Quantitative EEG changes in cocaine withdrawal: evidence for long-term CNS effects.

Quantitative EEG changes were studied during cocaine withdrawal in 36 subjects. All subjects had used cocaine orally (n = 28) or intravenously (n = 8) within 48 h of admission to an inpatient unit. EEGs were recorded 2 and 6 days following admission. Nine subjects returned for a 1-month follow-up EEG. Modal EEG frequency significantly decreased on day 6 compared to day 2. The most dramatic change in both absolute and relative power from day 2 to day 6 was a decrease in the beta 2 (18-26 Hz) band. Those subjects who returned for the 4-week follow-up showed a further decrease in beta 2 power. Power in the beta 2 band was significantly greater for the intravenous users than for the smokers, and the decrease in power from day 2 to day 6 was also significantly greater in this group. While acute effects of cocaine on the EEG have been reported to last only several hours, this study indicates that chronic use may cause longer lasting neuroadaptive changes, particularly in those who have used cocaine intravenously.