Memory for actions and dissociation in obsessive-compulsive disorder

Obsessive-compulsive symptoms and dissociative experiences: Suggested underlying mechanisms and implications for science and practice

A strong and specific link between obsessive-compulsive disorder or symptoms (OCD/S) and a tendency for dissociative experiences (e.g., depersonalization-derealization, absorption and imaginative involvement) cannot be explained by trauma and is poorly understood. The present theoretical formulation proposes five different models conceptualizing the relationship. According to Model 1, dissociative experiences result from OCD/S through inward-focused attention and repetition. According to Model 2, dissociative absorption causally brings about both OCD/S and associated cognitive risk factors, such as thought-action fusion, partly through impoverished sense of agency. The remaining models highlight common underlying causal mechanisms: temporo-parietal abnormalities impairing embodiment and sensory integration (Model 3); sleep alterations causing sleepiness and dreamlike thought or mixed sleep-wake states (Model 4); and a hyperactive, intrusive imagery system with a tendency for pictorial thinking (Model 5). The latter model relates to Maladaptive Daydreaming, a suggested dissociative syndrome with strong ties to the obsessive-compulsive spectrum. These five models point to potential directions for future research, as these theoretical accounts may aid the two fields in interacting with each other, to the benefit of both. Finally, several dissociation-informed paths for further developing clinical intervention in OCD are identified.

The Relationship Between Obsessive-Compulsive Symptoms and Dissociation: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis aimed to investigate the relationship between dissociation and obsessive-compulsive symptoms (OCS) and disorder (OCD). Specifically, the study aimed to (a) estimate the pooled prevalence of dissociative disorders among individuals with OCD; (b) systematically review the prevalence of OCD among individuals with dissociative disorders; (c) compare the severity of dissociative symptoms between individuals with OCD and non-clinical controls; (d) estimate the association between OCS and dissociative symptoms in the clinical and non-clinical populations. A systematic search was carried out in biomedical databases from inception to January 2022 according to PRISMA guidelines. A total of 41 studies met inclusion criteria (n = 9,438, 34.3% males). The pooled prevalence of dissociative disorders in adult samples with OCD was 8% (95% CI [3, 15], k = 5). Studies on adolescent and adult patients with dissociative disorders found that 17-32% reported comorbid OCD, while a prospective study of patients with early-onset dissociative disorders found no evidence of association with OCD. Individuals affected by OCD reported more dissociative symptoms than non-clinical controls (g = .67, 95% CI [.18, 1.16], k = 9). A moderate correlation between dissociative symptoms and OCS was detected (r = .43, 95% CI [.36, .51], k = 18). Sensitivity analyses showed small/moderate correlations between dissociative experiences and specific types of obsessions and compulsions. Findings suggest that dissociative symptoms are moderately related to OCS in both clinical and non-clinical populations. Interventions aimed to reduce dissociation might improve treatment response of patients suffering from OCD.

Maladaptive Daydreaming and Obsessive-Compulsive Symptoms: A confirmatory and exploratory investigation of shared mechanisms

Maladaptive Daydreaming (MD) is a newly proposed mental disorder characterized by excessive, vivid fantasy activity impairing functioning. There is a high comorbidity of MD with Obsessive-Compulsive Spectrum Symptoms (OCSS), yet the mechanisms responsible for this relationship are still unclear. The present study set out to explore the relationship between MD and OCSS by: (1) examining dissociation, trauma, sense of control, and mind-wandering as potential mediators; (2) exploring whether MD is more strongly related to obsessions or compulsions; and (3) identifying patterns of specific obsessions and/or compulsions common in an MD sample. A group of 510 participants with self-identified MD completed a battery of online questionnaires. Dissociation and sense of control significantly mediated the MD-OCSS association. MD was moderately related to both obsessions and compulsions but was significantly more strongly related to the former. Frequently endorsed obsessions and compulsions among MD participants included checking and repetition compulsions, intrusive obsessions, and body-related obsessions and compulsions. We conclude that dissociative mechanisms, including dissociative absorption, play a major role in the relationship between MD and OCSS and may lead to consequent checking when transitioning back to reality, altered embodiment, intrusive images, and thoughts, and an impaired sense of mental control. Clinicians working with OCSS should be aware of the possible role of MD in the development or maintenance of symptoms. Future work should develop useful interventions for this type of shared psychopathology.

Dissociable source-monitoring impairments in obsessive-compulsive disorder and schizophrenia

BACKGROUND

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.

METHODS

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).

RESULTS

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.

CONCLUSIONS

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.

Review of source-monitoring processes in obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a severe mental illness characterized by persistent, intrusive and distressing obsessions and/or compulsions. Such symptoms have been conceptualized as resulting from a failure in source-monitoring processes, suggesting that patients with OCD fail to distinguish actions they perform from those they just imagine doing. In this study, we aimed to provide an updated and exhaustive review of the literature examining the relationship between source-monitoring and OCD. A systematic search in the literature through January 2019 allowed us to identify 13 relevant publications investigating source-monitoring abilities in patients with OCD or participants with subclinical compulsive symptoms. Most of the retrieved studies did not report any source-monitoring deficits in clinical and subclinical subjects compared with healthy volunteers. However, most of the studies reported that patients with OCD and subclinical subjects displayed reduced confidence in source-monitoring judgments or global cognitive confidence compared to controls. The present review highlighted some methodological and statistical limitations. Consequently, further studies are needed to explore source monitoring with regard to the subcategories of OCD symptoms (i.e., symmetry-ordering, contamination-washing, hoarding, aggressive obsession-checking, sexual-religious thoughts) and to clarify the relationship between source-monitoring subtypes (i.e., reality or internal source-monitoring) and confidence in these populations.

Mindfulness-based Cognitive Therapy for Obsessive-Compulsive Disorder: A Pilot Study

BACKGROUND

Cognitive-behavioral therapy (CBT) is the first-choice intervention for obsessive-compulsive disorder (OCD); however, a notable proportion of patients either do not respond to treatment or relapse after CBT. Mindfulness-based treatment has been suggested as an alternative or complementary therapeutic strategy for OCD. However, only a few studies have focused on its application in clinical samples.

OBJECTIVE

To evaluate the impact of a new treatment, called "Mindfulness-based Cognitive Therapy for OCD." It is an 11-session manualized group intervention that integrates elements of CBT, mindfulness, compassion-focused therapy, and acceptance and commitment therapy.

METHODS

The program was delivered to 35 patients with a primary diagnosis of OCD.

RESULTS

Participants demonstrated good adherence to the intervention. There was a significant reduction in mean total score on the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS-TS) (P<0.001; Cohen d=-0.72). One third of the participants (n=13) showed at least a 25% reduction on the Y-BOCS-TS, and 40% of the sample (n=14) were assigned to a lower Y-BOCS severity category after treatment. Significant changes were also found in depression (P<0.001; d=-0.80), worry (P<0.001; d=-0.79), alexithymia (P<0.01; d=-0.41), dissociation (P<0.05; d=-0.46), and general psychopathology (P<0.001; d=-0.58). Repeated measures linear mixed models showed that OCD symptom reduction was associated with an increase in mindfulness skills, in particular on the acting with awareness (P=0.006), nonjudging (P=0.001), and nonreactivity (P=0.001) facets.

CONCLUSIONS

Overall, these findings are promising and they suggest that randomized controlled studies be conducted to test the effectiveness of this new treatment program for this challenging and disabling mental disorder.

Evaluation of Relationship between Obsessive-compulsive Disorder and Dissociative Experiences

Objective

The aim of the study is to evaluate the relationship between obsessive-compulsive disorder (OCD) symptoms and dissociative experiences and the effect of childhood traumatic experiences on this relationship in OCD patients.

Methods

Fifty consecutive OCD patients and 50 healthy controls are enrolled for this study. Sociodemographic and Clinical Data Form, Dissociative Experiences Scale (DES), Padua Inventory (PI) and Childhood Trauma Questionnaire (CTQ) are applied to participants.

Results

Average DES total score in the patient group is 20.58 and in the control group it is 4.87. In the patient group, when we evaluate the relation strengths of DES total and subscale scores with PI total score, we found out that amnesia subscale has r=0.361 (p<0.01), absorption subscale has r=0.611 (p<0.01), depersonalization/derealization subscale has r=0.574 (p<0.01), and DES total score has r=0.55 (p<0.01) relation strengths with PI total score. In patient group both DES total score and CTQ total score have influence on PI total score independently from each other. In addition to this, the level of the influence of DES total scores on PI total scores is, R²=0.399 (p<0.01) and the level of the influence of CTQ total scores on PI total scores is R²=0.343 (p<0.01).

Conclusion

Dissociative experiences are seen more frequently in OCD patients than healthy controls. Among dissociative experiences, absorption has stronger relation with OCD symptoms. The relation between OCD and dissociation is independent from and stronger than the relation between childhood traumatic experiences and OCD.

The Cognitive Heterogeneity of Obsessive-Compulsive Checking

The present article reviews the phenomenology of obsessive-compulsive checking, examining how action processing can be differentially affected across distinct checking subtypes. Checking is a normal phenomenon which ensures that an intended goal has been actually completed. Checking symptoms have consistently been connected to impairments in processing information related to self-performances. Theoretical and empirical work has explained compulsive checking as a result of various cognitive deficits related to action processing (e.g., low confidence in cognitive abilities, impaired memory for actions, abnormal reality monitoring, overactive action monitoring, defective goal processing). Such apparent inconsistencies are, however, in agreement with clinical and empirical observations highlighting substantial variability in the subjective experience preceding/accompanying checking. Many factors can in fact prevent the cognitive system from determining whether or not an intended goal has actually been achieved. We argue that several action processing mechanisms are likely affected in checking; the related subjective experience may vary accordingly.

Ironic effects of compulsive perseveration

Individuals with obsessive-compulsive disorder (OCD) exhibit perseverative behaviours, like checking, to reduce uncertainty, but perseveration paradoxically enhances uncertainty. It is unclear what mechanism might be responsible. We hypothesised that perseverative OC-like behaviour produces "semantic satiation" and interferes with the accessibility of meaning. Healthy participants repeated 20 types of OC-like checking behaviour nonperseveratively (2 times) or perseveratively (20 times). Afterwards, they decided as quickly as possible whether a picture was semantically related to the checked object. The nonperseverative condition showed spreading of activation: Judgements were faster for related than for unrelated objects and pictures. The effect was blocked in the perseverative condition, where reaction times for related and unrelated items were similar. The results suggest that the ironic effects of compulsive perseveration are due to interference with spreading of activation.

Relations between childhood traumatic experiences, dissociation, and cognitive models in obsessive compulsive disorder

OBJECTIVE

Previous studies have indicated that obsessive compulsive disorder (OCD) is associated with childhood traumatic experiences and higher levels of dissociation. Dissociative tendency may arise when individual attempt to incorporate adverse experiences into cognitive schema.

METHODS

We investigated the possible links among childhood trauma, dissociation, and cognitive processes. We evaluated 95 patients with OCD using the Beck Depression Inventory (BDI), Thought-Action Fusion Scale (TAFS), Metacognitions Questionnaire (MCQ-30), White Bear Suppression Inventory (WBSI), Dissociative Experiences Scale (DES), and Childhood Trauma Questionnaire (CTQ-28).

RESULTS

The CTQ-28 total scores were not associated with Y-BOCS total, Y-BOCS insight, BDI, TAFS, MCQ-30, and WBSI scores. The TAFS Total, MCQ-30, WBSI, and BDI scores were significantly associated with DES scores. Regression analysis revealed that MCQ-30 and WBSI scores significantly predicted the DES scores.

CONCLUSIONS

These results suggest that in spite of pathological connotation of dissociative experiences, dissociation may primarily constitute a cognitive trait which is strongly associated with cognitive processes.

Obsessive-compulsive-like reasoning makes an unlikely catastrophe more credible

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.

Compulsive Hoarding: An Interpretative Phenomenological Analysis

Background: This project aimed to explore the experiences of people who compulsively hoard and how they make sense of their own hoarding behaviours. Method: A total of 11 compulsive hoarders were recruited and interviewed using a simple semi-structured interview format, designed for the purposes of the study. The resulting transcribed interviews were analyzed using interpretive-phenomenological analysis. Results: Four super-ordinate discrete, but interacting, themes were found: (1) childhood factors; (2) the participants' relationship to their hoarded items; (3) cognitive and behavioural avoidance of discard; and (4) the impact of hoarding on self, others and the home environment. The themes as a whole described people entrapped in massively cluttered physical environments of their own making. Efforts at discard appeared consistently sabotaged by cognitive/behavioural avoidance, thereby creating maintaining factors of associated personal distress and environmental decline. Conclusions: The results are discussed in the context of the extant evidence concerning hoarding, the distinct contribution made by the current results and the identified methodological shortcomings of the research approach.

Uncertainty about perception and dissociation after compulsive-like staring: time course of effects

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.

No deficits in nonverbal memory, metamemory and internal as well as external source memory in obsessive-compulsive disorder (OCD)

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.

Perseverative and compulsive-like staring causes uncertainty about perception

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.

Dissociative experiences differentiate bipolar-II from unipolar depressed patients: the mediating role of cyclothymia and the Type A behaviour speed and impatience subscale

BACKGROUND

Dissociative symptoms are often seen in patients with mood disorders, but there is little information on possible association with subgroups and temperamental features of these disorders.

METHODS

The Dissociative Experience Scale was administered to 85 patients with a DSM-IV Major Depressive Disorder (MDD) or Bipolar-II Disorder (BP-II). Both broad-spectrum dissociation (DES total score) and clearly pathological forms of dissociation (DES-Taxon) were assessed. Temperament was assessed using Akiskal and Mallya;s criteria of Affective Temperaments and the Jenkins Activity Survey (JAS) for Type A Behaviour.

RESULTS

Sixty-five patients gave valid answers to DES. The mean DES and DES-T scores were higher in BP-II (16.8 and 12.7 respectively) compared to MDD (9.0 and 5.7); DES odds ratio (OR)=1.58 (95% CI 1.15-2.18) and DES-T OR=1.60 (95% CI 1.14-2.25) using univariate logistic regression analyses. There was no significant difference in DES score in patients with (n=30) and without an affective temperament (n=35): mean (95% CI), 13.5 vs. 10.5 (-7.8 to 1.9), p=0.224. However the subgroup with a cyclothymic temperament (n=18) had higher DES scores (mean (95% CI): 17.8 vs. 9.7 (2.9-13.3), p=0.003), compared to patients without such a temperament. There was no significant difference in DES scores for patients with (n=35) or without (n=28) a Type A behaviour pattern (JAS>0): mean (95% CI) 12. 7 vs. 10.9 (-6.8 to 3.3), p=0.491), but a positive JAS factor S score (speed and impatience subscale) was associated with significantly higher DES scores than a negative S-score: mean (95% CI) 14.9 vs. 9.0 (1.1-10.7), p=0.017), and this was still significant (p=0.005) using multiple linear regression of DES scores vs. the JAS subscale scores. DES-T scores were significantly higher in patients with OCD (n=9) (mean (95% CI) 18.4 vs. 6.6 (6.0-17.7), p<0.001); eating disorder (n=13) (14.0 vs. 6.8 (1.8-12.6), p=0.009), psychotic symptoms during depressions (n=9) (16.6 vs. 6.9 (3.7-15.8), p=0.002), and in those with a history of suicide attempt (n=28) (11.9 vs. 5.4 (2.2-10.8), p=0.003), but only OCD was an independent predictor after multiple linear regression of DES-T scores vs. all co-morbid disorders (p=0.043).

LIMITATIONS

The major limitation of the present study is a non-blind evaluation of affective diagnosis and temperaments, and assessment in a non-remission clinical status.

CONCLUSIONS

Dissociative symptoms measured with the Dissociative Experience Scale are associated with bipolar features, using formal DSM-IV criteria, cyclothymic temperament and the speed and impatience subscale of the JAS.

Reality monitoring and motor memory in checking-prone individuals

Studies concerning reality monitoring and motor memory abilities in checkers have provided mixed results. The aim of this study was to re-examine this question by asking 75 undergraduate students to perform, watch the experimenter perform, imagine themselves performing, imagine the experimenter performing, or verbally repeat different daily actions. Two groups were created (checking-prone and nonchecking-prone subjects) based on participants' checking subscores on the revised version of the Obsessive-Compulsive Inventory. First, results suggested that checking-prone subjects have a poorer motor memory than nonchecking-prone participants. Second, our data indicated that checking-prone participants confused actions they had performed with actions the experimenter had performed more often than nonchecking-prone participants. In other words, checking-prone participants remembered events from an observer's viewpoint. Finally, our findings suggest that dissociation could be a mediating variable between some of the reality monitoring abilities and checking.

Dissociation and symptom dimensions of obsessive-compulsive disorder. A replication study

BACKGROUND

Obsessive-compulsive disorder (OCD) is a phenotypically very heterogeneous disease with high rates of comorbid psychiatric pathology. Previous studies have indicated that OCD is associated with higher levels of dissociation. The aims of the present study were to replicate and extend previous findings of a significant link between certain OCD symptom dimensions and dissociation.

METHODS

The study sample comprised 50 patients with OCD, as confirmed by the Mini International Neuropsychiatric Interview,who had a score of at least 16 on the Yale-Brown Obsessive-Compulsive Scale. All patients were assessed with the short version of the Hamburg Obsessive-Compulsive Inventory and the Dissociative Experience Scale (DES). Correlation analyses and multiple regression analyses were performed to evaluate the relationship between OCD symptom dimensions and dissociation.

RESULTS

The checking dimension was most strongly related to dissociation, followed by the symmetry/ordering and obsessive thoughts dimensions. In contrast, no significant relationship was found between dissociation and the washing/cleaning, counting/touching, and aggressive impulses/fantasies dimensions. Multiple regression analyses revealed that: (1) only the checking dimension showed an independent positive correlation with dissociation, and (2) only higher scores on the DES subscale "amnestic dissociation" were associated with higher scores for checking compulsions.

CONCLUSIONS

Our results suggest that there might be a specific link between checking behavior and dissociation in OCD. Moreover, checking compulsions seem to be particularly associated with amnestic dissociation. Further studies focusing on amnestic dissociation as a potentially important determinant of checking compulsions are warranted.

Dissociation as a predictor of cognitive behavior therapy outcome in patients with obsessive-compulsive disorder

BACKGROUND

Previous studies have found a strong association between dissociation and obsessive-compulsive disorder (OCD). The purpose of the present study was to evaluate whether dissociation is a predictor of cognitive behavior therapy (CBT) outcome in patients with OCD.

METHODS

Fifty-two patients with OCD were assessed using the Dissociative Experience Scale (DES), the Yale-Brown Obsessive-Compulsive Scale and the Beck Depression Inventory. CBT lasted on average 9.5 weeks and included exposure therapy.

RESULTS

Patients who dropped out due to noncompliance had higher baseline DES scores and depression scores compared to the 43 patients (83%) who completed the study. Significant OCD symptom reduction at posttreatment was observed in study completers with a large effect size (d = 1.7). More severe OCD symptoms at posttreatment were associated with higher DES scores at baseline, and treatment nonresponders had significantly higher baseline DES scores compared to responders. These associations with outcome were mainly due to the DES subfactor absorption-imaginative involvement. In regression analyses, higher absorption-imaginative involvement scores at baseline predicted poorer CBT outcome, even after controlling for depressive symptoms, comorbid axis I disorders and concomitant psychotropic drugs.

CONCLUSIONS

Results from this preliminary study suggest that higher levels of dissociation (particularly absorption-imaginative involvement) in patients with OCD might predict poorer CBT outcome. If our results can be replicated, treatment outcome might be improved by additional interventions for those patients with OCD who indicate high levels of dissociation, for example by using interventions aimed at improving coping with emotionally stressful situations.

Memory and attention in Obsessive-Compulsive Disorder: a review

The present manuscript reviewed studies investigating biases and deficits in memory and attention related to Obsessive-Compulsive Disorder (OCD). Although the research has been mixed concerning memory for verbal information, there is more consistent evidence suggesting impairment for non-verbal information, particularly for complex visual stimuli and the individual's own actions. Further, a number of studies indicate that patients with OCD report less confidence in their judgments about recognition memory. Finally, OCD appears to be associated with an attentional bias favoring threatening information, as well as reduced levels of cognitive inhibition. The manuscript concludes with a number of recommendations for future research.

Symptom subtypes of obsessive-compulsive disorder and their relation to dissociation

We examined relations between obsessive-compulsive disorder (OCD) symptoms and dissociation in three studies. Studies 1 and 2 established a strong level of convergence between our two OCD symptom measures. Specific types of symptoms showed a clear convergent/discriminant pattern, indicating that they can be meaningfully distinguished from one another. In both studies, dissociation correlated more strongly with checking and obsessive intrusions than with cleaning, ordering, and hoarding. Moreover, these associations remained substantial even after controlling for neuroticism (Study 1) and other types of anxiety (Study 2). In Study 3, we replicated our key findings in a psychiatric outpatient sample, indicating that they are generalizable to clinical participants. Taken together, our results (a) establish a strong link between dissociation and OCD, and (b) illustrate the importance of analyzing different types of OCD symptoms separately.

Interidentity amnesia for neutral, episodic information in dissociative identity disorder

Interidentity amnesia is considered a hallmark of dissociative identity disorder (DID) in clinical practice. In this study, objective methods of testing episodic memory transfer between identities were used. Tests of both recall (interference paradigm) and recognition were used. A sample of 31 DID patients was included. Additionally, 50 control subjects participated, half functioning as normal controls and the other half simulating interidentity amnesia. Twenty-one patients subjectively reported complete one-way amnesia for the learning episode. However, objectively, neither recall nor recognition scores of patients were different from those of normal controls. It is suggested that clinical models of amnesia in DID may be specified to exclude episodic memory impairments for emotionally neutral material.

Reality monitoring and metacognitive beliefs related to cognitive confidence in obsessive-compulsive disorder

The present study investigated general reality monitoring ability, and selective reality monitoring ability for anxiety relevant actions in a group of individuals with obsessive-compulsive disorder (OCD) and a group of non-anxious controls. In addition, reality monitoring confidence was assessed, as well as specific meta-cognitive beliefs related to cognitive confidence (by means of the Meta-Cognitions Questionnaire (MCQ)). No differences were found between both groups in actual reality monitoring ability. Unlike previous studies, the reality monitoring task included actions that were related to the individual concerns of the OCD patients and were ideographically selected. Nevertheless, no differential reality monitoring effect was observed for the anxiety relevant stimuli. Data from the MCQ, however, revealed that OCD patients had less overall confidence in their memory for actions and their reality monitoring ability. Analysis of the confidence ratings of the reality monitoring task showed that this reduced confidence was restricted to the neutral actions. No differences were observed for patients that reported low or high frequencies of checking behaviour. The whole of these data do not support memory deficit models of OCD, but are in line with recent emphasis on the importance of memory confidence and other meta-cognitive beliefs in OCD.

The links between the Adolescent Dissociative Experiences Scale (A-DES), fantasy proneness, and anxiety symptoms

The purpose of this study was to further examine the psychometric properties of the Adolescent Dissociative Experiences Scale (A-DES). A sample of normal adolescents (N = 331) aged 12 to 18 years completed the A-DES and questionnaires measuring posttraumatic stress disorder (PTSD) symptoms, other anxiety disorder symptoms, and fantasy proneness. Factor analysis indicated that the A-DES, at least in nonreferred youths, is assessing a single dimension of dissociation. Furthermore, A-DES scores are not only significantly related to PTSD symptoms but also to other anxiety disorder symptoms (i.e., generalized anxiety disorder, obsessive-compulsive disorder, and panic disorder) and fantasy proneness. Theoretical and practical implications of these findings are briefly discussed.

When dreams become a royal road to confusion: realistic dreams, dissociation, and fantasy proneness

Scientific discussions about false memories have, so far, mainly focused on external determinants (e.g., therapeutic interventions). However, in some cases, false memories might develop more spontaneously. For example, difficulties in distinguishing between dreams and reality may lead to false memories. The present article discusses two studies (N = 85 and 255, respectively) that examined to what extent such difficulties occur. In both studies, a nontrivial minority of respondents (11.8% and 25.9%, respectively) reported that they had had the experience of not being able to discriminate between dream and reality. As expected, respondents who reported this type of confusion scored higher on fantasy proneness and dissociation measures than respondents who did not report this confusion.