3843
Brain serotonin has been implicated in the pathophysiology of a wide spectrum of psychiatric disorders , as well as in the mechanism of action of psychotropic drugs .
 Chemical: serotonin
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: serotonin 
Answer:
 Chemical: serotonin