Effect of behavioural therapy on neural substrates of OCD: a single case study

There is increasing evidence that obsessive-compulsive disorder (OCD) is associated with altered neuronal activity, especially in cortico-striato-limbic brain regions. We examined the effect of behavioural therapy on neuronal processes in a drug-naïve female patient with OCD and compared the results with those of a healthy control. The subjects were repeatedly scanned while viewing disgust-inducing, affective neutral and patient specific symptom-provoking pictures in a pseudo-randomized order. Functional MRI revealed enhanced BOLD responses in the patient especially in the anterior cingulate cortex, the insula and the visual association cortices during the presentation of symptom-associated pictures compared to the control subjects. The neural responses of the patient were significantly reduced after therapy. These results ran parallel to decreased disgust and fear ratings. By contrast, the responses of the healthy subject remained unchanged. Disgust-inducing and affective neutral pictures led to comparable brain responses in the OCD-patient and the healthy subject during both fMRI sessions. Summarizing, individual symptom triggers provoked an enhanced involvement of the fronto-striato-parietal network in the OCD patient. The reactivity to OCD triggers was considerably reduced after behavioural therapy indicating a positive influence on these processes.