Amygdala hyperactivation during symptom provocation in obsessive–compulsive disorder and its modulation by distraction

Anxiety disorders have been linked to a hyperactivated cortico-amygdalar circuitry. Recent findings highlight the amygdala's role in mediating elevated anxiety in obsessive–compulsive disorder (OCD). However, modulation of amygdala hyperactivation by attentional distraction – an effective emotion regulation strategy in healthy individuals – has not yet been examined. While undergoing functional magnetic resonance imaging twenty-one unmedicated OCD patients and 21 controls performed an evaluation and a distraction task during symptom provocation with individually tailored OCD-relevant pictures. To test the specificity of responses, additional aversive and neutral stimuli were included. Significant group-by-picture type interactions were observed within fronto–striato–limbic circuits including the amygdala. In these regions patients showed increased BOLD responses during processing of OCD triggers relative to healthy controls. Amygdala hyperactivation was present across OCD symptom dimensions indicating that it represents a common neural correlate. During distraction, we observed dampening of patients' amygdala hyperactivity to OCD-relevant stimuli. Augmented amygdala involvement in patients during symptom provocation, present across OCD symptom dimensions, might constitute a correlate of fear expression in OCD linking it to other anxiety disorders. Attentional distraction seemed to dampen emotional processing of disorder-relevant stimuli via amygdala downregulation. The clinical impact of this strategy to manage anxiety in OCD should be further elucidated.