Table of Contents Introduction Table 1:Effects of LSD A Brief Foray Into Philosophy and the Cognitive Sciences The Suspects Figure 1: Structure of LSD Overview of Synaptic Transmission Theory: LSD Pre-synaptically Inhibits 5-HT Neurons Theory: LSD Post-synaptically Antagonizes 5-HT2 Receptors Figure 2: LSD Binding at 5-HT2 Receptor Theory: LSD Post-synaptically Partially Agonizes 5-HT2 Receptors Theory: LSD Post-synaptically Agonizes 5-HT1 Receptors Conclusion References Introduction The psychedelic effects of d-Lysergic Acid Diethylamide-25 (LSD) were discovered by Dr. Albert Hoffman by accident in 1938. In the 1950s and 1960s, LS