Chronic cocaine use has been shown to produce neurochemical alterations whi
ch persist after acute withdrawal. This study assessed the effects of cocai
ne use on the acoustic startle response and sensorimotor gating using prepu
lse inhibition (PPI) of startle. Nine male control subjects (mean age = 41.
6) and 15 male cocaine users (mean age = 43.2) were tested, the latter afte
r heavy cocaine use ranging from 4 to 27 years (mean age = 16.7). cocaine u
sers had been cocaine free for four days to six months (mean = 17 days) at
testing. Cocaine users exhibited a 68% reduction in startle amplitudes (F =
7.4; df = 1,22; p < .01) compared to controls. There were trends towards i
ncreased PPI in cocaine users under certain conditions; however, there were
not significant main effects. These results indicate that chronic cocaine
use produces impairment of the startle response which persists after cessat
ion of cocaine use. These findings may reflect changes in the dopaminergic
system resulting from chronic cocaine use. [Neuropsychopharmacology 22;89-9
6, 2000] (C) 1999 American College of Neuropsychopharmacology. Published by
Elsevier Science Inc.