The influence of progesterone on behavioral changes induced by lysergic acid diethylamide (LSD-25) in normal males

The influence of a steroid, progesterone, in altering the effects of LSD-25 on psychological behavior in normal male humans was investigated in this study. Some evidence was found that the magnitude of changes found to occur under LSD-25 in. behavior representing sensori-motor, perceptual and conceptual levels of organization, was reduced when LSD ingestion was preceded by progesterone ingestion.