Obsessive-compulsive disorder: a disorder of pessimal (non-functional) motor behavior

Early Behavioral Markers of Anxiety and Reduced Frontal Brain Alpha May Predict High Risk for Bullying Victimization

Bullying victimization has a profound negative impact on a child's emotional, social, and cognitive development. Childhood bullying victimization is reported across various social settings, suggesting common characteristics that increase a child's vulnerability to victimization. It is critical to identify early markers of such vulnerability to design preventative tools. Comprehensive semi-structured clinical interviews from mothers of child-victims and non-engaged control children included assessment of early developmental rituals and behavioral inhibition to social novelty, as potential behavioral correlates of anxiety. Neuropsychological and clinical assessment tools were used, and resting state spectral resting state EEG (rsEEG) was recorded. Increased frequency/severity of early developmental rituals and behaviorally inhibited responses to social novelty were apparent in all child-victims, alongside significantly reduced power of ventral prefrontal brain rsEEG alpha oscillations (8-13 Hz). This triad of findings, in line with prior studies, suggested an elevated early childhood anxiety, which, as current findings indicate, may be a cross-diagnostic marker of increased risk for life-long bullying victimization. Gaining insight into early childhood markers of anxiety may meaningfully complement neuropsychiatric prognosis and preventative efforts.

The motor profile of obsessive-compulsive rituals: psychopathological and evolutionary implications

BACKGROUND

Studies investigating obsessive-compulsive disorder from an ethological approach have highlighted a specific motor pattern of compulsive rituals with respect to corresponding ordinary behaviors. Particularly, compulsive motor profile is built through the repetition of acts, with prevalence of nonfunctional ones and redirection of attention to its basic structural units. These formal features would characterize ritual behavior throughout evolution, from nonhuman animals to human cultures. However, no study to date has investigated a possible relationship between such motor profile and underlying psychopathology. Therefore, the first objective of the study was to confirm previous findings on a larger sample size of obsessive patients; the second objective was to elucidate whether motor profile might be associated with obsessive-compulsive psychopathology and/or prepsychotic symptoms of schizophrenia.

METHODS

Twenty-one obsessive-compulsive outpatients provided a videotape of their rituals. An equal number of healthy controls, matched for sex and age, were registered for corresponding ordinary acts. Obsessive patients were administered the Yale-Brown Obsessive-Compulsive Scale, the Brown Assessment of Beliefs Scale, the Hamilton Rating Scale for Depression, and the Frankfurt Complaint Questionnaire.

RESULTS

The results of the present study confirm that ritual compulsions present a specific motor structure characterized by repetition of both functional and nonfunctional acts and their longer duration. Such a motor pattern is independent from obsessive-compulsive psychopathology, whereas it results specifically associated with prepsychotic symptoms of schizophrenia.

CONCLUSIONS

We argue that this association may reflect the adaptive significance of ritual behavior across evolution, that is, its homeostatic function in conditions of unpredictability.

Event Segmentation Deficits in ADHD

Event segmentation is the automatic cognitive process of chunking ongoing information into meaningful events. Event segmentation theory (EST) proposes that event segmentation is a grouping process fundamental to normal, everyday perceptual processing, taking a central role in attention and action control. The neurocognitive deficits observed among individuals with ADHD overlap those involved in event segmentation, but to date no research has examined event segmentation in the context of ADHD. Objective: The goal of this study was to document the event segmentation deficits of individuals with ADHD. Method: Seventy-five undergraduates with ADHD and seventy-nine without ADHD performed an event segmentation task. Results: Results revealed that undergraduates with ADHD identify significantly more large events. Conclusion: These findingssuggest explicit disturbances in the event model and updating system among those with ADHD. Future research directions include further elucidating these deficits with more varied stimuli and establishing associations with functional impairments.

Proximate and ultimate causes of ritual behavior

Ritual behaviour, intended as a specific, repetitive and rigid form of action flow, appears both in social and non-social environmental contexts, representing an ubiquitous phenomenon in animal life including human individuals and cultures. The purpose of this contribution is to investigate an evolutionary continuum in proximate and ultimate causes of ritual behavior. A phylogenetic homology in proximal mechanisms can be found, based on the repetition of genetically programmed and/or epigenetically acquired action patterns of behavior. As far as its adaptive significance, ethological comparative studies show that the tendency to ritualization is driven by the unpredictability of social or ecological environmental stimuli. In this perspective, rituals may have a "homeostatic" function over unpredictable environments, as further highlighted by psychopathological compulsions. In humans, a circular loop may have occurred among ritual practices and symbolic activity to deal with a novel culturally-mediated world. However, we suggest that the compulsion to action patterns repetition, typical of all rituals, has a genetically inborn motor foundation, thus precognitive and pre-symbolic. Rooted in such phylogenetically conserved motor structure (proximate causes), the evolution of cognitive and symbolic capacities have generated the complexity of human rituals, though maintaining the original adaptive function (ultimate causes) to cope with unpredictable environments.

Ingredients of 'rituals' and their cognitive underpinnings

Ritual is not a proper scientific object, as the term is used to denote disparate forms of behaviour, on the basis of a faint family resemblance. Indeed, a variety of distinct cognitive mechanisms are engaged, in various combinations, in the diverse interactions called 'rituals' - and each of these mechanisms deserves study, in terms of its evolutionary underpinnings and cultural consequences. We identify four such mechanisms that each appear in some 'rituals', namely (i) the normative scripting of actions; (ii) the use of interactions to signal coalitional identity, affiliation, cohesiveness; (iii) magical claims based on intuitive expectations of contagion; and (iv) ritualized behaviour based on a specific handling of the flow of behaviour. We describe the cognitive and evolutionary background to each of these potential components of 'rituals', and their effects on cultural transmission. This article is part of the theme issue 'Ritual renaissance: new insights into the most human of behaviours'.

Checking responses of goal- and sign-trackers are differentially affected by threat in a rodent analog of obsessive-compulsive disorder

In obsessive–compulsive disorder (OCD), functional behaviors such as checking that a door is locked become dysfunctional, maladaptive, and debilitating. However, it is currently unknown how aversive and appetitive motivations interact to produce functional and dysfunctional behavior in OCD. Here we show a double dissociation in the effects of anxiogenic cues and sensitivity to rewarding stimuli on the propensity to develop functional and dysfunctional checking behavior in a rodent analog of OCD, the observing response task (ORT). While anxiogenic manipulations of perceived threat (presentation of threat-associated contextual cues) and actual threat (punishment of incorrect responding on the ORT) enhanced functional checking, dysfunctional checking was unaffected. In contrast, rats that had previously been identified as “sign-trackers” on an autoshaping task—and therefore were highly sensitive to the incentive salience of appetitive environmental cues—selectively showed elevated levels of dysfunctional checking under a range of conditions, but particularly so under conditions of uncertainty. These data indicate that functional and dysfunctional checking are dissociable and supported by aversive and appetitive motivational processes, respectively. While functional checking is modulated by perceived and actual threat, dysfunctional checking recruits appetitive motivational processes, possibly akin to the “incentive habits” that contribute to drug-seeking in addiction.

Constructing Experience: Event Models from Perception to Action

Mental representations of everyday experience are rich, structured, and multimodal. In this article we consider the adaptive pressures that led to human construction of such representations, arguing that structured event representations enable cognitive systems to more effectively predict the trajectory of naturalistic everyday activity. We propose an account of how cortical systems and the hippocampus (HPC) interact to construct, maintain, and update event representations. This analysis throws light on recent research on story comprehension, event segmentation, episodic memory, and action planning. It also suggests how the growing science base can be deployed to diagnose impairments in event perception and memory, and to improve memory for everyday events.

Motor Abnormalities: From Neurodevelopmental to Neurodegenerative Through "Functional" (Neuro)Psychiatric Disorders

Background

Motor abnormalities (MAs) of severe mental disorders have been traditionally neglected both in clinical practice and research, although they are an increasing focus of attention because of their clinical and neurobiological relevance. For historical reasons, most of the literature on MAs has been focused to a great extent on schizophrenia, and as a consequence their prevalence and featural properties in other psychiatric or neuropsychiatric disorders are poorly known. In this article, we evaluated the extent to which catatonic, extrapyramidal and neurological soft signs, and their associated clinical features, are present transdiagnostically.

Methods

We examined motor-related features in neurodevelopmental (schizophrenia, obsessive compulsive disorder, autism spectrum disorders), "functional" (nonschizophrenic nonaffective psychoses, mood disorders) and neurodegenerative (Alzheimer's disease) disorders. Examination of the literature revealed that there have been very few comparisons of motor-related features across diagnoses and we had to rely mainly in disorder-specific studies to compare it transdiagnostically.

Results

One or more motor domains had a substantial prevalence in all the diagnoses examined. In "functional" disorders, MAs, and particularly catatonic signs, appear to be markers of episode severity; in chronic disorders, although with different degree of strength or evidence, all motor domains are indicators of both disorder severity and poor outcome; lastly, in Alzheimer's disease they are also indicators of disorder progression.

Conclusions

MAs appear to represent a true transdiagnostic domain putatively sharing neurobiological mechanisms of neurodevelopmental, functional or neurodegenerative origin.

Obsessive-compulsive disorder: Insights from animal models

Research with animal models of obsessive-compulsive disorder (OCD) shows the following: (1) Optogenetic studies in mice provide evidence for a plausible cause-effect relation between increased activity in cortico-basal ganglia-thalamo-cortical (CBGTC) circuits and OCD by demonstrating the induction of compulsive behavior with the experimental manipulation of the CBGTC circuit. (2) Parallel use of several animal models is a fruitful paradigm to examine the mechanisms of treatment effects of deep brain stimulation in distinct OCD endophenotypes. (3) Features of spontaneous behavior in deer mice constitute a rich platform to investigate the neurobiology of OCD, social ramifications of a compulsive phenotype, and test novel drugs. (4) Studies in animal models for psychiatric disorders comorbid with OCD suggest comorbidity may involve shared neural circuits controlling expression of compulsive behavior. (5) Analysis of compulsive behavior into its constitutive components provides evidence from an animal model for a motivational perspective on OCD. (6) Methods of behavioral analysis in an animal model translate to dissection of compulsive rituals in OCD patients, leading to diagnostic tests.

Structural differences among individuals, genders and generations as the key for ritual transmission, stereotypy and flexibility

We analysed a Zulu wedding ritual, posing two questions: (i) what makes a ritual stereotyped and rigid along with preserving certain flexibility; and (ii) does a ritual pass between generations and individuals en bloc, or as a smaller subset of acts? We found that the ritual repertoire constituted only one act that was common to all individuals that performed the ritual. Repetitive performance of this act conveyed the impression of a stereotyped ritual. This structure eases the transmission of the ritual, since it is only necessary to learn the performance of one act that can then be embedded in a sequence of ‘free-style’ acts. Gender difference was minimal, but young women performed more acts than adults, perhaps as a reflection of them being inexperienced actors. Altogether, the present study unveils underlying mechanisms that seem to characterize the evolution of rituals and thereby highlighting a foundation of human cultural behaviour in general.

Stove checking behaviour in people with OCD vs. anxious controls

BACKGROUND AND OBJECTIVES

A growing body of research suggests that the repetition of an action degrades memory for that action, as well as confidence that is has been done correctly. This has important implications for understanding the compulsive repetition of actions characteristic of obsessive compulsive disorder (OCD). At this time, though, much of the research has been conducted on analogue or nonclinical OCD samples in comparison to healthy controls and often using virtual, as opposed to actual, threat stimuli. Furthermore, although it has been argued that people with OCD are overly attentive to threat stimuli, the research on actual attention to threat is scant.

METHODS

People with a principal diagnosis of OCD (n = 30) and people with a clinically significant diagnosis of an anxiety disorder, but no OCD (n = 18) completed measures of memory confidence and responsibility and then underwent a stove-checking task in a functioning kitchen while wearing a portable eye tracking device. Pre- and post-task ratings of harm and responsibility were taken, along with post-task ratings of memory and certainty.

RESULTS

People with OCD did not exhibit poorer memory confidence than the anxious control (AC) group, but did report greater trait and state responsibility for harm. The OCD group checked longer than did the AC group and check duration predicted post-task ratings of harm, but to the same extent in both groups. People with OCD attended to threat items less than did the AC group. Greater visual attention to the stove during the checking period was associated with greater post-task ratings of responsibility and harm and with less certainty in and memory for the check - but only for the AC group.

LIMITATIONS

The sample size was modest, women were over-represented and problems with the eye tracking device reduced the amount of reliable data available for analysis.

CONCLUSIONS

Compulsions are complex actions that are mediated by many trait, state and contextual factors. People with OCD may be able to circumvent self-perpetuating checking processes under certain circumstances. Future research should explore the factors that determine whether or not self-perpetuating mechanisms are activated.

Responsibility and hand washing behaviour

BACKGROUND AND OBJECTIVES

Recent research suggests that compulsions persist due to a self-perpetuating mechanism of poor memory confidence and repetition. However, most of this work has examined checking compulsions and findings may not generalize well to washing compulsions. This study examined the role of responsibility in the persistence of washing behaviour.

METHODS

Hand washing was examined in undergraduates (n = 80) high and low in contamination fears (CF) under conditions of high or low responsibility (RL). Wash duration and number of visits to objects/locations key to the wash (e.g., soap) were examined.

RESULTS

Overvalued responsibility predicted washing duration across groups. Neither wash duration nor number of visits was associated with memory for the wash. Wash duration predicted post-wash certainty that the wash had prevented harm, but only in the high CF group, and that effect varied according to RL: longer wash duration predicted greater certainty under conditions of low RL but predicted less certainty under conditions of high RL. Greater repetition predicted poorer sensory confidence, but only in the high CF group under high RL conditions.

LIMITATIONS

The data were collected in an analogue sample of modest size. Replication in a clinical sample is required.

CONCLUSIONS

Self-perpetuating mechanisms identified in perseverative checking seem to also be present in perseverative washing, but only under conditions of high responsibility. Sensory confidence may be more important to perseverative washing than memory confidence. More research is required to understand self-perpetuating mechanisms at play when washing to under conditions of high responsibility.

Anxiety and ritualization: Can attention discriminate compulsion from routine?

Despite the wide occurrence of ritual behavior in humans and animals, much of its causal underpinnings, as well as evolutionary functions, remain unknown. A prominent line of research focuses on ritualization as a response to anxiogenic stimuli. By manipulating anxiety levels, and subsequently assessing their motor behavior dynamics, our recent study investigated this causal link in a controlled way. As an extension to our original argument, we here discuss 2 theoretical explanations of rituals—ritualized behavior and automated behavior—and their link to anxiety. We propose that investigating participant's locus of attention can discriminate between these 2 models.

Effects of Anxiety on Spontaneous Ritualized Behavior

Environmental uncertainty and uncontrollability cause psycho-physiological distress to organisms, often impeding normal functioning. A common response involves ritualization, that is, the limitation of behavioral expressions to predictable stereotypic and repetitive motor patterns. In humans, such behaviors are also symptomatic of psychopathologies like obsessive-compulsive disorder (OCD) and autism spectrum disorders (ASDs). Although these reactions might be mediated by different neural pathways, they serve to regain a sense of control over an uncertain situation by engaging in behavioral patterns characterized by redundancy (superfluous actions that exceed the functional requirements of a goal), repetitiveness (recurrent behaviors or utterances), and rigidity (emphasis on fidelity and invariance). We examined whether ritualized behavior will manifest spontaneously as a dominant behavioral strategy in anxiogenic situations. Manipulating anxiety, we used motion-capture technology to quantify various characteristics of hand movements. We found that induced anxiety led to an increase in repetitiveness and rigidity, but not redundancy. However, examination of both psychological and physiological pathways revealed that repetitiveness and rigidity were predicted by an increase in heart rate, while self-perceived anxiety was a marginally significant predictor of redundancy. We suggest that these findings are in accordance with an entropy model of uncertainty, in which anxiety motivates organisms to return to familiar low-entropy states in order to regain a sense of control. Our results might inform a better understanding of ritual behavior and psychiatric disorders whose symptoms include over-ritualization.

Semantic network mapping of religious material: testing multi-agent computer models of social theories against real-world data

Agent-based modeling allows researchers to investigate theories of complex social phenomena and subsequently use the model to generate new hypotheses that can then be compared to real-world data. However, computer modeling has been underutilized in regard to the understanding of religious systems, which often require very complex theories with multiple interacting variables (Braxton et al. in Method Theory Study Relig 24(3):267-290, 2012. doi: 10.1163/157006812X635709 ; Lane in J Cogn Sci Relig 1(2):161-180, 2013). This paper presents an example of how computer modeling can be used to explore, test, and further understand religious systems, specifically looking at one prominent theory of religious ritual. The process is continuous: theory building, hypothesis generation, testing against real-world data, and improving the model. In this example, the output of an agent-based model of religious behavior is compared against real-world religious sermons and texts using semantic network analysis. It finds that most religious materials exhibit unique scale-free small-world properties and that a concept's centrality in a religious schema best predicts its frequency of presentation. These results reveal that there adjustments need to be made to existing models of religious ritual systems and provide parameters for future models. The paper ends with a discussion of implications for a new multi-agent model of doctrinal ritual behaviors as well as propositions for further interdisciplinary research concerning the multi-agent modeling of religious ritual behaviors.

Animal models of obsessive-compulsive disorder: utility and limitations

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

Spatial behavior reflects the mental disorder in OCD patients with and without comorbid schizophrenia

OBJECTIVE

Resolving the entangled nosological dilemma of whether obsessive-compulsive disorder (OCD) with and without schizophrenia (schizo-OCD and OCD, respectively) are two independent entities or whether schizo-OCD is a combined product of its parent disorders.

METHODS

Studying motor activity in OCD and in schizo-OCD patients. Performance of the patients was compared with the performance of the same motor task by a matching control individual.

RESULTS

Behavior in both schizo-OCD and OCD patients differed from controls in the excessive repetition and addition of acts, thus validating an identical OC facet. However, there was a significant difference in spatial behavior. Schizo-OCD patients traveled over a greater area with less focused activity as typical to schizophrenia patients and in contrast to OCD patients, who were more focused and traveled less in a confined area. While schizo-OCD and OCD patients share most of the OC ritualistic attributes, they differ in the greater spread of activity in schizo-OCD, which is related to schizophrenia disorder.

DISCUSSION

It is suggested that the finding on difference in spatial behavior is a reflection of the mental differences between OCD and schizophrenia. In other words, this could be an overt and observable manifestation of the mental state, and therefore may facilitate the nosology of OC spectrum disorders and OCD.

CONCLUSION

It seems as if both the OCD patients' focus on specific thoughts, and the contrasting wandering thoughts of schizophrenia patients, are reflected in the focused activity of the former and wandering from one place to the next of the latter.

Ethological Approach to Autism Spectrum Disorders

The purpose of the study was to develop a new ethogram for the assessment of children and adolescents with autism spectrum disorders (ASD) and intellectual developmental disorder (IDD) and to test whether this instrument accurately distinguishes ASD participants ( n = 61) from IDD participants ( n = 61). An ethogram with 88 behavior elements was generated, including body postures, verbalizations, facial expressions, motor stereotypies, head postures, gaze behavior, gestures, and interpersonal distance. Significant differences were detected between both groups in classic ASD behaviors; in behaviors that are deficient in ASD according to established theoretical models, such as symbolic play, gaze direction, gaze following, and use of mental state language; in atypical behaviors that have also been described previously in ethological studies with ASD; and in the nonspecific behaviors of ASD, such as walk, look own body, explore, and cry. The predictive success of a diagnosis of ASD in the logistic regression model with the ethogram's factors was 98.4%. The results suggest that this ethogram is a powerful and useful tool for both the detailed study of the social behaviors of autistic children and adolescents, and for discriminating ASD and IDD.

The impact of precaution and practice on the performance of a risky motor task

The association between threat perception and motor execution, mediated by evolved precaution systems, often results in ritual-like behavior, including many idiosyncratic acts that seem irrelevant to the task at hand. This study tested the hypothesis that threat-detection during performance of a risky motor task would result in idiosyncratic activity that is not necessary for task completion. We asked biology students to follow a particular set of instructions in mixing three solutions labeled "bio-hazardous" and then repeat this operation with "non-hazardous" substances (or vice versa). We observed a longer duration of the overall performance, a greater repertoire of acts, longer maximal act duration, and longer mean duration of acts in the "risky" task when it was performed before the "non-risky" task. Some, but not all, of these differences were eliminated when a "non-risky" task preceded the "risky" one. The increased performance of idiosyncratic unnecessary activity is in accordance with the working hypothesis of the present study: ritualized idiosyncratic activities are performed in response to a real or illusionary threat, as a means to alleviate anxiety.

Marked inbred mouse strain difference in the expression of quinpirole induced compulsive like behavior based on behavioral pattern analysis

Obsessive-compulsive disorder (OCD) is a chronic and complex psychiatric disorder with a lifetime prevalence of 2-3%. Recent work has shown that OCD rituals were not only characterized by a high rate of repetition but also by an increased behavioral repertoire due to additional non-functional unique acts. These two behavioral characteristics may provide an ethological basis for studying compulsive behavior in an animal model of OCD. Here, quinpirole induced behavior (so far only investigated in rats) has been studied in A/J and C57BL/6J mice by using behavioral pattern analysis. The aim of this study is to investigate whether genetic background is mediating this behavior. Results showed that open field motor activity levels of saline treated C57BL/6J mice was significantly higher compared to A/J treated saline mice. Long-term quinpirole treatment increased open field motor activity levels in A/J, but not in C57BL/6J. Quinpirole treatment induced a strain dependent difference in behavioral repertoire. There was a dose dependent increase in the number of different behavioral patterns in A/J, whereas, in C57BL/6J there was a dose dependent decrease. This data suggest that genetic background is important in expressing quinpirole induced compulsive like behavior. Following quinpirole treatment, A/J mice express a greater behavioral repertoire with a high rate of repetition. This phenotype resembles that of OCD rituals in patients and indicates that this strain is very interesting to further validate for studying neurobiological mechanisms of compulsive behavior.

D1 and D2 dopamine receptor antagonists decrease behavioral bout duration, without altering the bout's repeated behavioral components, in a naturalistic model of repetitive and compulsive behavior

Nest building behavior in the pregnant female rabbit (Oryctolagus cuniculus) is a model for compulsive behavior in Obsessive Compulsive Disorder (OCD). This behavior comprises a cycle of repeated, stereotyped components (collecting straw, entering nest box and depositing the straw there, returning to collect more straw), which itself is repeated 80+ times in a single bout that lasts approximately 50min. The bout, in turn, is repeated if necessary, according to the rabbit's perception of whether or not the nest is finished. We administered SCH23390 (5-100μg/kg; D1/D5 antagonist) or raclopride (0.05-1.0mg/kg; D2/D3 antagonist), subcutaneously to day 28 pregnant female rabbits, 30 or 60min before placing straw inside their home cage. At doses that minimally affected ambulatory behavior in open field (5-12.5μg/kg SCH23390, 0.5-1.0mg/kg raclopride), both antagonists dramatically reduced bout duration while not significantly affecting the initiation of straw carrying behavior, the sequential performance of the individual cycle components, maximum cycle frequency, or the total number of bouts performed. These results point to an important role for dopamine neurotransmission for the prolonged expression of a normal, repetitive and compulsive-like behavior. Moreover, the finding that dopamine receptor antagonists decrease the time spent engaged in repetitive behavior (without significantly altering the form of the repetitive behavior itself) suggests a possible explanation for why neuroleptics can be clinically effective for treating OCD.

Behavioral pattern analysis and dopamine release in quinpirole-induced repetitive behavior in rats

Obsessive-compulsive disorder (OCD) is a chronic and disabling psychiatric disease with a lifetime prevalence of 2-3%. People with OCD suffer from intrusive, unwanted and recurrent thoughts (obsessions) and/or repetitive ritualistic behaviors (compulsions). The aim of this study is to quantify the dimensions of ritualistic 'compulsive-like' behavior in quinpirole-induced behavior in rats by using T-pattern behavioral analysis. In addition, we investigated whether the behavioral effects elicited by quinpirole sensitization remained after 2 weeks of cessation of treatment. Finally, to study the neurobiological underpinnings of this 'compulsive-like' behavior, we investigated the effect of quinpirole treatment on the extracellular dopamine levels in the nucleus accumbens. Once established, 'compulsive-like' behavior is dependent upon quinpirole administration, as this behavior rapidly normalized after cessation of treatment. After a single dose of quinpirole the dopamine level decreased more in saline pre-treated animals as compared with animals given quinpirole treatment continuously. Furthermore, T-pattern analysis revealed that quinpirole-induced behavior consists, unlike OCD rituals, of a smaller behavioral repertoire. As seen in patients with OCD, quinpirole-treated animals performed these behaviors with a high rate of repetition. These findings suggest that quinpirole-induced behavior mimics only part of the compulsive behavior as shown in OCD patients.

Video telemetry and behavioral analysis discriminate between compulsive cleaning and compulsive checking in obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) patients exhibit compulsive acts that share key characteristics that discriminate them from normal behaviors. In OCD, factor analysis of symptomatology has identified separate clusters (contamination/cleaning; harming/checking; symmetry/ordering; hoarding). Here we used video analysis of the motor characteristics of OCD compulsions derived from two separate clusters, checking and cleaning, in order to determine whether behavioral differences exist in the way these two compulsions are performed. We compared 22 behavioral components (acts) of 12 OC-cleaning rituals and 25 OC-checking rituals. A normal activity with the identical theme was matched for each OC ritual as a control. For each ritual and control, we measured 22 parameters (such as the duration and frequency of act performance), and the levels of functionality, by evaluating the degree to which the act appears to contribute toward achieving its goal. We found that both OC-cleaning and OC-checking rituals differed from their respective control activity, and that they also differ between themselves in seven out of the 22 parameters. OC-cleaning involved increased repetition of functional activity whereas OC-checking involved a relatively increased non-functional activity. These results suggest that OCD cleaning and checking rituals are sufficiently different to justify their division into different subtypes and presumably are sub-served by different mechanisms. A better understanding of the relationship between those behavioral parameters derived from video-telemetry, and the parameters assessed by means of clinical and neurobiological tools, would improve our understanding of the nosological significance of compulsive symptoms and contribute to advancing endophenotypic exploration of the heterogeneity of OCD.

Manifestation of incompleteness in obsessive-compulsive disorder (OCD) as reduced functionality and extended activity beyond task completion

BACKGROUND

This study focused on hypotheses regarding the source of incompleteness in obsessive-compulsive disorder (OCD). For this, we had to document the behavioral manifestation of incompleteness in compulsive rituals, predicting that an exaggerated focus on acts that are appropriate for the task will support the hypothesis on heightened responsibility/perfectionism. In contrast, activity past the expected terminal act for the motor task would support the "stop signal deficiency" hypothesis.

METHODOLOGY AND PRINCIPAL FINDINGS

We employed video-telemetry to analyze 39 motor OCD rituals and compared each with a similar task performed by a non-OCD individual, in order to objectively and explicitly determine the functional end of the activity. We found that 75% of OCD rituals comprised a "tail," which is a section that follows the functional end of the task that the patients ascribed to their activity. The other 25% tailless rituals comprised a relatively high number and higher rate of repetition of non-functional acts. Thus, in rituals with tail, incompleteness was manifested by the mere presence of the tail whereas in tailless rituals, incompleteness was manifested by the reduced functionality of the task due to an inflated execution and repetition of non-functional acts.

CONCLUSIONS

The prevalence of activity after the functional end ("tail") and the elevated non-functionality in OCD motor rituals support the "lack of stop signal" theories as the underlying mechanism in OCD. Furthermore, the presence and content of the tail might have a therapeutic potential in cognitive-behavior therapy.

Are there between-country differences in motor behavior of obsessive-compulsive disorder patients?

BACKGROUND

Cross-cultural factors attributed to obsessive-compulsive disorder (OCD) that are widely investigated around the world are mostly epidemiological, with no respect to the impact of culture on the structure of OCD behavior itself.

METHODS

Nine Israeli and nine British OCD patients with respective non-OCD individuals were compared. To determine whether OCD symptoms are consistent across cultures, similarities in behavior were analyzed, as well as differences due to a country effect. In each country, nine OCD patients and nine non-OCD individuals were videotaped while performing the task that the patients attributed to their behavior.

RESULTS

Except for a significantly higher rate of repetition and higher performance of idiosyncratic acts, patients from both Israel and the United Kingdom showed high levels of similarities in 22 out of 24 parameters. Compared with Israeli subjects, British OCD patients had significantly longer chains of idiosyncratic acts, and a twice-higher prevalence of brief (1-2 second) idiosyncratic acts. Between-country differences were mild, possibly overridden by the conspicuous impact of OCD pathology, resulting in a similar OCD phenotype.

CONCLUSION

These results qualitatively and quantitatively emphasize the universal appearance of the compulsions in OCD symptoms.

Pragmatic and idiosyncratic acts in human everyday routines: the counterpart of compulsive rituals

Our daily activities are comprised of motor routines, which are behavioral templates with specific goals, typically performed in an automatic fixed manner and without much conscious attention. Such routines can seem to resemble pathologic rituals that dominate the motor behavior of obsessive-compulsive disorder (OCD) and autistic patients. This resemblance raises the question of what differentiates and what is common in normal and pathologic motor behavior. Indeed, pathologic motor performance is often construed as an extended stereotyped version of normal everyday routines. In this study we applied ethological tools to analyze six motor routines performed by 60 adult human volunteers. We found that longer normal everyday routines included more repetitions, but not more types of acts, and that in each routine, most acts were performed either by all individuals (pragmatic acts) or by only one individual (idiosyncratic components). Thus, normal routines consist in a relatively rigid part that is shared by all individuals that perform the routine, and a flexible part that varies among individuals. The present results, however, do not answer the question of whether the flexible individual part changes or remains constant over routine repetition by the same person. Comparing normal routines with OCD rituals revealed that the latter comprise an exaggeration of the idiosyncratic component. Altogether, the present study supports the view that everyday normal routines and pathologic rituals are opposite processes, although they both comprise rigid motor behavioral sequences.