, working memory, processing speed, attention, and executive function. Three HPA axis measures were assessed: cortisol awakening response (CAR), diurnal cortisol slope, and cortisol suppression ratio with 0.25mg of dexamethasone (DSTR). Multiple linear regression analyses were performed to study the relationship between cortisol measures and cognition while controlling for potential confounders. We conducted an overall analysis in all participants to compare both MDD-remitted and MDD non-remitted groups with respect to HC. Another analysis including MDD patients only was used to explore a moderating effect by remission status.

RESULTS

MDD patients showed poorer cognitive performance compared with HC, without significant differences between remitters and non-remitters. Cortisol measures did not differ between remitters and non-remitters. Although most HPA axis measures were not associated with cognitive dysfunction, we found significant associations between cognitive performance in MDD-remitters and cortisol measures for visual memory, processing speed and executive function. A significant moderating effect for remission status was found between cortisol diurnal slope (but neither CAR nor DSTR) and performance in processing speed or executive function.

CONCLUSIONS

Remission status in MDD appears to moderate the association between some cognitive domains (processing speed and executive function) and HPA axis activity.

Brain structural correlates of obsessive-compulsive disorder with and without preceding stressful life events

Objectives There is growing evidence supporting a role for stressful life events (SLEs) at obsessive-compulsive disorder (OCD) onset, but neurobiological correlates of such effect are not known. We evaluated regional grey matter (GM) changes associated with the presence/absence of SLEs at OCD onset. Methods One hundred and twenty-four OCD patients and 112 healthy controls were recruited. Patients were split into two groups according to the presence (n = 56) or absence (n = 68) of SLEs at disorder's onset. A structural magnetic resonance image was acquired for each participant and pre-processed with Statistical Parametric Mapping software (SPM8) to obtain a volume-modulated GM map. Between-group differences in sociodemographic, clinical and whole-brain regional GM volumes were assessed. Results SLEs were associated with female sex, later age at disorder's onset, more contamination/cleaning and less hoarding symptoms. In comparison with controls, patients without SLEs showed GM volume increases in bilateral dorsal putamen and the central tegmental tract of the brainstem. By contrast, patients with SLEs showed specific GM volume increases in the right anterior cerebellum. Conclusions Our findings support the idea that neuroanatomical alterations of OCD patients partially depend on the presence of SLEs at disorder's onset.

Exon-focused genome-wide association study of obsessive-compulsive disorder and shared polygenic risk with schizophrenia

Common single-nucleotide polymorphisms (SNPs) account for a large proportion of the heritability of obsessive-compulsive disorder (OCD). Co-ocurrence of OCD and schizophrenia is commoner than expected based on their respective prevalences, complicating the clinical management of patients. This study addresses two main objectives: to identify particular genes associated with OCD by SNP-based and gene-based tests; and to test the existence of a polygenic risk shared with schizophrenia. The primary analysis was an exon-focused genome-wide association study of 370 OCD cases and 443 controls from Spain. A polygenic risk model based on the Psychiatric Genetics Consortium schizophrenia data set (PGC-SCZ2) was tested in our OCD data. A polygenic risk model based on our OCD data was tested on previous data of schizophrenia from our group. The most significant association at the gene-based test was found at DNM3 (P=7.9 × 10(-5)), a gene involved in synaptic vesicle endocytosis. The polygenic risk model from PGC-SCZ2 data was strongly associated with disease status in our OCD sample, reaching its most significant value after removal of the major histocompatibility complex region (lowest P=2.3 × 10(-6), explaining 3.7% of the variance). The shared polygenic risk was confirmed in our schizophrenia data. In conclusion, DNM3 may be involved in risk to OCD. The shared polygenic risk between schizophrenia and OCD may be partially responsible for the frequent comorbidity of both disorders, explaining epidemiological data on cross-disorder risk. This common etiology may have clinical implications.

Removing and reimplanting deep brain stimulation therapy devices in resistant OCD (when the patient does not respond): case report

BACKGROUND

Deep brain stimulation (DBS) is emerging as a promising tool in the treatment of refractory obsessive-compulsive disorder (OCD) but the search for the best target still continues. This issue is especially relevant when particularly resistant profiles are observed in some patients, which have been ascribed to individual responses to DBS according to differential patterns of connectivity. As patients have been implanted, new dilemmas have emerged, such as what to do when the patient does not respond to surgery.

CASE PRESENTATION

Here we describe a 22-year-old male with extremely severe OCD who did not respond to treatment with DBS in the nucleus accumbens, but who did respond after explanting and reimplanting leads targeting the ventral capsule-ventral striatum region. Information regarding the position of the electrodes for both surgeries is provided and possible brain structures affected during stimulation are reviewed. To our knowledge this case is the first in the literature reporting the removal and reimplantation of DBS leads for therapeutical benefits in a patient affected by a mental disorder.

CONCLUSION

The capability for explantation and reimplantation of leads should be considered as part of the DBS therapy reversibility profile in resistant mental disorders, as it allows application in cases of non-response to the first surgery.

Factors Associated with Long-Term Sickness Absence Due to Mental Disorders: A Cohort Study of 7.112 Patients during the Spanish Economic Crisis

Background

Mental health problems are very common and often lead to prolonged sickness absence, having serious economic repercussions for most European countries. Periods of economic crisis are important social phenomena that are assumed to increase sickness absence due to mental disorders, although research on this topic remains scarce. The aim of this study was to gather data on long-term sickness absence (and relapse) due to mental disorders in Spain during a period of considerable socio-economic crisis.

Methods

Relationships were analyzed (using chi-squared tests and multivariate modelling via binary logistic regression) between clinical, social/employment-related and demographic factors associated and long-term sickness absence (>60 consecutive days) due to mental disorders in a cohort of 7112 Spanish patients during the period 2008–2012.

Results

Older age, severe mental disorders, being self-employed, having a non-permanent contract, and working in the real estate and construction sector were associated with an increased probability of long-term sickness absence (gender had a mediating role with respect to some of these variables). Relapses were associated with short-term sick leave (return to work due to ‘improvement’) and with working in the transport sector and public administration.

Conclusions

Aside from medical factors, other social/employment-related and demographic factors have a significant influence on the duration of sickness absence due to mental disorders.

Predictive value of familiality, stressful life events and gender on the course of obsessive-compulsive disorder

BACKGROUND

Familiality, stressful life events (SLE) and gender significantly affect the onset of obsessive-compulsive disorder (OCD). However, their combined impact on the probability of OCD chronicity is largely unknown. With the objective of clarifying their predictive value, we tested a model of interaction effects between these influences.

METHODS

A sample of 449 patients with OCD was systematically assessed for familial loading, exposure to stressful life events, gender and course of the disease at the OCD referral unit at Bellvitge University Hospital. Multiple ordinal logistic regression was used to test interaction models.

RESULTS

Familiality presented a main negative association with chronicity (OR=0.83, CI97.5%=0.70-0.98). This association was additively moderated by both exposure to SLE before onset and gender, and showed a positive slope among female patients not exposed to SLE before onset (Familiality*SLEbo: OR=0.69, CI97.5%=0.47-1; Familiality*gender: OR=1.30, CI97.5%=0.91-1.84).

LIMITATIONS

The findings are based on cross-sectional data. Assessment of course is based on a retrospective measure, which may imply the possibility of overestimation of chronicity.

CONCLUSIONS

The predictive value of familiality on the course of OCD is only partially informative as both SLEbo and gender modify the association. When other risk factors are included in the model, familiality may predict decreased chances of chronicity. The mediation effects identified could explain the discrepancies found in previous research on this topic. Increased chances of presenting a chronic course of OCD may be found in association with familial vulnerability among female patients not exposed to SLEbo.

Brain structural correlates of sensory phenomena in patients with obsessive-compulsive disorder

BACKGROUND

Sensory phenomena (SP) are uncomfortable feelings, including bodily sensations, sense of inner tension, "just-right" perceptions, feelings of incompleteness, or "urge-only" phenomena, which have been described to precede, trigger or accompany repetitive behaviours in individuals with obsessive-compulsive disorder (OCD). Sensory phenomena are also observed in individuals with tic disorders, and previous research suggests that sensorimotor cortex abnormalities underpin the presence of SP in such patients. However, to our knowledge, no studies have assessed the neural correlates of SP in patients with OCD.

METHODS

We assessed the presence of SP using the University of São Paulo Sensory Phenomena Scale in patients with OCD and healthy controls from specialized units in São Paulo, Brazil, and Barcelona, Spain. All participants underwent a structural magnetic resonance examination, and brain images were examined using DARTEL voxel-based morphometry. We evaluated grey matter volume differences between patients with and without SP and healthy controls within the sensorimotor and premotor cortices.

RESULTS

We included 106 patients with OCD and 87 controls in our study. Patients with SP (67% of the sample) showed grey matter volume increases in the left sensorimotor cortex in comparison to patients without SP and bilateral sensorimotor cortex grey matter volume increases in comparison to controls. No differences were observed between patients without SP and controls.

LIMITATIONS

Most patients were medicated. Participant recruitment and image acquisition were performed in 2 different centres.

CONCLUSION

We have identified a structural correlate of SP in patients with OCD involving grey matter volume increases within the sensorimotor cortex; this finding is in agreement with those of tic disorder studies showing that abnormal activity and volume increases within this region are associated with the urges preceding tic onset.

Animal models of obsessive-compulsive disorder: utility and limitations

Obsessive-compulsive disorder (OCD) is a disabling and common neuropsychiatric condition of poorly known etiology. Many attempts have been made in the last few years to develop animal models of OCD with the aim of clarifying the genetic, neurochemical, and neuroanatomical basis of the disorder, as well as of developing novel pharmacological and neurosurgical treatments that may help to improve the prognosis of the illness. The latter goal is particularly important given that around 40% of patients with OCD do not respond to currently available therapies. This article summarizes strengths and limitations of the leading animal models of OCD including genetic, pharmacologically induced, behavioral manipulation-based, and neurodevelopmental models according to their face, construct, and predictive validity. On the basis of this evaluation, we discuss that currently labeled "animal models of OCD" should be regarded not as models of OCD but, rather, as animal models of different psychopathological processes, such as compulsivity, stereotypy, or perseverance, that are present not only in OCD but also in other psychiatric or neurological disorders. Animal models might constitute a challenging approach to study the neural and genetic mechanism of these phenomena from a trans-diagnostic perspective. Animal models are also of particular interest as tools for developing new therapeutic options for OCD, with the greatest convergence focusing on the glutamatergic system, the role of ovarian and related hormones, and the exploration of new potential targets for deep brain stimulation. Finally, future research on neurocognitive deficits associated with OCD through the use of analogous animal tasks could also provide a genuine opportunity to disentangle the complex etiology of the disorder.

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.

Brain regions related to fear extinction in obsessive-compulsive disorder and its relation to exposure therapy outcome: a morphometric study

BACKGROUND

The size of particular sub-regions within the ventromedial prefrontal cortex (vmPFC) has been associated with fear extinction in humans. Exposure therapy is a form of extinction learning widely used in the treatment of obsessive-compulsive disorder (OCD). Here we investigated the relationship between morphometric measurements of different sub-regions of the vmPFC and exposure therapy outcome in OCD.

METHOD

A total of 74 OCD patients and 86 healthy controls underwent magnetic resonance imaging (MRI). Cortical thickness and volumetric measurements were obtained for the rostral anterior cingulate cortex (rACC), the medial orbital frontal cortex and the subcallosal cortex. After MRI acquisition, patients were enrolled in an exposure therapy protocol, and we assessed the relationship between MRI-derived measurements and treatment outcome. Baseline between-group differences for such measurements were also assessed.

RESULTS

Compared with healthy controls, OCD patients showed a thinner left rACC (p = 0.008). Also, left rACC thickness was inversely associated with exposure therapy outcome (r - 0.32, p = 0.008), and this region was significantly thinner in OCD patients who responded to exposure therapy than in those who did not (p = 0.006). Analyses based on regional volumetry did not yield any significant results.

CONCLUSIONS

OCD patients showed cortical thickness reductions in the left rACC, and these alterations were related to exposure therapy outcome. The precise characterization of neuroimaging predictors of treatment response derived from the study of the brain areas involved in fear extinction may optimize exposure therapy planning in OCD and other anxiety disorders.

Spanish version of the Dimensional Obsessive-Compulsive Scale (DOCS): psychometric properties and relation to obsessive beliefs

OBJECTIVES

Our main goal was to provide the psychometric properties of the Spanish version of the Dimensional Obsessive-Compulsive Scale (DOCS) in a non-clinical sample (n = 237) and in adult patients with Obsessive-Compulsive Disorder (OCD) (n = 110). We also examined the association between OC symptom dimensions and obsessive beliefs.

METHODS

The psychometric properties involved four steps: reliability, structural validity, convergent and discriminant validity and diagnostic sensitivity. Linear regression analyses were used to assess the associations between OC symptoms and obsessive beliefs.

RESULTS

Exploratory and confirmatory factor analyses replicated the original four-factor structure in both samples. The DOCS showed good performance in terms of internal consistency, test-retest reliability and convergent validity in both samples. The DOCS showed better diagnostic sensitivity than another self-report instrument of OC symptoms, the Obsessive-Compulsive Inventory Revised. Findings of the relationship between obsessive beliefs and OC symptoms revealed that certain obsessive beliefs predicted specific OC symptom dimensions.

CONCLUSIONS

The Spanish version of the DOCS has similar psychometric properties than the original English instrument, although its performance is somewhat better in OCD patients than in students. It will be important to ascertain its ability to discriminate OCD from other associated disorders.

Amygdala activation and symptom dimensions in obsessive-compulsive disorder

BACKGROUND

Despite knowledge of amygdala involvement in fear and anxiety, its contribution to the pathophysiology of obsessive-compulsive disorder (OCD) remains controversial. In the context of neuroimaging studies, it seems likely that the heterogeneity of the disorder might have contributed to a lack of consistent findings.

AIMS

To assess the influence of OCD symptom dimensions on amygdala responses to a well-validated emotional face-matching paradigm.

METHOD

Cross-sectional functional magnetic resonance imaging (fMRI) study of 67 patients with OCD and 67 age-, gender- and education-level matched healthy controls.

RESULTS

The severity of aggression/checking and sexual/religious symptom dimensions were significantly associated with heightened amygdala activation in those with OCD when responding to fearful faces, whereas no such correlations were seen for other symptom dimensions.

CONCLUSIONS

Amygdala functional alterations in OCD appear to be specifically modulated by symptom dimensions whose origins may be more closely linked to putative amygdala-centric processes, such as abnormal fear processing.

Neural correlates of obsessive-compulsive related dysfunctional beliefs

There have been few attempts to integrate neurobiological and cognitive models of obsessive-compulsive disorder (OCD), although this might constitute a key approach to clarify the complex etiology of the disorder. Our study aimed to explore the neural correlates underlying dysfunctional beliefs hypothesized by cognitive models to be involved in the development and maintenance of OCD. We obtained a high-resolution magnetic resonance image from fifty OCD patients and 30 healthy controls, and correlated them, voxel-wise, with the severity of OC-related dysfunctional beliefs assessed by the Obsessive Beliefs Questionnaire-44. In healthy controls, significant negative correlations were observed between anterior temporal lobe (ATL) volume and scores on perfectionism/intolerance of uncertainty and overimportance/need to control thoughts. No significant correlations between OBQ-44 domains and regional gray matter volumes were observed in OCD patients. A post-hoc region-of-interest analysis detected that the ATLs was bilaterally smaller in OCD patients. On splitting subjects into high- and low-belief subgroups, we observed that such brain structural differences between OCD patients and healthy controls were explained by significantly larger ATL volumes among healthy subjects from the low-belief subgroup. Our results suggest a significant correlation between OC-related dysfunctional beliefs and morphometric variability in the anterior temporal lobe, a brain structure related to socio-emotional processing. Future studies should address the interaction of these correlations with environmental factors to fully characterize the bases of OC-related dysfunctional beliefs and to advance in the integration of biological and cognitive models of OCD.

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.

The interaction between Comt and Bdnf variants influences obsessive-compulsive-related dysfunctional beliefs

Cognitive models emphasize the importance of dysfunctional beliefs as overimportance/need to control thoughts, perfectionism, intolerance of uncertainty, responsibility, and overestimation of threat in obsessive-compulsive disorder (OCD). Twin studies suggest that these beliefs are significantly heritable, but candidate genes associated with them have not been analyzed. We genotyped the Val158Met in the COMT gene and Val66Met variant in the BDNF gene in 141 OCD patients and analyzed their single and interactive effects on the obsessive beliefs questionnaire (OBQ-44). Variability in dysfunctional beliefs was not affected by the COMT or BDNF genotype in isolation, but we detected a significant COMT×BDNF interaction effect on responsibility/overestimation of threat and overimportance/need to control thoughts scores. Subjects with the BDNF Met-present and the COMT Met-present genotype showed higher scores on responsibility/overestimation of threat. An interaction between dopaminergic and neurotrophic functional gene variants may influence dysfunctional beliefs hypothesized to contribute to the development of OCD.

Brain corticostriatal systems and the major clinical symptom dimensions of obsessive-compulsive disorder

BACKGROUND

Functional neuroimaging studies have provided consistent support for the idea that obsessive-compulsive disorder (OCD) is associated with disturbances of brain corticostriatal systems. However, in general, these studies have not sought to account for the disorder's prominent clinical heterogeneity.

METHODS

To address these concerns, we investigated the influence of major OCD symptom dimensions on brain corticostriatal functional systems in a large sample of OCD patients (n = 74) and control participants (n = 74) examined with resting-state functional magnetic resonance imaging. We employed a valid method for mapping ventral and dorsal striatal functional connectivity, which supported both standard group comparisons and linear regression analyses with patients' scores on the Dimensional Yale-Brown Obsessive-Compulsive Scale.

RESULTS

Consistent with past findings, patients demonstrated a common connectivity alteration involving the ventral striatum and orbitofrontal cortex that predicted overall illness severity levels. This common alteration was independent of the effect of particular symptom dimensions. Instead, we observed distinct anatomical relationships between the severity of symptom dimensions and striatal functional connectivity. Aggression symptoms modulated connectivity between the ventral striatum, amygdala, and ventromedial frontal cortex, while sexual/religious symptoms had a specific influence on ventral striatal-insular connectivity. Hoarding modulated the strength of ventral and dorsal striatal connectivity with distributed frontal regions.

CONCLUSIONS

Taken together, these results suggest that pathophysiological changes among orbitofrontal-striatal regions may be common to all forms of OCD. They suggest that a further examination of certain dimensional relationships will also be relevant for advancing current neurobiological models of the disorder.

Interaction of SLC1A1 gene variants and life stress on pharmacological resistance in obsessive-compulsive disorder

Genetic and environmental factors seem to interact and influence both the onset and the course of obsessive-compulsive disorder (OCD), but the role of glutamate transporter variants (SLC1A1) in pharmacological resistance is not known. We aimed to assess whether genetic variants in SLC1A1 and life stress at onset of the disorder interact and modulate pharmacological resistance in OCD. A single-marker association study of several single-nucleotide polymorphisms in the SLC1A1 genomic region was performed in a sample of 238 OCD patients. For the most strongly associated SNP (rs3087879), one copy of the risk allele increased the probability of higher treatment resistance (odds ratio=2.42; 95% confidence interval=1.39-4.21; P=0.0018), but only in OCD patients without life stress at onset of the disorder. These results suggest a gene-by-environment interaction effect on treatment resistance in OCD and strengthen the existing evidence of the role of the glutamatergic system in the phenomenology of OCD.

Association between the NMDA glutamate receptor GRIN2B gene and obsessive-compulsive disorder

BACKGROUND

Recent data from neuroimaging, genetic and clinical trials and animal models suggest a role for altered glutamatergic neuro transmission in the pathogenesis of obsessive-compulsive disorder (OCD). The aim of this study was to investigate whether variants in the GRIN2B gene, the gene encoding the NR2 subunit of the N-methyl-D-aspartate (NMDA) glutamate receptor, may contribute to genetic susceptibility to OCD or to different OCD subphenotypes.

METHODS

Between 2003 and 2008, we performed a case-control association study in which we genotyped 10 tag single-nucleotide polymorphisms (SNPs) in the 3' untranslated region (3' UTR) of GRIN2B. We performed SNP association and haplotype analysis considering the OCD diagnosis and different OCD subphenotypes: early-onset OCD, comorbid tic disorders and OCD clinical symptom dimensions.

RESULTS

We enrolled 225 patients with OCD and 279 controls recruited from the OCD Clinic at Bellvitge Hospital (Barcelona, Spain). No significant difference in the distribution of alleles or genotypes was detected between patients with OCD and controls. Nonetheless, on analyzing OCD subphenotypes, the rs1805476 SNP in male patients (95% confidence interval [CI] 1.37-4.22, p = 0.002) and a 4-SNP haplotype in the whole sample (rs1805476, rs1805501, rs1805502 and rs1805477; odds ratio 1.92, 95% CI 1.22-3.01; permutation p = 0.023) were significantly associated with the presence of contamination obsessions and cleaning compulsions.

LIMITATIONS

Study limitations included the risk of population stratification associated with the case-control design, use of psychiatrically unscreened blood donors as the control group, reduced sample size of participants with certain OCD subphenotypes and tested polymorphisms limited to 3' UTR and exon 13 of GRIN2B.

CONCLUSION

Our results converge with recent data suggesting a possible contribution of glutamatergic variants to the genetic vulnerability to OCD or at least to certain OCD manifestations. The dissection of OCD into more homogeneous subphenotypes may constitute a useful tool to disentangle the complex genetic basis of the disorder.

Variation in the BDNF Val66Met polymorphism and response to cognitive-behavior therapy in obsessive-compulsive disorder

BACKGROUND

Recent research suggests that the brain-derived neurotrophic factor (BDNF) may play a role in extinction learning. The goal of this study was to test whether variation in the BDNF Val66Met polymorphism is related to treatment response to exposure-based cognitive-behavior therapy (CBT), a form of extinction learning, in obsessive-compulsive disorder (OCD).

METHODS

One hundred and six OCD patients from a specialized clinic, who underwent a standardized CBT treatment after partial or non-response to a 12-week pharmacological trial, were genotyped for the BDNF Val66Met and the relationship between genotype and treatment response was analyzed.

RESULTS

Among 98 CBT completers, 36% of those carrying the BDNF Met allele were rated as CBT responders compared to 60% of nonMet allele carriers (P=0.027). When analyzing the different obsessive-compulsive symptom dimensions, in patients with contamination/cleaning symptoms, the Met allele was associated with a significantly worse CBT response (P<0.0001) and a lower obsessions severity decrease from pre- to posttreatment (P=0.046).

CONCLUSION

Genetic variation in BDNF may be associated with treatment response in exposure-based CBT in OCD, especially in those patients exhibiting contamination/cleaning symptoms.

Olfactory identification and discrimination in obsessive-compulsive disorder

BACKGROUND

Neuroimaging and neuropsychological data from patients with an obsessive-compulsive disorder (OCD) indicate the dysfunction of the orbitofrontal cortex (OFC). Olfactory processing has been associated with OFC function, although results from OCD studies regarding this sensory modality have been inconclusive. No previous study has analyzed both odor discrimination and identification capacity in OCD patients using "Sniffin' Sticks" tests. The aim of our study was to assess odor threshold, identification, discrimination, and nonverbal memory in OCD patients, in order to determine whether these functions were affected.

METHODS

Olfactory function was measured in 29 OCD patients and 29 healthy volunteers (HV) using the "Sniffin' Sticks" test and their nonverbal memory was scored with the Rey-Osterrieth Complex Figure Test.

RESULTS

OCD patients showed significant impairment in their odor performance and in their execution of the nonverbal memory task compared to HV. No statistical associations were found between the deficits in the two areas. The severity of depressive and obsessive-compulsive symptoms did correlate with olfactory identification.

CONCLUSION

Our findings support the hypothesis that olfactory and memory dysfunctions in OCD reflect different neurobiological alterations of the disorder, and point to the modulation effect of depressive and obsessive-compulsive symptoms on odor performance.

Stressful life events at onset of obsessive-compulsive disorder are associated with a distinct clinical pattern

BACKGROUND

Environmental stressors are considered to play an important role in the triggering of mental disorders such as obsessive-compulsive disorder (OCD). Although there is extensive literature on traumatic life events, little is known about the role of nontraumatic but nonetheless stressful life events (SLEs) in OCD. The aim of this study was to establish whether OCD preceded by an SLE presents a different clinical pattern compared to non-SLE-preceded OCD.

METHODS

We interviewed 412 OCD patients to assess both SLEs at onset of OCD and other clinical variables, including OCD symptom dimensions. Logistic regression was then applied to explore the relationship between clinical variables and OCD preceded by an SLE.

RESULTS

The SLE-preceded OCD group showed a later onset of the disorder (OR = 1.04, P = .015), a history of complicated birth (OR = 5.54, P<.001), less family history of OCD (OR = 0.42, P = .014), and the presence of contamination/cleaning symptoms (OR = 1.99, P = .01).

CONCLUSIONS

Patients with OCD onset close to an SLE and those without an SLE close to OCD onset show a distinct clinical pattern.

Variants in estrogen receptor alpha gene are associated with phenotypical expression of obsessive-compulsive disorder

Compelling data from animal and clinical studies suggest that sex steroids may play a role in the etiopathology of obsessive-compulsive disorder (OCD). The aim of this study was to investigate whether variants in estrogen receptor genes ESR1 and ESR2 may contribute to the genetic susceptibility to OCD, through a case-control association study using an extensive linkage disequilibrium-mapping approach. Twenty tag single-nucleotide polymorphisms (tagSNPs) covering the ESR2 region and nine tagSNPS from regions of ESR1 reported to be related to transcriptional control were genotyped in 229 OCD patients and 279 controls. SNP association and haplotype analysis were performed. The association of these genes and OCD subphenotypes was tested, considering early-onset OCD, comorbid tic and affective disorders, and OCD symptom dimensions. No significant difference in the distribution of alleles or genotypes was detected between controls and OCD subjects. Nevertheless, on analyzing OCD subphenotypes, SNP rs34535804 in ESR1 and a five SNPs haplotype, located at the 5' end of intron 1 of ESR1, were associated with the presence of contamination obsessions and cleaning compulsions. Specifically, carriers of the ACCCG haplotype, a combination of functional alleles related to higher ER alpha expression, showed a reduced risk of suffering from these symptoms. Our results suggest that the ESR1 gene may contribute to the genetic vulnerability to certain OCD manifestations. The dissection of OCD into more homogeneous subphenotypes may well help to identify susceptibility genes for the disorder.

Memory and strategic processing in first-degree relatives of obsessive compulsive patients

BACKGROUND

The same executive dysfunctions and alterations in neuroimaging tests (both functional and structural) have been found in obsessive-compulsive patients and their first-degree relatives. These neurobiological findings are considered to be intermediate markers of the disease. The aim of our study was to assess verbal and non-verbal memory in unaffected first-degree relatives, in order to determine whether these neuropsychological functions constitute a new cognitive marker for obsessive-compulsive disorder (OCD).

METHOD

Recall and use of organizational strategies in verbal and non-verbal memory tasks were measured in 25 obsessive-compulsive patients, 25 unaffected first-degree relatives and 25 healthy volunteers.

RESULTS

First-degree relatives and healthy volunteers did not show differences on most measures of verbal memory. However, during the recall and processing of non-verbal information, deficits were found in first-degree relatives and patients compared with healthy volunteers.

CONCLUSIONS

The presence of the same deficits in the execution of non-verbal memory tasks in OCD patients and unaffected first-degree relatives suggests the influence of certain genetic and/or familial factors on this cognitive function in OCD and supports the hypothesis that deficits in non-verbal memory tasks could be considered as cognitive markers of the disorder.

Spanish adaptation of the Dimensional Yale-Brown Obsessive-Compulsive Scale

BACKGROUND

The Dimensional Yale-Brown Obsessive-Compulsive Scale (DY-BOCS) is a promising new instrument that allows patient and clinician ratings of dimension-specific symptom severity, as well as estimates of global symptom severity in patients with obsessive-compulsive disorder (OCD). The goal of this study was to further explore the psychometric properties of the DY-BOCS in a Spanish sample.

METHODS

The internal consistency, reliability, and convergent and divergent validity of the Spanish adaptation of the DY-BOCS were assessed in a sample of 51 Spanish adult patients with OCD.

RESULTS

All the subscales of the Spanish DY-BOCS showed high internal consistency. The interrater reliability was excellent for all component scores, and the level of agreement between self-report and expert ratings was high for most symptom dimensions. The subscales of the DY-BOCS were largely independent from one another and from global OCD severity. The convergent and divergent validities of the DY-BOCS subscales were adequate.

CONCLUSIONS

The Spanish version of the DY-BOCS is a reliable and valid clinical tool for the assessment of obsessive-compulsive symptom dimensions.

A case-control study of sex differences in strategic processing and episodic memory in obsessive-compulsive disorder

Although clinical and genetic data for obsessive-compulsive disorder (OCD) support the hypothesis of sexual dimorphism, the neuropsychological findings remain inconclusive. The aim of our study was to determine whether there are differences in cognitive performance between men and women with OCD as compared with healthy controls (HCs). A neuropsychological battery was administered to 50 patients with OCD (31 men and 19 women) and 50 HCs matched by sex, age, and educational level with patients. We evaluated intelligence, attention, episodic memory, and use of organizational strategies during encoding of verbal and nonverbal information. Male patients scored worse than controls did in measures of nonverbal memory tasks, whereas the cognitive performance of women with OCD was consistent with that of their HC counterparts. These results suggest a distinct pattern of cognitive dysfunction specific to the patients' sex.

Comorbidity in pathological gambling: clinical variables, personality and treatment response

INTRODUCTION

Pathological gambling shows high comorbidity rates, especially with substance use disorders, although affective, anxiety and other impulse control disorders, as well as personality disorders, are also frequently associated.

OBJECTIVES

To explore comorbidity in pathological gambling with other mental disorders in a consecutive sample of patients attending a unit specialized in pathological gambling, and specifically the relationship between substance-related disorders, on the one hand, and personality and clinical variables in pathological gamblers, on the other.

METHOD

A total of 498 patients with a DSM-IV-TR diagnosis of Pathological Gambling (11.8% women) were assessed with a semi-structured clinical interview and several clinical and personality scales.

RESULTS

Higher comorbidity with affective disorders was found in women (30.5%), while higher comorbidity with substance-related disorders was found in men (11.2%). A positive association was also detected between a history of psychiatric disorders and current comorbidity with substance-use disorders, as well as between alcohol abuse and age. Finally, some personality traits such as low reward dependence (OR=0.964) and high impulsivity (OR=1.02) predicted other substance abuse (not alcohol). High selftranscendence scores predicted both alcohol and other substance abuse (OR=1.06).

CONCLUSIONS

Our results suggest a high prevalence of comorbid disorders in pathologic gambling, mainly with affective and substance-related disorders. The results of the present study, conducted in a broad sample of consecutively admitted pathologic gamblers, may contribute to understanding of this complex disorder and treatment improvement.