Relationship of prolonged acoustic startle latency to diagnosis and biotype in the bipolar-schizophrenia network on intermediate phenotypes (B-SNIP) cohort.

BACKGROUND

Latency of the acoustic startle reflex is the time from presentation of the startling stimulus until the response and provides an index of neural processing speed. Latency is prolonged in schizophrenia, is 90% heritable, and predicts conversion to schizophrenia in a high-risk population. The Bipolar-Schizophrenia Network for Intermediate Phenotypes (B-SNIP) consortium investigates neurobiological features found in psychotic disorders spanning diagnostic criteria for schizophrenia (SCZ), schizoaffective disorder (SAD), and psychotic bipolar disorder (BP). We investigated whether differences in startle latency and prepulse inhibition (PPI) occur in probands, their first-degree relatives, and neurobiologically defined subgroups of the probands (Biotypes).

METHODS

1143 subjects were included from the B-SNIP cohort: 143 with SCZ, 178 SCZ relatives (SCZ-Fam), 123 with SAD, 152 SAD relatives (SAD-Fam), 138 BP, 183 BP relatives (BP-Fam), and 226 controls (CON). A Biopac system recorded the eyeblink component of the startle reflex during startle testing.

RESULTS

Latency differed by diagnosis (F(3,620) = 5.10, p = 0.002): SCZ, SAD, and BP probands had slower latency than CON, with relatives intermediate. Biotypes 1 and 2 had slower latency than CON (p < 0.031) but Biotype 3 did not differ from CON. PPI did not separate CON from other subjects when analyzed by diagnoses nor when analyzed by biotype. Biotype 1 relatives had slower latency (F(3,663) = 3.49, p = 0.016) and more impaired PPI than Biotype 2 and 3 relatives (F(3,663) = 2.77, p = 0.041).

CONCLUSION

Startle latency is prolonged in psychotic disorders that cross traditional diagnostic categories. These data suggest a genetic difference between biotypes that span across clinically defined diagnoses.

Informations de copyright

Published by Elsevier B.V.

Déclaration de conflit d'intérêts

Declaration of competing interest Infrastructure support was provided by the Research and Development, the Mental Health Service Lines, and the Center of Visual and Neurocognitive Rehabilitation at the Atlanta Veterans Affairs Medical Center, Decatur, GA. Additional infrastructure support was provided by the Department of Psychiatry and Behavioral Sciences of the Emory University School of Medicine, Atlanta, GA. ED has received research support for work unrelated to this project from Auspex Pharmaceuticals, Inc. and Teva Pharmaceuticals, Inc. Other authors have nothing to disclose. ED is a full time attending psychiatrist in the Mental Health Service Line at the Atlanta Veterans Affairs Medical Center, Decatur, GA. The content is solely the responsibility of the authors and does not necessarily represent the official views of the Department of Veterans Affairs.