Higher volumes of hippocampal subfields in pediatric obsessive-compulsive disorder

• Published in: Psychiatry research. Neuroimaging Vol. 307; p. 111200
• Main Authors: Vattimo, Edoardo F.Q., dos Santos, Allan Christiano, Hoexter, Marcelo Q., Frudit, Paula, Miguel, Euripedes C., Shavitt, Roseli G., Batistuzzo, Marcelo C.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 30.01.2021
• Subjects: Adolescent; Adult; Child; Children; Hippocampal subregions; Hippocampus - diagnostic imaging; Hippocampus volume; Humans; Magnetic Resonance Imaging; Obsessive-Compulsive Disorder - diagnostic imaging; Pediatric obsessive-compulsive disorder; Temporal Lobe; Youth; Pediatric obsessive-compulsive disorder; Youth; Hippocampal subregions; Children; Hippocampus volume
• ISSN: 0925-4927; 1872-7506
• DOI: 10.1016/j.pscychresns.2020.111200

•Evidence suggests that the limbic system participates in the neurobiology of OCD.•No previous study has examined the hippocampus and its subfields in youth with OCD.•Enlarged whole hippocampal volumes was found in pediatric OCD.•Bilateral heads and left body were enlarged in patients when compared to controls.•No association was found with hippocampal volume and OCD severity. Differences in hippocampus volume have been identified in adult patients with obsessive-compulsive disorder (OCD). However, the role of this limbic structure in pediatric patients is unclear. This study aimed to investigate the hippocampus and its subregions in a sample of 29 children and adolescents with OCD compared to 28 healthy controls, matched for age, sex, education, and IQ. Volumetric segmentation was performed using the Freesurfer software to calculate the volumes of the subregions that reflect the hippocampal cytoarchitecture. The volumes of three anatomic subregions (tail, body, and head) were also calculated. ANCOVA was performed to investigate differences of these volumes between patients and controls, controlling for total gray matter volume. After Bonferroni correction for multiple comparisons (p-value < 0.00556 for the body and < 0.00625 for the head structures), patients presented statistically significant larger volumes of the following structures: left subiculum body; left CA4 body; left GC-DG body; left molecular layer body; right parasubiculum; left CA4 head; left molecular layer head; right subiculum head and right molecular layer head. These enlarged volumes resulted in larger left and right whole hippocampi in patients, as well as bilateral hippocampal heads and left hippocampal body (all p-values < 0.00625). There were no associations between OCD severity and hippocampal volumes. These findings diverge from previous reports on adults and may indicate that larger hippocampal volumes could reflect an early marker of OCD, not present in adults.