P50 sensory gating in adolescents from a pacific island isolate with elevated risk for schizophrenia.
BACKGROUND
Gating or inhibition of the P50 auditory evoked potential is a heritable neurobiological trait that has shown strong potential to serve as an endophenotype for schizophrenia. P50 sensory gating deficits have been found repeatedly in schizophrenic patients and in their unaffected first-degree relatives. P50 sensory gating has not yet been studied in high-risk (HR) offspring nor in prodromal adolescents.


METHODS
A paired-stimulus auditory event-related potential paradigm was used to examine P50 sensory gating in 44 genetically HR adolescent offspring and 43 clinically HR prodromal adolescents with the same low genetic liability as a comparison group of 39 normal adolescents.


RESULTS
Auditory sensory gating, as measured by the P50 ratio, was impaired in both genetically HR offspring and also in the clinically HR prodromal adolescents with no close affected relatives. In the genetically HR group, abnormal P50 sensory gating was found only in offspring who met criteria for the schizophrenia prodrome.


CONCLUSIONS
Our findings suggest that P50 deficits are associated with the presence of prodromal symptoms, regardless of genetic risk. The results are consistent with the hypothesis that genetic liability in HR offspring increases risk for prodromal symptoms, and prodromal symptoms, in turn, increase risk for impaired sensory gating.
Myles-Worsley
Marina
M
Department of Psychiatry, University of Utah School of Medicine, Salt Lake City, Utah 84132, USA.
Ord
Lisa
L
Blailes
Francisca
F
Ngiralmau
Hilda
H
Freedman
Robert
R
D000293:Adolescent; D001288:Attention / Q000502:physiology*; D001303:Auditory Cortex / Q000503:physiopathology; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000235:genetics* / Q000502:physiology; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005828:Genetics, Population; D006801:Humans; D008297:Male; D044468:Native Hawaiian or Pacific Islander / Q000235:genetics*; D009433:Neural Inhibition / Q000235:genetics* / Q000502:physiology; D019029:Palau; D010641:Phenotype; D011569:Psychiatric Status Rating Scales; D011930:Reaction Time / Q000235:genetics / Q000502:physiology; D012306:Risk; D012559:Schizophrenia / Q000175:diagnosis / Q000235:genetics* / Q000503:physiopathology; D012565:Schizophrenic Psychology; D012569:Schizotypal Personality Disorder / Q000175:diagnosis / Q000235:genetics / Q000503:physiopathology; D012815:Signal Processing, Computer-Assisted