title: Pituitary volume in unaffected relatives of patients with schizophrenia and bipolar disorder.
abstract: BACKGROUND
  Hypothalamic-pituitary-adrenal (HPA) axis hyperactivity has been demonstrated in both schizophrenia and bipolar disorder, but the mechanisms underlying this abnormality are still unclear. Enlarged pituitary volume has been recently reported in patients with first episode psychosis and been interpreted as a consequence of an increased activation of the HPA axis. The aim of this study was to assess the contribution of familial liability to pituitary volume in schizophrenia and bipolar disorder. Pituitary volume may be an indirect measure of HPA axis activity.
  
  
  METHODS
  MRI brain scans and measurements of pituitary volumes were obtained for 183 subjects: 26 patients with established schizophrenia or schizoaffective disorder, 44 of their unaffected first-degree relatives (22 familial schizophrenia, 22 non-familial schizophrenia), 29 patients with established bipolar disorder, 38 of their unaffected first-degree relatives, and 46 healthy comparison subjects.
  
  
  RESULTS
  We found a significantly larger pituitary volume (effect size=0.7) in unaffected relatives of patients with schizophrenia compared with controls (p=0.002); the pituitary was even larger in relatives of patients with familial schizophrenia (effect size=0.8, p=0.005). We did not find a significant difference in pituitary volume when comparing the relatives of bipolar patients with controls. Among patients, those with schizophrenia who were receiving prolactin-elevating antipsychotics had an increased pituitary volume compared with controls (effect size=1.0, p=0.006).
  
  
  CONCLUSIONS
  These results suggest that the larger pituitary volume previously reported in first episode schizophrenia could be partly due to a genetic susceptibility to over-activate the HPA axis.
authors.affiliation: Division of Psychological Medicine, Institute of Psychiatry, King's College London, London, UK. valeria.mondelli@iop.kcl.ac.uk
authors.forename: Valeria
authors.initials: V
authors.lastname: Mondelli
authors.forename: Paola
authors.initials: P
authors.lastname: Dazzan
authors.forename: Andrea
authors.initials: A
authors.lastname: Gabilondo
authors.forename: Kalliopi
authors.initials: K
authors.lastname: Tournikioti
authors.forename: Muriel
authors.initials: M
authors.lastname: Walshe
authors.forename: Nicolette
authors.initials: N
authors.lastname: Marshall
authors.forename: Katja K
authors.initials: KK
authors.lastname: Schulze
authors.forename: Robin M
authors.initials: RM
authors.lastname: Murray
authors.forename: Colm
authors.initials: C
authors.lastname: McDonald
authors.forename: Carmine M
authors.initials: CM
authors.lastname: Pariante
mesh_terms: D000328:Adult; D000368:Aged; D001714:Bipolar Disorder / Q000473:pathology*; D001921:Brain / Q000473:pathology; D016022:Case-Control Studies; D005190:Family; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D010902:Pituitary Gland / Q000473:pathology*; D012559:Schizophrenia / Q000473:pathology*