HALLUCINATION AND IMAGERY INDUCED BY MESCALINE

Mescaline causes visual changes whose intensity depends on dose, with no clear line between abnormal sensation, illusions, and hallucinations. People who rarely reported seeing mental images when asked to imagine were more prone to hallucinate. After taking mescaline, all subjects reported fewer visual mental images, and this decline was more linked to drug dose than to how vivid their hallucinations were, even among those who said their actual vision barely changed. Control subjects showed no such drop in visual imagery.

Study at a glance

Abstract

Mescaline produces altered visual experiences of several types, whose vividness and degree of distortion is proportionate to the size of the dose. There are no sharp boundaries dividing abnormal sensibility, illusions, and hallucinations. Subjects who gave fewer responses of the type "I see it" when asked to imagine situations were more likely to hallucinate than other patients. Visual responses declined still further after administration of mescaline in a degree more closely related to the amount of drug given than to the vividness of hallucinatory alterations, even in those experimental subjects who reported virtually no alteration in actual vision. The fall in reported visual imagery was not found in control subjects.