Zhang L, et al. - In a relatively large sample of medication-free obsessive–compulsive disorder (OCD) patients without comorbid depression, researchers identified alterations of hippocampal shape and subfield volumes. For this investigation, 3D T1-weighted Magnetic Resonance Imaging scans were gathered from 81 medication-free OCD patients and 95 age- and sex-matched healthy controls (HC). Findings suggested that alterations across hippocampal subfields and overall shape can contribute to the distinctive cognitive and affective abnormalities linked to OCD.