1003
In summary , further studies , particularly randomized , double - blind , placebo - controlled trials including larger and / or more homogenous patient groups over longer periods are urgently needed to enhance the scientific basis for drug treatment in tic disorders .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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