Pituitary Volume Predicts Future Transition to Psychosis in Individuals at Ultra-High Risk of Developing Psychosis
Received 16 December 2004; received in revised form 21 March 2005; accepted 11 April 2005. published online 18 July 2005.
Background
We examined pituitary volume before the onset of psychosis in subjects who were at ultra-high risk (UHR) for developing psychosis.
Methods
Pituitary volume was measured on 1.5-mm, coronal, 1.5-T magnetic resonance images in 94 UHR subjects recruited from admissions to the Personal Assessment and Crisis Evaluation Clinic in Melbourne, Australia and in 49 healthy control subjects. The UHR subjects were scanned at baseline and were followed clinically for a minimum of 1 year to detect transition to psychosis.
Results
Within the UHR group, a larger baseline pituitary volume was a significant predictor of future transition to psychosis. The UHR subjects who later went on to develop psychosis (UHR-P, n = 31) had a significantly larger (+12%; p = .001) baseline pituitary volume compared with UHR subjects who did not go on to develop psychosis (UHR-NP, n = 63). The survival analysis conducted by Cox regression showed that the risk of developing psychosis during the follow-up increased by 20% for every 10% increase in baseline pituitary volume (p = .002). Baseline pituitary volume of the UHR-NP subjects was smaller not only compared with UHR-P (as described above) but also compared with control subjects (−6%; p = .032).
Conclusions
The phase before the onset of psychosis is associated with a larger pituitary volume, suggesting activation of the HPA axis.
aMelbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne, Royal Melbourne Hospital, Sunshine Hospital and National Neuroscience Facility, Melbourne, Australia
bDivision of Psychological Medicine, Institute of Psychiatry, King’s College London, London, United Kingdom
dPersonal Assessment and Crisis Evaluation Clinic and Department of Psychiatry University of Melbourne
eMental Health Research Institute of Victoria, Melbourne, Australia
Address reprint requests to Carmine M. Pariante, M.D., M.R.C.Psych., Ph.D., King’s College London, Institute of Psychiatry, Division of Psychological Medicine, Section of Clinical Neuropharmacology PO51, Stress, Psychiatry and Immunology Laboratory, 1 Windsor Walk, Denmark Hill, London SE5 8AF, United Kingdom
ABSTRACT