title: Longitudinal Evidence for Smaller Hippocampus Volume as a Vulnerability Factor for Perceived Stress.
abstract: Hippocampal volume has been found to be smaller in individuals with stress-related disorders, but it remains unclear whether smaller volume is a consequence of stress or rather a vulnerability factor. Here, we examined this issue by relating stress levels to hippocampal volumes in healthy participants examined every 5 years in a longitudinal population-based study. Based on scores of 25- to 60-year-old participants on the perceived stress questionnaire, we defined moderately to high (n = 35) and low (n = 76) stress groups. The groups were re-examined after 5 years (at the 6th study wave). Historical data on subjective stress were available up to 10 years prior to Wave 5. At the first MRI session, the moderately to high stress group had a significantly smaller hippocampal volume, as measured by FreeSurfer (version 5.3), compared with the low-stress group. At follow-up, group differences in stress levels and hippocampal volume remained unchanged. In retrospective analyses of subjective stress, the observed group difference in stress was found to be stable. The long-term stability of group differences in perceived stress and hippocampal volume suggests that a small hippocampal volume may be a vulnerability factor for stress-related disorders.
authors.affiliation: From the Department of Nursing Department of Surgical and Perioperative Science Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden.
authors.forename: Lenita
authors.initials: L
authors.lastname: Lindgren
authors.affiliation: Department of Psychology Department of Clinical Dentistry, Faculty of Health Sciences, UIT - The Arctic University of Norway, Tromsø, Norway.
authors.forename: Jan
authors.initials: J
authors.lastname: Bergdahl
authors.affiliation: Department of Integrative Medical Biology Department of Radiation Sciences and Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Nyberg
mesh_terms: D000704:Analysis of Variance; D004198:Disease Susceptibility; D005260:Female; D005500:Follow-Up Studies; D006624:Hippocampus / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D010465:Perception; D012307:Risk Factors; D057566:Self Report; D013315:Stress, Psychological / Q000000981:diagnostic imaging*
keywords: healthy individuals; hippocampal volume; magnetic resonance imaging; stress; susceptibility