Sensory gating and psychosis vulnerability in cocaine-dependent individuals: preliminary data

Background: Factors increasing vulnerability of a cocaine user to develop psychotic symptoms are unknown. Deficits in sensory gating and attention, such as those occurring in idiopathic psychosis, might represent experimentally tractable factors contributing to vulnerability to cocaine-induced paranoia. Methods: Severity of cocaine-induced paranoid symptoms was assessed with the Cocaine Experience Questionnaire (CEQ) in 30 abstinent cocaine-dependent individuals. Sensory gating was assessed in a paired-click auditory evoked potential paradigm (S1 and S2) using the S2/S1 attenuation ratio of the P50 evoked response as the primary outcome measure. The Wender-Utah Rating Scale (WURS) for attention deficit was also administered. Results: Subjects were divided into those with high CEQ scores (n = 10) and those with low CEQ scores (n = 20). The mean P50 ratios were significantly higher for the high CEQ subjects compared with the low CEQ group (F = 4.6, p< .04). The WURS did not correlate with the total CEQ but correlated with the CEQ Severity subscale, r = .432, p< .02. Conclusions: The data suggest that deficient P50 sensory gating and attention deficits may be associated with increased proneness to developing psychotic symptoms in the context of cocaine use. Further exploration of these factors seems warranted.