Eight "stable" and four "variable" college-age subjects were given 160μg/kg psilocybin under conditions of sensory attenuation. Stability was defined by the magnitude of the standard deviation on handwriting area under predrug conditions.
Only the variable subjects, our large-standard deviants, responded to the drug with a significant decrease in mean pulse rate and increase in handwriting area. They also reported consistently more intense experiences under psilocybin than the small-standard deviants. The degree of variability on perceptual-behavioral measures, such as the SD on handwriting area, is significantly related to, and therefore a predictor of, the intensity of the ensuing drug-induced experience.
Panton Y, Fischer R. Hallucinogenic Drug-Induced Behavior Under Sensory AttenuationPrediction of Response to Psilocybin. Arch Gen Psychiatry. 1973;28(3):434-438. doi:10.1001/archpsyc.1973.01750330106017