Morphine effects on the spontaneous electroencephalogram in polydrug abusers: Correlations with subjective self-reports

Abstract

Tie spontaneous electroencephalogram (EEG) was recorded after the intramuscular (IM) injection of morphine sulfate (15, 30 mg) or saline (0.9% NaCl). Correlations between changes in EEG spectral power and subjective self-reports, as measured on subscales of the Addiction Research Center Inventory (ARCI), were evaluated. Morphine increased alphai and alphai power and theta power, and attenuated the increase in delta power observed after placebo. Positive correlations were found between the change in alphai, alphai, betai, and beta2 power in response to 30 mg of morphine and scores on Morphine-Benzedrine Group (MBG) subscale of the ARCl. Negative relationships were observed between changes in alphai, and betai and scores on the Pentobarbital Chlorpromazine Alcohol Group (PCAG) subscale. The findings indicate that positive subjective effects of opioids, as measured by the MBG subscale, are related to increases in alpha and beta activity and are associated with reduction of opioid-induced sedation, as measured by the PCAG subscale. © 1994 American College of Neuropsychopharmacology.