133. P300 amplitude for affective vs. visual categorization in cannabis smokers in relation to schizotypy

Abstract

Previous research has shown that cannabis use can mimic many of the traits of schizotypal personality disorder (SPD) including inattention, paranoia, and perceptual aberration. However, it is unclear as to whether cannabis use can also mimic the abnormalities in affect recognition found in SPD. In the present study, brain event-related potentials (ERPs) were utilized to assess whether cannabis use and schizotypy are associated with deficits in affective categorization and/or generalized attention. P300 was used to index attention in an oddball paradigm and affective/evaluative categorization (an extremely or moderately negative trait word embedded in a series of positive trait words). Schizotypy was assessed using the Schizotypal Personality Questionnaire (SPQ). The results show that there was a significant overall negative correlation between the P300 amplitude for the affectively negative stimuli and SPQ scores (r = −0.63) but there was no correlation for the visual discrepancy task (r = 0.03). There was a trend toward an increased P300 amplitude in the cannabis-using group for the extremely negative trait stimuli and the infrequent stimuli. There was also a trend-level negative correlation between the amount self-reported cannabis consumed and the P300 for moderately negative stimuli. The correlation between SPQ and the P300 amplitude in the affectively negative condition, suggests that the affect recognition deficits found in SPD may not reflect a dysregulation of general attention, but may be due to abnormal affect processing. In addition, cannabis use may accentuate the processing of extreme inconsistency (infrequent and extremely negative stimuli) and attenuate the processing of mild inconsistency (moderately negative stimuli).