The Jung aspect comes in a very meta way. How many Social Links have you done? How many times have you looked for a particular Persona to take with you to get the boost? How many times have you shaped your responses around what would get you the most points, what the person you're talking to reacts most positively, versus "oh, this is what Minato would say"?

There's your psychological aspect. That's basically the definition of a Persona, as Jung presented it. It's the way your ego changes to deal with the outside phenomena of the circumstances you're in.

Persona 3 captures this brilliantly through its game mechanics, transforming this psychological analysis into something that gamers actually experience.




As for Strega: Their Persona manifests unnaturally, and as such, is not fully controlled, and will seek to kill the Persona-user. The drugs allow it to be controlled, but are themselves deadly in the long term. Shinjiro took the drugs to suppress his Persona, to help ensure that the incident was never repeated.