EEG effects of hallucinogens and cannabinoids using sleep-waking behavior as baseline.

Three hallucinogens (d-lysergicacid diethylamide (LSD), mescaline, psilocybin) and two cannabinoid derivatives (tetrahydrocannabinol (THC), synhexyl) were tested for their long-term effects on the EEG of the cat. The drug-induced alterations in the EEG frequency spectrum were "drug-specific" in the sense that they would be statistically unlikely to occur during sleep-waking behavior. The two classes of compounds produced distinctly different EEG effects which were remarkably similar within each class. The duration of activity and relative potencies were consistent with those obtained by other measures, both in cats and in other species including man.