Indices of change in exposure and response prevention for contamination-based OCD

Disgust-reduction evaluative conditioning (DREC) and brain stimulation in patients with contamination-based obsessive-compulsive disorder: a protocol for a randomized control trial

BACKGROUND

The negative emotional valence of a stimulus can be altered if paired with a pleasant stimulus, a phenomenon referred to as evaluative conditioning. Disgust, as a central emotion in obsessive-compulsive disorder (OCD), particularly in the contamination subtype, may be an appropriate target for such a method. We know that disgust processing and OCD pathophysiology share in some brain areas, including the orbitofrontal cortex, as the neuromodulation techniques targeted in this area have been able to decrease OCD symptoms. We aim to conduct a randomized clinical trial to investigate the evaluative conditioning effect on disgust reduction in patients with contamination-based OCD when administered with or without neuromodulation targeted orbitofrontal cortex.

METHOD

In a single-blind randomized control trial (RCT), 55 patients with contamination-based OCD will be randomly assigned to four arms. In a factorial design, they will receive 10 sessions of evaluative conditioning training (either sham or real) plus cathodal transcranial direct current stimulation (tDCS) over the orbitofrontal cortex (either sham or real). The intensity of disgust experience and clinical symptoms will be investigated as primary outcomes and quantitative electroencephalogram and cognitive functions as secondary outcomes. The data will be collected at three assessment levels: baseline, after completing intervention sessions, and 2-month follow-up.

DISCUSSION

The present RCT is the first study that applies evaluative conditioning training in the OCD clinical sample. It will clarify the effect of the evaluative conditioning method alone and with tDCS on disgust reduction in patients with contamination-based OCD. It will provide initial evidence for such an emotion modulation method in the OCD population. The effect of this emotion-focused protocol on cognitive functions and electroencephalogram components is also of interest.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT05907369. Registered on 16 June 2023. Retrospectively registered.

Treatment of disgust in specific emotional disorders

Although conditioning approaches have highlighted potential characteristics of disgust in anxiety disorders, obsessive-compulsive disorder (OCD), and posttraumatic stress disorder (PTSD), these findings have yet to be translated into evidence-based treatments. Examination of the literature suggests various indicators of disgust that predict treatment outcome in these disorders. However, mechanisms remain unclear because studies examining disgust during the course of treatment are limited. Increasingly, the field has moved toward experimental investigation of strategies that reduce disgust. While cognitive reappraisal and imagery techniques appear promising, such techniques have yet to be examined as anxiety disorder treatments in large-scale randomized clinical trials. The literature also points to novel approaches to treating disgust, ranging from an inhibitory-informed approach to exposure therapy to transcranial direct current stimulation. However, the development of novel treatment approaches will require more rigorous experimental psychopathology approaches that can further elucidate processes that contribute to the etiology and/or maintenance of disorders of disgust.

Mechanisms of exposure and response prevention in obsessive-compulsive disorder: effects of habituation and expectancy violation on short-term outcome in cognitive behavioral therapy

BACKGROUND

Exposure and response prevention is effective and recommended as the first choice for treating obsessive-compulsive disorders (OCD). Its mechanisms of action are rarely studied, but two major theories make distinct assumptions: while the emotional processing theory assumes that treatment effects are associated with habituation within and between exposure sessions, the inhibitory learning approach highlights the acquisition of additional associations, implying alternative mechanisms like expectancy violation. The present study aimed to investigate whether process variables derived from both theories predict short-term outcome.

METHOD

In a university outpatient unit, 110 patients (63 female) with OCD received manual-based cognitive-behavioral therapy with high standardization of the first two exposure sessions. Specifically, therapists repeated the first exposure session identically and assessed subjective units of distress as well as expectancy ratings in the course of exposure sessions. Based on these data, individual scores for habituation and distress-related expectancy violation were calculated and used for prediction of both percentage change on the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and remission status after 20 therapy sessions.

RESULTS

In a multiple regression model for percentage change, within-session habituation during the first exposure was a significant predictor, while in a logistic regression predicting remission status, distress-related expectancy violation during the first exposure revealed significance. A path model further supported these findings.

CONCLUSIONS

The results represent first evidence for distress-related expectancy violation and confirm preliminary findings for habituation, suggesting that both processes contribute to treatment benefits of exposure in OCD, and both mechanisms appear to be independent.

Left Amygdala Functional Connectivity Decreased after Fear of Negative Events was Disregarded in Obsessive-Compulsive Disorder

Obsessive-compulsive disorder (OCD) is a chronic and debilitating mental disorder that affects patients throughout their lives, leading to a diminished quality of life for patients and families, reduced productivity, and higher health care costs. It is of clinical and theoretical importance to investigate a more efficacious therapeutic approach for OCD and the neurophysiological mechanism underlying the efficacy of treatment, potentially associated with the etiology of OCD. Recently, a novel psychotherapy designated cognitive-coping therapy (CCT) has been reported to have a large effect size in OCD treatment. CCT hypothesizes that fear of negative events plays a crucial role in OCD. The study entitled “Decreased left amygdala functional connectivity by cognitive-coping therapy in obsessive-compulsive disorder” attempted to investigate the potential neurophysiological mechanism underlying the efficacy of CCT for OCD. The study provides crystal evidence showing that 4-week pharmacotherapy plus CCT decreases the left amygdala seed-based functional connectivity (LA-FC) with the right anterior cingulate gyrus and the left paracentral lobule/the left superior parietal/left inferior parietal, and 4-week CCT decreases the LA-FC with the left middle occipital gyrus/the left superior parietal. The alteration of the LA-FC with the right anterior cingulate gyrus positively correlates to the reduction of the Yale-Brown obsessive-compulsive scale (Y-BOCS) score. Therefore, it provides new insights into understanding the neurophysiology and neuropsychology behind the onset and treatment of OCD.

Mechanisms and Effectiveness of Imagery Strategies in Reducing Disgust in Contamination-Related Obsessive–Compulsive Disorder: Comparing Imagery Rescripting, Imagery Self-compassion and Mood-Focused Imagery

Background

Strong feelings of disgust and anxiety are maintaining factors in contamination-related obsessive–compulsive disorder (C-OCD). To this day there are not many studies that investigated strategies for changing pathological disgust. In a previous study, it was shown that imagery rescripting could successfully change disgust. However, whether imagery rescripting or more general imagery processing, helps to reduce pathological disgust, remains unclear. Therefore, the aim of the present study was to investigate how successful imagery rescripting is in comparison to imagery self-compassion and a passive positive imagery condition in reducing disgust.

Methods

For this, the three strategies were compared to each other on 2 days (within-subject) in a laboratory experiment. The study included 24 subjects with diagnosed C-OCD, and 24 matched, healthy controls (between-subject).

Results

The results show that all three strategies changed disgust, they do not differ from each other and that different traits appear to influence the strategies’ success or failure. The theoretically derived underlying mechanisms of the strategies were found in an elaborate content analysis.

Conclusions

The present study provides first indications that imagery in general can help to change pathological disgust experience.

A comprehensive group-based cognitive behavioural treatment for blood-injection-injury phobia

OBJECTIVES

A key feature of blood-injection-injury (BII) phobia is activation of disgust responses, in addition to fear. Yet, standard treatments have largely neglected addressing disgust responses. The disorder is further complicated by fainting in 75% of sufferers. Moreover, treatments have been traditionally delivered in an individual format, which may not be as efficient as group treatment. The aim of this study was to develop a group-based programme for BII phobia, with components targeting fear, disgust, and fainting, to determine feasibility and effectiveness of such an intervention.

METHODS

Participants took part in an 8-session, group-based Cognitive Behavioural Therapy (CBT) programme for BII phobia (N = 40). The key outcome measure was the Multidimensional Blood/Injury Phobia Inventory, which assesses a range of phobic stimuli and responses (including fear, disgust, and fainting).

RESULTS

There were significant improvements, with large effect sizes, across symptoms over the course of treatment. Participants with higher disgust sensitivity reported higher pre-treatment symptom severity and greater life interference than those with lower disgust scores. Despite this, neither pre-treatment disgust sensitivity nor fainting history impacted on treatment response. For the first time, however, we showed that greater reductions in disgust to BII stimuli were associated with greater overall symptom reductions, highlighting the importance of disgust in the treatment of this disorder, and potentially others.

CONCLUSION

Despite the heterogeneous nature of BII phobia, this group-based, modified CBT intervention was effective in reducing a variety of phobic responses, including fear, disgust, and fainting.

PRACTITIONER POINTS

Disgust is a key maintaining factor in blood-injection-injury phobia, which clinicians should consider in their assessment and treatment of this disorder. There is little in the existing literature to guide clinicians in this regard. This study examined a novel group treatment for blood-injection-injury phobia which included strategies to target disgust, in addition to traditional CBT strategies to address fear and fainting. The treatment was feasible and acceptable. Symptoms of fear, disgust, and fainting reduced significantly over treatment. Changes in disgust symptoms were associated with overall symptom changes, however a control group is needed to determine the effects of individual treatment components and to make more robust conclusions about the benefits of this enhanced approach.

Attentional Processing of Disgust and Fear and Its Relationship With Contamination-Based Obsessive-Compulsive Symptoms: Stronger Response Urgency to Disgusting Stimuli in Disgust-Prone Individuals

Disgust has recently been characterized as a low-urgency emotion, particularly compared to fear. The aim of the present study is to clarify whether behavioral inhibition during disgust engagement is characteristic of a low-urgency emotion and thus indicates self-imposed attentional avoidance in comparison to fear. Therefore, 54 healthy participants performed an emotional go/no-go task with disgust- and fear-relevant as well as neutral pictures. Furthermore, heart rate activity and facial muscle activity on the fear-specific m. corrugator supercilli and the disgust-specific m. levator labii were assessed. The results partially support the temporal urgency hypothesis of disgust. The emotion conditions significantly differed in emotional engagement and in the facial muscle activity of the m. levator labii as expected. However, contrary to our expectations, no differences between the emotion conditions regarding behavioral inhibition as well as heart rate change could be found. Furthermore, individuals with a higher-trait disgust proneness showed faster reactions and higher activity of the m. levator labii in response to disgust stimuli. The results show that different trait levels influence attentional engagement and physiological parameters but have only a small effect on behavioral inhibition.