Sensory gating deficits in the attenuated psychosis syndrome

Madiha Shaikh*, Anirban Dutt, Matthew R Broome, Alberto G Vozmediano, Siri Ranlund, Alvaro Diez, Olalla Caseiro, Julia Lappin, Susan Amankwa, Francesco Carletti, Paolo Fusar-Poli, Muriel Walshe, Mei-Hua Hall, Oliver Howes, Lyn Ellett, Robin M Murray, Philip McGuire, Lucia Valmaggia, Elvira Bramon

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


BACKGROUND: Individuals with an "Attenuated Psychosis Syndrome" (APS) have a 20-40% chance of developing a psychotic disorder within two years; however it is difficult to predict which of them will become ill on the basis of their clinical symptoms alone. We examined whether P50 gating deficits could help to discriminate individuals with APS and also those who are particularly likely to make a transition to psychosis.

METHOD: 36 cases meeting PACE (Personal Assessment and Crisis Evaluation) criteria for the APS, all free of antipsychotics, and 60 controls performed an auditory conditioning-testing experiment while their electroencephalogram was recorded. The P50 ratio and its C-T difference were compared between groups. Subjects received follow-up for up to 2years to determine their clinical outcome.

RESULTS: The P50 ratio was significantly higher and C-T difference lower in the APS group compared to controls. Of the individuals with APS who completed the follow-up (n=36), nine (25%) developed psychosis. P50 ratio and the C-T difference did not significantly differ between those individuals who developed psychosis and those who did not within the APS group.

CONCLUSION: P50 deficits appear to be associated with the pre-clinical phase of psychosis. However, due to the limitations of the study and its sample size, replication in an independent cohort is necessary, to clarify the role of P50 deficits in illness progression and whether this inexpensive and non-invasive EEG marker could be of clinical value in the prediction of psychosis outcomes amongst populations at risk.

Original languageEnglish
Pages (from-to)277-282
Number of pages6
JournalSchizophrenia Research
Issue number2-3
Publication statusPublished - Feb 2015


  • APS
  • EEG
  • ERP
  • P50
  • Psychosis
  • Sensory-gating


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