P3a of event-related potential in chronic methamphetamine dependence

To investigate the psychophysiological features of methamphetamine (MAP) de pendence, we recorded auditory event-related potentials (ERPs) in 15 patien ts with MAP dependence and in 15 age-matched normal controls. ERPs were rec orded during a standard oddball task and a read task similar to those emplo yed by Squires et dr. (Squires NK, Squires KC, Hillyard SA [1975] Two varie ties of long-latency positive waves evoked by unpredictable auditory stimul i in man. Electroenceph Clin Neurophysiol 38:387-401). The patients with MA P dependence showed reduced P3a amplitude and area in the read task and del ayed P3b latency with normal P3b amplitude and area in the oddball task. Th ese results suggest that central noradrenergic dysregulation may persist af ter the remission of acute psychotic symptoms in MAP psychosis and that chr onic MAP dependence would produce impairment of the frontal cortex.