title: Hippocampal volume and mood disorders after traumatic brain injury.
abstract: BACKGROUND
  Recent evidence from clinical studies and animal models of traumatic brain injury (TBI) suggest that neuronal and glial loss might progress after the initial insult in selectively vulnerable regions of the brain such as the hippocampus. There is also evidence that hippocampal dysfunction plays a role in the pathogenesis of mood disorders. We examined the relationship between hippocampal damage and mood disorders after TBI and the effect of hippocampal atrophy on the outcome of TBI patients.
  
  
  METHODS
  The study group consisted of 37 patients with closed head injury who were evaluated at baseline and at 3, 6, and 12 months after trauma. Psychiatric diagnosis was made with a structured clinical interview and DSM-IV criteria. Quantitative magnetic resonance imaging scans were obtained at 3-months follow-up.
  
  
  RESULTS
  Patients with moderate to severe head injury had significantly lower hippocampal volumes than patients with mild TBI. Patients who developed mood disorders had significantly lower hippocampal volumes than patients without mood disturbance. Furthermore, there was a significant interaction between mood disorders diagnosis and severity of TBI, by which patients with moderate to severe TBI who developed mood disorders had significantly smaller hippocampal volumes than patients with equivalent severe TBI who did not develop mood disturbance. Finally, reduced hippocampal volumes were associated with poor vocational outcome at 1-year follow-up.
  
  
  CONCLUSIONS
  Our findings are consistent with a "double-hit" mechanism by which neural and glial elements already affected by trauma are further compromised by the functional changes associated with mood disorders (e.g., the neurotoxic effects of increased levels of cortisol or excitotoxic damage resulting from overactivation of glutaminergic pathways). Finally, patients with greater hippocampal damage were less likely to return to a productive life 1 year after trauma.
authors.affiliation: Department of Psychiatry, University of Iowa, Iowa City, IA 52242-1000, USA. ricardo-jorge@uiowa.edu
authors.forename: Ricardo E
authors.initials: RE
authors.lastname: Jorge
authors.forename: Laura
authors.initials: L
authors.lastname: Acion
authors.forename: Sergio E
authors.initials: SE
authors.lastname: Starkstein
authors.forename: Vincent
authors.initials: V
authors.lastname: Magnotta
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001284:Atrophy; D001930:Brain Injuries / Q000150:complications / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D016489:Head Injuries, Closed / Q000150:complications / Q000473:pathology*; D006624:Hippocampus / Q000293:injuries / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019964:Mood Disorders / Q000175:diagnosis / Q000209:etiology / Q000473:pathology*; D009929:Organ Size; D020127:Recovery of Function; D012720:Severity of Illness Index