We expected the high dose of risperidone to affect the explorative activity and locomotion of the animals87 in the open field test because the receptor occupancy of risperidone at a high dose is above 60% and at this level, 5-HT2 blockade may not be protective against EPS with the development of parkinsonism and motor retardation88. This evidence concerns the gene HTR2A and Parkinson disease.