Effects of Lysergic Acid Diethylamide (LSD-25) on Intellectual Functions

Previous studies on lysergic acid diethylamide (LSD-25) and memory suggest that memory impairment becomes evident at doses between 50 and 100 micrograms. At 40 or 50 micrograms, little or no memory impairment was found, but at 100 micrograms, scores were significantly lower on most visual and some auditory tests. One study using 1 microgram per kilogram of body weight also found impairment but only tested memory for unrelated words. The present study aims to determine whether memory for different types of material is differentially affected by LSD-25.

Study at a glance

Abstract

I. MemoryIntroduction. —The results of previous studies of the effect of lysergic acid diethylamide (LSD-25) on memory suggest that the minimal dose level at which impairment becomes evident lies somewhere between 50μg. and 100μg. Sloane and Lovett Doust,1working at the 40μg. level, and Jarvik et al.,2working at the 50μg. level, found little or no evidence of memory impairment in their studies. However, the latter investigators reported that when the dose level was raised to 100μg., scores were significantly lower on four of the five visual tests and on two of the four auditory tests that they employed. Bercel et al.,3who used 1μg/kg. body weight, also found evidence of impairment, but they studied memory for only one kind of material, a series of unrelated test words. The purpose of the present study was to determine whether memory for various kinds of material is differentially