Sensory gating in subjects at ultra high risk for developing a psychosis before and after a first psychotic episode

Abstract

Objectives. To explore sensory gating deficits in subjects at Ultra High Risk (UHR) for psychosis before and after transition to a first psychotic episode. Methods. Sensory gating was assessed with the paired click paradigm in 61 UHR subjects, of whom 18 (30%) made a transition to psychosis (UHR + T) over a 3-year follow-up period and 28 matched healthy controls. Subjects were assessed at inclusion and again after approximately 18 months. P50, N100 (N1) and P200 (P2) sensory gating was established using the amplitude on the first (S1) and second (S2) click, the ratio- (S2/S1) and the difference score (S1-S2). Psychopathology was also assessed. Results. At baseline, UHR + T subjects presented smaller N1 difference scores compared to UHR + NT subjects and controls. The N1 difference score contributed modestly to the prediction of a first psychotic episode. Repeated measure analyses revealed smaller N1 and P2 S1 amplitudes, smaller P2 difference scores and larger P2 ratio's at follow-up compared to baseline in UHR + T subjects. Conclusion. The N1 difference score may be helpful in predicting a first psychosis. N1 and P2 sensory gating measures also showed alterations between the prodromal phase and the first psychosis, suggesting that these changes may relate to the onset of a frank psychotic episode.

Key words::

• Ultra High Risk subjects
• psychosis prediction
• sensory gating
• psychopathology
• schizophrenia

Acknowledgements

The authors thank the EEG technicians of the Clinical Neurophysiology Unit for their assistance in the recordings. We also thank T. Boeree and A. Ziegelaar. This study was supported by a grant for the Dutch Prediction of Psychosis Study from ZON-MW (ZorgOnderzoek Nederland/NWO-Medische Wetenschappen, project # 2630.0001) and a grant from the European Commission in Brussels, Belgium for the European Prediction of Psychosis study (grant QLGU-CT-2001 - 01081). ZON-MW and the European Commission had no further role in the study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the paper for publication.

Statement of Interest

None to declare.