Original Articles

Insular volume abnormalities associated with different transition probabilities to psychosis

R. Smieskova^a1a2, P. Fusar-Poli^a3, J. Aston^a1, A. Simon^a4a5, K. Bendfeldt^a2, C. Lenz^a6, R.-D. Stieglitz^a1, P. McGuire^a3, A. Riecher-Rössler^a1 and S. J. Borgwardt^a1a2a3 c1

^a1 Department of Psychiatry, University of Basel, Switzerland

^a2 Medical Image Analysis Centre, University of Basel, Switzerland

^a3 Department of Psychosis Studies, King's College London, Institute of Psychiatry, London, UK

^a4 Specialized Out-patient Service for Early Psychosis, Department of Psychiatry, Bruderholz, Switzerland

^a5 University Hospital of Psychiatry, University of Bern, Switzerland

^a6 Radiological Physics, University Hospital Basel, Switzerland

Abstract

Background Although individuals vulnerable to psychosis show brain volumetric abnormalities, structural alterations underlying different probabilities for later transition are unknown. The present study addresses this issue by means of voxel-based morphometry (VBM).

Method We investigated grey matter volume (GMV) abnormalities by comparing four neuroleptic-free groups: individuals with first episode of psychosis (FEP) and with at-risk mental state (ARMS), with either long-term (ARMS-LT) or short-term ARMS (ARMS-ST), compared to the healthy control (HC) group. Using three-dimensional (3D) magnetic resonance imaging (MRI), we examined 16 FEP, 31 ARMS, clinically followed up for on average 3 months (ARMS-ST, n=18) and 4.5 years (ARMS-LT, n=13), and 19 HC.

Results The ARMS-ST group showed less GMV in the right and left insula compared to the ARMS-LT (Cohen's d 1.67) and FEP groups (Cohen's d 1.81) respectively. These GMV differences were correlated positively with global functioning in the whole ARMS group. Insular alterations were associated with negative symptomatology in the whole ARMS group, and also with hallucinations in the ARMS-ST and ARMS-LT subgroups. We found a significant effect of previous antipsychotic medication use on GMV abnormalities in the FEP group.

Conclusions GMV abnormalities in subjects at high clinical risk for psychosis are associated with negative and positive psychotic symptoms, and global functioning. Alterations in the right insula are associated with a higher risk for transition to psychosis, and thus may be related to different transition probabilities.

(Received August 02 2011)

(Revised October 25 2011)

(Accepted October 26 2011)

(Online publication November 30 2011)

Key Words:

• At-risk mental state (ARMS);
• insula;
• magnetic resonance imaging (MRI);
• psychosis;
• transition

Correspondence:

^c1 Address for correspondence: Dr S. J. Borgwardt, Professor of Neuropsychiatry, Department of Psychiatry, University of Basel, c/o University Hospital Basel, Petersgraben 4, 4031 Basel, Switzerland. (Email: sborgwardt@uhbs.ch)