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Worry and pre-pulse inhibition deficiencies

Worry and pre-pulse inhibition deficiencies

Drew Smith


Chronic, uncontrollable worry is a core feature of Generalized Anxiety Disorder (GAD; American Psychological Association, 2003). Worry is characterized by negative, intrusive, irrepressible thoughts that have been shown to affect information processing. Several studies have demonstrated that high worriers recruit greater cognitive resources in order to inhibit the impact of distracting information (Hirsch & Mathews, 2012). Studies also have shown worry to bias stimuli detection in an environment and contribute toward difficulties discriminating between indicators of threat or safety (Grillon & Ameil, 2001). Another body of literature suggests that worry activates a heightened physiological state in order to avoid a sudden change in negative affect (Llera & Newman, 2010). Taken together, worrying may result in an underactive attentional control mechanism, an over-active threat-detection system, or a combination of both. A heightened physiological state may contribute to variation within these systems. In order to evaluate how worry specifically affects early information processing, the current study sought to explore the relationship between worry and a specific inhibitory mechanism called pre-pulse inhibition (PPI). PPI is a measure of sensorimotor gating or the brain’s ability to inhibit sensory information. Difficulties inhibiting sensory information may contribute to attentional deficiencies. It was hypothesized that worry would be significantly related to PPI. It also was hypothesized that high worriers would demonstrate less PPI, or greater inhibitory deficits, compared to low or moderate worriers.


Fifty-six undergraduate students were recruited from a large Midwestern university. Participants completed a fear learning task while their startle response, perspiration, and heart rate were recorded respectively.


Analyses revealed a significant negative correlation between worry and percentage of PPI (%PPI) [r = -.267, p = 0.048], such that as worry increased % PPI decreased. Independent t-tests revealed no significant differences in % PPI between low and moderate, or moderate and high worriers. However, there was a significant difference between low and high worriers in % PPI [(F (2, 31) = 4.08, p =.034] such that low worriers exhibited 69% change in PPI and high worriers exhibited 49% change in PPI.


Overall, these results suggest a significant relationship between worry and PPI, such that high worriers exhibit greater inhibitory deficiencies compared to low worriers. These results indicate that worry may contribute to the modulation of PPI. Recent theoretical models suggest that worry may increase and maintain a heightened physiological state of arousal in order to avoid a stark contrast in negative emotional affect (Llera & Newman, 2010). Our results support this model, pointing toward an overactive physiological state and an underactive inhibitory mechanism as measured by PPI. These data suggest that deficits in the ability to inhibit sensory information may affect the propensity to worry.