What does "hopped up" mean?

Relating to a motor, especially a car engine, whose power has been increased. For example, Kids loved to ride around in hopped-up cars. [Slang; mid-1900s] Also see soup up.

Stimulated with, or as if with, a narcotic. For example, Their idea of a good time is to get all hopped up on marijuana or worse. This slangy usage dates from the 1920s but may be related to the late 19th-century use of the noun hop for a narcotic, especially opium.