There are theories suggesting the role of serotonin in schizophrenia which have been proposed decades prior, which was with the perception with lysergic acid diethylamide27,28 (a peripheral 5HT antagonist), using this Gaddum, Shaw, Wooley (1954) suggested that schizophrenia might be due to the decrease in serotonin level in the brain. This evidence concerns the gene HTR5A and schizophrenia.