Obsessive-compulsive Disorder Subgroups Research Articles

Identifying Neurobiological Markers in Obsessive–Compulsive Disorder: A Study Protocol for a Cross-Sectional Study in Subgroups of Differing Phenotype

Obsessive–compulsive disorder (OCD) represents a frequent and highly disabling mental disorder. Past attempts to characterize different disease subgroups focused on the time of onset (late vs. early onset), presence of insight (poor insight), and post-infectious forms (pediatric acute-onset neuropsychiatric syndrome, PANS). Each subgroup may be associated with a differing impact on cognition, functioning, sleep quality, and treatment response profile. Certain lines of evidence suggest brain-derived neurotrophic factor (BDNF) levels may differ between individuals living with OCD as compared with controls, but there is a lack of evidence on the variation of BDNF levels in OCD subgroups. Lastly, the potential of assessing inflammatory states, electroencephalogram, and polysomnography to characterize these subtypes has been hardly explored. Estimates of drug-resistance rates indicate that 20% and up to 65% of affected adults and up to 35% of the pediatric population may not benefit from pharmacological treatments. At least part of the variability in treatment response could depend on the underlying biological heterogeneity. In the present project, we aim to increase the accuracy in characterizing the phenotypical and biological signature for the different OCD subtypes through clinical, cognitive, and sleep markers, along with other possible markers that may be biologically plausible.

Differentiation of 2 Obsessive-Compulsive Disorder Subgroups with Regard to Demographic and Phenomenological Characteristics Combining Multiple Correspondence and Latent Class Analysis

Introduction: Classic factor analysis of obsessive-compulsive disorder (OCD) dimensions and attempts to identify valid subgroups have not yet produced definitive conclusions. Objective and Methods: This study aims to examine possible homogeneous subgrouping of demographic and phenomenological characteristics in 134 treatment-seeking OCD patients. A combination of multiple correspondence analysis (MCA) and latent class analysis (LCA) was used. Results: MCA showed 2 distinct subgroups of OCD patients and LCA confirmed this result by a two-class solution. Both analyses demonstrated (a) a clear subgroup of female patients with washing compulsions, obsessions related to contamination, and late age of onset and (b) a subgroup comprised mostly of male patients with earlier onset of OCD, checking rituals, and doubts or aggressive obsessions. Mental, ordering, hoarding compulsions, religious, or sexual obsessions and images appeared exclusively in this subgroup. Conclusions: Using 2 different analytic methods, we confirmed at least 2 subgroups in a clinical sample of Greek OCD patients. Future research combining dimensional and latent approaches could facilitate our understanding of the heterogeneous phenotype of OCD.

A critical review of cognitive behavioural therapy for hoarding disorder: How can we improve outcomes?

Psychological treatment for hoarding problems has historically been associated with poor outcomes. When treated as a subgroup of obsessive-compulsive disorder, individuals with hoarding beliefs were less likely to respond to treatment than individuals exhibiting other obsessive-compulsive beliefs and behaviours. When treated as its own disorder using cognitive behavioural therapy, individuals report approximately 25% improvement in symptoms on average. However, less than a third of people experience clinically meaningful change. Further, changes in functioning and quality of life are not routinely assessed. In this paper, we review the current conceptualization and treatment of hoarding problems to shed light on how treatment for hoarding disorder may be improved. Utilizing a harm reduction approach before administering treatment may be important to ensure the safety of individuals. Research should test whether treatment outcomes improve by including strategies that enhance a client's interpersonal functioning and ability to regulate emotions (i.e., based on dialectal behaviour therapy and mentalization-based treatments), especially while discarding and organizing belongings. We should also use modern learning theory to improve the delivery of exposure activities.

Distinct clinical manifestations of obsessive-compulsive disorder are associated with cortical thickness alteration.

Although brain structural changes have been reported in patients with obsessive-compulsive disorder (OCD), results from previous studies have been inconsistent. A growing number of studies have focused on obsessive beliefs and impulsivity which could be involved in the occurrence and maintenance of OCD symptoms. The present study aimed to examine whether there are distinct brain structural changes in patients with different OCD subgroups. Eighty-nine patients with OCD and 42 healthy controls were recruited to undergo structural magnetic resonance imaging brain scan. OCD patients were classified into subgroups according to scores of the Obsessive Belief Questionnaire (OBQ-44) and the Barratt Impulsiveness Scale (BIS-11) using cluster analysis. Group comparisons in cortical thickness and subcortical volumes between all OCD patients and healthy controls, as well as between subgroups of OCD patients and healthy controls, were carried out. OCD patients with more obsessive beliefs and attentional impulsivity (OCD_OB_AT) had reduced cortical thickness at the inferior parietal gyrus, the superior and middle temporal gyrus and the insula compared with OCD patients with higher score on the non-planning impulsivity (OCD_NP, corrected p < 0.05). The whole group of OCD patients and both subgroups showed reduced cortical thickness at the superior parietal gyrus compared with controls (uncorrected p < 0.01, number of vertices > 100). Our results suggest that apart from distinct phenomenology, there are distinct neural correlates of different OCD subgroups based on obsessive beliefs and impulsivity. These neural correlates may have clinical significance and should be considered in future research.

Metacognitions in Symptomatic and Remitted Patients with Obsessive Compulsive Disorder: Preliminary Evidence for Metacognitive State and Trait Markers.

Background:The phenomenon of metacognition is instrumental in the conceptualization and management of obsessive compulsive disorder (OCD). Studies on the comparison between metacognitions in OCD patients and healthy controls or those with other clinical conditions have been conducted. We aimed to compare metacognitions among currently symptomatic OCD (S-OCD) patients, currently remitted OCD patients (R-OCD), and healthy controls (HC).Method:This cross-sectional research was conducted in the Department of Psychiatry of a tertiary care hospital in North India. Purposive sampling method was used to recruit 40 OCD patients, including an equal number of R-OCD and S-OCD patients, and 20 HC matched for age and education. Meta-Cognition Questionnaire and Thought Control Questionnaire were used to assess metacognitive functions.Results:The findings showed a gradient of highest maladaptive metacognitions in the S-OCD group and lowest in HC. In the OCD subgroups, specific metacognitive beliefs (negative beliefs F = 65.52; need to control thoughts F = 61.03) and strategies (worry F = 83.55; low distraction F = 105.61) remained significantly different (P ≤ 0.001) between S-OCD and R-OCD patients. Certain other metacognitions remained consistently more or less stable between S-OCD and R-OCD patients, that is, metacognitive beliefs (cognitive confidence F = 11.43; cognitive self-consciousness F = 37.12) and strategies (punishment F = 17.45; low social control F = 12.89). This finding is further corroborated by positive correlations of severity of OCD with need to control thoughts (r = 0.66, P < 0.001), negative beliefs (r = 0.63, P < 0.001), and worry (r = 0.76, P < 0.001), and negative correlations with distraction (r = – 0.79, P < 0.001).Conclusion:The study provides preliminary evidence for specific metacognitions distinguished as potential state and trait markers for OCD, which needs to be established on a larger sample using a longitudinal study design.

Defining data-driven subgroups of obsessive\u2013compulsive disorder with different treatment responses based on resting-state functional connectivity

Characterization of obsessive–compulsive disorder (OCD), like other psychiatric disorders, suffers from heterogeneities in its symptoms and therapeutic responses, and identification of more homogeneous subgroups may help to resolve the heterogeneity. We aimed to identify the OCD subgroups based on resting-state functional connectivity (rsFC) and to explore their differences in treatment responses via a multivariate approach. From the resting-state functional MRI data of 107 medication-free OCD patients and 110 healthy controls (HCs), we selected rsFC features, which discriminated OCD patients from HCs via support vector machine (SVM) analyses. With the selected brain features, we subdivided OCD patients into subgroups using hierarchical clustering analyses. We identified 35 rsFC features that achieved a high sensitivity (82.74%) and specificity (76.29%) in SVM analyses. The OCD patients were subdivided into two subgroups, which did not show significant differences in their demographic and clinical backgrounds. However, one of the OCD subgroups demonstrated more impaired rsFC that was involved either within the default mode network (DMN) or between DMN brain regions and other network regions. This subgroup also showed both lower improvements in symptom severity in the 16-week follow-up visit and lower responder percentage than the other subgroup. Our results highlight that not only abnormalities within the DMN but also aberrant rsFC between the DMN and other networks may contribute to the treatment response and support the importance of these neurobiological alterations in OCD patients. We suggest that abnormalities in these connectivity may play predictive biomarkers of treatment response, and aid to build more optimal treatment strategies.

The impact of attention deficit hyperactivity disorder in obsessive-compulsive disorder subjects.

Recent findings suggest an association between attention deficit hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD). Thus, we evaluated the clinical associated features of ADHD in a large sample of adult OCD patients. A cross-sectional study including 955 adult patients with OCD from the Brazilian Research Consortium of Obsessive-Compulsive Spectrum Disorders (C-TOC). Clinical characteristics in adult OCD patients with and without comorbid ADHD were compared using Fisher's exact test, t-tests or Mann-Whitney tests. Bivariate analyses were followed by logistic regression analysis to identify clinical characteristics independently associated with ADHD comorbidity. The lifetime prevalence of ADHD in adult OCD patients was 13.7%. The current results indicate that OCD + ADHD patients were more severe, had an earlier onset of the obsessive-compulsive symptoms, a higher history of rheumatic fever, with higher frequencies of sensory phenomena and comorbidity with Tourette syndrome. They also had an increased risk for academic impairment and suicide attempts. Adult OCD patients with ADHD present some specific clinical features and may represent a special subgroup of adult OCD. Future studies should focus on the development of interventions more tailored to the phenotype of this subgroup of patients.

Mannose-Binding Lectin 2 Gene Polymorphism in PANDAS Patients.

Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS), a subgroup of obsessive-compulsive disorder (OCD), has received much attention even though the specific underlying mechanisms remain unknown. Mannose-binding lectin (MBL) is a key factor in the innate immune response. The aim of this study was to investigate the role of MBL2 gene polymorphisms in pediatric OCD patients diagnosed as PANDAS, PANDAS-Variant and non-PANDAS. The study included 102 pediatric OCD patients (59 [57.8% ] PANDAS, 20 [19.6% ] non-PANDAS, and 23 [22.5% ] PANDAS-Variant) and 60 healthy controls. Polymorphisms at codon 52, 54 and 57 of the MBL2 gene were investigated. Codon 54 polymorphism and any variant of MBL2 gene were significantly more frequent in the OCD group than in the control group (OR=2.97, 95% CI: 1.26-6.97; and OR=2.66, 95% CI: 1.32-5.38, respectively). According to regression analysis, the presence of any variant of MBL2 gene was found in 14.50-fold increased frequency in the PANDAS subgroup compared with the non-PANDAS subgroup (95% CI: 2.49-84.19). Our findings support an association between MBL2 genotypes and pediatric OCD, particularly PANDAS-OCD.

Combining genetic and epigenetic parameters of the serotonin transporter gene in obsessive-compulsive disorder

While genetic variants have been reported to be associated with obsessive-compulsive disorder (OCD), the small effect sizes suggest that epigenetic mechanisms such as DNA methylation may also be relevant. The serotonin transporter (SLC6A4) gene has been extensively investigated in relation to OCD, since serotonin reuptake inhibitors are the pharmacological treatment of choice for the disorder. The current study set three questions: Firstly, whether the high expressing loci of the SLC6A4 polymorphisms, 5-HTTLPR + rs25531, rs25532 and rs16965628 are associated with family-based (n = 164 trios) and case-control OCD (n = 186, 152, respectively). This was also examined by a meta-analysis. Secondly, whether DNA methylation and RNA levels of the SLC6A4 differ in saliva and blood of a subset of samples from pediatric and adult OCD patients and matched controls. And lastly, whether morning awakening cortisol levels correlate with the above. A meta-analysis confirmed the association of the LA-allele with OCD (OR = 1.21, p = 0.00018), maintaining significance in the early-onset OCD subgroup (OR = 1.21, p = 0.022). There was no association between rs25532 or rs16965628 and OCD. Our preliminary data showed that SLC6A4 DNA methylation levels in an amplicon located at the beginning of the first intron were significantly higher in the saliva of pediatric OCD patients compared to controls and adult patients with OCD, but no alterations in RNA levels or in polymorphism interactions were observed. Morning awakening salivary cortisol levels positively correlated with methylation levels, and negatively correlated with RNA levels. This study further supports the involvement of the SLC6A4 gene in OCD through both genetic and epigenetic mechanisms. This finding needs to be explored further in an independent large sample.

Is "not just right experience" (NJRE) in obsessive-compulsive disorder part of an autistic phenotype?

Harm avoidance (HA) and "not just right experience" (NJRE) have been proposed to be 2 core motivational processes underlying obsessive-compulsive disorder (OCD). The objective of this study was to explore whether NJRE demarcates a neurodevelopmental OCD subgroup distinct from HA related to autistic traits and/or to a broader phenotype of cognitive rigidity and sensory processing difficulties associated with an earlier age of OCD onset. A correlational design investigated whether NJRE and HA are distinct entities in OCD and explored their relationship to autism spectrum disorder (ASD) traits measured by the Autism Quotient (AQ), sensory processing, set-shifting, and age of OCD onset in an OCD sample (N=25). NJRE was only moderately (r=.34) correlated to HA and not significant in this study. Consistent with predictions, NJRE was associated with sensory processing difficulties and an earlier age of OCD onset. No significant relationships were found between NJRE and ASD traits as measured by the AQ or set-shifting difficulties. These preliminary findings suggest a lack of evidence demonstrating NJRE as a manifestation of core autistic traits as measured by the AQ. However, NJRE was associated with sensory abnormalities and an earlier age of OCD onset. The role of NJRE as a developmental, and possibly neurodevelopmental, risk factor for OCD possibly warrants further investigation.

Serotonin transporter promoter polymorphism is associated with executive function impairments in patients with obsessive compulsive disorder

Objective: In the present study, we investigate the association between the 5-HTTLPR polymorphism and executive functions in a sample of patients with obsessive compulsive disorder (OCD). Method: A total of 98 unmedicated patients diagnosed with OCD according to DSM-IV criteria and 80 healthy controls were included in this study. The genotype frequencies of 5-HTTLPR polymorphism were compared in OCD and healthy control groups. The four subgroups of OCD and healthy control participants, determined according to having LaLa genotype (high expressing) or S- and/or Lg alleles (low expressing), were also compared using neuropsychological tests of executive functions. Results: The frequency of SLa genotype of 5-HTTLPR polymorphism was found to be higher in patients with OCD compared with healthy controls. The mean scores of conceptual level responses of the Wisconsin Card Sorting Test (WCST) were significantly lower in the OCD-high-expressing subgroup compared with the low-expressing control group. The mean scores of the number of moves of the Tower of London were found to be significantly higher in the OCD-high-expressing subgroup, compared with the high-expressing subgroup of healthy controls. Conclusion: Our findings suggest that the high-expressing variant may be associated with lower performance on some abstraction and planning measures in OCD patients.

Admixture analysis of age at symptom onset and age at disorder onset in a large sample of patients with obsessive–compulsive disorder

BackgroundA number of studies tested for the presence of different homogeneous subgroups of obsessive–compulsive disorder (OCD) patients depending on the age at onset (AAO). However, none of the various thresholds of AAO have been validated. No study examined whether age at symptoms onset (ASO) and age at disorder onset (ADO) each define specific and diverse OCD subgroups. MethodsWe used normal distribution mixture analysis in a sample of 483 OCD patients to test whether we could identify subgroups of patients according to the AAO. We tested whether ASO and ADO had different distributions and identified different subgroups of OCD patients, and whether clinical correlates had similar patterns of associations with patients subgroups identified with ASO or ADO. ResultsThe mixture analysis showed a trimodal distribution for ASO (mean ASO: 6.9 years for the early onset, 14.99 years for the intermediate onset, and 27.7 years for the late onset component), and confirmed a bimodal distribution for ADO (mean ADO: 18.0 and 29.5 years). Significant differences in the clinical profile of the subgroups emerged, particularly when identified using ASO. LimitationsLimitations of our study are the retrospective investigation of AAO, and the fact that our sample may not represent the OCD population, as we enrolled patients referring to a tertiary center specialized in the treatment of OCD. Our findings need to be confirmed in community samples. Another limitation is the lack of information on medication status at enrollment. ConclusionsAge at symptom onset and ADO showed distinct patterns of distributions. Similarly, phenotypic delineation was specific for ASO and ADO identified subgroups. Accurate clinical and biological profiling of ADO and ASO subgroups might show distinct genetic liabilities, ultimately leading to better nosological models and possibly to improved treatment decision making of OCD patients.

Electrophysiology of facilitation priming in obsessive–compulsive and panic disorders

ObjectiveRepeated experience with stimuli often primes faster, more efficient neuronal and behavioural responses. Exaggerated repetition priming effects have previously been reported in obsessive–compulsive disorder (OCD), however little is known of their underlying neurobiology or disorder-specificity, hence we investigated these factors. MethodsWe examined event-related potentials (ERPs) and behaviour while participants with OCD, panic disorder and healthy controls (20 per group) performed a Go/NoGo task which manipulated target repetition sequences. ResultsBoth clinical groups showed stronger reaction time (RT) priming than HCs, which in OCD was greater in a checking, than washing, subgroup. Both clinical groups had similar RT deficits and ERP anomalies across several components, which correlated with psychopathology and RT priming. In OCD alone, N1 latency tended to increase to repeated stimuli, correlated with O–C symptoms, whereas it decreased in other groups. OCD-checkers had smaller target P2 amplitude than all other groups. ConclusionsEnhanced neural priming is not unique to OCD and may contribute to salient sensory-cognitive experiences in anxiety generally. These effects are related to symptom severity and occur to neutral stimuli and in the context of overall RT impairment, suggesting they may be clinically relevant and pervasive. The results indicate overlapping information-processing and neurobiological factors across disorders, with indications of OCD-specific trends and subgroup differences. SignificanceThis first electrophysiological investigation of OCD priming in OCD to include anxious controls and OCD subgroups allows for differentiation between overlapping and OCD-specific phenomena, to advance neurobiological models of OCD.

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.

Stigmatizing experiences of patients with psychiatric disorders and their caregivers

Background: There has been extensive research on the stigma experienced by patients with psychiatric disorders and their family members. However, very few studies have attempted to compare both the perspectives. Aim: To measure and compare the stigma experienced by patients with psychiatric disorders and their caregivers. Materials and Methods: A total of 143 patients suffering from various psychiatric disorders (including substance use disorders) who visited at the psychiatry out-patient clinic were included, along with their family members. In addition to the sociodemographic and clinical variables, they were assessed using a stigma scale (Hindi version). Results: Patients with psychiatric disorders scored significantly higher than their caregivers on the total stigma scale score as well as on the subscales for discrimination, disclosure and positive aspects. Patients with substance dependence as well as their caregivers had highest total stigma score. The mean difference among the patients and caregivers was highest among the obsessive compulsive disorder subgroup (P = 0.012) and lowest among the schizophrenia subgroup (P = 0.045). Conclusion: Stigma and discrimination are deeply rooted among patients and their caregivers. Tackling stigma and discrimination should form an integral part of the therapeutic process.

Prevalence of Obsessive-Compulsive Disorder in Relation to Depression and Cognition in an Elderly Population

We examined the 1-month prevalence of obsessive-compulsive disorder (OCD) and obsessive-compulsive symptoms (OCS) not fulfilling OCD criteria in relation to sex, age, social and mental function, comorbid depression, and cognitive functioning in an elderly nondemented population. Population-based sample (N = 900), stratified into two age groups: 70-year-olds (335 women and 224 men) and those aged 78 and above (341 women). Semi-structured interviews. Psychiatric symptoms were assessed with the Comprehensive Psychopathological Rating Scale and Mini-International Neuropsychiatric Interview, mental and social function with the GAF-scale, memory function with the Word Recall Task and general cognition with MMSE. OCD and Depression were diagnosed according to DSM-IV. The one-month prevalence of OCD was 2.9%; a further 21% had OCS. Among 70-year-olds, the prevalence of OCD was 1.3% in men and 4.5% in women. Depression was more common among those with OCD (34.6%) than among those with (12.7%) and without (8.0%) OCS. GAF-score was lower among those with OCD (74.8) and OCS (82.9) compared with individuals without obsessions and compulsions (88.2). The association between OCD and GAF-score remained after adjustment for age, sex, and depression. The OCD subgroup with checking behavior had more memory and concentration problems and did worse on Word Recall Task than other groups in our sample. We found that OCD and OCS are common among the elderly. Both conditions are related to depression and poorer mental and social functioning. Physicians who meet elderly patients need to be aware of OCD as it is potentially treatable.

Effects of the serotonergic agonist mCPP on male rats in the quinpirole sensitization model of obsessive–compulsive disorder (OCD)

The serotonergic agonist, meta-chlorophenylpiperazine (mCPP), produces inconsistent effects on obsessive-compulsive disorder (OCD) symptoms, perhaps because clinical studies have not utilized a homogenous OCD subgroup of patients. This study aimed to evaluate mCPP effects on functional components of compulsive checking, using the quinpirole sensitization rat model of OCD. In study 1, the effects of mCPP were evaluated in quinpirole rats with compulsive checking. Two experimental groups were co-injected with quinpirole (0.125mg/kg) and mCPP (0.625 or 1.25mg/kg), while one control group was co-injected with quinpirole (0.125mg/kg) and saline and the other control group received co-injections of saline. In study 2, mCPP (0, 0.3125, 0.625, and 1.25mg/kg) was administered repeatedly to naïve rats and induction of compulsive checking evaluated. mCPP significantly attenuated quinpirole-induced compulsive checking behavior by reducing vigor of checking (indexed by frequency of checking and length of check) and increasing rest after a bout of checking (indexed by time to the next checking bout), but it did not affect focus on the task of checking (indexed by recurrence time of checking and number of stops before returning to check). In naïve rats, mCPP did not induce compulsive behavior, but the highest dose reduced vigor of checking performance compared to saline controls. mCPP did not exacerbate or induce compulsive checking behavior. Instead, it ameliorated compulsive checking by reducing vigor of checking and increasing post-checking satiety, without affecting focus on checking. Ameliorative effects of mCPP may involve 5HT2A/2C receptors in substantia nigra pars reticulata that inhibit expression of motor vigor.

Symptom dimensions, clinical course and comorbidity in men and women with obsessive-compulsive disorder

The study aimed to compare male and female patients with obsessive-compulsive disorder (OCD) across symptom dimensions, clinical course and comorbidity. A cross-sectional study was undertaken with 858 adult OCD patients (DSM-IV) from the Brazilian Research Consortium on Obsessive-Compulsive Spectrum Disorders. Patients were evaluated using structured interviews, including the Dimensional Yale-Brown Obsessive-Compulsive Scale (DY-BOCS) and the Structured Clinical Interview for DSM-IV Axis I disorders (SCID-I). The sample was composed of 504 women (58.7%) and 354 men (41.3%) with a mean age of 35.4 years-old (range: 18–77). Men were younger, more frequently single and presented more tics, social phobia and alcohol use disorders. Among men, symptom interference occurred earlier and symptoms of the sexual/religious dimension were more common and more severe. Conversely, women were more likely to present symptoms of the aggressive, contamination/cleaning and hoarding dimension and comorbidity with specific phobias, anorexia nervosa, bulimia, trichotillomania, skin picking and “compulsive” buying. In the logistic regression, female gender remained independently associated with the aggressive and contamination/cleaning dimensions. In both genders the aggressive dimension remained associated with comorbid post-traumatic stress disorder, the sexual/religious dimension with major depression and the hoarding dimension with tic disorders. Gender seems to be relevant in the determination of OCD clinical presentation and course and should be considered an important aspect when defining more homogeneous OCD subgroups.

Is there a Role for Immunological Mechanisms in Etiopathogenesis of Obsessive Compulsive Disorder?

Byline: Naren. Rao, M. Reddy, Janardhan. Reddy Obsessive compulsive disorder (OCD) is a common and debilitating neuropsychiatric disorder with a prevalence of approximately 2%. Though selective serotonin reuptake inhibitors (SSRI) are the mainstay of treatment, it is increasingly being recognized that serotonin abnormality may be the final common pathway and other mechanisms may also play important roles in the etiopathogenesis of OCD. Growing evidence from different lines of research in the last few years suggest possible role of immunologicalabnormalities in the pathogenesis of OCD. [sup][1] Influential studies from National Institute of Mental Health suggested higher prevalence of OCD and tics in patients with Sydenham's chorea and group A Streptococcal infection, implicating immunological mechanisms in a subtype of childhood OCD such as pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS). [sup][2] Following this, studies examined other markers of immune abnormality and reported higher concentration of anti-basal ganglia antibodies [sup][3] and increased prevalence of B lymphocyte marker D8/17 [sup][4] in OCD patients than in healthy controls. Neuroimaging studies supported immune hypothesis in PANDAS, reporting decreased basal ganglia volume in children with streptococcus-associated OCD [sup][5] as well as correlation between basal ganglia volume and anti-basal ganglia antibody titers. [sup][5],[6] While these results suggest a role of immunological mechanisms in the pathogenesis of OCD, one needs to be careful before drawing final conclusion because these results are preliminary and not unequivocal. [sup][7] Recent research advances in psychoneuroimmunology have implicated cytokines as mediators between brain and immune system. In addition to their role in peripheral inflammation, cytokines affect central nervous system functioning by altering the neurotransmitter systems, importantly serotonin and glutamate. Pro- and anti-inflammatory cytokines have stimulatory and inhibitory effects, respectively, on the activity of enzyme indoleamine 2,3 dioxygenase (IDO). Stimulation of IDO converts tryprophan to kynurenine, decreasing tryptophan availability for serotonin production. Kynurenine is further converted to quinolinic acid, which is a glutamate (NMDA) receptor agonist. [sup][8] Hence, cytokines are proposed to play an important role in the pathogenesis of different neuropsychiatric disorders such as depression, post-traumatic stress disorder, schizophrenia, and dementia. In the last decade, studies have examined plasma cytokines in the pathogenesis of OCD, but have reported inconclusive results. On the other hand, few studies have reported elevated cytokine levels in OCD, with majority studies reporting absence of difference between patients and controls, as also corroborated by a recent meta-analysis. [sup][9] In summary, the existing data is inconsistent regarding the role of immunological mechanisms in the pathogenesis of OCD. The evidence does not conclusively suggest a role of immunological mechanisms in the pathogenesis for OCD in general, and, at the same time, does not rule out its possible role in a subgroup of OCD. Few possible reasons for the inconsistency are methodological. First, OCD is a heterogeneous disorder with varying age at onset, and pediatric OCD may be distinctly different from adult OCD. While pediatric OCD studies have implicated possible role for immunological mechanisms, results of studies in adult OCD are equivocal. In one study, age at onset had negative correlation with tumor necrosis factor-a levels, [sup][10] further supporting this view. Second confounding factor is the presence of comorbid diagnosis, importantly depression. Only few studies have examined OCD patients without comorbid diagnosis, and because immunological mechanisms are implicated in pathogenesis of other psychiatric disorders as well, it is difficult to delineate the effects specific to OCD. …

1555 – Repetitive behaviors in tourette syndrome

Introduction In Tourette Syndrome (TS), a neuropsychiatric disorder, tics are frequently associated with obsessivecompulsive symptoms that not always fulfill criteria for Obsessive- Compulsive Disorder (OCD). Phenomenological, genetic and epidemiologic studies suggest a strong association between TS and OCD, not only in patients but also in their relatives. Obsessive-compulsive symptoms can be found in 28-63% of TS patients. Motor portions of cortico-striato-thalamic-cortical circuits are implicated in tics and compulsions. Integrating these repetitive behaviors in Obsessive-Compulsive (OC) spectrum, a continuum between Compulsion and Impulsion, OCD tic-free is positioned at the compulsive end and tic-related OCD and ST are positioned between the two poles. Objectives This communication has as main objective to characterize the repetitive behaviors in TS by presenting the differences and similarities with compulsions. Aims To integrate TS in OC spectrum. Methods Articles’ selection in PUBMED and SCIENCEDIRECT databases and literature’s review about the theme. Results According to clinical features and treatment response, tic-related OCD has an intermediate position between OCD ticfree and TS, sharing common aspects with both entities. Conclusions TS may be differenciated from OCD subgroups, namely tic-related OCD, by its clinical features and therapeutic response. The presence of repetitive touching actions and ecophenomena seems to discriminate TS from OCD. The phenomenological characterization of repetitive behaviors in TS is extremely important, as tic and compulsion’s treatment is different.