Study of neurocognitive endophenotypes in drug-naïve obsessive-compulsive disorder patients, their first-degree relatives and healthy controls

The relationship between cognitive phenotypes of compulsivity and impulsivity and clinical variables in obsessive-compulsive disorder: A systematic review and Meta-analysis

BACKGROUND

This systematic review and meta-analysis explored the relationship between cognitive phenotypes of compulsivity and impulsivity and clinical variables in obsessive-compulsive disorder (OCD).

METHODS

We searched Pubmed, Scopus, Cochrane Library and PsychINFO databases until February 2023 for studies comparing patients with OCD and healthy controls on cognitive tests of compulsivity and impulsivity. The study followed PRISMA guidelines and was pre-registered on PROSPERO (CRD42021299017).

RESULTS

Meta-analyses of 112 studies involving 8313 participants (4289 patients with OCD and 4024 healthy controls) identified significant impairments in compulsivity (g = -0.58, [95%CI -0.68, -0.47]; k = 76) and impulsivity (g = -0.48, [95%CI -0.57, -0.38]; k = 63); no significant difference between impairments. Medication use and comorbid psychiatric disorders were not significantly related to impairments. No associations were revealed with OCD severity, depression/anxiety, or illness duration.

CONCLUSION

Cognitive phenotypes of compulsivity and impulsivity in patients with OCD appear to be orthogonal to clinical variables, including severity of OCD symptomatology. Their clinical impact is poorly understood and may require different clinical assessment tools and interventions.

Neurocognitive performance in the context of acute symptom reduction in OCD: Treatment effects and the impact of BDNF

BACKGROUND

Obsessive-compulsive disorder (OCD) has been associated with neurocognitive impairments. The present study examined the effect of treatment on neurocognitive performance in OCD and the relationship between neurocognitive change and symptom change. The present study also examined polymorphisms influencing brain derived neurotrophic factor (BDNF) as predictors of neurocognitive change.

METHOD

Treatment-seeking participants with OCD (N = 125) were assigned to cognitive behavioural therapy (CBT) alone, CBT combined with regular physical exercise, exercise alone, or a waitlist control group. Measures of OCD symptom severity and a neuropsychological battery were completed pre- and post-treatment. Blood or saliva samples were used to genotype the BDNF Val66Met polymorphism.

RESULTS

OCD symptom severity was not cross-sectionally associated with neurocognitive performance. Several neurocognitive measures improved over treatment. The BDNF Val66Met polymorphism was significantly associated with worse performance on the Stroop test but did not significantly predict change in neurocognitive performance over time.

LIMITATIONS

Limitations include lack of a healthy control group.

CONCLUSION

Improvement in neurocognitive performance corresponded to symptomatic improvement and was independent of the BDNF Val66Met genotype.

Opening new vistas on obsessive-compulsive disorder with the observing response task

Obsessive-compulsive disorder (OCD), a highly prevalent and debilitating disorder, is incompletely understood in terms of underpinning behavioural, psychological, and neural mechanisms. This is attributable to high symptomatic heterogeneity; cardinal features comprise obsessions and compulsions, including clinical subcategories. While obsessive and intrusive thoughts are arguably unique to humans, dysfunctional behaviours analogous to those seen in clinical OCD have been examined in nonhuman animals. Genetic, ethological, pharmacological, and neurobehavioural approaches all contribute to understanding the emergence and persistence of compulsive behaviour. One behaviour of particular interest is maladaptive checking, whereby human patients excessively perform checking rituals despite these serving no purpose. Dysfunctional and excessive checking is the most common symptom associated with OCD and can be readily operationalised in rodents. This review considers animal models of OCD, the neural circuitries associated with impairments in habit-based and goal-directed behaviour, and how these may link to the compulsions observed in OCD. We further review the Observing Response Task (ORT), an appetitive instrumental learning procedure that distinguishes between functional and dysfunctional checking, with translational application in humans and rodents. By shedding light on the psychological and neural bases of compulsive-like checking, the ORT has potential to offer translational insights into the underlying mechanisms of OCD, in addition to being a platform for testing psychological and neurochemical treatment approaches.

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.

Compensatory cognition in neurological diseases and aging: A review of animal and human studies

Specialized individual circuits in the brain are recruited for specific functions. Interestingly, multiple neural circuitries continuously compete with each other to acquire the specialized function. However, the dominant among them compete and become the central neural network for that particular function. For example, the hippocampal principal neural circuitries are the dominant networks among many which are involved in learning processes. But, in the event of damage to the principal circuitry, many times, less dominant networks compensate for the primary network. This review highlights the psychopathologies of functional loss and the aspects of functional recuperation in the absence of the hippocampus.

MICEmi: A method to identify cognitive endophenotypes of mental illnesses

BACKGROUND

Characterizing neurocognitive endophenotypes of mental illnesses (MIs) could be useful for identifying at-risk individuals, increasing early diagnosis, improving disease subtyping, and proposing therapeutic strategies to reduce the negative effects of the symptoms, in addition to serving as a scientific basis to unravel the physiopathology of the disease. However, a standardized algorithm to determine cognitive endophenotypes has not yet been developed. The main objective of this study was to present a method for the identification of endophenotypes in MI research.

METHODS

For this purpose, a 14-expert working group used a scoping review methodology and designed a method that includes a scoring template with five criteria and indicators, a strategy for their verification, and a decision tree.

CONCLUSIONS

This work is ongoing since it is necessary to obtain external validation of the applicability of the method in future research.

Neural Correlates of Executive Functioning in Anorexia Nervosa and Obsessive-Compulsive Disorder

Anorexia nervosa (AN) and obsessive-compulsive disorder (OCD) are commonly reported to co-occur and present with overlapping symptomatology. Executive functioning difficulties have been implicated in both mental health conditions. However, studies directly comparing these functions in AN and OCD are extremely limited. This review provides a synthesis of behavioral and neuroimaging research examining executive functioning in AN and OCD to bridge this gap in knowledge. We outline the similarities and differences in behavioral and neuroimaging findings between AN and OCD, focusing on set shifting, working memory, response inhibition, and response monitoring. This review aims to facilitate understanding of transdiagnostic correlates of executive functioning and highlights important considerations for future research. We also discuss the importance of examining both behavioral and neural markers when studying transdiagnostic correlates of executive functions.

Dissecting the genetic architecture of suicide attempt and repeated attempts in Korean patients with bipolar disorder using polygenic risk scores

BACKGROUND

Bipolar disorder (BD) has the greatest suicide risk among mental and physical disorders. A recent genome-wide association study (GWAS) of European ancestry (EUR) samples revealed that the genetic etiology of suicide attempt (SA) was not only polygenic but also, in part, diagnosis-specific. The authors aimed to examine whether the polygenic risk score (PRS) for SA derived from that study is associated with SA or repeated attempts in Korean patients with BD. This study also investigated the shared heritability of SA and mental disorders which showed an increased risk of SA and a high genetic correlation with BD.

METHODS

The study participants were 383 patients with BD. The history of SA was assessed on a lifetime basis. PRSs for reference disorders were calculated using the aforementioned GWAS data for SA and the Psychiatric Genomics Consortium data of BD, schizophrenia, major depressive disorder (MDD), and obsessive-compulsive disorder (OCD).

RESULTS

The PRS for SA was significantly associated with lifetime SA in the current subjects (Nagelkerke's R² = 2.73%, odds ratio [OR] = 1.36, p = 0.007). Among other PRSs, only the PRS for OCD was significantly associated with lifetime SA (Nagelkerke's R² = 2.72%, OR = 1.36, p = 0.007). The PRS for OCD was higher in multiple attempters than in single attempters (Nagelkerke's R² = 4.91%, OR = 1.53, p = 0.043).

CONCLUSION

The PRS for SA derived from EUR data was generalized to SA in Korean patients with BD. The PRS for OCD seemed to affect repeated attempts. Genetic studies on suicide could benefit from focusing on specific psychiatric diagnoses and refined sub-phenotypes, as well as from utilizing multiple PRSs for related disorders.

Polygenic risk for obsessive-compulsive disorder (OCD) predicts brain response during working memory task in OCD, unaffected relatives, and healthy controls

Alterations in frontal and parietal neural activations during working memory task performance have been suggested as a candidate endophenotype of obsessive-compulsive disorder (OCD) in studies involving first-degree relatives. However, the direct link between genetic risk for OCD and neuro-functional alterations during working memory performance has not been investigated to date. Thus, the aim of the current functional magnetic resonance imaging (fMRI) study was to test the direct association between polygenic risk for OCD and neural activity during the performance of a numeric n-back task with four working memory load conditions in 128 participants, including patients with OCD, unaffected first-degree relatives of OCD patients, and healthy controls. Behavioral results show a significant performance deficit at high working memory load in both patients with OCD and first-degree relatives (p < 0.05). A whole-brain analysis of the fMRI data indicated decreased neural activity in bilateral inferior parietal lobule and dorsolateral prefrontal cortex in both patients and relatives. Most importantly, OCD polygenic risk scores predicted neural activity in orbitofrontal cortex. Results indicate that genetic risk for OCD can partly explain alterations in brain response during working memory performance, supporting the notion of a neuro-functional endophenotype for OCD.

Neurocognitive endophenotypes in pediatric OCD probands, their unaffected parents and siblings

BACKGROUND

Limited extant research on neurocognitive endophenotypes in obsessive-compulsive disorder (OCD) show inconsistent results. Limitations of this body of literature include small sample sizes, strict exclusion criteria, lack of objective standard normalized test scores, and significant lack of studies utilizing pediatric probands. This study aimed to address these limitations.

METHODS

A large carefully screened cohort of pediatric OCD (n = 102), their unaffected siblings (n = 78), and parents (n = 164), completed a neuropsychological battery. To compare participants at different ages and developmental stages, standard scores were computed using test norms. Cluster-robust regression with sample size-adjusted sandwich estimates of variance, and interclass correlations were computed. False Discovery Rate procedures were employed to correct for multiplicity.

RESULTS

Probands, siblings and parents demonstrated deficient task performance (Z < -0.5) on the 'number of trials to complete first category' on the Wisconsin Card Sorting Test, and on the Stroop color naming trials. Compared to test norms, the three groups exhibited medium to large effect sizes on these outcome measures. No other meaningful familial trends were found.

CONCLUSIONS

OCD probands, their unaffected siblings and parents exhibited deficiencies in specific subdomains of cognitive flexibility and inhibitory control, namely, initial concept formation and proactive control, which may be valid candidate neurocognitive endophenotypes of OCD. No other meaningful familial effect has been found on other functions, including other executive function indices such as perseverations and interference control. These results highlight the need to carefully examine individual outcomes from executive function tests instead of the tendency to focus largely on major outcome measures.

Shared and unique neural mechanisms underlying pediatric trichotillomania and obsessive compulsive disorder

BACKGROUND

Little is known about the neural underpinnings of pediatric trichotillomania (TTM). We examined error-related negativity (ERN)-amplitude and theta-EEG power differences among youth with TTM, OCD, and healthy controls (HC).

METHODS

Forty channel EEG was recorded from 63 pediatric participants (22 with TTM, 22 with OCD, and 19 HC) during the Eriksen Flanker Task. EEG data from inhibitory control were used to derive estimates of ERN amplitude and event-related spectral power associated with motor inhibition.

RESULTS

TTM and HC were similar in brain activity patterns in frontal and central regions and TTM and OCD were similar in the parietal region. Frontal ERN-amplitude was significantly larger in OCD relative to TTM and HC, who did not differ from each other. The TTM group had higher theta power compared to OCD in frontal and central regions, and higher theta than both comparison groups in right motor cortex and superior parietal regions. Within TTM, flanker task performance was correlated with EEG activity in frontal, central, and motor cortices whereas global functioning and impairment were associated with EEG power in bilateral motor and parietal cortices.

CONCLUSIONS

Findings are discussed in terms of shared and unique neural mechanisms in TTM and OCD and treatment implications.

Neurocognitive Endophenotypes of OCD

In this chapter, I address the concept of endophenotypes for obsessive-compulsive disorder (OCD). Endophenotypes are objective and heritable quantitative traits hypothesized to be more biologically tractable than distal clinical phenotypes. This approach has been adopted to gain a better understanding of psychiatric conditions in general. It is theorized that endophenotypes will particularly assist in clarifying both the diagnostic status and aetiological origins of complex neuropsychiatric conditions such as OCD. At the cognitive level, separable constructs of relevance for OCD have been identified. The prevailing model for OCD assumes the development of abnormalities within fronto-striatal neural circuits leading to impairment of executive functions and their neuropsychological subcomponents. Here, I address whether this model can guide towards the identification of endophenotypes for this condition and discuss possible implications.

Correlations Between Working Memory Impairment and Neurometabolites of the Prefrontal Cortex in Drug-Naive Obsessive-Compulsive Disorder

PURPOSE

This study aimed to investigate the mechanism of working memory (WM) impairment in drug-naive obsessive-compulsive disorder (OCD) by using neuropsychological tests and proton magnetic resonance spectroscopy (¹H-MRS).

PATIENTS AND METHODS

A total of 55 patients with drug-naive OCD and 55 healthy controls (HCs) were recruited for this study. The working memory (WM) was evaluated using the digit span test (DST), visual space memory test (VSMT), and the 2-back task and stroop color word test (SCWT). The bilateral metabolite levels of the prefrontal cortex (PFC) were evaluated by 1H-MRS, then determined the ratios of N-acetyl aspartate (NAA), choline-containing compounds (Cho), and myo-inositol (MI) to creatine (Cr). The independent sample t-test was used to analyse the differences in WM performance and neurometabolite ratios. Multivariate linear regression analysis was performed to screen the influential factors of WM, with an introduction level of 0.05 and a rejection level of 0.10.

RESULTS

1) Patients with OCD performed significantly worse on DST (score), VSMT (score), 2-back task (accuracy rate), SCWT (execution time) when compared with HCs. 2) NAA/Cr and Cho/Cr in the left PFC (lPFC) and MI/Cr ratios in the bilateral PFC of OCD patients were significantly lower when compared to HCs. 3) For OCD patients, the NAA/Cr ratio in the lPFC was negatively correlated with the score of DST (forwards), the Cho/Cr ratio in the lPFC was positively correlated with the accuracy rate of 2-back task, and the MI/Cr ratio in the right PFC (rPFC) was positively correlated with the score of DST (forwards) and the accuracy rate of VSMT. We also found that the compulsive symptoms showed a positive correlation with MI/Cr ratio of the rPFC.

CONCLUSION

Drug-naive OCD patients have demonstrated WM impairments, including phonological loop, visual-spatial sketchpad and central executive system, and the WM impairments might be associated with hypometabolism in the PFC, especially the lPFC.

The effects of selective serotonin reuptake inhibitors on brain functional networks during goal-directed planning in obsessive-compulsive disorder

Whether brain network connectivity during goal-directed planning in patients with obsessive–compulsive disorder (OCD) is abnormal and restored by treatment with selective serotonin reuptake inhibitors (SSRIs) remains unknown. This study investigated whether the disrupted network connectivity during the Tower of London (ToL) planning task in medication-free OCD patients could be restored by SSRI treatment. Seventeen medication-free OCD patients and 21 matched healthy controls (HCs) underwent functional magnetic resonance imaging (fMRI) while performing the ToL task at baseline and again after 16 weeks of SSRI treatment. Internetwork connectivity was compared across the groups and treatment statuses (pretreatment versus posttreatment). At baseline, compared with the HCs, the OCD patients showed lower internetwork connectivity between the dorsal attention network and the default-mode network during the ToL planning task. After 16 weeks of SSRI treatment, the OCD patients showed improved clinical symptoms accompanied by normalized network connectivity, although their improved behavioral performance in the ToL task did not reach that of the HCs. Our findings support the conceptualization of OCD as a network disease characterized by an imbalance between brain networks during goal-directed planning and suggest that internetwork connectivity may serve as an early biomarker of the effects of SSRIs on goal-directed planning.

Meta-analysis of neurocognitive deficits in unaffected relatives of obsessive-compulsive disorder (OCD): comparison with healthy controls and patients with OCD

BACKGROUND

Obsessive-compulsive disorder (OCD) has been associated with cognitive deficits, particularly with executive functions. These findings support fronto-striatal dysfunction in OCD. However, it is not certain whether these findings are trait features of OCD. In recent years, a number of studies have investigated cognitive functions in unaffected relatives of OCD (OCDrel) but the findings of these studies are contradictory.

METHODS

A systematic review in Pubmed and Scopus databases was performed until 18 March 2019, to locate the studies comparing cognitive functions of OCDrel with healthy controls and OCD patients (OCDpt). A random-effects meta-analysis was conducted.

RESULTS

Current meta-analysis included 16 studies including 527 OCDrel, 445 OCDpt and 639 healthy controls. Healthy controls overperformed OCDpt in all cognitive domains (d = 0.36-0.86). OCDrel underperformed healthy controls in inhibition (d = 0.58, CI = 0.29-0.86), planning (d = 0.45, CI = 0.28-0.63), decision-making (d = 0.58, CI = 0.19-0.98). OCDrel also had small-sized deficits in set-shifting (d = 0.37, CI = 0.04-0.69) and visual memory (d = 0.28, CI = 0.08-0.49). OCDpt underperformed OCDrel in visual memory (d = 0.45, CI = 0.22-0.67) and set-shifting (d = 0.23, CI = 0.04-0.42).

CONCLUSIONS

Current findings suggest that abnormalities in inhibition, planning/problem solving and reward-based decision-making are shared features of OCDrel and OCDpt and might be trait markers related to vulnerability for developing OCD. Visual memory and set-shifting deficits might potentially be biomarkers of incipient illness or subthreshold OCD presentation among OCDrel. Further exploration of cognitive heterogeneity in OCDrel and investigating the effects of the subtypes of OCD in probands on cognitive impairment in OCDrel are needed.

Endophenotypes of executive functions in obsessive compulsive disorder? A meta-analysis in unaffected relatives

Endophenotypes are mediator traits between genetic influences and clinical phenotypes. Meta-analyses have consistently shown modest impairments of executive functioning in obsessive compulsive disorder (OCD) patients compared to healthy controls. Similar deficits have also been reported in unaffected relatives of OCD patients, but have not been quantified. We conducted the first meta-analysis combining all studies investigating executive functioning in unaffected relatives of individuals with OCD to quantify any deficits. A search of Pubmed, Medline and PsychInfo databases identified 21 suitable papers comprising 707 unaffected relatives of OCD patients and 842 healthy controls. Effect sizes were calculated using random effects models. Unaffected relatives displayed a significant impairment in global executive functioning. Analyses of specific executive functioning subdomains revealed impairments in: planning, visuospatial working memory and verbal fluency. Deficits in executive functioning are promising endophenotypes for OCD. To identify further biomarkers of disease risk/resilience in OCD, we suggest examining specific executive functioning domains.

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

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

Dysfunction between dorsal caudate and salience network associated with impaired cognitive flexibility in obsessive-compulsive disorder: A resting-state fMRI study

Background

Impaired cognitive flexibility has been implicated in the genetic basis of obsessive-compulsive disorder (OCD). Recent endophenotype studies of OCD showed neural inefficiency in the cognitive control network and interference by the limbic network of the cognitive control network. Exploring the relationship between the functional brain network and impaired cognitive flexibility may provide novel information about the neurobiological basis of OCD.

Methods

We obtained resting-state functional magnetic resonance imaging (rsfMRI) scans and measured the cognitive flexibility of 37 medication-free OCD patients and 40 healthy control (HC) participants using the Wisconsin Card Sorting Test (WCST). We explored the difference between OCD and HC groups in the functional brain network related to impaired cognitive flexibility from the amygdala and dorsal striatal regions of interest (ROIs) by using a seed-based approach.

Results

Significant differences between the OCD and HC groups were identified in the resting state functional network from the dorsal caudate. Increased functional connectivity from the dorsal caudate to the dorsal anterior cingulate cortex (dACC) and anterior insula (AI) was associated with poorer cognitive flexibility in the OCD group, but better cognitive flexibility in the HC group.

Conclusions

These results provide evidence that the impaired cognitive flexibility of OCD may be associated with dysfunctions of the brain network from the dorsal caudate (DC) to important nodes of the salience network. Our results extend the neuropsychological model of OCD by showing intrinsically different associations between OCD and HC in functional network and cognitive flexibility.

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Increased functional connectivity from the dorsal caudate to the dorsal anterior cingulate cortex and anterior insula was associated with poorer cognitive flexibility in the OCD group, but better cognitive flexibility in the HC group.

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Our results may suggest that the dysfunction from DC to SN is associated with impaired cognitive flexibility of OCD.

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These findings could provide additional insights into the important role of cooperative interactions between the dorsal striatum and the large-scale intrinsic brain networks in human cognitive function.

Planning functioning and impulsiveness in obsessive-compulsive disorder

Planning ability (PA) is a key aspect of cognitive functioning and requires subjects to identify and organise the necessary steps to achieve a goal. Despite the central role of executive dysfunction in patients with obsessive-compulsive disorder (OCD), deficits in PA have been investigated leading to contrasting results. Given these inconsistencies, the main aim of our work is to give a deeper and clearer understanding of PA in OCD patients. Moreover, we are interested in investigating the relationship between PAs and impulsivity traits and other clinical variables. Sixty-eight OCD patients and 68 healthy controls (HCs) matched for sex and age were assessed through the Stocking of Cambridge (SoC), a computerised version of the Tower of London. We examined planning sub-components for each difficulty levels (from 2 to 5 minimum moves). Our results showed that OCD patients needed longer initial thinking time than HCs during the execution of low demanding tasks (i.e. 2 and 3 moves), while the accuracy level between the two groups did not significantly differ. OCD patients required longer initial thinking time also during high demanding tasks (i.e., 4 and 5 moves), but in this case their accuracy was significantly worse than HCs' one. We did not find any association between impulsivity and PAs. Our results supported the hypothesis that OCD patients were not able to retain in memory the planned sequence and they had to reschedule their movements during the execution. Thus, future studies should deepen the interrelation between working memory and PA to better understand the influence between these two cognitive functions and their interaction with clinical variables in OCD patients.

Impaired planning in patients with obsessive-compulsive disorder and unaffected first-degree relatives: Evidence for a cognitive endophenotype

Patients with obsessive-compulsive disorder (OCD) show deficient planning capacity in the Tower of London (TOL) problem solving task. Preliminary evidence for similar deficits in unaffected first-degree relatives suggests that impaired planning may constitute an endophenotype of OCD. However, results on this issue are inconsistent, possibly owing to small sample sizes and variability in problem structure across TOL tasks. Here, we adopted a computerized version of the TOL task featuring a 2 × 2 factorial design (high/low search depth × full/partial tower goal state) and examined a well-characterized sample of n = 72 OCD patients, n = 76 unaffected first-degree relatives and n = 102 healthy comparison subjects. Both OCD patients and relatives exhibited significantly less accurate problem solving than controls. Search depth, goal hierarchy, or the number of minimum moves did not moderate these group differences. Medication, OCD symptoms, and depressive comorbidity did not affect TOL performance in patients, suggesting a state-independent effect. In conclusion, we found that OCD patients as well as unaffected first-degree relatives show deficient TOL performance across a range of task conditions, strongly supporting the role of impaired planning as an endophenotype of OCD, and contributing to the growing evidence for fronto-striatal dysfunctions in OCD.

Relationship of obsessive-compulsive symptoms to clinical variables and cognitive functions in individuals at ultra high risk for psychosis

Few studies have investigated the relationship between obsessive-compulsive symptoms (OCS) and clinical variables, and cognition in individuals at ultra high-risk (UHR) for psychosis. The aim of this study was to evaluate the frequency of OCS and their relationship with clinical variables and cognitive functions in individuals at UHR. Eighty-four individuals at UHR for psychosis were administered the Brief Psychiatric Rating Scale, the Yale-Brown Obsession Compulsion Symptom Check List and, the Calgary Depression Scale for Schizophrenia. A cognitive test battery was also applied. We compared the clinical, functional, and cognitive parameters of individuals at UHR with and without OCS and healthy controls. Thirty-five percent of the UHR sample had at least two obsessions/compulsions. The duration of subthreshold psychotic symptoms was longer in individuals with OCS. Those who can work/study before first presentation were more frequent in OCS-positive group. CDSS scores were higher in those with OCS. Compared to controls, OCS-negative group's performance was worse in 8 cognitive test items, while OCS-positive group performed worse in only one cognitive test item. Our findings suggest that OCS are common in the UHR group. OCS might be related to higher level of depression, but better work/study performance, and less cognitive deficits in UHR group.

Impaired Antisaccades in Obsessive-Compulsive Disorder: Evidence From Meta-Analysis and a Large Empirical Study

Increasing evidence indicates that patients with obsessive-compulsive disorder (OCD) exhibit alterations in fronto-striatal circuitry. Performance deficits in the antisaccade task would support this model, but results from previous small-scale studies have been inconclusive as either increased error rates, prolonged antisaccade latencies, both or neither have been reported in OCD patients. In order to address this issue, we investigated antisaccade performance in a large sample of OCD patients (n = 169) and matched control subjects (n = 183). As impaired antisaccade performance constitutes a potential endophenotype of OCD, unaffected first-degree relatives of OCD patients (n = 100) were assessed, as well. Furthermore, we conducted a quantitative meta-analysis to integrate our data with previous findings. In the empirical study, OCD patients exhibited significantly increased antisaccade latencies, intra-subject variability (ISV) of antisaccade latencies, and antisaccade error rates. The latter effect was driven by errors with express latency (80-130 ms), as patients did not differ significantly from controls with regards to regular errors (>130 ms). Notably, unaffected relatives of OCD patients showed elevated antisaccade express error rates and increased ISV of antisaccade latencies, as well. Antisaccade performance was not associated with state anxiety within groups. Among relatives, however, we observed a significant correlation between antisaccade error rate and harm avoidance. Medication status of OCD patients, symptom severity, depressive comorbidity, comorbid anxiety disorders and OCD symptom dimensions did not significantly affect antisaccade performance. Meta-analysis of 10 previous and the present empirical study yielded a medium-sized effect (SMD = 0.48, p < 0.001) for higher error rates in OCD patients, while the effect for latencies did not reach significance owing to strong heterogeneity (SMD = 0.51, p = 0.069). Our results support the assumption of impaired antisaccade performance in OCD, although effects sizes were only moderately large. Furthermore, we provide the first evidence that increased antisaccade express error rates and ISV of antisaccade latencies may constitute endophenotypes of OCD. Findings regarding these more detailed antisaccade parameters point to potentially underlying mechanisms, such as early pre-stimulus inhibition of the superior colliculus.

Response inhibition and error-monitoring processes in individuals with obsessive-compulsive disorder

Response inhibition (RI) has been putatively linked to the symptoms of OCD. Despite the enticing link between RI and OCD, there are points in the relationship that require clarification. We examined the RI-OCD relationship taking into account a) the potentially differential pattern of RI-OCD relationship between obsessions and compulsions, and b) the potentially confounding effect of negative affect, particularly in regards to depression. Additionally, we investigated how error-monitoring processes in the inhibitory context account for OCD symptoms. Results showed that the RI-OCD relationship is robust in regards to compulsion symptoms, but not for obsessions, even when controlling for negative affect. Additionally, while individuals with OCD display behavioral slow-down following commission errors on the stop-signal task, slow-down following successful inhibition is significantly related to compulsion symptoms. Findings suggest that future studies investigating RI in OCD should take into account heterogeneous clinical presentations in OCD, as well as incorporate error-monitoring variables to better understand RI processes in OCD.

Schizo-obsessive spectrum disorders: an update

The presence of obsessive-compulsive symptoms (OCS) and obsessive-compulsive disorders (OCD) in schizophrenia is frequent, and a new clinical entity has been proposed for those who show the dual diagnosis: the schizo-obsessive disorder. This review scrutinizes the literature across the main academic databases, and provides an update on different aspects of schizo-obsessive spectrum disorders, which include schizophrenia, schizotypal personality disorder (SPD) with OCD, OCD with poor insight, schizophrenia with OCS, and schizophrenia with OCD (schizo-obsessive disorder). An epidemiological discussion on the discrepancies observed in the prevalence of OCS and OCD in schizophrenia across time is provided, followed by an overview of the main clinical and phenomenological features of the disorder in comparison to the primary conditions under a spectral perspective. An updated and comparative analysis of the main genetic, neurobiological, neurocognitive, and pharmacological treatment aspects for the schizo-obsessive spectrum is provided, and a discussion on endophenotypic markers is introduced in order to better understand its substrate. There is sufficient evidence in the literature to demonstrate the clinical relevance of the schizo-obsessive spectrum, although little is known about the neurobiology, genetics, and neurocognitive aspects of these groups. The pharmacological treatment of these patients is still challenging, and efforts to search for possible specific endophenotypic markers would open new avenues in the knowledge of schizo-obsessive spectrum.

Volitional saccade performance in a large sample of patients with obsessive-compulsive disorder and unaffected first-degree relatives

Recent evidence indicates that patients with obsessive-compulsive disorder (OCD) as well as their unaffected first-degree relatives show deficits in the volitional control of saccades, suggesting that volitional saccade performance may constitute an endophenotype of OCD. Here, we aimed to replicate and extend these findings in a large, independent sample. One hundred and fifteen patients with OCD, 103 healthy comparison subjects without a family history of OCD, and 31 unaffected first-degree relatives of OCD patients were examined using structured clinical interviews and performed a volitional saccade task as well as a prosaccade task. In contrast to previous reports, neither patients nor relatives showed impairments in the performance of volitional saccades compared to healthy controls. Notably, medicated patients did not differ from nonmedicated patients, and there was no effect of depressive comorbidity. Additional analyses investigating correlations between saccade performance and OCD symptom dimensions yielded no significant associations. In conclusion, the present results do not support the notion that volitional saccade execution constitutes an endophenotype of OCD. Possible explanations for inconsistencies with previous studies are discussed.

Shared and disorder-specific task-positive and default mode network dysfunctions during sustained attention in paediatric Attention-Deficit/Hyperactivity Disorder and obsessive/compulsive disorder

Patients with Attention-Deficit/Hyperactivity Disorder (ADHD) and obsessive/compulsive disorder (OCD) share problems with sustained attention, and are proposed to share deficits in switching between default mode and task positive networks. The aim of this study was to investigate shared and disorder-specific brain activation abnormalities during sustained attention in the two disorders. Twenty boys with ADHD, 20 boys with OCD and 20 age-matched healthy controls aged between 12 and 18 years completed a functional magnetic resonance imaging (fMRI) version of a parametrically modulated sustained attention task with a progressively increasing sustained attention load. Performance and brain activation were compared between groups. Only ADHD patients were impaired in performance. Group by sustained attention load interaction effects showed that OCD patients had disorder-specific middle anterior cingulate underactivation relative to controls and ADHD patients, while ADHD patients showed disorder-specific underactivation in left dorsolateral prefrontal cortex/dorsal inferior frontal gyrus (IFG). ADHD and OCD patients shared left insula/ventral IFG underactivation and increased activation in posterior default mode network relative to controls, but had disorder-specific overactivation in anterior default mode regions, in dorsal anterior cingulate for ADHD and in anterior ventromedial prefrontal cortex for OCD. In sum, ADHD and OCD patients showed mostly disorder-specific patterns of brain abnormalities in both task positive salience/ventral attention networks with lateral frontal deficits in ADHD and middle ACC deficits in OCD, as well as in their deactivation patterns in medial frontal DMN regions. The findings suggest that attention performance in the two disorders is underpinned by disorder-specific activation patterns.

Cognitive dysfunction in body dysmorphic disorder: new implications for nosological systems and neurobiological models

Introduction Body dysmorphic disorder (BDD) is a debilitating disorder, characterized by obsessions and compulsions relating specifically to perceived appearance, and which has been newly classified within the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) Obsessive-Compulsive and Related Disorders grouping. Until now, little research has been conducted into the cognitive profile of this disorder.

METHODS

Participants with BDD (n=12) and participants without BDD (n=16) were tested using a computerized neurocognitive battery investigating attentional set-shifting (Intra/Extra Dimensional Set Shift Task), decision-making (Cambridge Gamble Task), motor response-inhibition (Stop-Signal Reaction Time Task), and affective processing (Affective Go-No Go Task). The groups were matched for age, IQ, and education.

RESULTS

In comparison to controls, patients with BDD showed significantly impaired attentional set-shifting, abnormal decision-making, impaired response inhibition, and greater omission and commission errors on the emotional processing task.

CONCLUSION

Despite the modest sample size, our results showed that individuals with BDD performed poorly compared to healthy controls on tests of cognitive flexibility, reward and motor impulsivity, and affective processing. Results from separate studies in OCD patients suggest similar cognitive dysfunction. Therefore, these findings are consistent with the reclassification of BDD alongside OCD. These data also hint at additional areas of decision-making abnormalities that might contribute specifically to the psychopathology of BDD.

Cognitive Dysfunction in Obsessive-Compulsive Disorder

Obsessive-compulsive disorder (OCD) is a mental disorder featuring obsessions (intrusive thoughts) and compulsions (repetitive behaviors performed in the context of rigid rituals). There is strong evidence for a neurobiological basis of this disorder, involving limbic cortical regions and related basal ganglion areas. However, more research is needed to lift the veil on the precise nature of that involvement and the way it drives the clinical expression of OCD. Altered cognitive functions may underlie the symptoms and thus draw a link between the clinical expression of the disorder and its neurobiological etiology. Our extensive review demonstrates that OCD patients do present a broad range of neuropsychological dysfunctions across all cognitive domains (memory, attention, flexibility, inhibition, verbal fluency, planning, decision-making), but some methodological issues temper this observation. Thus, future research should have a more integrative approach to cognitive functioning, gathering contributions of both experimental psychology and more fundamental neurosciences.

Are obsessive-compulsive symptoms impulsive, compulsive or both?

BACKGROUND

The relationships between obsessive-compulsive symptoms and distinct forms of impulsivity and compulsivity are unclear. Such examination would be relevant in terms of how best to classify psychiatric disorders and in understanding candidate 'traits' that extend across a continuum between normalcy and clinical disorders.

METHOD

515 young adults (aged 18-29years) completed the Padua Inventory and undertook detailed clinical and neurocognitive assessments. Relationships between obsessive-compulsive symptoms and distinct types of impulsivity and compulsivity were evaluated using linear regression modeling.

RESULTS

Obsessive-Compulsive symptoms were significantly predicted by female gender, lower quality of life, psychiatric disorders in general (but not impulse control disorders), and worse extra-dimensional set-shifting. Obsessive-Compulsive symptoms were not significantly predicted by alcohol/nicotine consumption, stop-signal reaction times, or decision-making abilities.

CONCLUSION

These data indicate that obsessive-compulsive symptoms are more related to certain forms of compulsivity than to impulsivity. These findings have important implications for diagnostic conceptualizations and neurobiological models.

Executive functions as a potential neurocognitive endophenotype in anxiety disorders: A systematic review considering DSM-IV and DSM-5 diagnostic criteria classification

Evidence in the literature indicates that neurocognitive impairments may represent endophenotypes in psychiatric disorders.

Objective

This study aimed to conduct a systematic review on executive functions as a potential neurocognitive endophenotype in anxiety disorder diagnosis according to the DSM-IV and DSM-5 classifications.

Methods

A literature search of the LILACS, Cochrane Library, Index Psi Periódicos Técnico-Científicos, PubMed and PsycInfo databases was conducted, with no time limits. Of the 259 studies found, 14 were included in this review.

Results

Only studies on obsessive-compulsive disorder (OCD) were found. The executive function components of decision-making, planning, response inhibition, behavioral reversal/alternation, reversal learning and set-shifting/cognitive flexibility were considered to be a neurocognitive endophenotypes in OCD.

Conclusion

Further studies on executive functions as a neurocognitive endophenotype in other anxiety disorders are needed since these may have different neurocognitive endophenotypes and require other prevention and treatment approaches.

Are there reliable changes in memory and executive functions after cognitive behavioural therapy in patients with obsessive-compulsive disorder?

INTRODUCTION

Patients with obsessive-compulsive disorder (OCD) have impaired memory and executive functions, but it is unclear whether these functions improve after cognitive behavioural therapy (CBT) of OCD symptoms. The primary aim of this study was to investigate whether memory and executive functions change after CBT in patients with OCD.

METHODS

We assessed 39 patients with OCD before and after CBT with neuropsychological tests of memory and executive functions. To correct for practice effects, 39 healthy controls (HCs) were assessed at two parallel time intervals with the neuropsychological tests.

RESULTS

There were no changes in memory and executive functions after CBT in patients with OCD when results were corrected for practice effects. Patients performed worse on a test of visuospatial memory and organisational skills (Rey complex figure test [RCFT]) compared to HCs both before and after CBT (ps = .002-.036).

CONCLUSIONS

The finding of persistent poor RCFT performances indicates that patients with OCD have impaired visuospatial memory and organisational skills that may be trait-related rather than state-dependent. These impairments may need to be considered in treatment. Our findings underline the importance of correcting for practice effects when investigating changes in cognitive functions.

Dissociation of decision making under ambiguity and decision making under risk: a neurocognitive endophenotype candidate for obsessive-compulsive disorder

Evidence in the literature suggests that executive dysfunction is regarded as an endophenotype candidate for obsessive-compulsive disorder (OCD). Decision making is an important domain of executive function. However, few studies that have investigated whether decision making is a potential endophenotype for OCD have produced inconsistent results. Differences in the findings across these studies may be attributed to several factors: different study materials, comorbidity, medication, etc. There are at least two types of decision making that differ mainly in the degree of uncertainty and how much useful information about consequences and their probabilities are provided to the decision maker: decision making under ambiguity and decision making under risk. The aim of the present study was to simultaneously examine decision making under ambiguity as assessed by the Iowa Gambling Task (IGT) and decision making under risk as measured by the Game of Dice Task (GDT) in OCD patients and their unaffected first-degree relative (UFDR) for the first time. The study analyzed 55 medication-naïve, non-depressed OCD patient probands, 55 UFDRs of the OCD patients and 55 healthy matched comparison subjects (CS) without a family history of OCD with the IGT, the GDT and a neuropsychological test battery. While the OCD patients and the UFDRs performed worse than the CS on the IGT, they were unimpaired on the GDT. Our study supports the claim that decision making under ambiguity differs from decision making under risk and suggests that dissociation of decision making under ambiguity and decision making under risk may qualify to be a neurocognitive endophenotypes for OCD.

Compensatory frontoparietal activity during working memory: an endophenotype of obsessive-compulsive disorder

BACKGROUND

Subtle deficits in executive functioning are present in patients with obsessive-compulsive disorder (OCD) and their first-degree relatives, suggesting involvement of the frontoparietal circuits. The neural correlates of working memory may be a neurocognitive endophenotype of OCD.

METHODS

Forty-three unmedicated OCD patients, 17 unaffected siblings, and 37 matched comparison subjects performed a visuospatial n-back task, with a baseline condition (N0) and three working memory load levels (N1, N2, N3) during functional magnetic resonance imaging. Task-related brain activity was compared between groups in frontoparietal regions of interest. Generalized psychophysiological interaction analyses were used to study task-related changes in functional connectivity.

RESULTS

Obsessive-compulsive disorder patients, compared with comparison subjects and siblings, showed increased error rates at N3. Compared with comparison subjects, OCD patients showed task-related hyperactivation in left dorsal frontal areas and left precuneus associated with better task performance. Siblings exhibited hyperactivation in a bilateral frontoparietal network. Increased task load was associated with increased task-related brain activity, but in OCD patients and siblings this increase was smaller from load N2 to N3 than in comparison subjects. Obsessive-compulsive disorder patients, compared with siblings and comparison subjects, showed increased task-related functional connectivity between frontal regions and bilateral amygdala.

CONCLUSIONS

These findings indicate that compensatory frontoparietal brain activity in OCD patients and their unaffected relatives preserves task performance at low task loads but is insufficient to maintain performance at high task loads. Frontoparietal dysfunction may constitute a neurocognitive endophenotype for OCD, possibly reflecting limbic interference with and neural inefficiency within the frontoparietal network.

Obsessive-compulsive symptoms in at-risk mental states for psychosis: associations with clinical impairment and cognitive function

OBJECTIVE

Obsessive-compulsive symptoms (OCS) constitute a major comorbidity in schizophrenia. Prevalence estimations of OCS for patients with at-risk mental states (ARMS) for psychosis vary largely. It is unclear how ARMS patients with or without comorbid OCS differ regarding general psychosocial functioning, psychotic and affective symptoms and neurocognitive abilities.

METHOD

At-risk mental states patients (n = 233) from the interventional trial PREVENT (Secondary Prevention of Schizophrenia) were stratified according to the presence or absence of comorbid OCS and compared on several clinical variables.

RESULTS

Patients, who fulfilled the criteria for obsessive-compulsive disorder (OCD) or presented with subclinical OCS (ARMSposOCS sample), did not significantly differ from patients without OCS (ARMSnegOCS) with regard to gender, age, premorbid verbal intelligence and levels of education. Furthermore, similar severity of depressive syndromes, basic cognitive, attenuated psychotic and brief limited intermittent psychotic symptoms were found. However, ARMSposOCS patients showed more impairment of psychosocial functioning and higher general psychopathology. In contrast, they scored higher in cognitive tasks measuring working memory and immediate verbal memory.

CONCLUSION

Findings extend upon previous results due to the multidimensional assessment. Subsequent longitudinal studies might elucidate how comorbid OCS influence differential treatment response, especially to cognitive behavioural interventions and the transition rates to psychosis.

Resting-state functional connectivity abnormalities in patients with obsessive-compulsive disorder and their healthy first-degree relatives

BACKGROUND

Obsessive-compulsive disorder (OCD) is a common, heritable neuropsychiatric disorder, hypothetically underpinned by dysfunction of brain cortical-striatal-thalamic-cortical (CSTC) circuits; however, the extent of brain functional abnormalities in individuals with OCD is unclear, and the genetic basis of this disorder is poorly understood. We determined the whole brain functional connectivity patterns in patients with OCD and their healthy first-degree relatives.

METHODS

We used resting-state fMRI to measure functional connectivity strength in patients with OCD, their healthy first-degree relatives and healthy controls. Whole brain functional networks were constructed by measuring the temporal correlations of all brain voxel pairs and further analyzed using a graph theory approach.

RESULTS

We enrolled 39 patients with OCD, 20 healthy first-degree relatives and 39 healthy controls in our study. Compared with healthy controls, patients with OCD showed increased functional connectivity primarily within the CSTC circuits and decreased functional connectivity in the occipital cortex, temporal cortex and cerebellum. Moreover, patients with OCD and their first-degree relatives exhibited overlapping increased functional connectivity strength in the bilateral caudate nucleus, left orbitofrontal cortex (OFC) and left middle temporal gyrus.

LIMITATIONS

Potential confounding factors, such as medication use, heterogeneity in symptom clusters and comorbid disorders, may have impacted our findings.

CONCLUSION

Our preliminary results suggest that patients with OCD have abnormal resting-state functional connectivity that is not limited to CSTC circuits and involves abnormalities in additional large-scale brain systems, especially the limbic system. Moreover, resting-state functional connectivity strength abnormalities in the left OFC, bilateral caudate nucleus and left middle temporal gyrus may be neuroimaging endophenotypes for OCD.

Obsessive-compulsive disorder is associated with broad impairments in executive function: A meta-analysis

Obsessive-compulsive disorder (OCD) is a serious and often chronically disabling condition. The current dominant model of OCD focuses on abnormalities in prefrontal-striatal circuits that support executive function (EF). While there is growing evidence for EF impairments associated with OCD, results have been inconsistent, making the nature and magnitude of these impairments controversial. The current meta-analysis uses random-effects models to synthesize 110 previous studies that compared participants with OCD to healthy control participants on at least one neuropsychological measure of EF. The results indicate that individuals with OCD are impaired on tasks measuring most aspects of EF, consistent with broad impairment in EF. EF deficits were not explained by general motor slowness or depression. Effect sizes were largely stable across variation in demographic and clinical characteristics of samples, although medication use, age, and gender moderated some effects.

Comorbid Obsessive-Compulsive Symptoms in Schizophrenia: Insight into Pathomechanisms Facilitates Treatment

Insight into the biological pathomechanism of a clinical syndrome facilitates the development of effective interventions. This paper applies this perspective to the important clinical problem of obsessive-compulsive symptoms (OCS) occurring during the lifetime diagnosis of schizophrenia. Up to 25% of schizophrenia patients suffer from OCS and about 12% fulfil the diagnostic criteria of obsessive-compulsive disorder (OCD). This is accompanied by marked subjective burden of disease, high levels of anxiety, depression and suicidality, increased neurocognitive impairment, less favourable levels of social and vocational functioning, and greater service utilization. Comorbid patients can be assigned to heterogeneous subgroups. It is assumed that second generation antipsychotics (SGAs), most importantly clozapine, might aggravate or even induce second-onset OCS. Several epidemiological and pharmacological arguments support this assumption. Specific genetic risk factors seem to dispose patients with schizophrenia to develop OCS and risk-conferring polymorphisms has been defined in SLC1A1, BDNF, DLGAP3, and GRIN2B and in interactions between these individual genes. Further research is needed with detailed characterization of large samples. In particular interactions between genetic risk constellations, pharmacological and psychosocial factors should be analysed. Results will further define homogeneous subgroups, which are in need for differential causative interventions. In clinical practise, schizophrenia patients should be carefully monitored for OCS, starting with at-risk mental states of psychosis and longitudinal follow-ups, hopefully leading to the development of multimodal therapeutic interventions.

Cognitive functioning in obsessive-compulsive disorder: a meta-analysis

BACKGROUND

Substantial empirical evidence has indicated impairment in the cognitive functioning of patients with obsessive-compulsive disorder (OCD) despite inconsistencies. Although several confounding factors have been investigated to explain the conflicting results, the findings remain mixed. This study aimed to investigate cognitive dysfunction in patients with OCD using a meta-analytic approach.

METHOD

The PubMed database was searched between 1980 and October 2012, and reference lists of review papers were examined. A total of 221 studies were identified, of which 88 studies met inclusion criteria. Neuropsychological performance and demographic and clinical variables were extracted from each study.

RESULTS

Patients with OCD were significantly impaired in tasks that measured visuospatial memory, executive function, verbal memory and verbal fluency, whereas auditory attention was preserved in these individuals. The largest effect size was found in the ability to recall complex visual stimuli. Overall effect estimates were in the small to medium ranges for executive function, verbal memory and verbal fluency. The effects of potentially confounding factors including educational level, symptom severity, medication status and co-morbid disorders were not significant.

CONCLUSIONS

Patients with OCD appear to have wide-ranging cognitive deficits, although their impairment is not so large in general. The different test forms and methods of testing may have influenced the performance of patients with OCD, indicating the need to select carefully the test forms and methods of testing used in future research. The effects of various confounding variables on cognitive functioning need to be investigated further and to be controlled before a definite conclusion can be made.

5-HT3 receptor influences the washing phenotype and visual organization in obsessive-compulsive disorder supporting 5-HT3 receptor antagonists as novel treatment option

A role of the HTR3A-E genes in obsessive-compulsive disorder (OCD) can be expected based on promising effects of 5-HT3 receptor antagonists as adjunctive treatment of OCD. We therefore genotyped six common coding or promoter variants within the HTR3A-E genes in a case-control-sample consisting of N=236 OCD patients and N=310 control subjects and in N=58 parent-child-trios. Given the heterogeneous OCD phenotype, we also investigated OCD symptom dimensions and cognitive endophenotypes in subsamples. OCD patients scoring high for the washing subtype were significantly more likely to carry the c.256G-allele of the HTR3E variant rs7627615 (p=0.0001) as compared to OCD patients low for this symptom dimension. Visual organization was impaired in OCD patients and unaffected relatives as compared to healthy control subjects and carriers of the HTR3E c.256G/c.256G-genotype performed significantly worse (p=0.007). The case-control analyses revealed a nominal significant association of the HTR3D variant rs1000592 (p.H52R) with OCD (p=0.029) which was also evident after combination of the case-control and the trio-results (p=0.024). In male subjects, the variant rs6766410 (p.N163K) located in the HTR3C was significantly associated with OCD (p=0.007). The association findings of the HTR3C and the HTR3E remained significant after correction for the number of variants investigated. These findings indicate a role of common variants of the HTR3A-E genes in OCD and OCD-related phenotypes and further support the use of 5-HT3 receptor antagonists as novel treatment options. The HTR3E gene is a novel candidate gene impacting on the individual expression of OC symptoms and OCD-related cognitive dysfunction.

Stable cognitive deficits in schizophrenia patients with comorbid obsessive-compulsive symptoms: a 12-month longitudinal study

BACKGROUND

Amongst schizophrenia patients, a large subgroup of up to 25% also suffers from comorbid obsessive-compulsive symptoms (OCSs). The association between comorbid OCSs in these patients and neuropsychological impairment remains unclear and somewhat contradictory. Longitudinal approaches investigating the stability of OCS-associated cognitive deficits are missing.

METHODS

Thirty-seven patients with schizophrenia and comorbid OCSs and 43 schizophrenia patients without OCS were assessed with a comprehensive cognitive test battery and compared at baseline and, again, 12 months later.

RESULTS

Schizophrenia patients with comorbid OCSs showed significant pronounced deficits, with increasing effect sizes over the 12-month assessment period in specific cognitive areas such as visuospatial perception and visual memory (WAIS-R block design, Rey-Osterrieth Complex Figure Test), executive functioning (perseveration in the Wisconsin Card Sorting test), and cognitive flexibility (Trail Making test B). These cognitive domains are correlated with OCS severity and are known to be candidate cognitive domains in obsessive-compulsive disorder (OCD).

CONCLUSIONS

OCSs in schizophrenia is associated with specific and longitudinally stable cognitive deficits, strongly arguing for at least partially overlapping neurobiological mechanisms with OCD. Prospective studies involving patients with at-risk mental states for psychosis are necessary to decipher the interaction of cognitive impairment and the clinical manifestations of schizophrenia and OCSs. This might facilitate the definition of patients at high risk for OCSs, an early detection of subclinical levels, therapeutic interventions, and clinical monitoring.

Comorbid obsessive-compulsive symptoms in schizophrenia: contributions of pharmacological and genetic factors

A large subgroup of around 25% of schizophrenia patients suffers from obsessive-compulsive symptoms (OCS) and about 12% fulfill the diagnostic criteria of an obsessive-compulsive disorder (OCD). The additional occurrence of OCS is associated with high subjective burden of disease, additional neurocognitive impairment, poorer social and vocational functioning, greater service utilization and high levels of anxiety and depression. Comorbid patients can be assigned to heterogeneous subgroups. One hypothesis assumes that second generation antipsychotics (SGAs), most importantly clozapine, might aggravate or even induce second-onset OCS. Several arguments support this assumption, most importantly the observed chronological order of first psychotic manifestation, start of treatment with clozapine and onset of OCS. In addition, correlations between OCS-severity and dose and serum levels and duration of clozapine treatment hint toward a dose-dependent side effect. It has been hypothesized that genetic risk-factors dispose patients with schizophrenia to develop OCS. One study in a South Korean sample reported associations with polymorphisms in the gene SLC1A1 (solute carrier family 1A1) and SGA-induced OCS. However, this finding could not be replicated in European patients. Preliminary results also suggest an involvement of polymorphisms in the BDNF gene (brain-derived neurotrophic factor) and an interaction between markers of SLC1A1 and the gene DLGAP3 (disc large associated protein 3) as well as GRIN2B (N-methyl-D-aspartate receptor subunit 2B). Further research of well-defined samples, in particular studies investigating possible interactions of genetic risk-constellations and pharmacodynamic properties, are needed to clarify the assumed development of SGA-induced OCS. Results might improve pathogenic concepts and facilitate the definition of at risk populations, early detection and monitoring of OCS as well as multimodal therapeutic interventions.

Molecular genetics of obsessive-compulsive disorder: a comprehensive meta-analysis of genetic association studies

Twin studies indicate that obsessive-compulsive disorder (OCD) is strongly influenced by additive genetic factors. Yet, molecular genetic association studies have yielded inconsistent results, possibly because of differences across studies in statistical power. Meta-analysis can yield greater power. This study reports the first comprehensive meta-analysis of the relationship between OCD and all previously examined polymorphisms for which there was sufficient information in the source studies to compute odds ratios (ORs). A total of 230 polymorphisms from 113 genetic association studies were identified. A full meta-analysis was conducted for 20 polymorphisms that were examined in 5 or more data sets, and a secondary meta-analysis (limited to the computation of mean effect sizes) was conducted for 210 polymorphisms that were examined in fewer than 5 data sets. In the main meta-analysis, OCD was associated with serotonin-related polymorphisms (5-HTTLPR and HTR2A) and, in males only, with polymorphisms involved in catecholamine modulation (COMT and MAOA). Nonsignificant trends were identified for two dopamine-related polymorphisms (DAT1 and DRD3) and a glutamate-related polymorphism (rs3087879). The secondary meta-analysis identified another 18 polymorphisms with significant ORs that merit further investigation. This study demonstrates that OCD is associated with multiple genes, with most having a modest association with OCD. This suggests a polygenic model of OCD, consistent with twin studies, in which multiple genes make small, incremental contributions to the risk of developing the disorder. Future studies, with sufficient power to detect small effects, are needed to investigate the genetic basis of OCD subtypes, such as early vs late onset OCD.

Impaired volitional saccade control: first evidence for a new candidate endophenotype in obsessive-compulsive disorder

Recent research suggests that patients with obsessive-compulsive disorder (OCD) have deficits in the volitional control of saccades. Specific evidence comes from increased latencies of saccadic eye movements when they were volitionally executed but not when they were visually guided. The present study sought to test whether this deviance represents a cognitive endophenotype. To this end, first-degree relatives of OCD patients as genetic risk carriers were compared with OCD patients and healthy controls without a family history of OCD. Furthermore, as volitional response generation comprises selection and initiation of the required response, the study also sought to specify the cognitive mechanisms underlying impaired volitional response generation. Twenty-two unaffected first-degree relatives of OCD patients, 22 unmedicated OCD patients, and 22 healthy comparison subjects performed two types of volitional saccade tasks measuring response selection or only response initiation, respectively. Visually guided saccades were used as a control condition. Our results showed that unaffected first-degree relatives and OCD patients were significantly slowed compared to healthy comparison subjects in volitional response selection. Patients and relatives did not differ from each other. There was no group difference in the visually guided control condition. Taken together, the study provides first evidence that dysfunctional volitional response selection is a candidate endophenotype for 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.

Neuropsychological predictors of response to randomized treatment in obsessive-compulsive disorder

OBJECTIVE

To identify neuropsychological predictors of treatment response to cognitive-behavioral therapy (CBT) and fluoxetine in treatment-naïve adults with obsessive-compulsive disorder (OCD).

METHOD

Thirty-eight adult outpatients with OCD underwent neuropsychological assessment, including tasks of intellectual function, executive functioning and visual and verbal memory, before randomization to a 12-week clinical trial of either CBT or fluoxetine. Neuropsychological measures were used to identify predictors of treatment response in OCD.

RESULTS

Neuropsychological measures that predicted a better treatment response to either CBT or fluoxetine were higher verbal IQ (Wechsler Abbreviated Scale of Intelligence) (p=0.008); higher verbal memory on the California Verbal Learning Test (p=0.710); shorter time to complete part D (Dots) (p<0.001), longer time to complete part W (Words) (p=0.025) and less errors on part C (Colors) (p<0.001) in the Victoria Stroop Test (VST). Fewer perseverations on the California Verbal Learning Test, a measure of mental flexibility, predicted better response to CBT, but worse response to fluoxetine (p=0.002).

CONCLUSION

In general, OCD patients with better cognitive and executive abilities at baseline were more prone to respond to either CBT or fluoxetine. Our finding that neuropsychological measures of mental flexibility predicted response to treatment in opposite directions for CBT and fluoxetine suggests that OCD patients with different neuropsychological profiles may respond preferentially to one type of treatment versus the other. Further studies with larger samples of OCD patients are necessary to investigate the heuristic value of such findings in a clinical context.

Antisaccade performance in patients with obsessive-compulsive disorder and unaffected relatives: further evidence for impaired response inhibition as a candidate endophenotype

Cognitive dysfunctions such as inhibitory deficits and visuospatial abnormalities are often found in patients with obsessive-compulsive disorder (OCD). Recent findings in unaffected relatives indicate that response inhibition and other neuropsychological functions may also constitute endophenotypes of OCD. In the present study, 30 OCD patients, 30 first-degree relatives, and 30 healthy control subjects were assessed using a comprehensive neuropsychological test battery. A subsample of 21 subjects of each group also performed an antisaccade task. The samples were matched according to age, gender, education, and verbal intelligence. The OCD patients and the unaffected OCD relatives showed increased antisaccade error rates compared with the healthy control group (p = 0.003, p = 0.028, respectively). Significantly prolonged antisaccade latencies as compared to prosaccade latencies were only found in the OCD patients compared with the healthy control group (p = 0.019). Only OCD patients but not the unaffected OCD relatives were impaired with regard to visuospatial functions, problem-solving, and processing speed. Antisaccade errors did not correlate with severity of OCD or depressive symptoms. This study confirms inhibitory deficits, as indicated by increased antisaccade error rates, as a candidate endophenotype of OCD. In agreement with previous findings from imaging studies, our data suggest that functional abnormalities in frontostriatal and parietal cortical regions form part of the vulnerability for OCD.

Neuropsychological study of patients with obsessive-compulsive disorder and their parents in China: searching for potential endophenotypes

OBJECTIVE

The existence of neuropsychological deficits has been implicated in obsessive-compulsive disorder (OCD), particularly memory, attention, and executive functions. However, few studies have focused on neuropsychological deficits in the relatives of OCD patients. The aim of this study was to investigate cognitive deficits in OCD patients and their parents.

METHODS

Forty patients with OCD, 48 parents of these patients, and 87 healthy controls completed a neuropsychological testing battery.

RESULTS

Both OCD patients and their parents showed impairments in delayed verbal memory and delayed visual memory. Furthermore, they performed worse than healthy controls in problem-solving ability.

CONCLUSION

Our study demonstrated familial aggregation of delayed memory deficits and impaired problem-solving ability, which may be the potential neuropsychological endophenotypes of hereditary susceptibility to OCD.