Anxiety and pupil reactivity in cocaine dependent subjects endorsing cocaine-induced paranoia: preliminary report

There has been the clinical impression that people with higher levels of anxiety and central arousal are more prone to develop cocaine-induced paranoia (CIP), but this notion has not been formally studied. In the current study, we examined the differences between 28 CIP-endorsing and 16 CIP-denying chronic cocaine users in their levels of state and trait anxiety as measured by the Spielberger State-Tait Anxiety Inventory. We also studied levels of central arousal and reactivity using pupil size measures both during exposure to neutral, abstract, non-drug cues, and after exposure to a cocaine cue. Levels of trait (but not state) anxiety were significantly higher in the CIP group than in the non-CIP group. Moreover, while there were no significant pupil size differences or changes between the two groups while viewing neutral, abstract video images, the CIP group had significantly greater pupillary dilation in response to a video image of crack cocaine than did the non-CIP group. These significant differences remained even after covarying for anxiety scores. The study findings seem relevant to studies of autonomic reactivity in response to drug cues in cocaine-dependent patients; such studies might remain attentive to potential cue reactivity differences between patients endorsing and those denying CIP. Finally, this is the first study showing higher trait anxiety in patients with CIP.