title: Cortical thickness in youth with major depressive disorder.
abstract: BACKGROUND
  Studies in adults with major depressive disorder (MDD) have implicated dysregulation of frontal-limbic circuits in the symptomology of this disorder. We hypothesized that the middle frontal gyrus (MFG; a core portion of the dorsolateral prefrontal cortex or DLPFC) and the anterior cingulate (caudal), regions implicated in emotive and cognitive control, would display a reduced cortical thickness in youth with MDD as compared to healthy, non-depressed adolescents.
  
  
  METHODS
  Sixteen healthy control adolescents (17.19 ± 1.87 years; 7 males, 9 females) and thirty MDD participants (16.89 ± 2.01 years; 9 males, 21 females) underwent magnetic resonance imaging (MRI). Cortical thickness analysis was carried out using FreeSurfer software.
  
  
  RESULTS
  Counter to our hypothesis, we observed thicker right and left rostral MFG in MDD adolescents as compared to controls (p = 0.004 and p = 0.005, respectively). Furthermore, the left caudal anterior cingulate cortex was thicker in MDD subjects as compared to controls (p = 0.009). In MDD subjects, there was a significant inverse correlation between age and left MFG thickness (r = -0.45, p = 0.001).
  
  
  CONCLUSIONS
  These results have implications for the developmental trajectory of the frontal lobe in adolescent MDD. The MFG is implicated in the frontal-limbic circuits underlying executive functioning and their interaction with affective processing. Alterations in this region are likely involved with the symptoms of MDD. Limitations include a small sample size and cross sectional design.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Reynolds
authors.forename: Normand
authors.initials: N
authors.lastname: Carrey
authors.forename: Natalia
authors.initials: N
authors.lastname: Jaworska
authors.forename: Lisa Marie
authors.initials: LM
authors.lastname: Langevin
authors.forename: Xiao-Ru
authors.initials: XR
authors.lastname: Yang
authors.affiliation: Department of Psychiatry, University of Calgary, Behavioral Research Unit, Alberta Children's Hospital, 2888 Shaganappi Trail NW, Calgary, AB T3B 6A8, Canada. fmacmast@ucalgary.ca.
authors.forename: Frank P
authors.initials: FP
authors.lastname: Macmaster
mesh_terms: D000293:Adolescent; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000473:pathology*; D005260:Female; D006179:Gyrus Cinguli / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D017397:Prefrontal Cortex / Q000473:pathology*; D055815:Young Adult