In the investigation described, the hypothesis was tested that 5-hydroxytryptamine (5HT) acts to reduce the psychological effects of lysergic acid diethylamide (LSD). The method was to inject 5-hydroxytryptophan (5HTP) prior to LSD and to compare the results of psychological tests performed after these injections. Placebo controls were used.
The present analysis pertains to the experiment reported by Brengelmann, Pare and Sandler (15) to assess the effect of 5-hydroxytryptophan (5-HTP) on lysergic acid diethylamide (LSD) by means of psychological tests. In the following, problems of measurement and validity of the LSD- “psychosis” are discussed.