• at-risk mental state;
  • hypothalamic–pituitary–adrenal axis;
  • magnetic resonance imaging;
  • pituitary gland;
  • schizophrenia


Enlarged pituitary gland has been reported in schizophrenia, possibly reflecting hypothalamic–pituitary–adrenal hyperactivity. The aim of the present study was to examine whether individuals at risk of psychosis also have similar changes.


Magnetic resonance imaging was used to examine the pituitary volume in 22 individuals with at-risk mental state (ARMS; 11 male, 11 female), 64 first-episode patients with schizophrenia (FESz; 37 male, 27 female), and 86 healthy controls. The control subjects were divided into age- and gender-matched controls for ARMS (11 male, 11 female) and FESz (37 male, 27 female).


Both the ARMS and FESz groups had a larger pituitary volume compared with matched controls, but no difference was found between the ARMS and FESz subjects. There was no association between the pituitary volume and clinical variables (symptommeasures at scanning, daily dosage or duration of antipsychotic medication) in either clinical group. The pituitary volume did not differ significantly between the ARMS individuals who later developed schizophrenia (n = 5) and those who did not (n = 17). The pituitary volume was larger in women than in men for all diagnostic groups.


The finding of increased pituitary volume in both ARMS and FESz subjects may reflect a common vulnerability to stress in early psychosis. Further work in a larger ARMS sample is required to examine the possible relationship between pituitary volume and emergence of psychosis.