Dyskinesia and impulsive compulsive behaviour in Parkinson's disease are not related: Insights from a study with a wearable sensor.

INTRODUCTION: Previous studies have suggested an association between Impulsive Compulsive Behaviour (ICB) and dyskinesia in Parkinson's disease (PD). However, none of these studies have employed an objective home-based measure of dyskinesia. OBJECTIVES: To evaluate in advanced PD the relationship between ICB and dyskinesia, objectively measured with a wearable device. METHODS: In this cross-sectional study, ICB and other neuropsychiatric symptoms were assessed by means of structured clinical interview and specific screening instruments. Presence and severity of motor fluctuations and dyskinesia were rated with patient's and clinician's based rating instruments. Motor fluctuations and dyskinesia were also measured at home for 5-days using a validated wearable devise, the Parkinson's KinetiGraph™(PKG). RESULTS: We included 89 subjects with PD (29 females, 62 ± 7 years, disease duration 10.3 ± 4.5), of whom 36 (40%) had ICB. Patients with and without ICB did not differ by presence and severity of dyskinesia measured by clinical scales and PKG. There was no association between the presence of ICB and dyskinesia in the whole sample. CONCLUSION: Our data suggest that ICB and dyskinesia are common but unrelated disorders in advanced PD.

Anxiety predicts impulsive-compulsive behaviours in Parkinson's disease: Clinical relevance and theoretical implications.

Patients with Parkinson's disease (PD) often present symptoms of anxiety, depression and apathy. These negative affect manifestations have been recently associated with the presence of impulsive compulsive behaviours (ICBs). However, their relation with the use of dopamine replacement therapy (DRT), a renewed risk factor for ICBs, is still not fully understood. Elucidating the role of these different ICBs predictors in PD could inform both prevention/intervention recommendations as well as theoretical models. In the present study, we have analysed data collected in 417 PD patients, 50 patients with Parkinsonian symptoms but with scan without evidence of dopaminergic deficit (SWEDD), and 185 healthy controls (HC). We examined each patient's clinical profile over a two-year time window, investigating the role of both negative affect and DRT on ICBs. Results confirmed the presence of higher levels of anxiety in both the clinical groups, and of higher level of ICBs in SWEDD patients, respect to both PD and HC. Mixed model analyses revealed a statistically significant association between anxiety and ICBs in the SWEDD patients who did not take any DRT. Findings suggest the independence between anxiety and DRT in ICBs development, and provide new evidence for the motivational opponency theoretical framework.

Risk factors of impulsive-compulsive behaviors in PD patients: a meta-analysis.

OBJECTIVE: To summarize the reliable risk factors of impulsive-compulsive behaviors (ICBs) in Parkinson's disease (PD) patients through a meta-analysis on studies in which PD-ICBs were diagnosed by clinical interview. METHODS: PubMed, Embase, Web of Science, CNKI and Wanfang databases were searched. We selected studies ensuring that diagnosis of ICBs in PD patients depends on semi-structured interviews according to the clinical diagnostic criteria of ICBs. The Newcastle-Ottawa Scale was used to evaluate quality of the included studies. The analyzed factors included demographic information, clinical characteristics of PD and medications. RESULTS: A total of 856 records were screened and 66 full texts were evaluated, and 13 studies (684 PD patients with ICBs [PD-ICBs] and 3,382 PD patients without ICBs [PD-non-ICBs]) were included. Compared with PD-non-ICBs, PD-ICBs were younger in age (- 3.7 [- 5.53, - 1.87], P < 0.0001), with a greater proportion of males (1.64 [1.21, 2.22], P = 0.001), with a younger age of PD onset (- 5.42 [- 7.87, - 2.97], P < 0.0001) and a longer course of PD (1.30 [0.38, 2.22], P = 0.005). PD-ICBs were also associated with higher HAM-D (1.74 [0.47, 3.01], P = 0.007), more levodopa dosage (1.74 [1.09, 2.77], P = 0.02) and dopamine receptor agonists (DA) use (3.96 [2.74, 5.71), P < 0.00001), and higher average dose (levodopa 117.53 [53.59, 181.46], P = 0.0003; DA 80.03 [46.16, 113.90], P < 0.00001), as well as more amantadine use (2.20 [1.42, 3.40], P = 0.0004). The meta-analysis of most factors showed less heterogeneity, except age, age of onset, PD duration, Hoehn and Yahr stage, MMSE and drug dosage. However, whether rapid eye movement sleep behavior disorder, dyskinesia, genetic polymorphism and other factors are risk factors for PD-ICBs remains unclear. CONCLUSION: This meta-analysis suggests that males, young, early disease onset, long disease duration, depression, dose of levodopa, dopamine receptor agonists and amantadine are risk factors of ICBs in PD patients.

Compulsions without obsession following stroke.

BACKGROUND: Obsessive-compulsive disorder (OCD) is characterized by intrusive and irrational thoughts as well as repetitive behaviours. OCD-like behaviours have been described in a wide range of neurological disorders. In cerebrovascular accidents, the semiology arises mostly from lesions to the basal ganglia - though cortical regions may also be involved. In the past few years, the mechanisms underlying OCD in psychiatric patients have been re-examined, in particular the functional relationship between anxiety, obsessions and compulsions. Traditionally, obsessions are viewed as a trigger for compulsive behaviour that represents an attempt to reduce anxiety. By contrast, other models place compulsions - as a manifestation of an imbalance between goal-directed action and automatic habits that leads to maladaptive habit learning - at the core of OCD. CASE: We show neurological evidence of pure compulsions without obsession in a patient following stroke in the left subcortical regions. Furthermore, we present comprehensive neuropsychological findings that identify specific alterations across executive and emotional domains. Finally, MRI analyses reveal that the subcortical stroke had resulted in a strong decrease of connectivity suggestive of large network alterations. CONCLUSIONS: Our case provides direct information on how brain structure and function relate in an OCD patient, highlighting the central role of compulsions in the pathology.

Joint contributions of metacognition and self-beliefs to uncertainty-guided checking behavior.

Checking behavior is a natural and adaptive strategy for resolving uncertainty in everyday situations. Here, we aimed at investigating the psychological drivers of checking and its regulation by uncertainty, in non-clinical participants and controlled experimental settings. We found that the sensitivity of participants' explicit confidence judgments to actual performance (explicit metacognition) predicted the extent to which their checking strategy was regulated by uncertainty. Yet, a more implicit measure of metacognition (derived from asking participants to opt between trials) did not contribute to the regulation of checking behavior. Meanwhile, how participants scaled on questionnaires eliciting self-beliefs such as self-confidence and self-reported obsessive-compulsive symptoms also predicted participants' uncertainty-guided checking tendencies. Altogether, these findings demonstrate that checking behavior is likely the outcome of a core explicit metacognitive process operating at the scale of single decisions, while remaining influenced by general self-beliefs. Our findings are thus consistent with two mechanisms (micro vs. macro) through which this otherwise adaptive behavior could go awry in certain psychiatric disorders such as obsessive-compulsive disorder.

Mediating effect of intolerance of uncertainty in the relationship between coping styles with stress during pandemic (COVID-19) process and compulsive buying behavior.

Novel CoronaVirus Disease (COVID-19) has begun to expand swiftly beyond all borders and turned into a global source of infection for humans in that all media corporations began to repeatedly share breaking news to release the latest data of all countries. The consequence of that has been a heightened level of anxiety among humans and opting for unorthodox consumption behaviors as consumers. In this study the attempt was to analyze human behaviors during the ongoing pandemic process from the perspective of psychology and marketing fields of science. In so doing, interrelation among anxiety, which surfaced because of Covid-19 pandemic, coping style with stress of individuals and compulsive purchase behavior has been explored. Based on these interrelations, a structural model was suggested. Findings of the research indicated that anxiety has high effect on the helpless approach dimension, which is one of the coping styles with stress; and that helpless approach alone has an effect on compulsive buying behavior. Besides, another objective of the study was to evaluate the mediating effect of intolerance of uncertainty between coping style with stress and compulsive buying behavior. That analysis evidenced that intolerance of uncertainty in such an interrelation had a partial mediating effect.

Subarachnoid hemorrhage in C57BL/6J mice increases motor stereotypies and compulsive-like behaviors.

OBJECTIVE: Long-term behavioral, mood, and cognitive deficits affect over 30% of patients with subarachnoid hemorrhage (SAH). The aim of the present study was to examine the neurobehavioral outcomes following endovascular perforation induced SAH in mice. METHODS: C57BL/6 J (B6) mice were exposed to endovascular perforation induced SAH or control surgery. Three weeks later, mice received a series of behavioral tests, e.g. motor function, stereotypy, learning, memory, behavioral flexibility, depression and anxiety. The immunohistologic experiment examined neuronalloss in the cortex following SAH. RESULTS: SAH mice exhibited increased marble burying and nestlet shredding compared to that of control mice. Although SAH did not affect memory, learning or reversal learning,mice displayed greater overall object exploration in the novel object recognition test, as well as elevated perseveration during probabilistic reversal learning.In the forced swim and open field tests, SAH mice performed comparably to that of control mice. However, SAH mice exhibited an increased frequency in 'jumping' behavior in the open field test. Histological analyses revealed reduced neuron density in the parietal-entorhinal cortices of SAH mice on the injured side compared to that of control mice. DISCUSSION: The findings suggest that parietal-entorhinal damage from SAH increases stereotyped motor behaviors and 'compulsive-like' behaviors without affecting cognition (learning and memory) or mood (anxiety and depression). This model can be used to better understand the neuropathophysiology following SAH that contributes to behavioral impairments in survivors with no gross sensory-motor deficits.

Effects of Motor Symptom Laterality on Clinical Manifestations and Quality of Life in Parkinson's Disease.

BACKGROUND: The asymmetry of motor manifestations present in Parkinson's disease (PD) suggests the existence of differences between both hemispheres. As a consequence, this asymmetry might contribute to different PD clinical phenotypes. OBJECTIVE: To study the relationship between motor symptom laterality with motor, non-motor symptoms (NMS), freezing of gait (FOG), and quality of life (QoL) impairment in PD. METHODS: In this cross-sectional study, we measured motor symptoms severity and complications with the Unified Parkinsons' disease Rating Scale (UPDRS), FOG with the FOG questionnaire, QoL with the 39-item PD Quality of Life Questionnaire Summary Index, and NMS with the NMS, Visual Analogue Scales for Pain and Fatigue, Beck Depression Inventory-II, Impulsive-Compulsive Disorders, and PD Sleep and Cognitive Rating scales. We defined left and right motor laterality using the UPDRS part III. We used comparative, regression, and effect size analyses to evaluate the impact of asymmetry on motor and NMS, FOG, and QoL. RESULTS: 342 left (LPD) and 310 right (RPD) patients, with a mean age of 62.0±8.8 years, were included. In multivariate regression analysis, LPD was associated with a greater motor (OR = 1,50, 95% CI 1.02-2.21), FOG (OR = 1.56, 95% CI 1.01-2.41), and overall NMS impairment (OR = 1.43, 95% CI 1.001-2.06), and better QoL (OR = 0.52 95% CI 0.32-0.85). Overall, only a mild effect size was found for all comparisons in which significant differences were present. CONCLUSION: In this large multicenter study, motor symptom laterality seems to carry a mild but significant impact on PD clinical manifestations, and QoL.

Dynamics of impulsive-compulsive behaviors in early Parkinson's disease: a prospective study.

INTRODUCTION: Impulsive compulsive behaviors (ICBs) in Parkinson's disease (PD) are debilitating disorders of repetitive, excessive, and compulsive nature affecting up to one third of PD patients. Objectives are to address clinical, psychiatric, and cognitive characteristics of ICBs and to define risk factors in PD patients in the initial motor stage, followed up for 5 years. METHODS: We analyzed 106 consecutive PD outpatients at Hoehn and Yahr disease stage 1 and 125 healthy controls. The participants were assessed for the presence of any ICB using the current clinical criteria and underwent comprehensive clinical, psychiatric, and neuropsychological evaluations. The patients completed the same protocol at Years 1, 2, 3, and 5. RESULTS: ICBs were present in 21 (19.8%) PD patients and 13 (10.4%) healthy controls at baseline. Prevalence of ICBs increased to 29.2% at Year 5, significantly after Year 2. Multiple ICBs were present in 4,7% and 61.9% of PD-ICBs at the baseline and Year 5, respectively. ICBs resolved in 30% of cases (most often compulsive eating). Dopamine agonist treatment at the baseline carried five times higher risk of having or developing ICB(s) anytime during follow-up. We identified risk factors for compulsive eating (dopamine agonist treatment at baseline), hypersexuality (males), compulsive buying (depression and younger age), and punding (younger age and higher levodopa dose at baseline). Significant interaction of rate of motor progression and ICB diagnosis was shown. CONCLUSIONS: PD patients showed increasing frequency of most ICBs during the 5-year follow-up. Specific risk factors were identified for different types of ICBs.

Effect of behavior therapy for Tourette's disorder on psychiatric symptoms and functioning in adults.

BACKGROUND: Although behavior therapy reduces tic severity, it is unknown whether it improves co-occurring psychiatric symptoms and functional outcomes for adults with Tourette's disorder (TD). This information is essential for effective treatment planning. This study examined the effects of behavior therapy on psychiatric symptoms and functional outcomes in older adolescents and adults with TD. METHOD: A total of 122 individuals with TD or a chronic tic disorder participated in a clinical trial comparing behavior therapy to psychoeducation and supportive therapy. At baseline, posttreatment, and follow-up visits, participants completed assessments of tic severity, co-occurring symptoms (inattention, impulsiveness, hyperactivity, anger, anxiety, depression, obsessions, and compulsions), and psychosocial functioning. We compared changes in tic severity, psychiatric symptoms, and functional outcomes using repeated measure and one-way analysis of variance. RESULTS: At posttreatment, participants receiving behavior therapy reported greater reductions in obsessions compared to participants in supportive therapy ($\eta _p^2 $ = 0.04, p = 0.04). Across treatments, a positive treatment response on the Clinical Global Impression of Improvement scale was associated with a reduced disruption in family life ($\eta _p^2 $ = 0.05, p = 0.02) and improved functioning in a parental role ($\eta _p^2 $ = 0.37, p = 0.02). Participants who responded positively to eight sessions of behavior therapy had an improvement in tic severity ($\eta _p^2 $ = 0.75, p < 0.001), inattention ($\eta _p^2 $ = 0.48, p < 0.02), and functioning ($\eta _p^2 $ = 0.39-0.42, p < 0.03-0.04) at the 6-month follow-up. CONCLUSION: Behavior therapy has a therapeutic benefit for co-occurring obsessive symptoms in the short-term, and reduces tic severity and disability in adults with TD over time. Additional treatments may be necessary to address co-occurring symptoms and improve functional outcomes.

Evolution of impulsive-compulsive behaviors and cognition in Parkinson's disease.

The longitudinal course of ICBs in patients with Parkinson's disease (PwP) relative to controls has not been explored as of yet. The aim of this study is to determine the frequency, evolution and associated cognitive and clinical features of impulsive and compulsive behaviors (ICBs) over 4 years of prospective follow-up in a population-based cohort with early Parkinson's disease (PD). We recruited 124 cognitively intact participants with early PD and 156 matched controls from the Norwegian ParkWest study. ICBs were assessed using the self-report short form version of the Questionnaire for Impulsive-Compulsive Disorders in PD. Cognitive changes were examined in PwP with and without ICBs who completed the 4-year follow-up. Generalized linear mixed modelling and mixed linear regression were used to analyze clinical factors and cognitive changes associated with ICBs in PwP over time. ICBs were more common in PwP than controls at all visits, with an age-adjusted odds ratio (OR) varying between 2.5 (95% CI 1.1-5.6; p = 0.022) and 5.1 (95% CI 2.4-11.0; p < 0.001). The 4-year cumulative frequency of ICBs in PwP was 46.8% and 23.3% developed incident ICBs during the study period, but the presence of ICBs was non-persistent in nearly 30%. ICBs were independently associated with younger age (OR 0.95, 95% CI 0.91-0.99: p = 0.008) and use of dopamine agonist (OR 4.1, 95% CI 1.56-10.69). Cognitive changes over time did not differ between patients with and without ICBs. In conclusion, ICBs are common in PwP, but are often non-persistent and not associated with greater cognitive impairment over time.

Association between REM sleep behavior disorder and impulsive-compulsive behaviors in Parkinson's disease: a systematic review and meta-analysis of observational studies.

BACKGROUND: Both REM sleep behavior disorder (RBD) and impulsive-compulsive behaviors (ICBs) are well-recognized non-motor features in patients with Parkinson's disease (PD). Studies have given contradictory results about the potential association between RBD and ICBs. METHODS: PubMed, Embase (via Ovid), and the Cochrane Central Registry of Controlled Trials (CENTRAL) databases were systematically searched till August 20, 2019 to identify studies that explored the possible correlation between RBD and ICBs in patients with PD. Two authors independently screened records, extracted data and evaluated quality of included studies. Pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated by employing a random or fixed-effects model. We performed subgroup and sensitivity analyses, and we assessed potential publication bias. RESULTS: A total of 134 references were screened and 10 studies involving 2781 PD patients were included. Overall, RBD was associated with a more than twofold higher risk of developing ICBs (OR 2.12, 95% CI 1.43-3.14, I2 = 56.7%, P < 0.01). Similar results were obtained in sensitivity analyses and in meta-analyses of subgroups stratified based on multivariable adjustment and methods for diagnosing RBD and ICBs. No significant risk of publication bias was found. CONCLUSION: RBD in PD is confirmed to be a risk factor for ICBs. Clinicians should be aware of this association to help them improve patient management.

Obsessive-Compulsive Symptoms are Less Common in Huntington's Disease than Reported Earlier.

BACKGROUND: Previous research using the Symptom-Checklist-90-Revised (SCL-90-R) has shown that compulsive symptoms in Huntington's disease (HD) occur in 10% to 52% of all cases. The "Hamburger-Zwangsinventar" (HZI), a self-rating questionnaire comprising 188 items, taps into the domain of compulsiveness in greater detail, but has not been used in HD so far. In addition, little is known about the association of obsessive-compulsive symptoms with pre-clinical stages of HD. OBJECTIVE: Comparison of OC symptoms measured by the SCL-90-R and the HZI in pre-HD and HD. METHODS: 29 premanifest mutation carriers (pre-HD) and 40 manifest HD patients completed both questionnaires. Clinical characteristics of HD were rated by using the UHDRS. RESULTS: Compared to data from general population prevalence of OC symptoms were not higher as expected in preHD and only slightly elevated in manifest HD if using HZI. Both instruments detected more OC symptoms in HD patients compared to pre-HD. The SCL-90-R more often detects compulsivity than the HZI. Results of both questionnaires showed correlations to cognition, depression, and disease duration. Compared to findings from OCD patients, there was a subordinate role in the HZI subscale for "washing and cleaning" in HD. CONCLUSIONS: OC symptoms in pre-HD occur not more often than in general population. The HZI appears to be useful for examining OC symptoms in detail in pre-HD and HD. HZI-subscale ratings for washing and cleaning compulsions were less pronounced in HD compared to OCD patients, possibly due to loss of disgust. The SCL-90-R might overestimate OC symptoms in both groups.

Forced person-following: a new type of stimulus-bound behavior.

We report a new type of stimulus-bound behavior, denoted forced person-following, which we documented for a patient with hypoxic encephalopathy following a suicide attempt with carbon monoxide poisoning. The patient's brain was damaged in the bilateral frontal, parietal, and temporal lobes and in the basal ganglia. The patient was compelled to follow any person who came into his sight and would continue to do so until the person went out of his sight. The patient also exhibited certain primitive reflexes. The forced person-following exhibited by our patient appears to be a consequence of stimulus-bound behavior due to frontal lobe dysfunction and, to a lesser degree, severe cognitive dysfunctions, e.g., visuospatial deficits, which are related to damage in posterior cortices. The unique behavior exhibited by this patient might contribute to our understanding of innate human behavior.

Saccadic Direction Errors are Associated with Impulsive Compulsive Behaviours in Parkinson's Disease Patients.

Fifteen individuals with Parkinson's disease (PD) and impulsive compulsive behaviours (PD+ICB) were compared to 15 PD patients without ICBs (PD-ICB) and 15 healthy controls (HC) on a pro-saccades and an anti-saccades task to assess if ICBs are associated with distinct saccadic abnormalities. PD+ICB made shorter saccades than HC and more direction errors in the anti-saccades task than PD-ICB and HC, suggesting that patients with ICBs have greater difficulty in suppressing automatic saccades towards a given target. Saccadic assessment has the potential to evolve into a marker to guide therapeutic decisions in patients at risk of developing ICBs.

Understanding the Role of Healthy Eating and Fitness Mobile Apps in the Formation of Maladaptive Eating and Exercise Behaviors in Young People.

BACKGROUND: Healthy eating and fitness mobile apps are designed to promote healthier living. However, for young people, body dissatisfaction is commonplace, and these types of apps can become a source of maladaptive eating and exercise behaviors. Furthermore, such apps are designed to promote continuous engagement, potentially fostering compulsive behaviors. OBJECTIVE: The aim of this study was to identify potential risks around healthy eating and fitness app use and negative experience and behavior formation among young people and to inform the understanding around how current commercial healthy eating and fitness apps on the market may, or may not, be exasperating such behaviors. METHODS: Our research was conducted in 2 phases. Through a survey (n=106) and 2 workshops (n=8), we gained an understanding of young people's perceptions of healthy eating and fitness apps and any potential harm that their use might have; we then explored these further through interviews with experts (n=3) in eating disorder and body image. Using insights drawn from this initial phase, we then explored the degree to which leading apps are preventing, or indeed contributing to, the formation of maladaptive eating and exercise behaviors. We conducted a review of the top 100 healthy eating and fitness apps on the Google Play Store to find out whether or not apps on the market have the potential to elicit maladaptive eating and exercise behaviors. RESULTS: Participants were aged between 18 and 25 years and had current or past experience of using healthy eating and fitness apps. Almost half of our survey participants indicated that they had experienced some form of negative experiences and behaviors through their app use. Our findings indicate a wide range of concerns around the wider impact of healthy eating and fitness apps on individuals at risk of maladaptive eating and exercise behavior, including (1) guilt formation because of the nature of persuasive models, (2) social isolation as a result of personal regimens around diet and fitness goals, (3) fear of receiving negative responses when targets are not achieved, and (4) feelings of being controlled by the app. The app review identified logging functionalities available across the apps that are used to promote the sustained use of the app. However, a significant number of these functionalities were seen to have the potential to cause negative experiences and behaviors. CONCLUSIONS: In this study, we offer a set of responsibility guidelines for future researchers, designers, and developers of digital technologies aiming to support healthy eating and fitness behaviors. Our study highlights the necessity for careful considerations around the design of apps that promote weight loss or body modification through fitness training, especially when they are used by young people who are vulnerable to the development of poor body image and maladaptive eating and exercise behaviors.

A high-refined carbohydrate diet facilitates compulsive-like behavior in mice through the nitric oxide pathway.

Obesity is characterized by abnormal adipose tissue expansion and is associated with chronic inflammation. Obesity itself may induce several comorbidities, including psychiatric disorders. It has been previously demonstrated that proinflammatory cytokines are able to up-regulate inducible nitric oxide synthase (iNOS) and nitric oxide (NO) release, which both have a role in compulsive related behaviors. OBJECTIVE: To evaluate whether acute or chronic consumption of a high-refined carbohydrate-containing (HC) diet will modify burying-behavior in the Marble Burying Test (MBT) through augmentation of NO signaling in the striatum, a brain region related to the reward system. Further, we also verified the effects of chronic consumption of a HC diet on the reinforcing effects induced by cocaine in the Conditioned Place Preference (CPP) test. METHODS: Male BALB/c mice received a standard diet (control diet) or a HC diet for 3 days or 12 weeks. RESULTS: An increase in burying behavior occurred in the MBT after chronic consumption of a HC diet that was associated with an increase of nitrite levels in the striatum. The pre-treatment with Aminoguanidine (50 mg/kg), a preferential inhibitor of iNOS, prevented such alterations. Additionally, a chronic HC diet also induced a higher expression of iNOS in this region and higher glutamate release from striatal synaptosomes. Neither statistical differences were observed in the expression levels of the neuronal isoform of NOS nor in microglia number and activation. Finally, the reinforcing effects induced by cocaine (15 mg/kg, i.p.) during the expression of the conditioned response in the CPP test were not different between the chronically HC diet fed mice and the control group. However, HC diet-feeding mice presented impairment of cocaine-preference extinction. CONCLUSION: Altogether, our results suggest that the chronic consumption of a HC diet induces compulsive-like behavior through a mechanism possibly associated with NO activation in the striatum.

Developing image sets for inducing obsessive-compulsive checking symptoms.

Visual stimuli are often used for obsessive-compulsive (OC) symptom provocation in research studies. We tested the induction of anxiety and OC checking symptoms across different types of checking provocation stimuli in three populations: individuals with obsessive compulsive disorder (OCD), individuals with checking symptoms but without a diagnosis of OCD, and control individuals with neither checking symptoms nor a clinical diagnosis. One set of provocative images depicted objects that are commonly associated with checking anxiety. Another set ('enhanced provocative images') depicted similar objects but also included contextual cues suggesting a specific harmful scenario that could occur. As expected, the enhanced provocative images were more effective at inducing anxiety and OC symptoms than the standard provocative images. Future studies requiring checking symptom provocation should therefore consider incorporating similarly suggestive images. Individuals with clinical OCD reported the greatest provocation in response to these images, followed by those with nonclinical checking, followed by control individuals. Thus, these stimuli are able to provoke OC checking symptoms and anxiety differentially across groups, with the intensity of provocation reflecting diagnostic status. All groups demonstrated a similar qualitative pattern of provocation across images. Finally, in all groups, reported anxiety closely tracked intrusive thoughts and checking urges.