Hippocampus volume alterations and the clinical correlates in medication naïve obsessive compulsive disorder.

BACKGROUND

Converging evidence suggests the role of hippocampus in the pathophysiology of Obsessive-Compulsive Disorder (OCD). The role of hippocampus, which might have a cardinal role in the neurobiology of OCD through its mediating effect on various cognitive and affective processes, needs further investigation. This study is a region-of-interest analysis of hippocampal volume and its clinical correlates in a medication-naïve sample with low comorbidity rate.

METHOD

T1 weighted MRI (1.5T) was analysed for medication-naive DSM IV OCD patients (n = 26) patients and 20 age and sex matched healthy controls (HC) using a region-of-interest (ROI) method separately for the anterior and posterior subdivisions of hippocampus.

RESULTS

We found significantly greater left hippocampus volume compared to healthy controls. Furthermore, the severity of the compulsion score and the left posterior hippocampus volume demonstrated a significant negative correlation among the OCD patients.

LIMITATION

Modest sample size precludes examination of the effect of symptom dimensions on hippocampal volume.

CONCLUSIONS

The study results highlight the role of hippocampus in the neurobiological basis of OCD and in mediation of the illness severity.