Increased intrasubject variability in reaction time in unaffected preschoolers at familial risk for bipolar disorder

Friday, November 08, 2013 — Poster Session III
10:00 a.m. – 12:00 p.m.	FAES Academic Center (Upper-Level Terrace)	NIMH	BEHAV-8

Authors

J.Y. Yi
N.E. Adleman
C.M. Deveney
A. Guyer
D. Pine
E. Leibenluft
M.A. Brotman

Abstract

Objective: Deficits in attention are a potential bipolar disorder (BD) endophenotype. Both pediatric BD patients and healthy youth at familial risk (siblings or offspring of affected individuals) have increased variance in reaction time (ISV-RT). To explore whether these deficits also exist in early developmental stages, we hypothesized that attention deficits, as measured by increased ISV-RT, would be evident in very young at-risk children (preschoolers). Method: Subjects were at-risk (AR, N=15, 11 males, 4.6±0.6y) and healthy (HV, N=34, 17 males, 4.9±0.8y) preschoolers. Reaction times (RT) were measured during a flanker task in which subjects identified the color of a center stimulus flanked by congruent (same color) or incongruent (different color) distractors. RT coefficients of variation (CV), a measure of IST-RT, were calculated for each subject. CVs across trials (congruent and incongruent) were compared between groups. Results: After covarying percent errors of omission to account for between-group accuracy differences, AR demonstrated increased ISV-RT (greater CV) compared with HV on incongruent trials (p=0.03). Conclusions: Deficits in attention are evident in unaffected preschool-age relatives of patients with BD, suggesting that these deficits are present early in development. This lends support to previous findings that increased ISV-RT may represent an endophenotype for BD.