Stimulator VS Stimulant / Stimulus Addiction VS Stimulation Addiction

Hey there, I am having trouble with the proper use of the following words:

stimulation vs stimulus especially in the context of defining an addiction.
and stimulator vs stimulant in defining a trigger to the stimulation/stimulus addiction

Example:

Somebody cannot sit still and constantly has to visit websites such as Facebook and Twitter, browse youtube.com and play video games. He is addicted to those activities. Does he now suffer from stimulation or stimulus addiction?
What's the difference?

And are those addiction triggers stimulators or stimulants?
What's the difference?

I know "stimulant" is most often used with substances,e.g. drugs, but one of the definitions is also: "something that increases activity, interest, or enthusiasm in a specified field" (source Mac OS X Included Dictionary)

Other examples:

Carl was a drug addict. His favorit stimulant was Cocaine.

Proper use?

Mindy is addicted to stimulation. Facebook and Twitter are her favorite stimulators?

Or stimulant here?

Maxim cannot live without constant supply of arousing stimuli such as pornographic movies and junk food.

I am confused.

Thanks to whomever can clarify.