Artificial Persona users are Persona users whose Persona has been pulled out by force, breaking the rules of obtaining it naturally. If measures are not taken to control the erratic Personas, they will attack and possess the host, causing them to transform into Demons or Shadows.
Persona 2: Eternal Punishment
If the player takes Nanjo's route in Eternal Punishment there will be a document of research material written by Takahisa Kandori on how to separate a Joker from its user, as well as how to artificially create Persona users using the former as a basis. Having one's Persona artificially awakened may case severe side-effects.
In Tatsuya's Scenario in the remake of Eternal Punishment, Shiori Miyashiro was turned into a Joker and is captured by the NWO alongside other infected civilians. The NWO attempted experiments on her that involve giving a human a Persona, which results in her body being possessed by the demon Wendigo.
The members of Strega are artificial Persona users created by the Kirijo Group. They were picked up off the street along with a variety of kids and were used as fodder for the corporation's experiments. Because their Personas were not awakened naturally, they must take suppressants supplied by Shuji Ikutsuki. The drugs keep their Personas from killing them, but have lethal side-effects.
Persona -trinity soul-
The Marebito are a group of artificial Persona-users who were implanted with what was known as a Complex Persona by Keisuke Komatsubara. This allowed them to steal and absorb other Persona's into their own in order to increase their own power, under a pretense this would help get access to a higher plane of consciousness. In reality, this was Komatsubara's way of gathering Persona's to use for the awakening of his daughter, Ayane Komatsubara, clone.
The more they absorb the more difficult it is to control their own Persona, thus forcing them to use Persona Suppressors at strict intervals. Failure to do so results in their Complex Persona overpowering them, rendering them in an almost coma-like state, as it goes on a rampage, and inflicting anyone caught in its attack with Apathy Syndrome.