Abstract
Background Hippocampus (HIP) was an important limbic structure, and concurrent emotion disorders may occur in medication-overuse headache patients. The aim of this study is to investigate altered HIP and HIP subfields volume in relation with the anxiety in medication-overuse headache patients using a state-of-the-art hippocampal segment method. Results The current study presented that a significant lower HIP and HIP subfields volume were identified in medication-overuse headache compared with that in normal controls except right HIP tail, bilateral parasubiculums, and HIP fissure. The left HIP and right subiculum presented negative correlation with headache variables, and the right subiculum, Cornu Ammonis 4, granule cell layer of dentate gyrus, bilateral Cornu Ammonis 1, molecular layer, and whole HIP presented negative correlation with Hamilton Anxiety Scale score, which were further confirmed by the linear regression analysis with the exclusion of psychological variables and headache variables, respectively. Conclusions The lower HIP and HIP subfields volume were identified in medication-overuse headache patients, and negatively related with anxiety condition. The potential mechanism for the comorbidity medication-overuse headache and anxiety might be interpreted as the reciprocal causation relationship and co-occurrence relationship.