Event-related potential indices of auditory selective attention in dependent amphetamine users

Background: The aim of the present study was to further investigate a previ ously reported attention-related impairment in dependent amphetamine users using event-related potential (ERP) indices of selective attention. Methods: ERPs were recorded during an auditory selective attention task (SA T) that involved detecting infrequent long-duration target tones presented among short-duration tones that varied in location (left vs. right ear) and pitch (low vs. high). Amphetamine users (n = 19) were divided into two gro ups, high dependence (n = 10) and low dependence (n = 10), based on ampheta mine Severity of Dependence Scale scores, and compared to an age-matched co ntrol group (n = 9). Results: The high-dependence group showed slowed reaction time and reduced early processing negativity and peak NI amplitude to location-relevant nont arget stimuli. Poor performance on the SAT was highly correlated with defic its in early processing, which were also related to poor performance on the Wechsler Memory Scale Attention/Concentration index. Conclusions: It is suggested that severely dependent users suffer an inabil ity to selectively enhance the sensory processing of relevant auditory info rmation. This may produce poor automatic preferential processing of relevan t information and increase load on limited attentional resources. (C) 1999 Society of Biological Psychiatry.