title: Cross-sectional study of abnormal amygdala development in adolescents and young adults with bipolar disorder.
abstract: BACKGROUND
  In vivo imaging studies in adult bipolar patients have suggested enlargement of the amygdala. It is not known whether this abnormality is already present early in the illness course or whether it develops later in life. We conducted a morphometric MRI study to examine the size of specific temporal lobe structures in adolescents and young adults with bipolar disorder and healthy control subjects, as well as their relationship with age, to examine possible neurodevelopmental abnormalities.
  
  
  METHODS
  Subjects included 16 DSM-IV bipolar patients (16 +/- 3 years) and 21 healthy controls (mean age +/- SD = 17 +/- 4 years). Measures of amygdala, hippocampus, temporal gray matter, temporal lobe, and intracranial volumes (ICV) were obtained.
  
  
  RESULTS
  There was a trend to smaller left amygdala volumes in patients (mean volumes +/- SD = 1.58 +/- .42 mL) versus control subjects (1.83 +/- .4 mL; F = 3.87, df = 1,32, p = .06). Bipolar patients did not show significant differences in right or left hippocampus, temporal lobe gray matter, temporal lobe, or right amygdala volumes (analysis of covariance, age, gender, and ICV as covariates, p > .05) compared with healthy control subjects. Furthermore, there was a direct correlation between left amygdala volumes and age (r =. 50, p = .047) in patients, whereas in healthy controls there was an inverse correlation (r = -.48, p = .03).
  
  
  CONCLUSIONS
  The direct correlation between left amygdala volumes and age in bipolar patients, not present in healthy control subjects, may reflect abnormal developmental mechanisms in bipolar disorder.
authors.affiliation: Department of Psychiatry, The University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229-3900, USA.
authors.forename: Barbara K
authors.initials: BK
authors.lastname: Chen
authors.forename: Roberto
authors.initials: R
authors.lastname: Sassi
authors.forename: David
authors.initials: D
authors.lastname: Axelson
authors.forename: John P
authors.initials: JP
authors.lastname: Hatch
authors.forename: Marsal
authors.initials: M
authors.lastname: Sanches
authors.forename: Mark
authors.initials: M
authors.lastname: Nicoletti
authors.forename: Paolo
authors.initials: P
authors.lastname: Brambilla
authors.forename: Matcheri S
authors.initials: MS
authors.lastname: Keshavan
authors.forename: Neal D
authors.initials: ND
authors.lastname: Ryan
authors.forename: Boris
authors.initials: B
authors.lastname: Birmaher
authors.forename: Jair C
authors.initials: JC
authors.lastname: Soares
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000679:Amygdala / Q000254:growth & development / Q000473:pathology*; D000704:Analysis of Variance; D001714:Bipolar Disorder / Q000473:pathology*; D001921:Brain / Q000473:pathology; D001931:Brain Mapping; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D012737:Sex Factors