Meta-analysis is a statistical tool used to combine and synthesise the results of multiple independent studies on a particular topic. To this end, researchers isolate important moderators and mediators to investigate their influence on outcomes. This paper introduces a novel approach to meta-analysis, known as multidimensional meta-analysis (mi-MA), to study memory performance in those with obsessive-compulsive disorder (OCD). Unlike traditional meta-analyses, mi-MA allows researchers to extract multiple data points (e.g., using different measures) from single studies and groups of participants, facilitating the exploration of relationships between various moderators while avoiding multicollinearity issues. Therefore, in the first instance, we outline the use of the mi-MA approach to quantify the impact of complex models of memory performance in individuals with OCD. This approach provides novel insights into the complex relationship between various factors affecting memory in people with OCD. By showcasing the effectiveness of mi-MA in analysing intricate data and modelling complex phenomena, the paper establishes it as a valuable tool for researchers exploring multifaceted phenomena, both within OCD research and beyond.

Background/Objectives: Tourette Syndrome (TS), Obsessive Compulsive Disorder (OCD), and Body-Focused Repetitive Behaviors (BFRB) are three disorders that share many similarities in terms of phenomenology, neuroanatomy, and functionality. However, despite the literature pointing toward a plausible spectrum of these disorders, only a few studies have compared them. Studying the neurocognitive processes using Event-Related Potentials (ERPs) offers the advantage of assessing brain activity with excellent temporal resolution. The ERP components can then reflect specific processes known to be potentially affected by these disorders. Our first goal is to characterize 'when' in the processing stream group differences are the most prominent. The second goal is to identify 'where' in the brain the group discrepancies could be. Methods: Participants with TS (n = 24), OCD (n = 18), and BFRB (n = 16) were matched to a control group (n = 59) and were recorded with 58 EEG electrodes during a visual counting oddball task. Three ERP components were extracted (i.e., P200, N200, and P300), and generating sources were modelized with Standardized Low-Resolution Electromagnetic Tomography. Results: We showed no group differences for the P200 and N200 when controlling for anxiety and depressive symptoms, suggesting that the early cognitive processes reflected by these components are relatively intact in these populations. Our results also showed a decrease in the later anterior P300 oddball effect for the TS and OCD groups, whereas an intact oddball effect was observed for the BFRB group. Source localization analyses with sLORETA revealed activations in the lingual and middle occipital gyrus for the OCD group, distinguishing it from the other two clinical groups and the controls. Conclusions: It seems that both TS and OCD groups share deficits in anterior P300 activation but reflect distinct brain-generating source activations.

How well do we distinguish between different memory sources when the information from imagination and perception is similar? And how do metacognitive (confidence) judgments differ across different sources of experiences? To study these questions, we developed a reality monitoring task using semantically related words from the Deese-Roediger-McDermott (DRM) paradigm of false memories. In an orientation phase, participants either perceived word pairs or had to voluntarily imagine the second word of a word pair. In a test phase, participants viewed words and had to judge whether the paired word was previously perceived, imagined, or new. Results revealed an interaction between memory source and judgment type on both response rates and confidence judgments: reality monitoring was better for new and perceived (compared to imagined) sources, and participants often incorrectly reported imagined experiences to be perceived. Individuals exhibited similar confidence between correct imagined source judgments and incorrect imagined sources reported to be perceived. Modeling results indicated that the observed judgments were likely due to an externalizing bias (i.e., a bias to judge the memory source as perceived). Additionally, we found that overall metacognitive ability was best in the perceived source. Together, these results reveal a source-dependent effect on response rates and confidence ratings, and provide evidence that observers are surprisingly prone to externalizing biases when monitoring their own memories.

Aberrations to metacognition-the ability to reflect on and evaluate self-performance-are a feature of poor mental health. Theoretical models of post-traumatic stress disorder propose that following severe stress or trauma, maladaptive metacognitive evaluations and appraisals of the event drive the development of symptoms. Empirical research is required in order to reveal whether disruptions to metacognition cause or contribute to symptom development in line with theoretical accounts, or are simply a consequence of ongoing psychopathology. In two experiments, using hierarchical Bayesian modelling of metacognition measured in a memory recognition task, we assessed whether distortions to metacognition occur at a state-level after an acute stress induction, and/or at a trait-level in a sample of individuals experiencing intrusive memories following traumatic stress. Results from experiment 1, an in-person laboratory-based experiment, demonstrated that heightened psychological responses to the stress induction were associated with poorer metacognitive efficiency, despite there being no overall change in metacognitive efficiency from pre- to post-stress (N = 27). Conversely, in experiment 2, an online experiment using the same metamemory task, we did not find evidence of metacognitive alterations in a transdiagnostic sample of patients with intrusive memory symptomatology following traumatic stress (N = 36, compared to 44 matched controls). Our results indicate a relationship between state-level psychological responses to stress and metacognitive alterations. The lack of evidence for pre- to post-stress differences in metamemory illustrates the importance for future studies to reveal the direction of this relationship, and consequently the duration of stress-associated metacognitive impairments and their impact on mental health.

It is clear evidence that individuals diagnosed with obsessive-compulsive disorder (OCD) lack confidence in their memory and have low metamemory performance (judgment and accuracy). However, it is still unclear whether low metamemory performance is specific to first, domain general or domain specific, and second, to stimulus domain. To address these issues, we compared individuals diagnosed with OCD and healthy controls (HCs) on recognition, retrospective (judgments of learning [JOL]) and prospective (feeling of knowing [FOK]) metamemory judgments and under three different episodic memory tasks, which consisted of symptom-free, familiar and unfamiliar stimuli (word, scene, and face photo). OCD patients showed lower recognition performance, JOL and FOK judgments, and accuracy in all tasks than HCs. Also, OCD patients were slower than HCs during all cognitive performances. In both groups, metamemory performances were lower in familiar items than unfamiliar items. However, recognition performances were not affected by stimulus type. Our results support the idea of general episodic memory and a metamemory deficit in OCD. Moreover, metamemory deficits in OCD are domain general.

Obsessive-compulsive disorder (OCD) is often characterized by rigidity regarding rules and perfectionism, which suggests a formal reasoning style. However, other characterizations suggest an overreliance on internal cues for behavior termination, which suggests a more intuitive reasoning style. We examine reasoning styles in OCD by assessing categorization preferences traditionally classified to rule-based and family resemblance categorization.

An initial study (n = 41) and an online replication (n = 85) were conducted. In both studies, groups scoring high and low on OCD symptoms were compared. Categorization preferences and confidence ratings were examined via a modification of a classic categorization task. The task was administered in three conditions: under time limits, with no time limits, and with explicit explanation of both categorization styles.

Aggregating results from both studies showed that obsessive-compulsive symptoms were associated with a reduced preference for rule-based categorization reflecting a tendency towards a more intuitive, non-formal reasoning style. This preference was apparent even when rules were explicitly described. Group differences regarding confidence were inconclusive.

Generalizing results to the clinical population requires further research, and specificity to OC symptoms should be determined.

Challenging the expected association between OCD and rigidity and perfectionism, findings support suggestions that OCD reasoning strays from formal reasoning. This may explain some of the subjective and idiosyncratic rules adopted by individuals with OCD.

People with obsessive-compulsive disorder (OCD) tend to distrust their memory, perception, and other cognitive functions, and many OCD symptoms can be traced to diminished confidence in one's cognitive processes. For example, poor confidence in recall accuracy can cause doubt about one's memory and motivate repeated checking. At the same time, people with OCD also display performance deficits in a variety of cognitive tasks, so their reduced confidence must be evaluated in relation to their actual performance. To that end, we conducted an exhaustive review and meta-analysis of studies in which OCD participants and non-clinical control participants performed cognitive tasks and reported their confidence in their performance. Our search resulted in 19 studies that met criteria for inclusion in the quantitative analysis, with all studies addressing either memory or perception. We found that both performance and reported confidence were lower in OCD than in control participants. Importantly, however, confidence was more impaired than performance in participants with OCD. These findings suggest that people with OCD are less confident in their memory and perception than they should be, indicating a genuine under-confidence in this population. We discuss potential mechanisms that might account for this finding and suggest avenues for further research into under-confidence and related meta-cognitive characteristics of OCD.

Human behaviours are guided by how confident we feel in our abilities. When confidence does not reflect objective performance, this can impact critical adaptive functions and impair life quality. Distorted decision-making and confidence have been associated with mental health problems. Here, utilising advances in computational and transdiagnostic psychiatry, we sought to map relationships between psychopathology and both decision-making and confidence in the general population across two online studies (N's = 344 and 473, respectively). The results revealed dissociable decision-making and confidence signatures related to distinct symptom dimensions. A dimension characterised by compulsivity and intrusive thoughts was found to be associated with reduced objective accuracy but, paradoxically, increased absolute confidence, whereas a dimension characterized by anxiety and depression was associated with systematically low confidence in the absence of impairments in objective accuracy. These relationships replicated across both studies and distinct cognitive domains (perception and general knowledge), suggesting that they are reliable and domain general. Additionally, whereas Big-5 personality traits also predicted objective task performance, only symptom dimensions related to subjective confidence. Domain-general signatures of decision-making and metacognition characterise distinct psychological dispositions and psychopathology in the general population and implicate confidence as a central component of mental health.

Metacognition is the ability to reflect on our own cognition and mental states. It is a critical aspect of human subjective experience and operates across many hierarchical levels of abstraction-encompassing local confidence in isolated decisions and global self-beliefs about our abilities and skills. Alterations in metacognition are considered foundational to neurologic and psychiatric disorders, but research has mostly focused on local metacognitive computations, missing out on the role of global aspects of metacognition. Here, we first review current behavioral and neural metrics of local metacognition that lay the foundation for this research. We then address the neurocognitive underpinnings of global metacognition uncovered by recent studies. Finally, we outline a theoretical framework in which higher hierarchical levels of metacognition may help identify the role of maladaptive metacognitive evaluation in mental health conditions, particularly when combined with transdiagnostic methods.

Obsessive-Compulsive Disorder (OCD) is a leading cause of disability world-wide (World Health Organization, 2008). Treatment of OCD is a specialized field whose aim is recovery from illness for as many patients as possible. The evidence-based psychotherapeutic treatment for OCD is specialized cognitive behavior therapy (CBT, NICE, 2005, Koran and Simpson, 2013). However, these treatments are not accessible to many sufferers around the world. Currently available guidelines for care are deemed to be essential but insufficient because of highly variable clinician knowledge and competencies specific to OCD. The phase two mandate of the 14 nation International OCD Accreditation Task Force (ATF) created by the Canadian Institute for Obsessive Compulsive Disorders is development of knowledge and competency standards for specialized treatments for OCD through the lifespan deemed by experts to be foundational to transformative change in this field. This paper presents knowledge and competency standards for specialized CBT for adult OCD developed to inform, advance, and offer a model for clinical practice and training for OCD. During upcoming ATF phases three and four criteria and processes for training in specialized treatments for OCD through the lifespan for certification (individuals) and accreditation (sites) will be developed based on the ATF standards.

We reviewed studies that have specifically explored the memory deficit hypothesis of Obsessive Compulsive Disorder (OCD) checking, highlighting the methodological differences between these studies that may explain inconsistencies regarding memory deficits in OCD checkers. Based on Conway's proposition that one function of episodic memories is to keep an adaptive record of recent goal processing in order to check that actions have actually been accomplished, we suggest that impaired autonoetic consciousness -one of the main features of episodic memory- may be at the heart of the issue of checking compulsion. Autonoetic consciousness, that can be experimentally assessed by the Remember/Know/Guess paradigm,could be impaired in OCD checkers leading them to be unable to mentally relive their actions in order to be assured that they have been accomplished (e.g., having locked the door). We make methodological suggestions to improve the assessment of autonoetic consciousness deficit in OCD checkers and understand its role in the etiology and maintenance of compulsive checking.

Based on the observed clinical overlap between obsessive-compulsive disorder (OCD) and schizophrenia (SCZ), both conditions may share, at least in part, common cognitive underpinnings. Among the cognitive deficits that could be involved, it has been hypothesized that patients share a failure in their abilities to monitor their own thoughts (source monitoring), leading to confusion between what they actually did or perceived and what they imagined. Although little is known regarding source-monitoring performances in patients with OCD, numerous studies in patients with SCZ have observed a relationship between delusions and/or hallucinations and deficits in both internal source- and reality-monitoring abilities.

The present work compared source-monitoring performances (internal source and reality monitoring) between patients with OCD (n = 32), patients with SCZ (n = 38), and healthy controls (HC; n = 29).

We observed that patients with OCD and patients with SCZ displayed abnormal internal source-monitoring abilities compared to HC. Only patients with SCZ displayed abnormalities in reality monitoring compared to both patients with OCD and HC.

Internal source-monitoring deficits are shared by patients with OCD and SCZ and may contribute to the shared cognitive deficits that lead to obsessions and delusions. In contrast, reality-monitoring performance seems to differentiate patients with OCD from patients with SCZ.

Our behavior is constantly accompanied by a sense of confidence and its' precision is critical for adequate adaptation and survival. Importantly, abnormal confidence judgments that do not reflect reality may play a crucial role in pathological decision-making typically seen in psychiatric disorders. In this review, we propose abnormalities of confidence as a new model of interpreting psychiatric symptoms. We hypothesize a dysfunction of confidence at the root of psychiatric symptoms either expressed subclinically in the general population or clinically in the patient population. Our review reveals a robust association between confidence abnormalities and psychiatric symptomatology. Confidence abnormalities are present in subclinical/prodromal phases of psychiatric disorders, show a positive relationship with symptom severity, and appear to normalize after recovery. In the reviewed literature, the strongest evidence was found for a decline in confidence in (sub)clinical OCD, and for a decrease in confidence discrimination in (sub)clinical schizophrenia. We found suggestive evidence for increased/decreased confidence in addiction and depression/anxiety, respectively. Confidence abnormalities may help to understand underlying psychopathological substrates across disorders, and should thus be considered transdiagnostically. This review provides clear evidence for confidence abnormalities in different psychiatric disorders, identifies current knowledge gaps and supplies suggestions for future avenues. As such, it may guide future translational research into the underlying processes governing these abnormalities, as well as future interventions to restore them.

As part of a larger clinical trial, this ecological momentary assessment (EMA) study pursued the main goal of demonstrating that the EMA method is sensitive to treatment effects of detached mindfulness and cognitive restructuring for obsessive-compulsive disorder (OCD). A second goal was to provide a descriptive analysis of OCD symptoms and influencing factors in participants' everyday lives. Thirty-nine participants were included in the final analyses. EMA sampling involved a smartphone and comprised 4 days with 10 random prompts per day both before (Pre-Treatment EMA) and after the completion of a 2-week clinical intervention of either detached mindfulness or cognitive restructuring (Post-Treatment EMA) that participants had been randomly allocated to. The EMA questionnaire included items on the frequency of obsessions, subjective burden due to obsessions, perceived current stress, emotions, and on the frequency of compulsions and other dysfunctional behaviors. Descriptive Pre-Treatment EMA results highlight the importance of compulsions and emotional states of tension/discomfort in OCD. Pre-Post comparisons showed a significant reduction of avoidance behavior, obsessions, and burden due to obsessions, with a nonsignificant trend also indicating a reduction of compulsions. There was no pre to post effect concerning emotions. This study adds to the existing research on OCD symptoms and offers further evidence in confirmation of established theoretical models of OCD. Also, our results can be taken as evidence for treatment sensitivity of the EMA method in OCD. Further research is needed to replicate, broaden, and generalize our results.

This paper presents a theoretical model suggesting that doubt and certainty are two extremes of a continuum. Different people can be located in different locations on this continuum, according to how much they tend to seek refutation vs. confirmation. In both ends of the continuum lay mental disorders, which can be seen as extreme deviations from the usual relatively stable equilibrium between the two thinking processes. One end is defined by excessive skepticism and manifested as obsessive compulsive disorder (OCD), a disorder characterized by incessant doubt. The other end is defined by excessive certainty and lack of doubt, manifested as delusional disorders. Throughout this article, we demonstrate that the differences between normative thoughts and delusional thoughts are relatively vague, and that in general, the human default tendency is to prefer certainty over doubt. This preference is reflected in the confirmation bias as well as in other cognitive constructs such as overconfidence and stereotypes. Recent perspectives on these biases suggest that the human preference for confirmation can be explained in evolutionary terms as adaptive and rational. A parallel view of the scientific enterprise suggests that it also requires a certain equilibrium between skepticism and confirmation. We conclude by discussing the importance of the dialectic relationship between confirmation and refutation in both lay thinking and scientific thought.

Individuals with obsessive-compulsive disorder (OCD) often complain of doubt related to memory. As neuropsychological research has demonstrated that individuals with OCD tend to focus on details and miss the larger context, the construct of source (contextual) memory may be particularly relevant to memory complaints in OCD. Memory for object versus contextual information relies on partially distinct regions within the prefrontal cortex, parietal and medial temporal lobe, and may be differentially impacted by OCD. In the present study, we sought to test the hypothesis that individuals with OCD exhibit impaired source memory retrieval using a novel memory paradigm - The Memory for Rooms Test (MFRT) - a four-room memory task in which participants walk through four rooms and attempt to encode and remember objects. Demographically matched individuals with OCD and healthy controls studied objects in the context of four rooms, and then completed a memory retrieval test while undergoing functional magnetic resonance imaging (fMRI). While no differences were observed in source memory accuracy, individuals with OCD exhibited greater task related activation in the posterior cingulate cortex (PCC) relative to healthy controls during correct source memory retrieval. During correct object recognition, individuals with OCD failed to recruit the dorsolateral prefrontal(DLPFC)/premotor, left mPFC, and right parietal regions to the same extent as healthy controls. Our results suggest abnormal recruitment of frontal-parietal and PCC regions during source verses object memory retrieval in OCD. Within the OCD group, activation in the PCC and the premotor/DLPFC was associated with greater pathological doubt. This finding is consistent with the observation that OCD patients often experience extreme doubt, even when memory performance is intact.

The inferential confusion hypothesis postulates that obsessive doubt is perpetuated by a subjective form of reasoning characterized primarily by a distrust of reality and an overreliance on imagined possibilities. However, experimental evidence for this hypothesis may be compromised by a potential confound between type of information (reality vs. possibility) and its valence (danger vs. safety). In the present study we aimed to untangle this potential confound.

Forty OCD and 40 non-clinical participants underwent two versions of the Inferential Processes Task (Aardema, F., et al. (2009). The quantification of doubt in obsessive-compulsive disorder. International Journal of Cognitive Therapy, 2, 188-205). In the original version, the reality-based information is congruent with the safety hypothesis, whereas the possibility-based information is congruent with the danger hypothesis. In the modified version incorporated in the present study, the reality-based information is congruent with the danger hypothesis, whereas the possibility-based information is congruent with the safety hypothesis.

Our findings did not support the inferential confusion hypothesis: both OCD and control participants changed their estimations of the probability of unwanted events based on the type of information they received (whether it conveyed danger or safety) regardless of whether it was framed as reality or possibility.

The design of the present study does not lend itself to examining alternative explanations for the persistence of doubt in OCD.

The hypothesized inferential confusion in OCD requires further validation. It is particularly important to demonstrate that findings do not reflect a prudential reasoning strategy.

Individuals who are not clinically diagnosed with obsessive-compulsive disorder (OCD) but still display obsessive-compulsive (OC) tendencies may show cognitive impairments. The present study investigated whether there are subgroups within a healthy group showing characteristic cognitive and emotional performance levels similar to those found in OCD patients and whether they differ from OCD subgroups regarding performance levels. Of interest are those cases showing subclinical symptomatology. The results revealed no impairments in the subclinical OC participants on the neuropsychological tasks, while evidence suggests that there exist high and low scores on two standardised clinical instruments (Yale-Brown Obsessive Compulsive Scale and Cognitive Assessment Instrument of Obsessions and Compulsions) in a healthy sample. OC symptoms may diminish the quality of life and prolong sustainable return to work. It may be that occupational rehabilitation programmes are more effective in rectifying subclinical OC tendencies compared to the often complex symptoms of diagnosed OCD patients. The relationship between cognitive style and subclinical OC symptoms is discussed in terms of how materials and information might be processed. Although subclinical OC tendencies would not seem to constitute a diagnosis of OCD, the quality of treatment programmes such as cognitive behavioural therapy can be improved based on the current investigation.

Obsessive-compulsive (OC) patients typically display reduced metacognitive confidence, but findings regarding the scope of this phenomenon and factors that mediate it have been inconsistent. This study aimed to further the understanding of reduced metacognitive confidence in obsessive-compulsive disorder (OCD) by exploring the relationship between metacognitive processes and OC tendencies.

High and low OC participants answered a general-knowledge questionnaire, rated their confidence in each answer, and decided whether or not to report each answer.

High and low OC participants did not differ either in their performance (general knowledge) or in their subjective estimations or confidence regarding their performance. The two groups also did not differ in the effectiveness of their metacognitive monitoring or in the relationship between monitoring and report-control decisions (control sensitivity). However, the two groups did differ in response criterion, with high OC participants less willing to report answers held with low-to-medium levels of subjective confidence.

The study was conducted with non-clinical participants, which limits generalization to OCD.

These results suggest that conservative response criterion among OC individuals might be the critical factor underlying feelings of doubt and uncertainty endemic in OCD.

Easy to administer behavioral measures of checking are needed to improve the assessment of this hallmark feature of OCD. We recently developed a new computer-based behavioral assessment of OCD in a previous study. As a follow-up experiment for this method, the goal of this study was to examine whether the new computer-based behavioral assessment would be capable of differentiating behaviors in adults with OCD characterized by checking behavior from those without checking behavior. We compared 22 OCD patients with compulsive checking behaviors (OCD checkers), 17 OCD controls without checking behavior (OCD controls), and 31 healthy controls (HCs) on a novel computer-based behavioral measure of checking behavior. Despite similar levels of successfully completed tasks, OCD checkers demonstrated longer duration of checking behaviors than OCD controls or HCs. Interestingly, no differences were found between OCD controls and HCs in any of the dependent variables. Our new behavioral measure offers a novel, objective, and ecologically valid measure of checking behaviors in a sample of adults with OCD.

The present study was designed to test whether OC tendencies are associated with indecisiveness and increased need for objective feedback in vague decision situations. This hypothesis was tested using a neutral color judgment task that places minimal demands on working memory.

Sixty-one participants completed several measures of OC symptoms and tendencies. Indecisiveness was tested on a novel computerized task in which participants can move along a continuum marked by two colors at the extreme ends and are instructed to choose the color they judge to be the exact mid-point on the continuum.

OC scores were positively correlated with indecisiveness on the task, as assessed by the amount of time it took participants to complete the task and the extent of their search through the color continuum. This association was most pronounced when feedback for performance was not routinely provided. Requests for feedback were also positively correlated with OC scores. OC scores were not associated with actual performance on the task (accuracy levels) or with confidence ratings.

The study relies on non-clinical participants and the extent to which these results would extend to OCD patients in unknown. Some effects may be confounded by the fixed order in which the task phases were administered.

The findings support the hypothesis that OC tendencies are associated with general indecisiveness and reliance on external feedback.

We have previously hypothesized that obsessive-compulsive (OC) tendencies are associated with a general lack of subjective conviction regarding internal states, which leads to compensatory seeking of and reliance on more discernible substitutes (proxies) for these states (Lazarov, A., Dar, R., Oded, Y., & Liberman, N. (2010). Behaviour Research and Therapy, 48, 516-523). This article presents two studies designed to provide further support to this hypothesis by using false biofeedback as a proxy for internal states.

In Study 1 we presented high and low OC participants with pre-programmed false feedback showing either increasing or decreasing levels of muscle tension. In Study 2 we presented similar false feedback on level of relaxation to non-selected participants, half of which received instructions that undermined their confidence in their ability to assess their own level of relaxation.

In Study 1, high OC participants were more affected by false biofeedback when judging their own level of muscle tension than were low OC participants. In Study 2, undermined confidence participants were more affected by false biofeedback when judging their own level of relaxation as compared to control participants.

Our findings are based on a non-clinical, highly functioning, largely female student sample and their generalization to OCD requires replication with a sample of OCD patients.

These results provide converging evidence for our hypothesis by replicating and extending our previous findings. We discuss the implication of our hypothesis for the understanding and treatment of OCD and outline directions for future research.

Patients with body dysmorphic disorder (BDD) typically have very poor insight into their disorder. Their conviction in their ugliness is often of delusional intensity. Reality monitoring is the ability to distinguish in memory between things that one has imagined and things that one has perceived. Deficits in reality monitoring have been associated with the development of other delusional beliefs. Therefore, in the present study we investigated whether individuals with BDD (n = 20) demonstrate impairments in reality monitoring relative to individuals with obsessive-compulsive disorder (OCD; n = 20) and healthy controls (n = 20). This hypothesized impairment might predispose people with BDD to confuse memories of how they imagine themselves to appear (i.e., ugly) with memories of how they actually appear (i.e., normal). All participants completed a memory task assessing reality-monitoring ability for verbal stimuli. The BDD patients did not exhibit a reality-monitoring deficit despite elevated levels of focal delusionality. The results suggest that impairments in reality monitoring do not contribute to the development or maintenance of appearance-related beliefs in BDD.

When obsessive-compulsive (OC) patients are confronted with disorder-relevant situations, they tend to reason in chains of small steps between the current situation and a highly improbable catastrophe. It was hypothesized that this type of "perseverative reasoning" would increase the subjective likelihood of the feared catastrophe. In an experiment with 63 healthy undergraduates, we tested whether OC-like perseverative reasoning induces feelings of uncertainty about a harmful outcome and makes this outcome more credible. Furthermore, we explored whether making multiple series of events increases these effects. Participants were administered a neutral situation with a catastrophic improbable outcome. In a pre- and post-test, they rated the credibility of this outcome and feelings of uncertainty about the outcome. In between, two experimental groups were instructed to generate respectively one or five series of intermediate steps between the situation and the harmful outcome, while a control group carried out a filler task. Consistent with the predictions, perseverative reasoning enhanced the credibility of a negative, improbable outcome. However, there were no differences between the two experimental conditions (one or five reasoning chains), and perseverative reasoning did not increase uncertainty about the outcome. The OC-like generation of small steps between an innocuous situation and a negative outcome increases the credibility of a feared outcome, potentially serving to maintain obsessive-compulsive disorder (OCD) problems.

In addition to the central role of compulsive behaviors in obsessive compulsive disorder (OCD), recent data have documented the presence of compulsive behaviors in individuals with generalized anxiety disorder (GAD). However, there is a lack of information about potential similarities and differences with regard to the quality, or content, of checking associated with worry and obsessions. The two studies presented herein are an initial step towards gathering this information. Findings of Study 1, from a large unselected undergraduate sample, showed that symptoms of OCD and GAD were both significantly associated with checking behaviors. However, while OCD symptoms were associated with checking related to both objects and interpersonal situations, GAD symptoms were only significantly associated with interpersonal checking. Findings of Study 2, using a separate sample, suggest links between interpersonal checking and features characteristic of GAD, namely emotion regulation difficulties, and between object checking and a cognitive feature of OCD, namely thought-action fusion. In summary, the current studies add to a growing body of literature suggesting that checking may be important in numerous forms of psychopathology, while also suggesting that the nature and function of checking may differ for various symptom profiles.

This study replicated and extended previous research regarding utility of an inference-based approach (IBA) to the study of Obsessive-Compulsive Disorder (OCD). The IBA is a model for the development of OCD symptoms through false reasoning. One of its key features is inferential confusion-a form of processing information in which an individual accepts a remote possibility based only on subjective evidence. In a nonclinical sample, this study examined the specificity of relations between the expanded Inferential Confusion Questionnaire (ICQ-EV) and OC symptoms. Results were that the ICQ-EV significantly predicted OC symptoms after controlling for general distress, anxiety, and depression. This finding supports the unique association between inferential confusion and OCD. Further, the ICQ-EV was a stronger predictor of certain OC symptoms than scales from the Obsessive Beliefs Questionnaire, which itself has shown strong relations with OC symptoms. Thus, both inference-based and cognitive appraisal models appear useful for understanding OCD.

The role of meta-memory and meta-cognition in obsessive-compulsive disorder (OCD) symptoms and checking was examined in a student sample, using the memory and cognitive confidence scale (MACCS; Nedeljkovic, M., & Kyrios, M. (2007). Confidence in memory and other cognitive processes in obsessive-compulsive disorder. Behaviour Research and Therapy, 45, 2899-2914). Confirmatory factor analysis supported the MACCS's previously reported structure, and hierarchical regression supported its relationship to OCD symptom severity over-and-above depression and other OCD-related beliefs. Specifically, general confidence in memory was found to be a unique predictor of overall OCD severity. Implications for theory and research are discussed.

The memory deficit or forgetfulness hypothesis of obsessive-compulsive disorder (OCD) has received considerable attention and empirical effort over the past decades. The present study aimed to provide a fair test of its various formulations: (1) memory dysfunction in OCD is ubiquitous, that is, manifests irrespective of modality and material; (2) memory dysfunction is found for nonverbal but not verbal material, (3) memory dysfunction is secondary to executive impairment; and (4) memory dysfunction affects meta-memory rather than memory accuracy. Participants comprised 43 OCD patients and 46 healthy controls who were tested on the Picture Word Memory Test (PWMT), which provides several unconfounded parameters for nonverbal and verbal memory accuracy and confidence measures across different time-points. In addition, the Trail-Making Test B was administered to test assumption number 3. Replicating earlier work of our group, samples displayed similar performance on all indices. None of the different formulations of the memory deficit hypothesis were supported. In view of waning evidence for a global memory deficit in OCD, neuropsychological research on OCD should more thoroughly investigate moderators and triggers of occasional instances of impaired performance, particularly cognitive biases such as perfectionism and an inflated sense of responsibility.

Obsessive-compulsive disorder (OCD) is a clinically heterogeneous disorder; nonetheless, most of the previous neuropsychological studies for assessing the involvement of memory dysfunction grouped together patients with different symptoms, thereby potentially accounting for the inconsistencies of results. The goals of this study were to compare the memory dysfunction of two main subtypes of OCD and to identify the type of memory dysfunction that is associated with the checking symptoms in OCD patients. The sample population comprised the cleaning-type OCD group (N=23), checking-type OCD group (N=24), and a control group of healthy volunteers (N=20). All the OCD patients were selected from the outpatient clinic. All the subjects underwent the Rey-Osterreith Complex Figure Test (RCFT) for the assessment of nonverbal memory function, the Hopkins Verbal Learning Test (HVLT) for verbal memory function, the Wechsler Adult Intelligence Scale-Revised (WAIS-R), and the Wisconsin Card Sorting Test (WCST). The immediate and delayed memory scores of RCFT were significantly lower in the checking-type OCD group; there were no significant differences in HVLT scores amongst the three groups. Our results indicate that the checking-type compulsion of OCD patients is associated with nonverbal memory deficits and not with verbal memory deficits.

Repeated and compulsive-like checking reduces confidence in memory for the last check. Obsessive-compulsive (OC) patients are not only uncertain about memory, but may also be uncertain about perception, while this perceptual uncertainty may be associated with prolonged visual fixation on the object of uncertainty. It was reported earlier that, among healthy participants, prolonged staring at light bulbs or gas rings induces OC-like uncertainty about perception and feelings of dissociation [van den Hout, M. A., Engelhard, I. M., de Boer, C., du Bois, A., & Dek, E. (2008). Perseverative and compulsive-like staring causes uncertainty about perception. Behaviour Research and Therapy, 46, 1300-1304]. In that study, staring continued for 10min. For patients, however, staring intervals seem to be considerably shorter. To test the clinical credibility of the paradigm as a model of the maintenance of OC perceptual uncertainty, we investigated whether the effects of staring materialize long before 10min. Five groups of 16 undergraduates participated: one group did not stare at a gas stove while the others stared for 7.5, 15, 30 or 300s. In the absence of staring, no pre-to-post increase in dissociation/uncertainty was reported, but after staring it was. The larger part of the observed dissociation/uncertainty after 5min had occurred within 30s, and around 50% of this maximal increase was reported between 7.5 and 15s. Thus, even relatively short intervals of staring induce uncertainty about perception and dissociative experiences. Perseverative looking at objects may be a counter-productive OC strategy, which increases uncertainty about perception and may serve to maintain the disorder.

A large body of literature suggests that some symptoms of obsessive-compulsive disorder (OCD) result from mnemonic dysfunctions. The present study tested various formulations of the memory deficit hypothesis considering important moderators, such as depression and response slowing. Thirty-two OCD patients and 32 healthy controls were presented verbal or nonverbal instructions for actions (e.g. simple gestures). These actions should either be performed or imagined. For recognition, previously presented as well as novel actions were displayed. Decisions had to be made whether an action was previously displayed (verbally vs. nonverbally) or not and whether an action was performed or imagined (internal source memory). Moreover, both judgments required confidence ratings. Groups did not differ in memory accuracy and metamemory for verbally presented material. Patients displayed some impairment for nonverbally presented material and imagined instructions, which, however, could be fully accounted for by response slowing and depressive symptoms. The study challenges the view that primary memory deficits underlie OCD or any of its subtypes. We claim that research should move forward from the mere study of objective impairment to the assessment of cognitive performance in conjunction with personality traits such as inflated responsibility.

Earlier studies have found that perseverative checking provokes memory distrust for checked stimuli, suggesting that compulsive checking is a counter-productive strategy to increase memory confidence. Obsessive Compulsive (OC) uncertainty also occurs for functions other than memory, like perception. Uncertainty about perception in OC patients gives rise to prolonged attending to the issues that patients feel uncertain about. In an experiment with 40 healthy volunteers, it was tested whether OC-like, perseverative (visual) attending induces OC-like experiences of dissociation and perceptual uncertainty. Participants had to look at an object (a gas stove or a light bulb) during a pre-test and a post-test. In between these tests, participants in the experimental condition were asked to stare at an object that was the same as the to-be-looked-at object during the pre/post-tests. Participants in the control condition stared at an object that was different from the object they looked at during pre/post-test. Both in the experimental and control conditions, dissociation was observed; the effects were equally strong. Critically, with regards to OC-like perceptual uncertainty, the effects were significantly stronger in the experimental condition. The findings indicate that OC-like perseveration induces distrust, not only about memory, but also about perception. To explain the results, we suggest that perseveration interferes with spreading of activation and that cognitive uncertainty (and possibly derealisation) is the experiential end-product of perseveration. It is suggested that all forms of OC perseveration share such interference and that all undermine confidence in cognitive operations.

Memory failures reported by obsessive-compulsive (OC) checkers often seem to be errors of "reality-monitoring", or misremembering whether one performed or imagined performing an action. To examine these memory processes in the context in which such errors are said to occur, an in-home reality-monitoring experiment involving bothersome and non-bothersome actions was conducted with 21 OC checkers and 24 non-clinical controls. OC checkers reported poorer confidence in memory, but both groups performed similarly on tests of immediate and delayed free and prompted recall. Among OC checkers (but not controls), accuracy in recall and confidence in memory were correlated. Theoretical implications are discussed.