As nouns the difference between atypical and paliperidone is that atypical is (pharmacy) an atypical antipsychotic while paliperidone is 9-hydroxyrisperidone, an atypical antipsychotic drug.
As an adjective atypical is not conforming to the normal type.
Not conforming to the normal type.
Unusual or irregular.
(pharmacy) An atypical antipsychotic.