We analyzed the ERP data of 58 inpatients and 17 outpatients (42 male) at New York State Psychiatric Institute and 46 healthy adults (20 male) who had participated in at least one of two visual memory paradigms. Most participants performed both RM (session 1) and WM (session 2) tasks at two different recording sessions within a week, typically 1–2 days apart. Left-handed individuals (Oldfield, 1971) and those with a history of neurological illness or substance abuse, as well as participants performing at or below chance level, were excluded. Most importantly, only patients for which clinical ratings of auditory hallucinations were available for the time of ERP testing were included. The auditory hallucination item of the Scale for the Assessment of Positive Symptoms (SAPS; Andreasen, 1984) was used to form symptom subgroups by separating patients who reported experiencing auditory hallucinations (AH) in the past week (SAPS auditory hallucination item ≥ 1) from those who did not (NH).
