To investigate the neuro-mechanisms underpinning persistent avoidance in OCD patients
Many compulsions displayed by obsessive-compulsive disorder (OCD) patients serve to protect against perceived threat and can, therefore, be conceptualized as 'avoidance responses'. Exposure treatment with response prevention (ET+RP) is aimed at exposing patients to their obsessive thoughts and perceived threats while preventing engagement in compulsive avoidant responses. This induces extinction of threat perception and fearful arousal and hence reduces the motivation to avoid. While successful in many patients, however, as much as 40% dropout during treatment or display persistent avoidance after ET+RP. There is a clear need for treatment improvement for these often highly disabled patients. Improving ET+RP outcomes requires a deeper understanding of the mechanisms that drive excessive and persistent avoidance in OCD patients. Psychological theories ascribe an important role to the relief that follows avoidance when the anticipated threat is successfully averted. This positive feeling arguably functions as a reward to reinforce the foregoing avoidance actions. Indeed, fMRI studies have found that the neurocircuitry of relief overlaps with that of reward, including the ventral tegmental area, ventral striatum and orbitofrontal cortex. Here, the authors will test the hypothesis that excessive-persistent avoidance is linked to exaggerated activation of the relief circuitry in OCD patients. For that purpose, we will acquire functional brain images of OCD patients in an MRI scanner and compare to healthy participants, while they participate in a computer task that is designed to model avoidance learning and relief.
Study Type
OBSERVATIONAL
Enrollment
40
Participants from the two groups will perform an avoidance-relief task inside an MRI scanner
Psychiatry | UZ Leuven campus Gasthuisberg
Leuven, Belgium
RECRUITINGAvoidance responses during the avoidance-relief task
Avoidance responses during avoidance learning and test will be recorded in terms of button press and Reaction times
Time frame: 1 hour for avoidance task
Relief during the omissions of the US
Relief will be measured as: Brain data during fMRI: whole-brain activations, as well as activations in specific regions of interest (ROI: VTA, NAcc, OFC) at the moment of the omissions of the electrical stimulation (US) during both the avoidance learning and the extinction learning phase of the avoidance-relief task; Individual ratings: relief pleasantness ratings measured on a Likert scale from 0 (neutral) to 3 (very pleasant) after each omission of the electrical stimulation (US) during both the avoidance learning and the extinction learning phase of the avoidance-relief task; Physiological data: skin conductance responses (SCR) at the moment of the omissions of the electrical stimulation (US) during both the avoidance learning and the extinction learning phase of the avoidance-relief task.
Time frame: 1 hour to perform the avoidance task
Tolerance to stress
The individual level of tolerance to distress will be measured via the self-administration of the Distress Tolerance Scale
Time frame: 1 hour to perform the avoidance task
Therapeutic outcome in OCD
The therapeutic outcome in OCD individuals will be evaluated by using the Y-BOCS (self-administered) questionnaire
Time frame: 1 hour to perform the avoidance task
Resting-state connectivity
The strength of connectivity between NAcc, VTA, and OFC, will be measured during the resting state MRI acquisition
Time frame: 1 hour to perform the avoidance task
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