Víctor Pérez

YNICL Journal 2016 Journal Article

Neurophysiological evidence of impaired self-monitoring in schizotypal personality disorder and its reversal by dopaminergic antagonism

• Mireia Rabella
• Eva Grasa
• Iluminada Corripio
• Sergio Romero
• Miquel Àngel Mañanas
• Rosa Mª. Antonijoan
• Thomas F. Münte
• Víctor Pérez

BACKGROUND: Schizotypal personality disorder (SPD) is a schizophrenia-spectrum disorder characterized by odd or bizarre behavior, strange speech, magical thinking, unusual perceptual experiences, and social anhedonia. Schizophrenia proper has been associated with anomalies in dopaminergic neurotransmission and deficits in neurophysiological markers of self-monitoring, such as low amplitude in cognitive event-related brain potentials (ERPs) like the error-related negativity (ERN), and the error positivity (Pe). These components occur after performance errors, rely on adequate fronto-striatal function, and are sensitive to dopaminergic modulation. Here we postulated that analogous to observations in schizophrenia, SPD individuals would show deficits in self-monitoring, as measured by the ERN and the Pe. We also assessed the capacity of dopaminergic antagonists to reverse these postulated deficits. METHODS: We recorded the electroencephalogram (EEG) from 9 SPD individuals and 12 healthy controls in two separate experimental sessions while they performed the Eriksen Flanker Task, a classical task recruiting behavioral monitoring. Participants received a placebo or 1 mg risperidone according to a double-blind randomized design. RESULTS: After placebo, SPD individuals showed slower reaction times to hits, longer correction times following errors and reduced ERN and Pe amplitudes. While risperidone impaired performance and decreased ERN and Pe in the control group, it led to behavioral improvements and ERN amplitude increases in the SPD individuals. CONCLUSIONS: These results indicate that SPD individuals show deficits in self-monitoring analogous to those in schizophrenia. These deficits can be evidenced by neurophysiological measures, suggest a dopaminergic imbalance, and can be reverted by dopaminergic antagonists.

YNIMG Journal 2008 Journal Article

Abnormal P300 in people with high risk of developing psychosis

• Elvira Bramon
• Madiha Shaikh
• Matthew Broome
• Julia Lappin
• Daniel Bergé
• Fern Day
• James Woolley
• Paul Tabraham

Background Individuals with an “at-risk mental state” (or “prodromal” symptoms) have a 20–40% chance of developing psychosis; however it is difficult to predict which of them will become ill on the basis of their clinical symptoms alone. We examined whether neurophysiological markers could help to identify those who are particularly vulnerable. Method 35 cases meeting PACE criteria for the at-risk mental state (ARMS) and 57 controls performed an auditory oddball task whilst their electroencephalogram was recorded. The latency and amplitude of the P300 and N100 waves were compared between groups using linear regression. Results The P300 amplitude was significantly reduced in the ARMS group [8. 6±6. 4 microvolt] compared to controls [12. 7±5. 8 microvolt] (p <0. 01). There were no group differences in P300 latency or in the amplitude and latency of the N100. Of the at-risk subjects that were followed up, seven (21%) developed psychosis. Conclusion Reduction in the amplitude of the P300 is associated with an increased vulnerability to psychosis. Neurophysiological and other biological markers may be of use to predict clinical outcomes in populations at high risk.

YNIMG Journal 2006 Journal Article

Corrigendum to “Striatal D2 receptor binding as a marker of prognosis and outcome in untreated first-episode psychosis” [NeuroImage 29 (2006) 662–666]

• Iluminada Corripio
• Víctor Pérez
• Ana M. Catafau
• Esther Mena
• Ignasi Carrió
• Enric Alvarez

YNIMG Journal 2006 Journal Article

Striatal D2 receptor binding as a marker of prognosis and outcome in untreated first-episode psychosis

• Iluminada Corripio
• Víctor Pérez
• Ana M. Catafau
• Esther Mena
• Ignasi Carrió
• Enric Alvarez

In a preliminary 123I-IBZM SPECT study in first-episode psychosis, a relationship between striatal dopaminergic D2 receptor (D2R) binding and premorbid adjustment was suggested. These results were replicated in the present study (n = 18), and D2R binding at diagnosis predicted a high probability for schizophrenia outcome by 2-year follow-up. The present findings contribute to the evidence of abnormal D2R binding in schizophrenia and suggest that SPECT might be useful for outcome prediction in first-episode psychosis.