title: Subgenual anterior cingulate cortex and hippocampal volumes in depressed youth: The role of comorbidity and age.
abstract: OBJECTIVE
  Many studies have reported that adults with recurrent major depressive disorder (MDD) have smaller hippocampal volumes than control participants. The data are more variable in youth with MDD, where findings have been inconsistent and the effects of factors such as age and co-morbidity have not been systematically examined. This study therefore assessed hippocampus and subgenual anterior cingulate (sgACC) morphometry in 168 youth, aged 12-25, with or without MDD and comorbid anxiety.
  
  
  METHODS
  Structural magnetic resonance imaging (MRI) scans and clinical assessments were obtained from 80 participants with MDD (36 with comorbid anxiety disorder) and 88 age-matched control participants.
  
  
  RESULTS
  Participants with MDD had smaller right hippocampi than controls (p=.013). Older depressed participants (20.1-25 years) had smaller hippocampal volumes than younger ones (<20.1 years; p=.05); this age effect was not apparent in controls (p=.46). Depression scores, indexed by the HAMD17, correlated with hippocampal volumes in older depressed youth. Depressed participants with comorbid anxiety had smaller sgACC, but not hippocampal, volumes than those without anxiety (p=.042).
  
  
  CONCLUSIONS
  Longitudinal, versus cross-sectional, studies can most optimally assess the influence of depression on neurodevelopmental profiles. Though our participants were largely treatment-naïve or in their first week of pharmacotherapy, a handful had extensive treatment histories; thus, treatment history may have influenced brain morphometry.
  
  
  CONCLUSIONS
  Age effects were apparent when hippocampal volumes of older and younger participants with MDD were compared; such differences were not apparent in healthy participants. Comorbid anxiety was associated with decreased sgACC volumes suggesting delayed or altered neurodevelopment in a key emotion regulation region.
authors.affiliation: Department of Psychiatry, McGill University, Montreal, Quebec, Canada; Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Natalia
authors.initials: N
authors.lastname: Jaworska
authors.affiliation: Department of Anatomy, Yeditepe University, Istanbul, Turkey.
authors.forename: Kaan
authors.initials: K
authors.lastname: Yücel
authors.affiliation: Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Allegra
authors.initials: A
authors.lastname: Courtright
authors.affiliation: Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Frank P
authors.initials: FP
authors.lastname: MacMaster
authors.affiliation: Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Mariko
authors.initials: M
authors.lastname: Sembo
authors.affiliation: Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada. Electronic address: gmmacque@ucalgary.ca.
authors.forename: Glenda
authors.initials: G
authors.lastname: MacQueen
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D001008:Anxiety Disorders / Q000453:epidemiology* / Q000473:pathology*; D016022:Case-Control Studies; D002648:Child; D015897:Comorbidity; D003865:Major Depressive Disorder / Q000453:epidemiology* / Q000473:pathology*; D005260:Female; D006179:Gyrus Cinguli / Q000473:pathology*; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009929:Organ Size; D055815:Young Adult
keywords: Comorbid anxiety; Hippocampus; Major depressive disorder (MDD); Subgenual anterior cingulate cortex (sgACC); Youth