Final answer:
Risperidone causes very little EPS due to its antagonism of other receptors, additional serotonin receptor modulation, and the balance it provides to dopaminergic activity in the brain.
Step-by-step explanation:
Risperidone causes very little EPS (extrapyramidal symptoms) despite binding with high affinity to the dopaminergic D2 receptor through its mechanism of action.
One possible explanation is that risperidone also antagonizes other receptors, such as adrenergic and histaminergic H1 receptors, in addition to D2 receptors. These additional receptor antagonisms can mitigate the effects of D2 receptor binding and reduce the occurrence of EPS.
Furthermore, the antagonism of serotonin type 2 receptors by risperidone can also play a role in reducing EPS. The modulation of serotonin signaling can help balance the dopaminergic activity in the brain, contributing to the lower incidence of EPS despite high D2 receptor affinity.